Runout

[B_Regal Racing]

Assuming all things being equal, what would the effect of wheel runout have on overall speed of a car (other than the preverbial "slower" answer)? Say the FDW has 3 1000ths of an inch runout and and then is replaced with a wheel that has no runout. Is the difference in speed significant or negligible?

 

[HurriCrane Racing]

I'd say it would be significant. That's almost like going from a raw wheel to a rage wheel.

 

[TRE]

i have taken wheels right out of the box ran them then trued them and picked up 01

 

[bracketracer]

i have taken wheels right out of the box ran them then trued them and picked up 01

How much weight did you take off though? Some of the speed may have come from the lighter weight.

The thing to do would be to weigh stock wheels, measure the runout, run them, true them, re-weigh, run them again, then re-cut them to remove an identical amount of weight again, and re-run them. See how much of an improvement you get at each step? You're going to reduce the diameter a small amount at each step but I don't believe that will hurt the test. You'd only be reducing the diameter by .006 or .008" each time.

I spent a ton of time re-doing my wheel cutting setup to get my concentricity from .0008" down to under .0002" but I didn't pick up any noticeable speed BUT that's a lot smaller jump than going from .003" to close to zero.

I'm not really sure I'd want to spend the time to test such a thing, though, since it couldn't possibly be faster to run wobbly wheels, could it? lol

 

[gWebber]

While I'm no expert, I think basic science would suggest a perfectly round wheel spinning perfectly centered on an axle will always yield better results than one that's "off"

 

[DerbyDad4Hire]

I hope to goodness you aren't getting a wheel that out of round from me!!!!

I would guess .005.

 

[B_Regal Racing]

no....