Technical Center rear pumpkin on open wheeled car?

Guys,
Do you prefer to center your rear diff? ie cut one side down?

or if you have something close like a mustang 8" or bronco 9" just roll with it? have it offset?

Like a channeled A coupe?

Curious thanks!

 

Does it need to fit in the middle of the A spring arch?

 

Depends. Can it be seen easily from behind? If it is on display, I would run it centered.
An offset center section takes care of uni operating angle.

 

There isn't a lot of room under a Model A. I had my housing centered so the driveline was straight and I had room for an exhaust system.

 

Nope, never centered them. Neither under my 65 Lemans and not under my 31'tudor.

Never did it for a customer either. Always did an even cut off of both axles....


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No.

 

Then it shouldn’t matter as no one will ever be able to see it.

 

The old pumpkin centered VS pinion centered debate. For a short wheelbase car like a Model A I would go pinion centered if you plan to actually drive it. If it's an trailer queen show car center the pumpkin

 

Depend on the vehicle. Last two hiboys I centered the pumpkin, otherwise I center the pinion.

 

It rather deepens on if you are anal about the drive shaft being straight and centered or want the pumpkin centered as viewed from the rear. I could give a shit about the driveshaft being exactly straight because they have run at and angle on every Ford with a nine inch since 1957. ON the other hand not having the pumpkin centered when looking from the rear looks like hell warmed over.

I've had guys claim that the U joints will wear more on a driveshaft that runs angled to the pinion along with it's normal angle up and down but don't remember replacing more U joints in Ford than cars with the pinion centered in the years I turned wrenches for a living.

 

^^^ agree a 100%^^^

The u-joint doesn't care about where the angle is, whether it's to the side, up or down as in pinion angle etc.

That angle has been built into ford's for ever and I've seen plenty of them that had been over 100 mph and that driveshaft angle never caused vibration problems nor ever added to u-joint wear.

It's strictly a "looks" kind of thing or it makes the driveshaft tunnel easier to build...


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It seems to me that I remember reading that the U joint is good for one angle, up and down or side to side other than that you should have a CV joint. The pinion should be centered behind the transmission.

 

Looks better centered when used with a transverse leaf spring.

 

Whether the driveline is centered or not , there's only ONE driveline functional angle .

 

U-joints don't care about how many angles.

Ford has proved that for over 60 yrs. Behind manuals, automatics, 150 horse to over 400 horse.

There is tons of machinery out there in the world today and all over the world that have u-joints running at different angles with no problems. Sorry but to me these are just old wives tales.....

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No.

 

And that is a continuously changing compound angle.

 

Try to think 3-dimensionally instead of sticking with 2 ( plane vs solid geometry )

 

XKE Jags have their pinion offset to one side from the factory.

 

How low will the car be? If it will have a tunnel for the driveshaft, it will need to be centered. Or the tunnel will have to be at an angle. That will impact seating on a super low car.

 

Put a quick change rear axle in it, and the driveshaft will be centered...

 

Mock it up, center the housing, lay plastic pipe to mimic a drive shaft, any issue with up/down travel? If so then center the pinion

 

I can't quite see how there is a third dimension involved.

 

For those that think angles don't matter...maybe this will help.
Very good short video of what really happens.

Drive shaft velocity