Suspension Tuning/Discussion

[bokinator]

Hello,

I thought I'd start off a thread on discussing suspension tuning - rebound/damping etc, what shock/fork you are running, how each setting affects one another, what pressure to use and how to optimize suspension settings.

I think it'd be nice just to share what everyone knows about this area of expertise so that other people including myself can benefit from this information and make riding that much better!

[ESHER SHORE]

well i currently run the 2008 Lyric 2-step fork and 2008 Fox DHX 5 air shock on my bike (Wildcard) and find it provides a great "front/rear" balance for aggressive riding, and also provides a setup that can be firmed up within seconds (using the pro-pedal switch on shock and the floodgate on fork) for climbing and pedalling-about duties


something not related to my bike, but suspension related that always surprises me, is how few mountain bikers here in England accept that suspension tuning and setup needs to be done when buying a new bike, fork or shock...or even after buying the bike or suspension products

I had plenty of MX friends in the past who would think nothing of stripping down their new bike after some break-in rides, and spending $$ to have the fork and shock tuned or upgraded


we sell alot of custom builds and production bikes with suspension, and I always worry when I calculate the spring rate for a rear shock on a new bike and 14 stone rider says "don't worry i'm just gonna ride it for a while and see what happens.."

its sad because he's just dropped GBP

[FullMonty]

generally, the less rebound damping, the better.

oh, and marzocchi's recommended PSI for air forks is way high... I'm running about 135psi (which is still under the recommended 147 for fat guys,) and I'm not getting full travel off of 4-5' drops...

[Wayne P]

Originally Posted by FullMonty

generally, the less rebound damping, the better.

uhh....... what?

[FullMonty]

Originally Posted by Wayne P

uhh....... what?

up to a point... you want the wheels to follow the terrain, so the minimum necessary to keep you from being ejected into the stratosphere...

[biggles604]

Originally Posted by FullMonty

up to a point... you want the wheels to follow the terrain, so the minimum necessary to keep you from being ejected into the stratosphere...

True. This seems to be the most common mistake I find with people's setups. So many out there set the rebound really slow and claim they like it like that. Most prefer it when I fiddle and speed it up (less packing up), but some still go back to the really slow.

I play around with the RC2 cartridge in my fork depending on the riding I am doing, it makes a massive difference, I firm up the compression and preload for bigger hits, and then back it way off if I am doing a mellower flowy ride. Low speed gets bumped up for pedalling.

Here's a question: Is the difference between high/low speed compression a speed sensitive valving difference, or is it the difference between compression rates in the lower vs upper travel of the shock/fork, or is it manufacturer dependent?

[BlazinDayz]

Originally Posted by biggles604

Here's a question: Is the difference between high/low speed compression a speed sensitive valving difference, or is it the difference between compression rates in the lower vs upper travel of the shock/fork, or is it manufacturer dependent?

I've always thought that compression damping was in direct relation to the speed of the stroke(Speed Sensitive Valving). e.g. LSC is for a pedaling platform and hsc was for big drops.

[ESHER SHORE]

compression damping is related to shaft velocity within the shock or fork, when talking about the difference between low and high speed adjustments

typically low speed is rider input (from pedalling and honking on bars), brake dive and trail chatter (small scale terrain features) - too much low speed compression reduces the ability of the wheels to map the terrain

typically high speed is large square edge bumps or big impacts at speed

however, high speed compression damping does not necessarily mean a high "speed" impact but also a high "load" impact (i.e. a big huck) which forces the shock or fork to move at a very high shaft speed

[BillfromtheHill]

LSC to HSC compression on most forks is typically just a LSC threshold blowoff point, the LSC circuit controlls the damnpnin, untill the amount of oil being moved through the circuit is too great and it blows off into the HSC circuit. Bottoming your suspension is not always a HSC problem, G-outs, landing drops to a steep tranny and such are generally handled by the LSC circuit. Square edged hits are HSC. That is the biggest problem I have found with people tuning Fox 40's saying they bottom to easily of minor drops and g-outs even with the HSC cranked. A mild understanding of the Fox cartridge would point them to try cranking the LSC up and backing the HSC way down, this way the fork always rides higher in the travell, resists diving, and bottoming off slow speed hits (drops) yet still be able to blow open quickly with a mild HSC setting to have butter smooth travell over the rough stuff. A quick rebound helps the fork recover quickly between hits so it is able to ride higher in its travell.

[biggles604]

Originally Posted by BillfromtheHill

LSC to HSC compression on most forks is typically just a LSC threshold blowoff point, the LSC circuit controlls the damnpnin, untill the amount of oil being moved through the circuit is too great and it blows off into the HSC circuit. Bottoming your suspension is not always a HSC problem, G-outs, landing drops to a steep tranny and such are generally handled by the LSC circuit. Square edged hits are HSC. That is the biggest problem I have found with people tuning Fox 40's saying they bottom to easily of minor drops and g-outs even with the HSC cranked. A mild understanding of the Fox cartridge would point them to try cranking the LSC up and backing the HSC way down, this way the fork always rides higher in the travell, resists diving, and bottoming off slow speed hits (drops) yet still be able to blow open quickly with a mild HSC setting to have butter smooth travell over the rough stuff. A quick rebound helps the fork recover quickly between hits so it is able to ride higher in its travell.

That's how I've always tuned my bike. The one thing that gives most people confusion is small stutters. I figure that they will always suck, no matter what the condition.

[Wayne P]

My new Revelation air shocker thingy is teh wicked good. That's all I have to add.

[Sharon]

I slowed the rebound dampening on the fox DHX3 that is on my Norco Atomic that I've been riding in the bike park to stop the bike from bouncing too much when I landed.

I also slowed the rebound dampening on my Swinger on my XC bike and that improved the climbing of the bike considerably. With too quick rebound I bounced around too much, slowing the rebound down allowed the rear wheel to stick to the ground more.

I prefer a slower rebound.

Would you describe LSC as the feedback you feel in your handlebars just riding down rough terrain?

How does the pro-pedal affect shock performance on the DHX? i.e.; firm vs plush. It is my understanding that the 'platform' should only affect pedaling feedback, not how the shock performs... or is this just the theory.

Great thread!

[0_o]

Originally Posted by Sharon

I also slowed the rebound dampening on my Swinger on my XC bike and that improved the climbing of the bike considerably. With too quick rebound I bounced around too much, slowing the rebound down allowed the rear wheel to stick to the ground more.

I prefer a slower rebound.

I will keep these things in mind as we rebuild your fork/shock.

Now that we know your riding style we will need to know your body weight to more accurately set up your suspension components.

Just kidding.

[Sharon]

Originally Posted by 0_o

I will keep these things in mind as we rebuild your fork/shock.

Now that we know your riding style we will need to know your body weight to more accurately set up your suspension components.

Just kidding.

but I'm still learning! Plush bottomless! That's all I ask for!

150-155lbs!

Are you saying I should bring a case over? not just a 6 pack?

[0_o]

Did someone say beer?