Compression Adjustment?

[DaveH]

We will save around £192 by not having compression adjustment on our shocks. i.e. using fox vanilla r's instead of rc's.

Is compression adjustment useful to have?

Cheers, Dave

[DaveH]

We will save around £192 by not having compression adjustment on our shocks. i.e. using fox vanilla r's instead of rc's.

Is compression adjustment useful to have?

Cheers, Dave

[Denny Trimble]

Yes, compression adjustment is useful, but not critical if it breaks your budget.

More important is that the Vanilla R doesn't have the piggyback reservoir, and at least on my mountain bike, it was very prone to overheating. Upgrading to the RC fixed the problem. I can't say if you'll have the overheating problem, but here was the setup on my bike:
Rider Weight: 230lbs
Spring Rate: 650lbs/in
Shock Stroke: 2.0
Wheel Travel: 5.0
Installation Ratio: .4
Bumps: A little worse than the silverdome parking lot http://fsae.com/groupee_common/emoticons/icon_smile.gif Stop by Whistler (BC) or Plattekill (NY) for a sampling of the fun stuff.

University of Washington Formula SAE ('98, '99, '03, '04)

[Kevin Hayward]

I'm going to sort of disagree with Denny here.

Compression adjustment on a shock is desirable. However the adjustment on the Fox Vanillas is merely a preload adjuster. Hence all it really does is move the blow off point higher or lower on its initial slope. Ideally you would want to be able to change the gradient of the slope rather than the preload for blowoff (if you only had one adjustment).

If you take apart one of the shocks you will find out what I mean (or if you do some shock dyno work).

From a purely testing perspective we have used the Fox Vanilla RC's for the last three years and have found very little gains in compression adjustment (which matches the type of adjustment they have). Apart from the fact the the very low settings are no good.

Hence if the Fox Vanilla R shocks have a 'knee' location equivalent to at least halfway adjustment on the RC model then I would say that there is no real problem going with them.

Cheers,

Kev

Design Ape
UWA Motorsport

[Jackson]

Denny;

Keep in mind that the rear suspension on a mountain bike is going to go through a LOT more travel at a (probably) lower frequency than an FSAE application. I'm thinking even with higher frequencies the energy absorbed by the shocks on a FSAE car will be significantly less than going balls out down Whistler Mtn http://fsae.com/groupee_common/emoticons/icon_smile.gif

Curious, what were the symptoms of overheating? Vaporization in the shocks leading to loss of damping?

Brian
WSU FSAE

[Denny Trimble]

Jackson,
Yeah I was being a little silly; if you notice the specs, most FSAE cars run 225 to 300lb/in springs, and mine is a 650, on the same shock. Add to that the fact that it's constantly going through its full stroke at high speed, and yes, it has a lot of work to do on a mountain bike. At FSAE speeds, I think FSAE shocks probably have 1/2 to 1/4 of the energy to dissipate (each), compared to the poor shock on the back end of my bike http://fsae.com/groupee_common/emoticons/icon_smile.gif

The symptoms of overheating were hissing noises as the shock traveled, and a loss of compression and rebound damping force.

University of Washington Formula SAE ('98, '99, '03, '04)