Negative wheel travel
Negative wheel travel
(OP)
Hi everyone!
I've been given a project to fix (race car), and the first thing I've noticed is the ride is crap...
Having a look at the suspension, front shocks have a total of 6 inches of stroke, but just 2 when the car is with the wheels on the ground. Same thing happens in the rear, 1 out of 3 inches.
I don't know much about suspension, I'm more into engines and engine management but, my idea is, on a race car you want as little neg travel to keep the wheel movement to the minimum, right?? Should I order shorter (as in body length) shocks?? Or am I being paranoid??
I've been given a project to fix (race car), and the first thing I've noticed is the ride is crap...
Having a look at the suspension, front shocks have a total of 6 inches of stroke, but just 2 when the car is with the wheels on the ground. Same thing happens in the rear, 1 out of 3 inches.
I don't know much about suspension, I'm more into engines and engine management but, my idea is, on a race car you want as little neg travel to keep the wheel movement to the minimum, right?? Should I order shorter (as in body length) shocks?? Or am I being paranoid??





RE: Negative wheel travel
Regards
Pat
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RE: Negative wheel travel
RE: Negative wheel travel
Artificially limiting wheel travel, negative or positive, is generally bad juju. If you're on the bump stops often, things have gone south. If you're wheel is dangling off the ground, you're obviously not getting any benefit from even having it. Race cars (that can mean many different conflicting things, so you need to be more specific) can tend towards short suspension travel as a means to reach other goals (low CG, etc). It is not the end goal in itself.
RE: Negative wheel travel
RE: Negative wheel travel
RE: Negative wheel travel
% travel means nothing. If it has1/4" travel, then 100 % extra is still SFA.
If it has 25" of travel then 20% is still quite a bit.
Yes, some race cars have 25" of travel and still have wheels come off the ground.
Regards
Pat
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RE: Negative wheel travel
Alternatively throw changes at it, spend money, and continue to lose races. Your call.
Cheers
Greg Locock
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RE: Negative wheel travel
RE: Negative wheel travel
The suspension travel is related to the spring rate - do the springs rattle at full droop?
An 800lb/in spring is unlikely to defect much between full droop and ride height.
The actual deflection depends on the weight carried by the wheel and the mechanical advantage of the linkage.
The 6" full travel looks like the factory standard amount; the stiffer springs won't move as much.
Your suspension travel is the wrong way around - you will need a small amount between full droop and ride height and the rest above that. this is a very common problem on amateur modified cars.
You need to read as much as you can - carrol smiths "Tune to win" or Fred Puhns "How to Make Your car handle".
Be careful with this car - if there is insufficient travel the driver may loose control over bumps.
RE: Negative wheel travel
Lifting from roll stiffness is a consequence of disproportionate roll stiffness at that end of the car compared to the weight being supported and is always seen at the non-driven end. It should be the front of a rear drive car and the rear of a front drive. Cornering on three wheels is not necessarily bad, but it does indicate that the car setup has reached or is reaching the limit of setup adjustment.