Stable Plaform

[LZYBOY]

I know the 04 MTB bike year has only started but can I be so bold in saying that we could almost call it the year of the "Stable Platform"?

Any decent 04 Full Sus bike has either a Fox Propedal or a Manitou SPV. Now has anyone ridden on a bike with one of these yet? How is it?

I just bought an 03 bike for a discounted price but should I have waited for the 04 model which comes with a Fox Float with Propedal?

This question may have been asked but can you upgrade the Floats/Vanillas to the new ProPedal system? How much do you think this upgrade would cost?

[naz]

shouldnt cost much just got to change the damping shims around,
fox teralogic would work better than spv, coz the terralogic valving works on inertia
my 2.2 c(inc gst) :?

[Turley]

Upgrading to pro pedal via dirtworks.au wont be available until the end of 04 so the only way to get pro pedal is to buy a new shock :(

[LordNikon]

I haven't ridden either but I've been told you need to be an aggressive rider for the suspension to react.

*shrugs*

Makes no difference to me yet, my fork doesn't move at all when I'm pedalling unless I stand up and really pump the pedals.

[S.]

I know the 04 MTB bike year has only started but can I be so bold in saying that we could almost call it the year of the "Stable Platform"?

Any decent 04 Full Sus bike has either a Fox Propedal or a Manitou SPV. Now has anyone ridden on a bike with one of these yet? How is it?

I just bought an 03 bike for a discounted price but should I have waited for the 04 model which comes with a Fox Float with Propedal?

This question may have been asked but can you upgrade the Floats/Vanillas to the new ProPedal system? How much do you think this upgrade would cost?

I'm pretty sure ProPedal isn't SPV, seeing as you need to licence SPV to be allowed to use it... it's some other mechanical means of stiction.

[Turley]

Pro pedal from what I heard is just an internally set low speed compression(assuming low speed compression is hte compression setting you set to prevent pedalling bob on spv).

[S.]

Pro pedal from what I heard is just an internally set low speed compression(assuming low speed compression is hte compression setting you set to prevent pedalling bob on spv).

Ok, I'm not 100% sure about this - but isn't SPV done by air pressure rather than just compression damping?

[Wattsy]

the spv(manituo) and propedal(fox) r pretty much the same but made in different ways. its just valves along with air presure to stop the pedal bob, but the suspentions reacts the same as any other, i should know, ima runing an manituo swinger 4way. in allways id recomend the manituo but its ya decision. thew manituo performs much better

[RaID]

im pretty sure thats it socket

[Turley]

Yeah, my explaination is how it happens not why it happens. Low speed compressions is still low speed compression wether you use air or oil. :D

[Daver]

OK... manitou SPV is a cheaper version of Progressive's 5th element system. The point of stable platform valving is to allow suspension to be supple in the bumps, yet remain 'bob' free. A byproduct of their dampening shim style is the ability to increase bottom out resistance.

The stable platform technology was originally conceived by curnut suspension for motocross, and Brent Foes (Foes bikes) pushed curnut to enter the mtb market. As such, Curnut's remain the best anti-bob design out there...

In an SPV/5th element shock: (using the 6way/5th as an example) there are 6 adjustments:
1. Preload
2. Rebound
3. Beginning stroke compression- this is the antibob valve. It allows riders to tune how hard the shock is initially. Simply- how much force is required for the shock to move.
4. Ending stroke (hi-speed) compression- the same as the compression adjuster on a 'normal' rear shock- controls the oil flow through the shim stack- how quickly the shock reacts to bumps.
5. Bottom out- this is determined by the bottom out nut on the shock. It does as it says. It works through:
-compressing the air (*see below) in the chamber, meaning that the force required to compress the air is much greter (eg: normal air shock)
6. Air- despite popular belief, the air adjustment controls sag only. More air= less sag. The air pressure is also used by the bottom out valve. AIR DOES NOT MAKE THE SHOCK STIFFER OR BOB LESS!!!!!

Fox 'propedal' achieves a simular result through variing the shim stack- which is much more reliable than the Manitou/Progressive style. This is how most 'off the shelf' motocross bikes come...

[Ty]

AIR DOES NOT MAKE THE SHOCK STIFFER OR BOB LESS!!!!!

yes it does, we tested it with a good shock pump and some serious car park sprint testing, the difference between 50psi and 150psi is clear when observed on a flat testing surface.

i do believe good old preload is used to set sag.

[Daver]

Would you mind if i referred you to page 9 of the 5th element tuning guide?

With fox shocks, preload does affect sag.

On 5th elements and Manitou SPV's, preload does not affect sag!!! The air pressure would make the chock sag less, and 150psi would mean that the compression through pedalling COULD be limited...

just like when my friend ride my bullit they get no sag- purely because the shock is set up for me(100kgs/hucker) - they can't compress the initial part of travel due to my air pressure. but once again read the tuning guide... i'll find a link and post 1 up soon.

[Ty]

ok now read what you said, first you said it wont bob less, then you say, 'they can't compress the initial part of travel due to my air pressure' which would indicated when on the bike it would 'bob less' under pedaling forces.

please explain how it's hard to compressing the inital part of the travel due to high air pressure and how not bobing due to high air pressure are different.

[Daver]

oohhh... i get it now.... i was talking about sag.... i ment that it won't sag as much (ie compress as much?)....

but yeah... sag ain't adjusted by preloading the springs***according to the 5th element tuning guide***

[shmity]

dont worry daver, ive got it for you http://www.progressivesuspension.com/pdf/5th%20Element%20Guide%20-%20English.pdf
my favorite bit in that manual where they say the spring pre load is what is used to adjust the sag, with the air pressure also playing a part..."Because your air pressure adjustment (outlined above)also affects your starting spring force,you should always adjust your air pressure before adjusting the spring preload & sag"
The way i understand it is the adjustments are as follows:
Air pressure
Air volume
Start stroke compression
End stroke compression
Rebound

From what i can see the air volume affects how progressive the shock feels at the end of the stroke, and the air pressure affects how hard it is to initiate a full shock stroke.

[Daver]

yeah... i forgot that bit...


***just a side note... erm why is a 5th element meant to have 5 adjustments and a swinger 6-way has the same adjustments...?

[Ty]

mantiou count preload as a adjustment where 5th don't bother

air pressure
air volume
start stroke
end stroke
rebound


preload

[Daver]

just wondering.... thnaks again... :P

[naz]

ride a hardtail for christs sake :lol:

[S.]

oohhh... i get it now.... i was talking about sag.... i ment that it won't sag as much (ie compress as much?)....

but yeah... sag ain't adjusted by preloading the springs***according to the 5th element tuning guide***

Well that's bullshit, you might also adjust it by doing something else, but what else does preload do? It barely makes any difference to the overall spring rate (maybe 1% or something) before it starts inducing a movement threshold and stuffing up your rate. More preload = less sag.

[S.]

Yeah, my explaination is how it happens not why it happens. Low speed compressions is still low speed compression wether you use air or oil. :D

I didn't think they used the air for damping tho, which is what the oil does...

[shmity]

Air is a good spring, but not a good damper since it compresses, hence its not part of the damping system but part of the 'stable platform'.

[S.]

That's what I was thinking... but I don't own one so I'm not sure.

[shmity]

You dont really need one to understand that, look at air shocks, the air is the spring, then look at hydro brakes, they use oil because it doesn't compress.

[S.]

haha but look at some XC forks... air damping.

[nicklouse]

yep air is used to set the threshhold (sp) at which the shock starts moving. they really could have used a knob and used that to vary the threshhold but the shock would have been a lot bigger! using air allowed for a compact design and an easy way to set the threshhold point!

[nicklouse]

air can be used but the valving is smaller and needs to be more accurate hence more cost.

[MUNGUS]

on manitou swinger shocks, all of your sag should be adjusted by your preload, not your air pressure. if it is the other way around then your shock is set up wrong.

airpressure in ur shocks makes it harder for the spv valve to open up when compressed hence making the oil flow past the valve be harder or easier acording to airpressure. due to this, it is possible for the airpressure to have a bearing on ur sag because if you are running more airpressure then initially it is going to take more force to open the valve and oil to start flowing. this is the whole idea behind spv. so by having the shock set up correctly, you can still have a proper amount of sag which will be set by ur preload yet you will be able to achieve pedaling stability through ur air pressure. this stability effects how active ur shock will be to small and low speed compressions and due to this i don't like to run it on every track. if it is too stable the shock can start to become inactive over small bumps and that can affect ur bikes ability to keep the rear wheel planted on the ground which is what we all want. as well as the valve there is the low speed compression dial which does much the same thing. the other advantage of the air pressure is that the bottom out resistance of the shock can be adjusted. for racing i prefer mine almost all the way out but if freeriding you might like it quite a way in. theis resistance is very noticeable and can stop you fulling using the stroke of the shock if it is wound in too much when your not doing hucks. there is also the high speed compression dial which partners with the bottom out resistance dial to adjust how much and when the shock ramps up. and finaly there is the rebound which is the same as any other shock, no explanation needed.

this is how the spv shocks work as best of my knowledge and i hope it has helped clarify anything that you were unsure about.

[naz]

well put mungus, still think fox terralogic 'inertia' valving is easier to understand and would work well on dh if they tweaked it, the inertia valve is a brass clylinder on a spring and the damping elemen is in a tube goin through the middle wit a hole at the top, so when forks are unweighted the brass cyclinder is being pushed up by the spring bein locked out, and when u push down on the forks the inertia of the brass cyclinder wants it to move up thus still locked out elimininating any rider induced bob, but the minute a bump from the bottom of the forks comes thru, the brass cyclinder moves down openin the damping circuit.
hehe,
so any shock from underneath opens the damping and any from above(rider) keeps it locked out

[nicklouse]

simliar principle to a good old SU carb. (well similar not exactly but i think any petrol head will see the similarities).

[dillon]

Oh no the SU ! noooooooo........
My friend has been stuffing around with one and has finally admitted defeat to me and will go EFI on his Fiat 850 turbo.

(those bloody minis cause us trouble on the track :) Mate of a mate built some with Suzuki 1300 DOHC's.

[S.]

well put mungus, still think fox terralogic 'inertia' valving is easier to understand and would work well on dh if they tweaked it, the inertia valve is a brass clylinder on a spring and the damping elemen is in a tube goin through the middle wit a hole at the top, so when forks are unweighted the brass cyclinder is being pushed up by the spring bein locked out, and when u push down on the forks the inertia of the brass cyclinder wants it to move up thus still locked out elimininating any rider induced bob, but the minute a bump from the bottom of the forks comes thru, the brass cyclinder moves down openin the damping circuit.
hehe,
so any shock from underneath opens the damping and any from above(rider) keeps it locked out

The only problem with that is that it can and will lock out midair.... so that 40ft road gap is suddenly to a rigid landing :)

[Rik]

Gravity-affected damping is a bad thing IMO. I say it to customers and I beleive it, I want my bike to work no matter what the orientation of my suspension.

Fair enough for trail riding it isn't as huge an issue, but if I wanna ride upside down, i want my suspension to work :lol:

[naz]

it will lock out but the minute it touches the earth the damping will open up coz the inertia valve will kick in
it isnt gravity damping, its inertia, I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
so when a bump comes from below the the fork leg moves up wards the brass mass will remain in the same position but the internals will move upwards allowing the damping circuit to kick in once again hehe.

[naz]

hey i just made a flash animation to explain terralogic hope it helps
http://www.geocities.com/naz5210/inertia.html

[shmity]

now see, im a fan of mechanical as opposed to themro fluid solutions. I-drives cause me to jizz repeatedly in my pantyloons.

[MUNGUS]

yeah i still don't like the idea of that intertia thing. if i decide i want to force down on my forks to pump into something i want them to work, not to lock out.

even with ur flash thing, i'm struggling to get my head around how the downward force is different from a force from the bottom. as long as the fork compresses then isn't the compression rod going to ove as well which would mean the brass mass would move and therefore boycotting the whole idea??

i just can't see how it could work and work well.

i don't think spv or this inertia thing has a plce in forks at all, leave it to the rear shock. i want my forks fully active all the time. a bit of bob isn't going to do anything really

[naz]

its has notin to do wit compressin the fork, but the whole fork if it suddenly moves up the inertia of the brass mass does not move but teh fork moves around it, if u wanted to pump somethin just lift then pop the fork itll open the dampng

[S.]

now see, im a fan of mechanical as opposed to themro fluid solutions. I-drives cause me to jizz repeatedly in my pantyloons.

Same, cept I'm not much of an i-drive person.

[MUNGUS]

its has notin to do wit compressin the fork, but the whole fork if it suddenly moves up the inertia of the brass mass does not move but teh fork moves around it, if u wanted to pump somethin just lift then pop the fork itll open the dampng


i still can't understand wat ur saying. i understand spv but this is beyond me. :?

[naz]

haha its cool im confusing myself now, hardtails much easier to comprehend

[MUNGUS]

yes indeed