And they use thicker rims to handle the torque and flexing too! I've seen tires that were on wheels with extreme offsets, and they often wear funny and cup the tread.

 

Hi, therefore you recommend me NOT to narrow the rear end due to extra wear on the ring and pinion, bearings and studs and I should stay with the stock length.

The current tyres installed on the camaro measure 255/60/15. The overall wheel width is close to 11" (10" width). There is 4" back space and 7" front space. With this backspacing, the wheel sits approx 1/2" out from the fender lip.

Perhaps I need the tyre to fit under the inner fender lips and not as it is, when I order the new wheels, I have to increase the backspace say to 5" (will calculate this exactly later on)

The planned 295/35/18 will be installed on an 11" width wheel (over all wheel width close to 12 inch). If my calculations are correct, the new wheel B/S needs to be close to 6 - 6.5". This will leave 5.5" - 6" dish.

Do you agree? Or is there other methods?

 

The width of the rear axle has nothing to do with bearing wear or failure. It's the amount of BS your wheels have that will determine bearing life, and as Damon mentioned the extreme BS are prone to cause early bearing failure, not the axle width.

 

Like I mentioned before. I have 5.75" of BS. No more will fit. A 10" wheel will fit a 3)295 much better than an 11". I don't know where your numbers came from but my nittos have a12.6" section width. They are 315's. So all I'm saying is use a 10" wheel. The bs will never be 6" or more unless you cut something. The be should still be 5.75". Then you have 4 or so inches to tuck under the wheel lip. It will fit just right.

 

Ok, now I am getting the picture. The less the BS (the larger the negative offset) the more the bearing wear / early bearing failure.

 

Hi Damon,

You have 315/30/17 Nitto N'555's with a cross section of 12.6"
Mine planned 295/35/18 Toyo Proxes T1-R with a cross section of 11.6" (if Toyo are good tyres)

Questions:-
For what reason a 10" wheel will fit a 295 much better than an 11"?
What width is your rim?
Is it possible to post some pictures of your rear wheel and tyre and how it sits in the fender so I can see it?
Cheers

 

Hi guys. Done some research on pinion angle set up. Does any one know how much it should be on 78 camaro. From what I read, the pinion angle may vary if using leaf springs or 4 link.
My question is here. To find the correct pinion angle, you need to have the rear end, the engine and transmission in place. So, if the rear end will come without mounting perches installed, what should be the angle between the axle pinion axis and the mounting perches?

Has anyone did this before? Just for my knowledge.

 

You can't preset pinion angle. As you mentioned it all needs to be together and weigh what it will when done. Pinion angle on a rear axle with perches is set by determining trans angle, and stance of the car. Once you know those, the pinion has to be the same angle as the trans so the driveline wont have vibration. If the two angles don't match, then one U joint will create a vibration from turning at a different speed than the other. If the trans is down 3 degrees, then the pinion needs to be up 3 degrees.
Since you're planning on purchasing a 4 link, I would assume it's fully adjustable. You don't need to set pinion angle until you put it under the car, and then you can adjust the link ends to set the angle.
When I install a rear axle with leaf springs, I bolt it all together without welding the spring perches. Once I have everything mocked up, I check the transmission angle, and then set the pinion angle, plus center the axle. Then I tack weld the perches and drop the axle out to do the final welding.
Here's a great video that will entertain and inform you!

 

Great video Val. I was aways taught to get them withing 3*. I understand the video totally but from what your saying you point the tail shaft right at the pinion? There has to be some angularity or the bearings in the U Joints will burn up, at least thats what I've read for years now. But now seeing what is really happening I would think they wouldnt burn due to suspension travel. This is all VERY important to me right now. My T56 has .50:1 final drive. That is spinning the drive shaft at twice the engine speed. Not saying I'll ever see 6500 rpm in 6th gear but if I did the drive shaft has to be spot on at 13,000 rpm. Mine will certainly come from a reputable driveshaft shop. This is one I am too worried to do myself. I know I could make one but balance and driveline angle are gonna be important.

When it comes to driveline Clacia, this is where it pays to read as much as you can. I have had some scares at the track. A buddy snapped a shaft about 12" from the trans and it beat that car so bad. The trans case was shattered. The floor pan had LONG slices in it. But the worst is the cloud of smoke and dust that went in the air. We were at the starting line. This happened at about 1000ft. We were in a panic that it flipped at full speed. If there hant been a safety loop it would have turned into a tragedy.

 

No Damon, you do not point the tailshaft right at the pinion. Only way that would work is if the pinion was also pointed right at the tailshaft so they had no driveline angle at the U joints. The 3 degree thing is for U joint lubrication, and it can vary more or less than 3 degrees. If there was no angle the U joint wouldn't do anything but spin, and never have any movement to keep the needle bearings moving, other than the occasional suspension change.
The key is in matching ends, so if your transmission is 4 degrees to the driveline, then the pinion needs to be 4 degrees to the driveline. Whatever angle one end is to the driveline, the other needs to be the same to cancel out the inherent vibration. In my Falcon I had to get creative when setting pinion angle, as the Explorer rear axle is an offset pinion. It required me to point the pinion right at the tailshaft because the offset made the angle 3-4 degrees to the right, so if I also made it 3-4 degrees down it would total twice the angle, and create huge vibration issues.