Bicycle Mechanics - FSAE shock questions

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View Full Version : FSAE shock questions


SuspensionGuy
02-06-02, 07:42 AM
Hi All,
Allow me to preface my questions with some background information having to do with this particular application. I am on the Virginia Tech formula SAE team. We build a miniature racecar each year. Because the total vehicle weight is around 680 lbs the wheel loads are similar to what would be seen on mountain bike with an adult rider (680/4 = 170lbs). Thus, we use mountain bike shocks to dampen the motion of our vehicle. Specifically, we use Fox Vanilla RC shocks. Recently we had these shocks dynoed and they blew at 8 inches per second. This leads me to believe that this particular shock had already started to go bad, as it had been used for a season of racing already.
I’m wondering how one might tell when a shock has blown or is starting to go bad? We have several other used shocks but if they are already starting to go we won’t bother using them on this year’s car.
I’m also curious as to what companies are good at revalving mountain bike shocks. I’d love to be able to specify a damping curve instead of just using what comes on the stock shocks.
Thanks for your help. If you want to check out pictures of some of our old cars you can visit the following web sight.
http://filebox.vt.edu/org/sae/

Suspension Guy


Buddy Hayden
02-06-02, 01:49 PM
HI , a shock that has/is going/gone bad tell tale signs include : Bad stiction (static friction), weeping seals , Binding on the compression stroke (look for wear marks on the centre shaft), extreme topping out : extreme bottoming out etc ....:)