Fellas.. First time builder here with a question for the crowd... I recently picked up a 95 Camaro axle to put into my Model A. I didn't realize it at the time, but the U-joint connection is offset in relation to the true center of the axle by 1/2 inch. Being a highboy, I'd prefer to have the spacing between the hubs and the car equal on both sides but if I set it up that way...the driveshaft will automatically be 1/2in off centerline... I've thrown together a video on my channel to discuss this and another question I have...LINK BELOW. Looking for sage advice as to my available options. For those not into the vid option. Is there a problem having the driveshaft 'slightly' off center? Or should I maintain a straight line between the axle and the transmission output spline but adding a spacer to one of the hubs to make it visually correct (spacing) on the outside of the car? Or should I cheat the axle (left in my case) and split the 1/2 difference between true center and the offset? ***uming that it'll not be noticeable? Any info is appreciated! R/ Boxcar
No, it is often very typical on lots of factory cars & trucks....and some are much more offset than that small amount. .
Most Ford 9 inches have the pinion over to one side a little bit if they haven't been shortened or had it centered by some rodder. They are one of the go to rear ends for hot rods so they must work like that. The rear end under my A is a Bronco 9 inch. I centered the rear end housing in the frame and didn't worry about if the pinion was a little bit over to one side.
A few things to consider. Your Camaro rear end is 61" and 58" is about perfect for a model A. Your tire/ wheel combination comes into play as to the offset of the wheels and bolt hole application. I think a high boy looks kind of funny if the rear end is too wide for the body.
So there's a wheel and tire combo that I'm leaning towards that....if I've planned correctly should leave around an inch of space between the inside bulge of the tire and the side of body. It'll be a tallish combo....around 32in from the ground. That being said....I am hopeful that I've planned this out correctly because I'd tend to agree with you.... nothing worse that getting that wrong. There's a bias play lookalike called Excelsior that I'm gonna use for the car. Kinda, period looking hotrod steel rim '17in' in the back.
This is something that comes up on all rod boards about every other day because some guys about poop their pants in fear of the dreaded slightly angled off to the side driveshaft. The OMG that won't work on a hot rod but as they mentioned above every Ford with a nine inch rear left the factory with that offset outside of maybe some vans that have rear axles that have a lot of difference in length. The Camaro that that rear came out of went a lot of miles with no U joint issues that weren't caused by lack of care or a lead foot. That is something to think of . It only has to do with appearance if it can be seen standing back from the car at all or driving behind it and for that the rear end is going to have to be jacked up pretty high. As far as width it looks like you have done your homework and backspacing .
The reason the pinion is off set is to make the u joint rollers move when the driveshaft turns. It keeps the rollers from getting flat spots on them from not moving.
Just some facts The actual pinion offset of a 9" is 15/16" from the center of the carrier.. Normally, the OE engine/trans is also offset to match the pinion, or close to it. If the pinion is centered, the carrier will favor the driver's side; this can be obvious from behind, and is why many hot rods have an offset pinion, to center the carrier. There are two types of U-joint angles; single plane and compound. Single plane is when the engine/trans and pinion are in line when viewed from the top OR side, but not both. Compound is when the engine/trans and pinion are NOT in line when viewed from the top AND side. Both of these conditions ***ume the engine/trans and pinion are parallel. Normal single plane U-joint working angles are 1-3 degrees, but a compound angle needs to be calculated to make sure the working angles are not excessive. The link below should answer any questions. https://www.waterousco.com/media/wysiwyg/pdfs/content/J3311-1-DSSP.pdf
The Jalopy Journal
