Pinion Angle Question

[Pilot20]

I have a 57 Chevy that I am installing Air-Ride suspension on all corners. On the back I am also installing the 4-link AirBar system. My motor and transmission are setting at 3.5 degrees at ride height. I was planning on setting the pinion angle (front up) also at 3.5 degrees. Is this correct? Because of the low ride height, the back of the drive shaft will actually be a little higher then the front. Does this sound right? Thanks for the help.

[Vegas69]

Make sure and read the directions. I have the G bar which is the sister of the air bar. The instructions said to install it with 1 degree less angle than the drivline angle for pinioin angle change under hard acceleration. I went with .5 less since mine is driven on the street 95% of the time. So you would be at 3.5 driveline sloping down towards the rear of the car and 3.0 pinion sloping up towards the front of the car. \\ My driveshaft also slope up due to the low ride height. It's fine if your angles are correct.

[chicane]

Yes... that is fine.

Follow the linky... http://www.markwilliams.com/driveshafttech.aspx

[PRRC]

Yep, You will be fine. A Lot of the cars we set up the rear end is a little higher than the trans.

[Pilot20]

Thanks. I just wanted to make sure before welding everything up.

[The WidowMaker]

ive got to disagree again. if your pinion is higher, you want to point it down. you cant go off of what you have at your tranny, without measuring all of your working angles. if you have 3.5* down at the tranny, and now your DS points up towards the rear, you now have a WA of greater than 3.5*. check the specs on your u-joints, but most want an angle as close to 1* as possible (without going below), and no more than .5* difference btwn WA's.

for YEARS!!! its been common to match the pinion to the tranny ( \-\ ), but especially with your pinion being higher, you need to be like this ( \_/ ).

you could also raise the rear of you tranny to make its angle less. this would also lower your WA's.

check out this site. it lists the commonly accepted driveline configurations, and (third down) lists your up, down, up configuration as one of the unacceptable.

http://www.vibratesoftware.com/html_...igurations.htm

Tim

[chicane]

Uhm...gee. I dont know about that. Agree to disagree then. My fourty+ year old F-body was shipped from the factory with a -4* powertrain and a +4* pinion... creating the null that cancels the working angle and maintains the "equal and opposite" theory that you dispute.

Just looking at that site and it's intripritation of any and all "one piece" prop shaft configurations basically it states that all of the OEM manufacturers for the last... uhmm I dont know, 60+ years... are wrong ??

Transmission Angle Propshaft Angle Rear Pinion Angle
UP UP UP
UP UP DOWN
UP DOWN UP
UP DOWN DOWN
DOWN UP UP
DOWN UP DOWN
DOWN DOWN UP
DOWN DOWN DOWN

I dont think so.

There is a general misunderstanding about "dropping the pinion down" several degrees. This is a practice that could be applied only to leaf spring cars without any traction control devices where springs can “wrap” and change pinion angle. This practice would not apply to 4-link, ladder bar or torque arm or high rate leaf spring equipped cars that have the ability to control the IC. Failure to maintain matched and minimum operating angles increase erratic non-uniform output velocity from the drive shaft to the differential.

[BBC69Camaro]

I'm certainly just a beginner, but what I was taught in my Suspension class was that you didn't want the driveshaft perfectly straight (0deg working angle). That was because the needle bearings inside the bearing cap need some force to rotate. Without rotation they can exert a constant force in one spot and cause damage to the bearing journal.

Least that is what I have in my notes. Is this not a valid concern? (trying to learn here).

[LateNight72]

Originally Posted by BBC69Camaro

Least that is what I have in my notes. Is this not a valid concern? (trying to learn here).

Yes it is a concern. And why drive shafts are never designed to be perfectly straight.

[Vegas69]

The driveshaft can be level but you must have a working angle at both joints. (The driveshaft can't be on the same plane as the pinion or output shaft)