ABS for mountain bikes? Possible?

[MrPlow]

I know a 'skilled' driver in a car or motorbike can stop the vehicle quicker than an ABS system can.
But lets face it, most of us aren't that skilled:o

So I was wondering, would ABS on a MTB (particularly DH) be possible, and if it were would you think it would be an advantage?

I would like to try it, but can't really figure out how, I was thinking it should be possible to buy a setup made for a Moto, but haven't been able to find much on the interweb.

Discuss...

[cam-o]

I'm sure it's possible, just need sensors on the wheel and servos in the brake system to work the brake. It'd probably weigh a bit.
It's been done on motos, from memory the Honda CBR1000 has it, as does the Goldwing.

Benefit? Doubt it. Definitely not on the rear as locking and drifting the rear is an essential part of riding. I could possibly see some benefit on the front but it'd have to be bloody quick to catch a lockup in time to avoid a lowside.
I don't think it'd help for straightline braking much as you are limited in brake force by the tendency to flip OTB which isn't really a factor in cars.

[toodles]

WD-40?

ABS on a bike would be a horrible thing IMO, I can't see any benefit to it.

[MrPlow]

I was thinking you could set it up just for the front. Or both ends and allow the rear to slip a little before ABS engages.
As for weight, I am sure any setup adapted from a moto would be a bit weighty, but a specific system could be trimmed I guess. Small battery to run it from a light setup?

[Oddjob]

I know a 'skilled' driver in a car or motorbike can stop the vehicle quicker than an ABS system can.
But lets face it, most of us aren't that skilled:o

So I was wondering, would ABS on a MTB (particularly DH) be possible, and if it were would you think it would be an advantage?

I would like to try it, but can't really figure out how, I was thinking it should be possible to buy a setup made for a Moto, but haven't been able to find much on the interweb.

Discuss...

With the 4 channel systems and brake distribution technology ABS will actually be faster to bring a car to a halt than the skilled driver doing cadence braking. The problem is if the ABS kicks in too early when setting up for a corner. ABS is also pretty useless in off road applications as the frictional coefficient will often be higher when the wheel is locked. This is why you never see ABS on WRC cars.

[MrPlow]

WD-40?

ABS on a bike would be a horrible thing IMO, I can't see any benefit to it.

You have a point, apart from being able to slam the pics on as hard as you can without skidding out I couldn't see any advantage either.
With the 4 channel systems and brake distribution technology ABS will actually be faster to bring a car to a halt than the skilled driver doing cadence braking. The problem is if the ABS kicks in too early when setting up for a corner. ABS is also pretty useless in off road applications as the frictional coefficient will often be higher when the wheel is locked. This is why you never see ABS on WRC cars.
Aha! Now we are getting somewhere.
Would this be because the dirt would build around the tyre when it is skidding???

[brisneyland]

How often do people lock up their front brakes? I've certainly never done it unintentionally.

[John U]

the motor bikes you mention are all road bikes. i don't know if any off road moto's have abs. i think if you find that it hasn't been done for off road motos this would be your answer

[Oddjob]

Aha! Now we are getting somewhere.
Would this be because the dirt would build around the tyre when it is skidding???

Can't honestly say. You might have to ask someone with better physics knowledge then myself like Naz.

[MrPlow]

the motor bikes you mention are all road bikes. i don't know if any off road moto's have abs. i think if you find that it hasn't been done for off road motos this would be your answer

I see your point, but if everyone took that point of view nothing would ever progress:)
And different applications react differently to different technologies, I.e, Moto's don't need stable platform or linkage rear suspension either.

Brisney, you have never washed the front out???

[S.]

Brisney, you have never washed the front out???

Not from locking up a front wheel, no.

[scblack]

ABS is also pretty useless in off road applications as the frictional coefficient will often be higher when the wheel is locked. This is why you never see ABS on WRC cars.

ABS is very good on tarmac, but much less use for off-road applications.

Mr.Plow, the sensors would read the dirt/sand as being locked up on, as there is no friction there from loose dirt, and the brakes would receive very little power through the system.

More advanced ABS systems are able to read this a little, and allow some lock-up in dirt, but it is far less efficient than a skilled driver. A braking system for dirt needs to lock up, to some extent to get past the loose dirt, down to where there is some substance to provide braking/tyre friction.

Personally I can't see how a ABS system could be useful on a MTB, or a dirt motocross bike.

[MrPlow]

Aaah well, I will just stick with the Gyro/clutch idea then:D

[cam-o]

On a similar note I once read a review of a dirt bike with traction control.
The recreational cummunity responded with a resounding 'WTF?!??'.

Possibly handy for rounding up sheep, but climbing a hill with the back wheel lit up is half the point of a dirt bike :D

[brisneyland]

Not from locking up a front wheel, no.

^ what he said.

[skwiz05]

Ive raced with ABS on my DHer on some days......
oh shit, or that could have been the DTs from a hard night........(or the parkinsons disease....)

[MrPlow]

Ive raced with ABS on my DHer on some days......
oh shit, or that could have been the DTs from a hard night........(or the parkinsons disease....)

Your attempt at humour humours me.

[rhyno]

I was talking to Rob from Quad brakes whilst at a bike show in France last year (yeah, how pro does that sound!;) ) Quad isn't really well known in Aus, they don't do high end stuff but do some good quality mid range stuff, heavier but very functional. Anyway, he was showing me and explaining a new rotor design he was working on (patented) that basically gave a mechanical ABS feel to it. By having points that had more and less surface area, it would slip/grab. I didn't get to test them, but when he explained it, i was sold.

As for whether we need ABS on an MTB, thats for the masses/market to decide.

Link: http://www.quadbrakes.com/cbsrotor.html

[Turner_rider]

.....This is why you never see ABS on WRC cars.

No there is no ABS on WRC because its effectively banned by the rules. ABS can be made to work very well on dirt, but for a road car like most things setup is a compromise.

Section 5.5 from FIA Art 255.

The braking system is free, provided that:
- it includes at least two independent circuits operated by the same pedal
(Between the brake pedal and the callipers, the two circuits must be separately identifiable, without any interconnection other than the mechanical braking force balancing device)
- there is no device or "system" fitted between the master cylinder and the callipers
Data logging sensors, contact switches for the rear red lights or front and rear mechanical limiters and handbrakes activated directly by the driver are not considered as “systems”.

[bloodzkull]

personally i don't think it could be used to an real affect.

also i prefer not to have abs on car i drive, there are situations where abs is a hazard. and these are the situations you are most likely to crash in.

[scblack]

personally i don't think it could be used to an real affect.

also i prefer not to have abs on car i drive, there are situations where abs is a hazard. and these are the situations you are most likely to crash in.

Where would ABS be a hazard on a road car? Excluding dirt/ice.

[miko]

Actually, a friend of mine did a drivers training course in his car (which shall remain nameless), and did quite well until it came to a swerving/stopping situation. He speared off out of control and was told by the instructor that it was quite common in these cars. If the ABS received too many inputs it would get confused and give up, giving you a completely different car to drive!

This is a fairly new mainstream car as well...

[scblack]

Actually, a friend of mine did a drivers training course in his car (which shall remain nameless), and did quite well until it came to a swerving/stopping situation. He speared off out of control and was told by the instructor that it was quite common in these cars. If the ABS received too many inputs it would get confused and give up, giving you a completely different car to drive!

This is a fairly new mainstream car as well...

That doesn't sound right to me. The main idea behind ABS (for road use) is that you can steer while getting full braking power. That is the point of ABS.

Is it possible that he was simply losing control, by driving beyond the cars handling limits, and no amount of great ABS would have stopped the car spearing off. I am not having a go at your mate, but that is possible.

Too many inputs to the ABS? Just makes little sense.:confused:

[toodles]

You have a point, apart from being able to slam the pics on as hard as you can without skidding out I couldn't see any advantage either.

Ah ok... you could still go over the bars or have your wheel slide out without it locking up.

And ABS doesn't decrease stopping distance, just aids in maintaining control.

Seriously, ABS on dirt would be such a fantastic way to die :rolleyes: It would INCREASE your braking distance substantially and at the same time make your suspension have a heart attack. I can't even imagine the fun it would be in braking bumps.

[bloodzkull]

simple, abs does in fact increase braking distances for any car over an experienced driver, what it is designed to do is get rid of your average persons reaction of trying to push the pedal through the floor.

the term threshold braking is what is most effective, just off locked brakes, the problem being abs usually reads this as being locked.

and if your wondering i have never locked the brakes on mine or any other car without meaning to do it, that being said, like anything it's only a matter or time.

[scblack]

simple, abs does in fact increase braking distances for any car over an experienced driver, what it is designed to do is get rid of your average persons reaction of trying to push the pedal through the floor.

the term threshold braking is what is most effective, just off locked brakes, the problem being abs usually reads this as being locked.

and if your wondering i have never locked the brakes on mine or any other car without meaning to do it, that being said, like anything it's only a matter or time.

Ok, that makes sense.;)

[THRILLHOUSE]

Toodles I am pretty sure that ABS does decrease stopping distance. As when your car wheels are locked up, the wheel bounce over the top of the surface without creating much friction. Obviously ABS stops it from skidding in more efficient braking. (just what my physics teacher told me, i think..)

[brisneyland]

Toodles I am pretty sure that ABS does decrease stopping distance.

Not when the surface is inconsistent, as it is on dirt.

[scblack]

Toodles I am pretty sure that ABS does decrease stopping distance. As when your car wheels are locked up, the wheel bounce over the top of the surface without creating much friction. Obviously ABS stops it from skidding in more efficient braking. (just what my physics teacher told me, i think..)

No it does not. ABS does not decrease stopping distance.;)

Read what bloodZkull has said.

I will clarify.

For a skilled driver ABS will take LONGER to stop, than a non ABS car.

But for a hack, like most drivers, who will simply stomp on the brakes, and lock up the wheels, THEN ABS will stop quicker.

[bloodzkull]

not only on dirt bit also on most aussie roads:D lol
the main idea was to stop people swerving as they are locking the brakes and thus entering an uncontrolled slide.

here's a question for ya all, see if anyone know the exact meaning, what does abs stand for?

[scblack]

not only on dirt bit also on most aussie roads:D lol
the main idea was to stop people swerving as they are locking the brakes and thus entering an uncontrolled slide.

here's a question for ya all, see if anyone know the exact meaning, what does abs stand for?
Anti-lock Braking System

[mattvincent]

Havnet read all this thred so sorry if i repeat, just think of it as backing up the point

I reakon it is pointless, first most of the time if there is an obsticle in your way you can generally bunnyhop it, i dont drive yet but i doubt you cout bunnyhop a car (not saying it isnt posible i know there is a family guy episode where two truckie wheelie their truck). so hense cars have abs.

Also your foot has a much worse reaction time to your hand you can generally modulate brake wiht your finger i know i do sumtimes, and even if it does lock it takes a fraction of a second to let go.

so basicly.
you cant bunny hop a car
Its is posible to wheelie a truck
And I dont think Abs is suited to MTB

I have actually though about this subject b4.

[Turner_rider]

here's a question for ya all, see if anyone know the exact meaning, what does abs stand for?

Easy one: ABS = Australian Bureau of Statistics ;)

[bloodzkull]

ha ha not quite, it stands for anti blok system, blok being german for lock as it was a concept invented it germany.

yeah sorry for hijacking the thread

[thecat]

Anyway, he was showing me and explaining a new rotor design he was working on (patented) that basically gave a mechanical ABS feel to it. By having points that had more and less surface area, it would slip/grab. I didn't get to test them, but when he explained it, i was sold.


So he has basically found an excuse for the pulsing people complain about with wavy juice rotors???;)

I fail to see how ABS is of any benefit on a MTB. You get plenty of feed back with hydros and it's not hard to learn to feather the brakes yourself.
You are much smarter then an ABS... well hang on. You may have a point.:D

[S.]

I was talking to Rob from Quad brakes whilst at a bike show in France last year (yeah, how pro does that sound!;) ) Quad isn't really well known in Aus, they don't do high end stuff but do some good quality mid range stuff, heavier but very functional. Anyway, he was showing me and explaining a new rotor design he was working on (patented) that basically gave a mechanical ABS feel to it. By having points that had more and less surface area, it would slip/grab. I didn't get to test them, but when he explained it, i was sold.

As for whether we need ABS on an MTB, thats for the masses/market to decide.

Link: http://www.quadbrakes.com/cbsrotor.html (http://www.quadbrakes.com/cbsrotor.html)

Yeah but that's physically impossible, I can see what they're thinking and also why it wouldn't work. A given clamping FORCE at the calipers generates a given pressure distributed over the brake pads/rotor FOR A GIVEN SURFACE AREA. Keeping in mind that pressure = force/area, and thus force = pressure x area, if you decrease the contact area you'll increase the pressure proportionally. Given that friction between two hard surfaces can be pretty well linearly approximated as being directly proportional to the pressure times the area times the coefficient of friction, a proportional drop/increase in the respective area and pressure gives no change in the total friction force, and any small change that DOES occur from the slight nonlinearities of the coefficient of friction, will simply result in a pulsing/vibrating feel with no real anti-lock effect.... in fact I'd say it'd be even MORE likely to lock the wheels if the braking force varies rapidly.

[the F.H.B]

Well reading this has made me think... We diss the idea of ABS because it would struggle on dirty uneven surfaces, be heavy and sometimes we'll hook the rear to skid a corner...
Thats all well and good but how many people utealise the modulation avalible in their brakes well? I mean I often hear people talk about 'snappy' brakes, and I have riden some bikes where the brakes feel either full off or full on. Surely you would go faster and have more control if you didn't lock your brakes (I'd be curious how often Hill or Rennie etc actually lock up, data acquesition anyone?)
I guess im floating off topic a bit here but what im tring to get to is that modulation and predictablity would be far more important to riding than an ABS style system.......

[S.]

Well reading this has made me think... We diss the idea of ABS because it would struggle on dirty uneven surfaces, be heavy and sometimes we'll hook the rear to skid a corner...
Thats all well and good but how many people utealise the modulation avalible in their brakes well? I mean I often hear people talk about 'snappy' brakes, and I have riden some bikes where the brakes feel either full off or full on. Surely you would go faster and have more control if you didn't lock your brakes (I'd be curious how often Hill or Rennie etc actually lock up, data acquesition anyone?)
I guess im floating off topic a bit here but what im tring to get to is that modulation and predictablity would be far more important to riding than an ABS style system.......

Once you're moving fast, it's very hard to lock up a front wheel because a) your weight pitches onto it and b) the rotational momentum of the wheel resists it more as the speeds increase. If you don't want to lock your wheels, don't pull so hard on the lever. If you have brakes that are less inclined to lock up when you pull hard on them, you'll also find they just have less power outright, and that tends to really suck IMO. Bring on the bitey brakes!

[No Skid Marks]

I was talking to Rob from Quad brakes whilst at a bike show in France last year (yeah, how pro does that sound!;) ) Quad isn't really well known in Aus, they don't do high end stuff but do some good quality mid range stuff, heavier but very functional. Anyway, he was showing me and explaining a new rotor design he was working on (patented) that basically gave a mechanical ABS feel to it. By having points that had more and less surface area, it would slip/grab. I didn't get to test them, but when he explained it, i was sold.

As for whether we need ABS on an MTB, thats for the masses/market to decide.

Link: http://www.quadbrakes.com/cbsrotor.html

I have a Quad 6" rotor for sale in the for sale section(black centred rotor).
I locked up my front wheel at least twice today at Lithgow. Once on wet rocks down the switch backs after rock garden and once leaned over on a wet root. I think you'd find you do it more often than you think. What would the lever feel be like when the ABS kicked in?YUK.
Silly silly idea sorry and I can't beleive we're discussing it. Although like all posts on Farkin I guess I did learn some stuff.

[miko]

That doesn't sound right to me. The main idea behind ABS (for road use) is that you can steer while getting full braking power. That is the point of ABS.

Is it possible that he was simply losing control, by driving beyond the cars handling limits, and no amount of great ABS would have stopped the car spearing off. I am not having a go at your mate, but that is possible.

Too many inputs to the ABS? Just makes little sense.:confused:

Well I think in this particular case the car was turning, had become unweighted to some degree, and basically behaved completely differently to how it behaved during normal driving. I guess this is something that may only happen 1% of the time, but the point I was trying to make is that the controlling of your vehicle is down to a system which may not necessarily be infalible, and thinking it is could well be dangerous. I do understand the point of ABS, when it works it's great, and I've read that more modern ABS systems can actually compete with a decent driver that is threshold braking.

It shouldn't, however, replace driver/rider ability.

[fallboy]

I know a 'skilled' driver in a car or motorbike can stop the vehicle quicker than an ABS system can.
But lets face it, most of us aren't that skilled:o

So I was wondering, would ABS on a MTB (particularly DH) be possible, and if it were would you think it would be an advantage?

I would like to try it, but can't really figure out how, I was thinking it should be possible to buy a setup made for a Moto, but haven't been able to find much on the interweb.

Discuss...

The best part of a modern car abs system is that it can lock and unlock each of the four wheels individually- something that no driver can do as a driver can only work all four brakes at once. So the system can do something above and beyond what the driver can do. On a bike on the other hand two wheels two brakes two hands it all works. We can already lock and unlock individual wheels so a skilled rider can already do what a computer would do anyway.

May sell well as a gimmick on road/commuter/touring bikes though.

[Turner_rider]

Found these scary little beasties by chance. While not true ABS as such they're probably as close as you can get to a commercial attempt at ABS for bikes.

Apparently the roller is slighlty offset and pulses the pads for the ABS effect. In practise I have no idea how they actually worked (performance wise) but given they must have been a sales flop I'd assume it wasn't too good ;)

A copy of the manual can be found here http://www.blackbirdsf.org/brake_obscura/brovedani_man.pdf


http://www.blackbirdsf.org/brake_obscura/images/mtb/brovedani.jpg

[kip01]

to run abs on a bike you will need speed sensors on each wheel a computer (ecu) abs pump which needs to run of 12v and it would be gay because your wheels wouldent lock so that means no cool skids

[allstar]

Well reading this has made me think... We diss the idea of ABS because it would struggle on dirty uneven surfaces, be heavy and sometimes we'll hook the rear to skid a corner...
Thats all well and good but how many people utealise the modulation avalible in their brakes well? I mean I often hear people talk about 'snappy' brakes, and I have riden some bikes where the brakes feel either full off or full on. Surely you would go faster and have more control if you didn't lock your brakes (I'd be curious how often Hill or Rennie etc actually lock up, data acquesition anyone?)
I guess im floating off topic a bit here but what im tring to get to is that modulation and predictablity would be far more important to riding than an ABS style system.......

i think you'll find that you only get that bitey feel of some brakes when your rolling slowy along, because as S. said it is much harder to lock the wheel when it has more weight/speed behind it. this is why i dont feel the need to ugrade my hayes 9's, because when your pinnin it down a DH course you normally get the modulation other brakes offer with the same if not more power. my opinion anyway

[wombat]

Found these scary little beasties by chance. While not true ABS as such they're probably as close as you can get to a commercial attempt at ABS for bikes.
Hahaha, I was wondering why it took so long for those things to pop up!
I've got a MTB Action buyers guide circa 1995 and it has those little beasties in it.

I reckon they'd be right at home on a nice old Proflex (with half-melted bumpers) :) .

[user name]

I know that the BMW Dakar bikes have ABS on them,

Brake System -BMW EVO with partial integral ABS
Front Brakes-Two, four-piston fixed calipers
Front Rotor-12.0 inch dual floating rotors
Rear Brakes-Single, two-piston floating caliper
Rear Rotor-10.4 inch single, fixed rotor
Actuation-DOT 4 fluid type
if youve seen The Long Way Round, youll know because it screws up :).

As for MTBs why bother with this tecnology, why not just become a more skilled rider? keeping in mind that the more rubber you have on the ground
the more force you can apply, so why not invest in wider tyres? More effective suspension wouldnt go astray either..

[Sleeman]

ABS on bikes? So you want breaks that don't work??

There was a proto type come out a few years back that tested an anti skid braking system for commuters, can't remember what brand it was, possibly a sub-division of Shimano? but it was found that it was too unpredictable and increased braking distances greatly.

Surely it can't be that hard to release the brakes a little if you think you are sliding too much...

[MrPlow]

ABS on bikes? So you want breaks that don't work??

There was a proto type come out a few years back that tested an anti skid braking system for commuters, can't remember what brand it was, possibly a sub-division of Shimano? but it was found that it was too unpredictable and increased braking distances greatly.

Surely it can't be that hard to release the brakes a little if you think you are sliding too much...
Sure,
I am sure if the concept was viable it would be here now.
The point of the thread is to learn why, and get opinions.
Stating the obvious like surely you can feather the brakes;)

[Tomas]

to run abs on a bike you will need speed sensors on each wheel a computer (ecu) abs pump which needs to run of 12v and it would be gay because your wheels wouldent lock so that means no cool skids
Dont speak.


My 2c:
Certain fast cars are aerodynamically designed to route air onto brake rotors to cool them. Why cant we have little fins on our forks and frame to cool the rotor/caliper mid-run? Hey, a punter like me would benefit from cool brakes the most.

[MrPlow]

Dont speak.


My 2c:
Certain fast cars are aerodynamically designed to route air onto brake rotors to cool them. Why cant we have little fins on our forks and frame to cool the rotor/caliper mid-run? Hey, a punter like me would benefit from cool brakes the most.
That isn't such a bad idea either, look at some moto's they have a plastic (ABS) guard over the rotor with a big scoop on the front of it to cool the caliper.
Even on our local run here I can notice my Juicy's going juicy because of overheating...

[Kasplat]

nice topic Mr Plow....ABS sucks in cars...all it does is stops it from skidding....and did you know in cars the come standard with hydro hand brakes, the ABS will actully come in it you use a Hydro hand "aggresivly" (or for serious fun)

ABS would suck on an MTB i agree with what has been said, they would cause such an issue with stopping distance etc...yeah and no squid skids!

[whywalkwhenucanroll]

i think you'll find that you only get that bitey feel of some brakes when your rolling slowy along, because as S. said it is much harder to lock the wheel when it has more weight/speed behind it. this is why i dont feel the need to ugrade my hayes 9's, because when your pinnin it down a DH course you normally get the modulation other brakes offer with the same if not more power. my opinion anyway

I rode an Iron Horse G-spot with Psylo's and a brand new set of 05 HFX 9's with an 8inch rotor up front. They were ridiculously bitey, mabe 'cos they hadn't bedded in but after a large handfull of rides I took em off cos I'd touch the lever and they were full on. I ran em with a 6inch rotor and no probs. I now run em with the 8 on my DH bike (ATX1) and have no probs.

No it does not. ABS does not decrease stopping distance.;)

Read what bloodZkull has said.

I will clarify.

For a skilled driver ABS will take LONGER to stop, than a non ABS car.

But for a hack, like most drivers, who will simply stomp on the brakes, and lock up the wheels, THEN ABS will stop quicker.

I think to really argue the first point here we need some hard proof not just peoples opinion. So here's my opinion: ABS is designed to give you maximum control with maximum braking so that you can still controll the car in an emergency. So when you slam on the brakes in a non ABS car you slide straight into what ever is in front (simply put). With ABS you should be able to slow the car dreamatically and steer around the obsticle. Depending on conditions and car setup (i.e. weight, tyres, suspension etc.), ABS may or may not give a shorter stopping distence (I don't think its the point of the system specifically) but I would imagine that a good ABS system would be better. A computer can slam the brakes on and off and get perfect modulation (i.e threshold) much faster then a human can (I think they hit the brakes at 30 times a second? mabe?). Obviously a skilled driver is less likely to get into a situation where they need to slam the brakes on but hey Peter Brock is dead now so it can happen to anyone (full respect to Peter and his family). So if a computer can get better modulation and more grip for the amount of braking to my mind means that it would stop the car faster. All thats left is the computer's interpretation of its environment which is where a human might win.

simple, abs does in fact increase braking distances for any car over an experienced driver, what it is designed to do is get rid of your average persons reaction of trying to push the pedal through the floor.

the term threshold braking is what is most effective, just off locked brakes, the problem being abs usually reads this as being locked.

Again we need some hard evidence not just yours and my opinion. And no I aint got any. I don't see any reason that a computer would read the threshold as being locked. I agree with the pedal through the floor bit.

and if your wondering i have never locked the brakes on mine or any other car without meaning to do it, that being said, like anything it's only a matter or time.

So you've never had to do an emergency stop in the wet? I'm impressed. Unlikely but possible.

As far as ABS on bikes is concerned I do agree that it probably wouldn't give you that much advantage. ABS on cars is an emergency thing so on a bike I would imagine that it would be of little use unless in an emergency. It'd be a cool thing to try though.

P.s. I'm not trying to hack on people here just discussing points. It's all very well to have your opinion but with somthing like ABS it shouldn't be dissed without some real evidence. and yes I'm as bad as the rest cos I like my opinion and also have no hard proof either way. Except that ABS is on a crap load of cars so it can't be that bad...

P.P.S. sorry for the massive post.

[Turner_rider]

I know a 'skilled' driver in a car or motorbike can stop the vehicle quicker than an ABS system can.
But lets face it, most of us aren't that skilled:o

So I was wondering, would ABS on a MTB (particularly DH) be possible, and if it were would you think it would be an advantage?

Discuss...

Wading through all the posts, this seems to have gone a bit off topic in some respects. So in summary we have the following:

Would ABS on a MTB be possible? Yes.

Would it be an advantage? At this point in time with current technology No.

In reality with such a wide range of track conditions for a system to be tuned to it points to requiring some tuning of threasholds etc for track conditions by the end user. This in itself can be an issue espcially if you consider that there are relatively few riders who tune their suspension systems to track conditions. Although a system of basic settings like dry, hard, loose, mud etc may be an option.

Even simple setpoints like the speed threashold at which the system switches on/off could be difficult to set as the speed of some courses is relatively low compares to current automotive/motorbike application.

If anyone's looking for an engineering thesis this could be an interesting topic....:)

[FuTAnT]

I'm sure it's possible, just need sensors on the wheel and servos in the brake system to work the brake. It'd probably weigh a bit.
It's been done on motos, from memory the Honda CBR1000 has it, as does the Goldwing.

ABS is fitted to the ST1300 and the Goldwing. DCBS (Dual Combined Braking system) is fitted to VFR800, CBR1100XX. The sports bike (or hyper sports bikes if that's what you want to call it) are all conventional split systems, ie back independant from the front and no combined or servo assistance etc.

BMW has a number of models with ABS, including their Enduro or off-road type models. Often it is selectable however, so you can turn it on/off depending on the conditions. I think their latest system is much lighter than previous, so I'd say it's only a matter of time before it starts becoming more place on weight junkie machines.

Anyhoo, to MTB. ABS would be entirely possible, it's just a weight and electrical power issue. The servos require a battery etc, as well as the extra mechanics involved. Even if it was just a rear ABS type system I think it could work pretty well! Of course locking up the rear has it's advantages at times too, so it would have to depend on the track. If you could turn it on/off that'd be a goer.

[fieldy]

My 2c:
Certain fast cars are aerodynamically designed to route air onto brake rotors to cool them. Why cant we have little fins on our forks and frame to cool the rotor/caliper mid-run? Hey, a punter like me would benefit from cool brakes the most.


most punters would most likely not be able to go fast enough to generate enough air flow to cool the rotors effectively.




As for ABS on a dh bike it is just plain stupid as certain obstacles on dh courses require the rider to lock up their brakes or have the exact braking performance they require for the fastest line. eg. you may need to do a little skid or nose wheelie to get around a sharp corner.

[FuTAnT]

Dont speak.


My 2c:
Certain fast cars are aerodynamically designed to route air onto brake rotors to cool them. Why cant we have little fins on our forks and frame to cool the rotor/caliper mid-run? Hey, a punter like me would benefit from cool brakes the most.

Well, the idea of running ducts to the brakes is to cool them down, due to lack of natural ventilation. However, when we look at a MTB, the brakes are already rather exposed so they don't suffer from poor ventilation. They are already outin the open flapping in the breeze so to speak. The addition of some sort of routed ventilation I would imagine would have very little effect on braking performance in this case. If they were covered up somewhow, or shielded, then yeah, but for the way they are at the moment, I can't see it helping.

[bloodzkull]

well whywalkwhenucanroll you are correct about the more control part. but than again you can also (depending on car setup) gain even more control and lose less speed while still avoiding whatever obstacle by using the throttle. but that is beyond most drives and most definetly most drives in an emergency situation.

ulimatly abs is a good thing for the average car but not necassarily for the performance car.

and yes i am still impressing myself that i never have had to do an emergency stop in the wet, but like i said, it's only a matter of time.

[FuTAnT]

and yes i am still impressing myself that i never have had to do an emergency stop in the wet, but like i said, it's only a matter of time.

But do you practice them anyway? It's a good thing to do on a wet piece of road, check behind, make sure no one is around and jam on the anchors. Keeps the practice up. If in doubt, get a passenger to yell out "stop" for you to try and give you the surprise part.

[DeSloth]

For whoever said friction coefficient is higher once sliding, I think you'll find it isn't. Dynamic (sliding) friction is less than static (rolling).

I personally don't think there would be much merit to any form of anti-lock system on a bicycle. Why? Generally if you've locked the front wheel you are riding on marbles, and you're more of less screwed anyway. During this 'holy crap' phase it's pretty easy to modulate baking manually until collect a sufficiently large tree.

Also, possibly more significant than this - I think ABS on a bike would make things worse. Why? Riders don't generally crash in a straight line - the wheel washes out, leaving them to fail and die. This is TRANSVERSE slip of the wheel. The contact patch of the tire is only able to generate a set amount of frictional force, determined by the frictinal characteristics of the tyre and ground. It can handle a fair bit of 'straight-ahead' friction, and more of less the same amount of 'sideways' (transverse) friction, but a combination of both results in decreased performance in both directions. You are a mech? engineer? it's the same deal as Mohrs circle with shear and axiel loading

This kind of crap:
http://www.geocities.com/prohibition_us/frictionrain.gif

You can brake hard, or corner hard, but when you try to do both, the line you are drawing on that diagram is on an angle to the axes, desulting in decreased performance in both braking and turning.

Most of this stuff is used for asphalt, and I'm not certain of it's validity off-road. There's a lot more variables, and tyres are designed by smart people with expensive testing equipment. But anyway, I made you read it. ;)

Finially - without sliding everywhere, it wouldn't be fun ! :D

[S.]

For whoever said friction coefficient is higher once sliding, I think you'll find it isn't. Dynamic (sliding) friction is less than static (rolling).

I personally don't think there would be much merit to any form of anti-lock system on a bicycle. Why? Generally if you've locked the front wheel you are riding on marbles, and you're more of less screwed anyway. During this 'holy crap' phase it's pretty easy to modulate baking manually until collect a sufficiently large tree.

Also, possibly more significant than this - I think ABS on a bike would make things worse. Why? Riders don't generally crash in a straight line - the wheel washes out, leaving them to fail and die. This is TRANSVERSE slip of the wheel. The contact patch of the tire is only able to generate a set amount of frictional force, determined by the frictinal characteristics of the tyre and ground. It can handle a fair bit of 'straight-ahead' friction, and more of less the same amount of 'sideways' (transverse) friction, but a combination of both results in decreased performance in both directions. You are a mech? engineer? it's the same deal as Mohrs circle with shear and axiel loading

This kind of crap:
http://www.geocities.com/prohibition_us/frictionrain.gif

You can brake hard, or corner hard, but when you try to do both, the line you are drawing on that diagram is on an angle to the axes, desulting in decreased performance in both braking and turning.

Most of this crap is used for asphalt, and I'm not certain of it's validity off-road. There's a lot more variables, and tyres are designed by smart people with expensive testing equipment. But anyway, I made you read it. ;)

Finially - without sliding everywhere, it wouldn't be fun ! :D

Good explanation, but being a pedant I'm gonna fix a couple of things on your behalf :). Maximum grip for most rubber tyres is apparently at roughly 25% surface slippage (by area) on asphalt (if I've gotten that arse-about somehow, someone let me know). On dirt it's a totally different effect, coefficient of friction (which is actually pretty much irrelevant on asphalt anyway) goes straight to hell, and dynamic friction effects suddenly outweigh static friction effects (note how rally cars are constantly and deliberately sliding in the dirt). However, dynamic friction (especially with varying surfaces) is far harder to control since you now have a multi-degree-of-freedom vehicle to handle (especially if it's a bike and it requires a specific friction force to hold it upright whilst cornering!).

BTW the Mohr's circle analogy is only really true in the sense that it's a circle (especially since a Mohr's circle doesn't necessarily have its centre at the axes' origin). However, true grip representations are always somewhat elliptical (depending on weight transfer effects, tread patterns, and if we're talking cars, aerodynamic effects too). They're all over the place for off-road stuff too, because the surface changes so much.

Long story short: ABS is pretty useless on a bike. Skidding a back wheel isn't much of a big deal, front wheels never lock up anyway (CoM is high enough relative to wheelbase that you go over the bars before locking the front wheel, unless you get waaaay over the back of the bike), and if you're braking in a corner then as you said, you're losing both ways and you're going to suffer from a lack of lateral grip (washing out), not longitudinal grip (locking up).

[dh4eva]

a few years ago giant had this kinda thing on some of there bikes, it was pretty much a small spring inside the noode on the front brakes to stop people from grabbing the brake to hard and flipping over the bars

[DeSloth]

Good explanation, but being a pedant I'm gonna fix a couple of things on your behalf :). Maximum grip for most rubber tyres is apparently at roughly 25% surface slippage (by area) on asphalt (if I've gotten that arse-about somehow, someone let me know). On dirt it's a totally different effect, coefficient of friction (which is actually pretty much irrelevant on asphalt anyway) goes straight to hell, and dynamic friction effects suddenly outweigh static friction effects (note how rally cars are constantly and deliberately sliding in the dirt). However, dynamic friction (especially with varying surfaces) is far harder to control since you now have a multi-degree-of-freedom vehicle to handle (especially if it's a bike and it requires a specific friction force to hold it upright whilst cornering!).



I read that a few times and I'm still not sure what you are saying. Offroad tyres grip better while rolling, or sliding?


BTW the Mohr's circle analogy is only really true in the sense that it's a circle (especially since a Mohr's circle doesn't necessarily have its centre at the axes' origin). However, true grip representations are always somewhat elliptical (depending on weight transfer effects, tread patterns, and if we're talking cars, aerodynamic effects too). They're all over the place for off-road stuff too, because the surface changes so much.


You and I know this, but I have a gut feeling nobody else really cares. :p The general concept is exactly the same.

You obviously know your stuff - did you have any 'essential reading' (books and such) for a dumbass who might be intersted in moto / car suspenion configuration? I know a bit, but not a lot. PM me if you'd prefer. :)

[S.]

I read that a few times and I'm still not sure what you are saying. Offroad tyres grip better while rolling, or sliding?



You and I know this, but I have a gut feeling nobody else really cares. :p The general concept is exactly the same.

You obviously know your stuff - did you have any 'essential reading' (books and such) for a dumbass who might be intersted in moto / car suspenion configuration? I know a bit, but not a lot. PM me if you'd prefer. :)

On surfaces that shear and deform (ie dirt) you do actually get more frictional force (grip) whilst sliding (up to a certain degree anyway, but the point where grip is lessened due to the speed of the sliding is more like wheelspinning or something in a car, not drifting it sideways). There are a whole shitload of reasons for this and to my knowledge it's not something that's understood very well - there are just so many variables to account for.

Nah I'm not very well-read as such (mostly just stuff I've figured out myself, and learned from various obscure sources - I don't know much about car specific suspension). Try Tony Foale's "Motorcycle Handling and Chassis Design" if you're interested in that kind of stuff though - www.tonyfoale.com (http://www.tonyfoale.com)
Mostly about road bikes though, as far as I'm aware (haven't actually got a copy myself but am intending to buy one at some stage).

[DeSloth]

Cool, thanks.

[fat_tyre_nick]

Yeh for DH that would be good but i think that the added weight and extra parts isnt worth the effort of having it on there in the first place.

[bloodzkull]

Good explanation, but being a pedant I'm gonna fix a couple of things on your behalf . Maximum grip for most rubber tyres is apparently at roughly 25% surface slippage

^^ exactly. and abs pretty much reads 25% slippage as locked so you are therefore not getting the absolute best braking. but have you ever tried turning wilst braking hard, not quite as good.

[S.]

Good explanation, but being a pedant I'm gonna fix a couple of things on your behalf . Maximum grip for most rubber tyres is apparently at roughly 25% surface slippage

^^ exactly. and abs pretty much reads 25% slippage as locked so you are therefore not getting the absolute best braking. but have you ever tried turning wilst braking hard, not quite as good.

ABS doesn't actually read slippage as such, it measures sudden decelerations and variations between wheel speeds. What I meant by slippage is that the contact patch is deforming and shearing so that ~25% of the contact patch is slipping over the ground, but the other ~75% is not (because rubber can deform very easily, especially with raised tread blocks). This isn't a hard and fast rule, but that's why you hear tyres starting to growl (in a car) before they let go and the car starts sliding. The effects are much harder to analyse or even just comment about on a bike though, because the bike leans over, the knobs on the tyres are of a much lower aspect ratio (higher for given area) and deform a lot more, and so forth.

[Red Rocket]

The effects are much harder to analyse or even just comment about on a bike though


So in other words, most bicycle tyre companies don't have too much in the way of quantitative testing, they just go with a bit of good 'ol guess 'n check as to what works and what doesn't? (which, at the end of the day isn't a bad way of doing things IMO)

[hyperkona]

ok... well I read this thread and just have to say my 2 cents worth :eek:

1. I have a car with ABS and hate it. Ive had 'performance cars as such that didnt have ABS and you have a lot more control and pull up alot quicker.

2. If you are thinking of wanting ABS on your MTB then you are thinking too much about riding instead of actually riding! Seriously. Toughen up. How many times have we all been in situations where wheels may or may not have locked up, front tyres slipped out and we act on 'skill' and 'instinct' to stop ourselves goin tits up? If you had ABS - you become reliant on that and then if you are relying on that - then you arent relying on your skills and guts to pull you out of a stuation and I'd pick you'd end tits up anyways, wondering why your ABS didnt save you.

Go hard - or go home!

[S.]

So in other words, most bicycle tyre companies don't have too much in the way of quantitative testing, they just go with a bit of good 'ol guess 'n check as to what works and what doesn't? (which, at the end of the day isn't a bad way of doing things IMO)

I seriously have no idea what bike tyre companies do in the way of testing (other than handing protos to their sponsored riders). I know the road moto tyre mobs (which includes Maxxis and Michelin obviously) use FEA software for their stuff, but whether or not that's cost effective or even worth doing in terms of accuracy for MTB stuff, I really don't know.

[Tomas]

Go hard - or go home!

Yeah! me and you! we'll ride thredbo on a rigid this year! fuck suspension. its overrated anyway!!! Ripper

:rolleyes: . Innovation bro.

[MrPlow]

ok... well I read this thread and just have to say my 2 cents worth :eek:

1. I have a car with ABS and hate it. Ive had 'performance cars as such that didnt have ABS and you have a lot more control and pull up alot quicker.

2. If you are thinking of wanting ABS on your MTB then you are thinking too much about riding instead of actually riding! Seriously. Toughen up. Go hard - or go home!
Tell me to toughen up to my face ;)
It's called technology, Tomas sums up the inteligence of your post well.
Now, toughen up and go and throw your computer out the window.

[hyperkona]

Tell me to toughen up to my face
It's called technology, Tomas sums up the inteligence of your post well.
Now, toughen up and go and throw your computer out the window.

Yeah! me and you! we'll ride thredbo on a rigid this year! fuck suspension. its overrated anyway!!! Ripper

. Innovation bro.

haha... girls girls girls.... dont have a hissy fit! Firstly... no problems in telling you to toughen up to ya face :rolleyes: And if you dont like other peoples opinion and valid ones at that - then dont read forums?? I mean for frigs sake ABS on a mountain bike!!! WHAT THE???? Ill say it again. Toughen up! Stick to ya trials with ya reflective jackets, spokey dokeys and safety flags - and dont forget ya bell. :D

And as for riding Threbo on a rigid.... go for it bro...!! I ride full DH (with suspension).... oh... and I rate it. I think my opinion was on ABS - not suspension.

[No Skid Marks]

ok... well I read this thread and just have to say my 2 cents worth :eek:

1. I have a car with ABS and hate it. Ive had 'performance cars as such that didnt have ABS and you have a lot more control and pull up alot quicker.



Possibly your sport cars had much bigger brakes.

[ma7rk]

I have to agree with hyperkona on this. This is a pretty ridiculous idea. Apart from the logistics of the whole thing, can you imagine geting the crap shaken out of you when you are trying to stop in a panic situation? Or whatabout all the times when you would want to skid the wheels. I think overall it would be a pain in the balls.

Most performance motorbikes are not equiped with abs. Also its a fact that cars equiped with abs and driven by a driver with average skills will perform worse on gravel and loose surfaces than a car without it, so unless your on a nice surface its only going to make things worse.

Just my two cents.

PS Toughen Up! Skiding is fun! ;)

[MrPlow]

Sure,
I am sure if the concept was viable it would be here now.
The point of the thread is to learn why, and get opinions.
Stating the obvious like surely you can feather the brakes;)

Tell me to toughen up to my face
It's called technology, Tomas sums up the inteligence of your post well.
Now, toughen up and go and throw your computer out the window.

Yeah! me and you! we'll ride thredbo on a rigid this year! fuck suspension. its overrated anyway!!! Ripper

. Innovation bro.

haha... girls girls girls.... dont have a hissy fit! Firstly... no problems in telling you to toughen up to ya face :rolleyes: And if you dont like other peoples opinion and valid ones at that - then dont read forums?? I mean for frigs sake ABS on a mountain bike!!! WHAT THE???? Ill say it again. Toughen up! Stick to ya trials with ya reflective jackets, spokey dokeys and safety flags - and dont forget ya bell. :D

And as for riding Threbo on a rigid.... go for it bro...!! I ride full DH (with suspension).... oh... and I rate it. I think my opinion was on ABS - not suspension.

I have to agree with hyperkona on this. This is a pretty ridiculous idea. Apart from the logistics of the whole thing, can you imagine geting the crap shaken out of you when you are trying to stop in a panic situation? Or whatabout all the times when you would want to skid the wheels. I think overall it would be a pain in the balls.

Most performance motorbikes are not equiped with abs. Also its a fact that cars equiped with abs and driven by a driver with average skills will perform worse on gravel and loose surfaces than a car without it, so unless your on a nice surface its only going to make things worse.

Just my two cents.

PS Toughen Up! Skiding is fun! ;)

Read up guys, it was more a topic for interest sakes.

[Tomas]

[quote=hyperkona;753065] I mean for frigs sake ABS on a mountain bike!!! WHAT THE???? quote]

Mate, 10 years ago if you had said to someone "in 10 years, everyone will be riding 8" dual suspension bikes and toyota will be making bikes that cost upwards of 100g", you would have been laughed at.

100 years ago, if you had said men will walk on the moon, you would have been laughed at.

10000 years ago, had you said the earth was a sphere, and not the center of the universe, you would have been laughed at.

In 10 years, do you think you think we'll be laughed at for trying to upgrade what is a very basic braking system? As i said before, its called innovation.
They say that time changes things, but you actually have to change them yourself. You say this is a public forum, and you have a right to express your opinion. Great, well done. But the fact it is very narrow minded, short sighted and counter productive. Why bother to state that it's useless without backing it up with fact, logical arguement or reason.

Being dismissive and narrow minded is stupid. Letting people know that your stupid and narrow minded just reinforces what we already knew. Stop beating a dead horse.