Rear end geometry 67-72 questions - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

VA72C10 · 10-15-2009, 03:51 PM

I appreciate that info and that will assist in the final setup once I determine ride height.

My question really relates to the physical characteristic of the rear end....it is 1" longer from the yoke to the backing plate behind the axle on the driver's side (I think) than the passenger. So since the saddles for the trailing arm are the exact same distance from the yoke, when you center the yoke, it puts the wheels off center in relation to the frame. Once you center the wheels, you end up with one U-bolt under your frame, and one next to it. Just making sure that's normal. Both rears I have (72 5 bolt and 70 6 bolt) measure the same so I assume it is...just trying to determine the factory logic behind it because it wasted 2 hours of my time trying to figure out why I couldn't center both the yoke and wheels

Twisted78SS · 10-15-2009, 04:22 PM

Now you got me wondering if mine is the same way. I'll take some measurements tonight when I get home, I have two to look at, one in a truck and one out. Maybe it will help.

fixit-p · 10-15-2009, 04:58 PM

Quote:

Originally Posted by SCOTI

This is where the 'adjustable' feature of the Super Track Bars kits SUCK. As soon as you pull the bar to re-adjst the C/L, the whole freakin thing wants to shift one way or the other & you have to struggle w/re-aligning everything again. Unless..... you use a true double adjustable PHB. Then you can establish the baseline centerline & tweak L or R w/o removing the bar.

Does anybody make those with RH and LH opposing ends? Would be sweet.

SCOTI · 10-15-2009, 05:02 PM

Quote:

Originally Posted by fixit-p

Does anybody make those with RH and LH opposing ends? Would be sweet.

Porterbuilt Streetrods (tell him I sent 'ya

).

SCOTI · 10-15-2009, 05:05 PM

Quote:

Originally Posted by VA72C10

I appreciate that info and that will assist in the final setup once I determine ride height.

My question really relates to the physical characteristic of the rear end....it is 1" longer from the yoke to the backing plate behind the axle on the driver's side (I think) than the passenger. So since the saddles for the trailing arm are the exact same distance from the yoke, when you center the yoke, it puts the wheels off center in relation to the frame. Once you center the wheels, you end up with one U-bolt under your frame, and one next to it. Just making sure that's normal. Both rears I have (72 5 bolt and 70 6 bolt) measure the same so I assume it is...just trying to determine the factory logic behind it because it wasted 2 hours of my time trying to figure out why I couldn't center both the yoke and wheels

Don't center the yoke, center the 'housing' or the pinion. I put a carpenters square @ the edge of the axle tube & flange of the housing across the rear diff cover. I square up a piece of steel on the opposite side (same location) & scribe the cover w/my C/L. Hang a plumb-bob off the frame @ the C/L off the frame rails as close as you can adjacent to the rear diff cover.

Adjust until the two marks align. You should be able to cross check the measurements to the ends of the tubes @ the backing plates.

VA72C10 · 10-15-2009, 05:34 PM

So the axle is off center? I've just never seen anyone mention that...
I double checked that I was centered by measuring from the inside of the discs to the frame and right now at my estimated ride height I am dead centered....the yoke is about 1/2" out...I figure that isn't a huge deal with a two piece driveshaft...but just wanted to make sure it was typical.

PBFAB.COM · 10-15-2009, 05:35 PM

Quote:

Originally Posted by fixit-p

Does anybody make those with RH and LH opposing ends? Would be sweet.

As SCOTI mentioned, I offer a fully adjustable PHB... that can be adjusted while ON THE TRUCK. None of the unbolting one side so you can lengthen or shorten the throw. We use a heavy duty rod-end on each side, one RH, and one LH.

SCOTI · 10-15-2009, 05:42 PM

Quote:

Originally Posted by VA72C10

So the axle is off center? I've just never seen anyone mention that...
I double checked that I was centered by measuring from the inside of the discs to the frame and right now at my estimated ride height I am dead centered....the yoke is about 1/2" out...I figure that isn't a huge deal with a two piece driveshaft...but just wanted to make sure it was typical.

I've never measured to see how much it's off..... I just make sure the truck arm pads are centered. Since they're equal-distance from the pinion housing, I've used the housing to base my measurements off.

On a 'custom' rear housing (12-bolt perf, 9", Dana, etc), for big power it might be beneficial to center the pinion/yoke.

SCOTI · 10-15-2009, 05:54 PM

Quote:

Originally Posted by porterbuilt

As SCOTI mentioned, I offer a fully adjustable PHB... that can be adjusted while ON THE TRUCK. None of the unbolting one side so you can lengthen or shorten the throw. We use a heavy duty rod-end on each side, one RH, and one LH.

It's the OK-bar

Twisted78SS · 10-15-2009, 06:04 PM

Quote:

Originally Posted by VA72C10

So the axle is off center? I've just never seen anyone mention that...
I double checked that I was centered by measuring from the inside of the discs to the frame and right now at my estimated ride height I am dead centered....the yoke is about 1/2" out...I figure that isn't a huge deal with a two piece driveshaft...but just wanted to make sure it was typical.

I think your measurement about it being off an inch to the pass side sounds just like what this guy says in his thread

Re: Rear end conversion
Ok so im really confused.. The whole rear is over to the drivers side two inchs more than the pass. side .. But the where the drive shaft conncts its it is not dead center of the axle.Its over one inch to the pass side.. Is it suppose to be centered or what?
Here is the thread - http://67-72chevytrucks.com/vboard/s...=362458&page=2

10-15-2009, 03:51 PM	#26
VA72C10 VA72C10 Join Date: Mar 2008 Location: Midlothian, VA Posts: 25,267	Re: Rear end geometry 67-72 questions I appreciate that info and that will assist in the final setup once I determine ride height. My question really relates to the physical characteristic of the rear end....it is 1" longer from the yoke to the backing plate behind the axle on the driver's side (I think) than the passenger. So since the saddles for the trailing arm are the exact same distance from the yoke, when you center the yoke, it puts the wheels off center in relation to the frame. Once you center the wheels, you end up with one U-bolt under your frame, and one next to it. Just making sure that's normal. Both rears I have (72 5 bolt and 70 6 bolt) measure the same so I assume it is...just trying to determine the factory logic behind it because it wasted 2 hours of my time trying to figure out why I couldn't center both the yoke and wheels __________________ Looking for a 67-72 swb or blazer project in or around VA.

10-15-2009, 04:22 PM	#27
Twisted78SS Wide n'Low Join Date: Jan 2007 Location: La Center, WA Posts: 1,511	Re: Rear end geometry 67-72 questions Now you got me wondering if mine is the same way. I'll take some measurements tonight when I get home, I have two to look at, one in a truck and one out. Maybe it will help. __________________ Trippin Hazard.. 67 swb, Gold Member.. 68 Suburban Air Force Retired

10-15-2009, 05:34 PM	#31
VA72C10 VA72C10 Join Date: Mar 2008 Location: Midlothian, VA Posts: 25,267	Re: Rear end geometry 67-72 questions So the axle is off center? I've just never seen anyone mention that... I double checked that I was centered by measuring from the inside of the discs to the frame and right now at my estimated ride height I am dead centered....the yoke is about 1/2" out...I figure that isn't a huge deal with a two piece driveshaft...but just wanted to make sure it was typical. __________________ Looking for a 67-72 swb or blazer project in or around VA.



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