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Author Topic:   pinon angle / traction
neil rucker
posted February 26, 2003 06:27 PM
I have been told that 6 to 10 degrees down, (pinion angle) will give you more bite. (camaro hobbystock w/leafsprings) i also have been told pinion angle is NOT related to bite or traction and to much angle cause drag as well as efecting ujoint wear.anyone? is 4 degrees not enough? how can i find out other than spitting driveshafts out at 7500rpm? thanks very much. neil

posted February 26, 2003 08:27 PM
Pinion angle has NO AFFECT on traction. It is only there to keep the u-joints straight under power.

posted February 27, 2003 12:26 AM
it does not effect it but the way guys say it does is by using it to mesure the angle of it when you shorten up the top control arms on a 4 link shortening the top control arms changes the geometery

posted February 27, 2003 09:55 AM
Aw, c'mon guys----lets fight this one out again! LOL

posted February 27, 2003 11:07 AM
Lets look at it this way when your under acceleration the rear is twisting backward therefore when this happens with more pinion angle it pulls on the upper arms forcing the frame of the car to push down on the spring with gives more forward bite hope this maybe clears up things up.

posted February 27, 2003 12:05 PM
Rear tire planting is based on rear control arm INSTANT CENTER location and rear tire height. A torque(moment)is resisted by a force acting on an imaginary lever arm at the instant center. As the car is lifted by this force, an equal and opposite force presses the tire to the track. The instant center is located at the point where the rear suspension arms would intersect if extended. A lot of stock 4 links have the IC BEHIND the rear end. This un-plants the tire on acelleration and plants it on braking. Depending on how the rear end brackets are welded determines pinion angle and IC location. The IC could be located perfectly and the pinion would be pointed backwards if you welded it that way!! The two are not related, only by coincidence like 17 j said. Also on a leaf spring car, the pinion angle is very dynamic so initial settings are somewhat meaningless on the track.

posted February 27, 2003 01:09 PM
hmmmmm....."pinion angle has no effect on traction".......I think there are a lot of Winston Cup chassis/suspension builders, among others, that would disagree with you.

posted February 27, 2003 01:53 PM
pinion angle itself has nothing to do with traction. Show me the physics that prove where the angle of the pinion has one thing to do with it. The only performance gains realized with changing pinion angle are those associated with relieving a mechanical bind in the driveshaft U-joints as the suspension travels.

posted February 27, 2003 06:15 PM
agreed gahainsey. bob bolles says that racers think they're getting more bite by adding pinion angle, when in fact they are robbing horsepower due to the extra binding of the u-joints which helps the car hook up and mistaking that for more forward bite. i've fell in that trap myself.

rico 08
posted February 27, 2003 07:46 PM
My theory is that once the driveshaft reaches a level line between the rearend pinion and the trans ander acceleration,anti-squat stops,so in effect you want to start this early,with more angle(up to a certain point)to take max advantage before it quits when driveshaft levels out.

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