Pinion Angle

[dereksehi]

Does running a negative pinion angle increase forward bite on a leaf spring car without a lift bar versus running a positive pinion angle?

[TALON75]

Should be about 7 degrees down, if it is higher than level you are losing a lot of bite.

[dereksehi]

I was running the pinion at 2 degress positive and did some reasearch and recently changed it to 7 degrees down hoping it would help my forward bite but wanted to make sure I made the right move.

[polsen3p]

Can someone explain how pinion angle creates bite? I hear it all the time but don't understand how it works.

[Lizardracing]

The best answer is it doesn't all by itself. Weight transfer(downward force on the tire) doesn't care if the pinion is straight up of even straight down. If it did 4X4's would be a very different experience.

It get's confused with u-joint angularity and Pull bar/Third link/Lift bar/Panhard bar affects of angle change.

U-Joint angles should be set to accommodate the rear axle travel through it range without putting the U-joint into bind. Usually 0 angle at full load and RPM is desirable for power transmission however compromises have to be made to ensure it doesn't bind. That might mean a smaller negative angle and positive angle at full load/rpm. For example I start mine at -6 and let it go to +2.

[dirtrace09]

On a leaf spring car, pinion angle plays a major role. 7 degrees down as mentioned is desirable. Once you clamp the leaf tight to the axle it relies on the upward rotation of the pinion to put pressure on the leaf. There are several ways to aid the leaf in planting the tires to the track. If you run positive pinion angle it will not create the proper spring pressure on the leaf. Anyone that has lost pinion angle on a leaf car knows that forward bite disappears quickly.

[modman1010]

Also take into consideration that it will affect the pan hard bar location and rear roll centers. Less pinion angle means it will have the pan hard bar higher on the pinion compared to having more pinion angle thru axle wrap

[polsen3p]

So It's not actually the angle of the pinion that creates drive but the change of other suspension points that the pinion angle represents.

[speedbuggy]

"polsen3p
Junior Member

Join Date
Mar 2011
Posts
9

So It's not actually the angle of the pinion that creates drive but the change of other suspension points that the pinion angle represents. "


Finally.... a non-emotionally charged discussion of pinion angle that comes to the correct conclusion?!

I'm in shock a little...

[Hobby Racr]

Here s video I found showing a leaf spring car notice pinion angle static and under full load also look at the front of the springshttp://www.youtube.com/watch?v=40AvvWW_lEo pretty neat video

[let-r-eat]

There have been many discussions here about pinion angle. You are correct in that pinion angle by itself does nothing on a leaf car by itself, the use of floaters and a pull or lift bar as an example. All that aside. Pinion angle in a leaf car is very important in enhancing forward bite. There are also other things involved like pickup point leverage ability and the like.

[Hobby Racr]

Well that link didn't work let me try it again

http://www.youtube.com/watch?v=tTn8VI0M6js