Pinion angle

[littlemanjoe]

Seting the pinion angle in a leaf spring stocker running CalTracs. I know Calvert wants the pinion yoke down 2 to 4 degrees.
What should the operating angle of the transmission to driveshaft be?

[garyc]

really not adjustable, all depends on height of pinion, should be "0" when pinion goes up under load??

[Mark Yacavone]

Ideally, it should be the inverse of the lower angle, but if you haven't moved anything around in a Camaro, it should be fine.

[FireSale]

Pinion angle and Caltracs has always confused me. A negative pinion angle is meant to negate axle/spring wrap under hard load, but the purpose of Caltracs is to prevent that. If you have a negative 4 degree pinion angle with Caltracs, it will remain negative 4 under load with the exception of the dime thickness racers leave as slack up front.


If I'm right, pinion angle is the relationship between the centerline of the crankshaft and the centerline of the pinion gear. It should be 0 (parallel) under load. A "nose down" pinion could wrap up to parallel with stock suspension but not with Caltracks.

[Mike Rietow]

Originally Posted by FireSale

Pinion angle and Caltracs has always confused me. A negative pinion angle is meant to negate axle/spring wrap under hard load, but the purpose of Caltracs is to prevent that. If you have a negative 4 degree pinion angle with Caltracs, it will remain negative 4 under load with the exception of the dime thickness racers leave as slack up front.


If I'm right, pinion angle is the relationship between the centerline of the crankshaft and the centerline of the pinion gear. It should be 0 (parallel) under load. A "nose down" pinion could wrap up to parallel with stock suspension but not with Caltracks.

Deflection at the drop is being accounted for. Down, with the damper fixed to the back side of the rearend gets the shaft of the damper exiting the main body of the shock/damper, which is correct also.

[rod]

the ? remains, except for you guys with mega $$ and a go pro camera mounted under the car to view movement...how do you know what the pinion is really doing. every car is different even if it is the same car [1 67 Camaro next to a duplicate 67 Camaro]
just because 1 guy says 4 degrees down tells you absolutely nothing. so the pinion is 4 degrees down, down from what, the ground?
the difference is between the pinion and the driveshaft. if the pinion is 4 down and the shaft is 4 down, then you have 8 degrees. [and y7ou could still have 0 to 1 degrees at the tailshaft] loss of hp, and a broken U-Joint in your future.
spring packs are different in stiffness. spring pads are different [most only a bit longer than housing dia. and therefore, offer very little resistance to movement]. shock position [front or rear of axle] shock stiffness [front or rear], tire size and width, tire pressure, launch RPM and launch hp,track traction and probably several more things cause pinion angle to change at launch. and how long will it stay.
all in all, be careful about making general statement about someone elses pinion angle.
Rod in AZ

[Mike Rietow]

Originally Posted by rod

the ? remains, except for you guys with mega $$ and a go pro camera mounted under the car to view movement...how do you know what the pinion is really doing. every car is different even if it is the same car [1 67 Camaro next to a duplicate 67 Camaro]
just because 1 guy says 4 degrees down tells you absolutely nothing. so the pinion is 4 degrees down, down from what, the ground?
the difference is between the pinion and the driveshaft. if the pinion is 4 down and the shaft is 4 down, then you have 8 degrees. [and y7ou could still have 0 to 1 degrees at the tailshaft] loss of hp, and a broken U-Joint in your future.
spring packs are different in stiffness. spring pads are different [most only a bit longer than housing dia. and therefore, offer very little resistance to movement]. shock position [front or rear of axle] shock stiffness [front or rear], tire size and width, tire pressure, launch RPM and launch hp,track traction and probably several more things cause pinion angle to change at launch. and how long will it stay.
all in all, be careful about making general statement about someone elses pinion angle.
Rod in AZ

The posts in here say Cal-Trac wants the pinion down 2 to 4 degree's. Down means down. That's not your pinion angle, the pinion angle is determined by the degree up or down the output, or in other words centerline of the crankshaft is adjusted.

This is where you're getting confused, Cal-Trac doesn't specify pinion angle, only they want the pinion down. This is to get the shaft of the damper exiting the shock/dampers main body with the shocks fixed on the backside of the rearend housing, at the drop.

[Gmirza]

The angle you need to be 2-4 deg. Is the one between the driveshaft and pinion. The pinion should be pointed slightly down compared to the driveshaft. This needs to be checked with the suspension at ride height.

[Gmirza]

The only way to find the perfect pinion angle would be to keep changing it and making runs until the car goes the fastest. 2-4 deg. Is a good starting point and is usually in the ballpark.

[Gmirza]

FireSale, the caltracs don’t stop the axle from rotating. The rotation of the axle creates the body separation. The bars stop the spring from wrapping up and transfers the weight to the tires. The twisting of the axle housing is the energy that makes the suspension work. It takes traction to make traction.