Pinion angle and traction....myth?

[Air Daddy]

How can pinion angle effect traction or wheel hop? I have been in a long running debate over this issue and thought I'd run it past you guys. I know there is a lot of info out there on the Internet and a lot of drag racing literature on this subject but I am having a hell of a time understanding this phenomenon. Think about it for a while and it's seems impossible for the actual pinion angle to have any effect on traction. The rear end pinion is attach to the driveshaft by a floppy u-joint and has no effect on how far the rear end housing rotates. Pinion angle should only be set for optimum drive line alignment after trailing arms , link bars and location devices have been set for optimum traction. If you're saying that by pointing your pinion down X amount of degrees is improving your traction, I'm saying it's not the angle of the pinion that helped but that you changed something that improved your instant center. Did you shorten your top bar to get the pinion down? Well now your drive line is out of whack!

I'm not trying to start a war over this but it is a subject that comes up often and I feel it's a little misunderstood.
Perhaps it's just me that's being dense.

[novaderrik]

i think any improvement from the pinion angle comes when you get it set so the rear u joint is perfectly straight when under power- you gain that extra 1/4hp from not having the u joint flex ever so slightly.

[LowBuckX]

i think any improvement from the pinion angle comes when you get it set so the rear u joint is perfectly straight when under power- you gain that extra 1/4hp from not having the u joint flex ever so slightly.

You never want your ujoints/drive line running straight you always want some offset or they will come apart.

[novaderrik]

You never want your ujoints/drive line running straight you always want some offset or they will come apart.

yeah, i meant to say at some ideal angle, but i typed "perfectly straight" instead.

[Damn True]

Not a myth, a misnomer.

Altering the lengths of upper or lower trailing arms changes the SVSA dimension which in turn impacts the way the car "plants" power by altering squat/anti-squat. The quickie measurement is pinion angle. People will say, "we adjusted the pinion angle" but what they have really done is changed the length of a trailing arm and thus changed the SVSA.

[GBodyGMachine]

Not a myth, a misnomer.

Altering the lengths of upper or lower trailing arms changes the SVSA dimension which in turn impacts the way the car "plants" power by altering squat/anti-squat. The quickie measurement is pinion angle. People will say, "we adjusted the pinion angle" but what they have really done is changed the length of a trailing arm and thus changed the SVSA.

What he said. So on a leaf sprung car, pinion angle is not really helping traction issues.

Jeff