What width rear end should I buy? 65 Lemans
 

Hey, guys
I have read a lot about the stock widths for the 65 but since I wasn't ready to upgrade I didn't pay attention. But, now I am ready and I have questions. So I am now running a stroked 461 and a 4L60 and a open rear end out of an Olds that has to go! What rear end width and tire/rim combo will get me the most traction? Should I go with a narrower then stock rear? If so what rim offset and back space is going to get me that traction? Or just go with the stock dimensions?

Personally when in your situation I buy the wheels I want and then mock them up under the car with tires mounted and order the the axle to fit that measurement.

There too many wheels out there that have limited offset options to go with someone else's axle measurements. Unless you're going to put the exact same wheels on the exact same year of car you may find what worked for another person won't work for you.

Definitely buy the wheels and tires first and then have the rear end made to the proper width as mentioned above.

You can always buy the wheels first and then bolt them onto your current rear end to give you a better perspective of what needs to be done to center the wheel inside the wheel wells. Of course have the cars full weight on the suspension when you’re doing the measurements.

A 275/60-15 tire on an 8” wide wheel is about the limit here and you really have to be on your game to stuff them in without rubbing.

This thread may be helpful, 1964 & 1965 are the same when it comes to wheel and tire fitment:

https://forums.maxperformanceinc.com...d.php?t=526735

When I purchased my 65 GTO it had the factory rear with stock Ralley I wheels. After measuring I decided on an aftermarket wheel 15 x 8 with a 5” backspace and 275 60/15 tires. The wheels fit nicely in the wheel wells. When the time comes for an upgrade I’m going with a Moser 12 bolt rear at the factory 65 width. If I ever want to put the Ralley I rims for whatever reason I know they will fit like stock. The trick is to find a wheel you like in the offset you need.

Thanks guys, great info here. I have another question, If I had the rear end made 1 inch narrower then stock the 4.5 inch backspaced rims would do the trick, right? I ask because there seems to be a bit more of selection for that backspacing.

This is my experience with a '65 using a 1969 Chevy 12-bolt from a Chevelle. I used a 8" rim with a 5" backspace with 275/60-15 tires.

Probably so.

But buy the wheels then use them to measure before buying your rear end.

Understood B-Man, I appreciate the info!

To roll around the shop my 65 has 275/60-15s on 81 Turbo 15/8 wheels . Pretty tight inner and outer. About a 4.5 back space. Stock width rear.

Skip,
Would a 1 inch narrower make your situation better?

So here’s two different guys saying 5 inch and about 4-1/2” backspace.

From what I’ve experienced 5” would be the number.

So this is exactly why you simply can’t trust anyone’s measurements but your own. :)

Out of curiosity, what style of wheel are you looking for? There are lots of companies that offer a 5” backspace.

On my '67 the magic number was 5.25" to exactly center the wheel with the stock '67 rear that is 1" wider than the early rearend. "If" your '65 just happens to have the same dimensions as my '67, then you would allow for the 1/2" per side shorter rear and end up with 4.75" backspace to center the wheel (5.25 - .5 = 4.75).

When I replaced the rear axle with a Strange Dana 60 I didn't want to buy new custom wheels so ended up sticking with the stock '67 width rearend so it would fit the 5.25" backspaced wheels already on the car.

So like the above advice, I matched the new rearend to the wheels.

No a rolled fender lip and a fatter wheel well like a mini tub! My 64 Impala is even tighter on the same sized tire-it needed zero offset wheels, they won't fit at all on the GTO.

I kinda like the Pontiac rallye wheels, and the old Cragar's but I've seen a lot of others I am warming to. Is there anything resembling the Rallye with a 5 inch back space?

Wheel Vintiques offers custom backspacing

I'm looking at them just now.

American Racing also has a "Rally II" wheel (custom 500)and you can get custom backspacing. Not cheap.

That was the point of this thread. I am buying a rear end from Quick Performance and I can get what ever width I want. So, if I cant get the right rim with the back space I need or if it costs a fortune then I can just order a rear end with the width I need.