HSCV or Damping?

[willmc92]

Searched, but im looking for a definition not an example.

Sorry if this is the wrong section, please steer me in the right direction if it is in the wrong place.(But still answer the question:))

Well, i wanna buy some 04 888r's and the Marzocchi Manual says they have HSCV. Which they refer to as a new system of damping and rebound adjustment. Basically what im asking is, What does damping mean? Does it have a big effect on the way a fork feels and if so, how does it affect the feel? And is HSCV a good attribute to a fork?

Thanks again, sorry about the wrong section possibly but its a dh fork, going on a dh bike, for dh racing, so i figured, it might be dh.

Will.

[No Skid Marks]

Damping controls the speed of the forks compression and rebound by pushing oil through small spaces. The oil resistance controls the speed. Picture a seringe,hard to push fluid through,but if you drill a bigger hole in the end,it'll push faster with the same pressure.

[willmc92]

Damping controls the speed of the forks compression and rebound by pushing oil through small spaces. The oil resistance controls the speed. Picture a seringe,hard to push fluid through,but if you drill a bigger hole in the end,it'll push faster with the same pressure.

So would it be fair to say it is sort of the speed through which the forks go through ttheir travel? Also, how does it affect riding situations etc?

[AngoXC]

Damping controls speed at which the fork extends to its max travel.

HSCV is an older Marzocchi design that had been around for a while in the likes of the SuperT, Marathon and so on.

Inside the cartridge is a piston from which, a rod extends up to the top of the fork (the rebound adjuster). The piston a couple of holes in it (think NSM's syringe anaology) with a one-way valve on the top of the piston so that oil can flow freely through the piston during the compression stoke (ie pushing on the forks). The rod (known as the damping rod) is hollow and oil can flow through it past the piston during compression and rebound. During the compression stroke, the damping rod pushes the piston down through the cartridge. Simultaneously, a quantity of oil is displaced by the volume of the damper rod entering the cartridge. Some of this oil is forced through four of the tiny holes near the bottom sides of the cartridge. If the bump is large enough, the oil won't be able to move quickly enough through the four tiny holes and the oil will force the HSCV shims to bend open exposing the remaining holes. The oil is forced moves into the area outside and above the cartridge unit. At this point, the fork is approaching full travel and since oil cannot be compressed, it is forced into the area underneath the preload caps. Here, a small pocket of air (this is where your oil height comes into play) is forced to compress which greatly ramps up the spring rate during the final part of your travel and prevents a harsh bottom-out.

In the rebound phase, oil is trying to move from above the piston (top of the cartridge) to below the piston. Oil is sucked back in from the fork legs into the cartridge through the tiny holes at the bottom of the cartridge. The size of these holes dictates the speed at which the oil flows through...this size is adjusted via the rebound adjustment knob.

(Info scabbed from Marzocchi Marathon Basic Tuning Instructions.)


From memory, the 888R will give you PreLoad (initial force needed to compress the spring), Rebound (extension) and compression adjustments to dial in your fork.

[top_dog]

04 888Rs also have compression damping adjustment I think. The preload adjustment is internal, you need to move a wire clip to a different slot on the damper rod. Very neat system. Oh and your compression damping is IMO more important than the rebound damping, and for racing the 04 and 05 888s did lack in that department to an extent.

[willmc92]

04 888Rs also have compression damping adjustment I think. The preload adjustment is internal, you need to move a wire clip to a different slot on the damper rod. Very neat system. Oh and your compression damping is IMO more important than the rebound damping, and for racing the 04 and 05 888s did lack in that department to an extent.

What do you mean? they lacked in compression adjustment or they lacked in rebound adjustment? If rebound, i always have mine set at max fast rebound, dont ask why its just my preference, i like them to shoot back out quickly.

[AngoXC]

What he means is that there wasnt much adjustable range in compression on the said fork.

Many higher-end DH forks feature both high and low speed compression adjustments.
High Speed compression handles square edges and strong impacts that compress the fork through all its travel at once. Increasing it will make the fork more resistant at the end of the travel, best used when big drops and rock gardens are expected. Low Speed compression controls small bump sensitivity as well as things like brake dive and pedaling forces.

The 888R just features High Speed compression adjustment.

If your rebound is set too fast, your at risk of topping out the fork. Should be set to return quickly enough to be ready to absorb the next bump without ‘kicking’ your arms. Slow rebound will cause the fork to ‘pack’ up and have less available travel for the next hit.

Proper set up, even of very basic forks is important. Other wise the really is no point having suspention. If/when you get these forks, take time out to learn (as you are now funnly enough!) what does what and so on...even quiz your bike shop and get them to help you dial the fork as well as the rear shock so that you will get the max performance out of your bike.

[S.]

04 888Rs also have compression damping adjustment I think. The preload adjustment is internal, you need to move a wire clip to a different slot on the damper rod. Very neat system. Oh and your compression damping is IMO more important than the rebound damping, and for racing the 04 and 05 888s did lack in that department to an extent.

No way in hell is compression damping more important than rebound damping, ever tried riding a bike with no rebound damper (eg blown shock)? It's quite dangerous really... you can live without compression though it's not ideal.

Anyway, HSCV is one of Marz's marketing acronyms that stands for High Speed Compression Valving, which basically means it's designed to take high speed hits without feeling harsh. I believe it has a shim stack or something like that inside the fork (you can't pull em apart without cutting the carts open unfortunately, though I think Udi did it at some stage), but at any rate it is/was their high-end compression damper.

As for what damping is, read this http://www.farkin.net/wiki/index.php/The_basics_of_suspension_-_terms_and_general_info

What Ango said about it being the rate at which a fork extends to max travel is not entirely correct, damping is simply a force acting to slow the movement of the suspension (in either direction), that is related to how fast the suspension is compressing/extending. This relationship is never linear and varies according to many different parameters. He gave a good description of how the fork works though.

Older 888s (pre-06 I believe) suffered from a lack of low speed compression damping early in the stroke, because they had what was essentially a position-sensitive damper, which had very little effect in the first half of the travel. It worked well to prevent bottom out on bigger hits, but did little to stabilise the bike on steep sections, or when cornering/braking.

[top_dog]

No way in hell is compression damping more important than rebound damping, ever tried riding a bike with no rebound damper (eg blown shock)? It's quite dangerous really... you can live without compression though it's not ideal.

I didn't mean no rebound damper ya goose. Just that a really good compression damper makes a bigger difference than a really good rebound damper, and performance wise there is bigger gains in tuning the compression stack.


Older 888s (pre-06 I believe) suffered from a lack of low speed compression damping early in the stroke, because they had what was essentially a position-sensitive damper, which had very little effect in the first half of the travel. It worked well to prevent bottom out on bigger hits, but did little to stabilise the bike on steep sections, or when cornering/braking.

Ango and WillMc92, thats what I meant when I said deficient in compression damping.

[No Skid Marks]

Rebound is more important. It controls traction and stability far more than compression damping. The spring itself slows the fork on compression(no nowhere near enough),but only your weight,slows it down from reversing the compression strokes energy.If cornering,the rebound stroke can break traction of the tyres if not retarded enough.

[top_dog]

Yeah but what if you don't give the spring the energy in the first place...by using good compression damping. Sure you need the rebound damping when you need it, but I remember S. saying a bike bucking off jumps generally is to do with not enough LSC rather than not enough rebound. Think about that. It makes total sense. You don't want the bike to pay out when it doesn't need to.

[No Skid Marks]

Good point about using less travel with correct Comp Damping,however if the spring is not storing the energy,the rider is absorbing it.
It's all a matter of when and how the energy is transferred.
Not enough travel used(too much comp D) and the rider will feel it. Travel used to quickly and the handling will be affected. Rebound speed not correctly controlled and the rider will absorb the initial impact through the stored energy and the bikes handling will be affected.
Controlling the suspensions speed in both dirrections is important.

[willmc92]

Good point about using less travel with correct Comp Damping,however if the spring is not storing the energy,the rider is absorbing it.
It's all a matter of when and how the energy is transferred.
Not enough travel used(too much comp D) and the rider will feel it. Travel used to quickly and the handling will be affected. Rebound speed not correctly controlled and the rider will absorb the initial impact through the stored energy and the bikes handling will be affected.
Controlling the suspensions speed in both dirrections is important.

Thanks to everyone for their advice, well seeing this thread is axctually working and getting good answers, ill throw one more in, are good condition 888r's from 2004, perfect working order just scratched worth $200? Cos thats what im offering to pay.

[top_dog]

Thanks to everyone for their advice, well seeing this thread is axctually working and getting good answers, ill throw one more in, are good condition 888r's from 2004, perfect working order just scratched worth $200? Cos thats what im offering to pay.

Probably more than that. I sold my 05 888RCs (much the same thing for) $400.

[willmc92]

Probably more than that. I sold my 05 888RCs (much the same thing for) $400.

SHHHHH im buying, he could be listening, and im not one to pay more just cos its worth more. But thanks anyway for the help.

[le chat]

From a sportbiking site but the principles discussed with respect to damping, both compression and rebound can be applied within mountain biking.

Compression Damping:
http://www.sportrider.com/tech/146_9608_tech/index.html

Rebound Damping:
http://www.sportrider.com/tech/146_9604_tech/index.html

Play around on Google and you're bound to find what you need!