What size wheels/tires for big brake kit?

[JWG]

I'm planning on installing a CPP big brake kit (front and rear) on my '65 C10.

What's the max width wheel and tire size I can get away with and have no rubbing?

I do plan to do the 2.5 drop spindles and would like to run 20" wheels.

Any help with tire size, wheel width and back spacing would be greatly appreciated.

Thanks!

[vin63]

There are a lot of factors involved, and some measurements are dependent on the other (e.g., backspacing relationship to width, etc.). It would be best to take measurements at ride height and at each turn lock to make sure. You can also use tools like this to help, but I've always had excellent results with a plumb bob, a square and/or straight edge, and tape measure.

[JWG]

Thanks for the information!

I'm hoping there are others that have have already done a big brake conversion that can share their wheel/tire sizes. I don't want to have to order the big brake kit, install it, then take measurements and have to order custom wheels and wait 4 weeks or more for them while my truck is sitting on jack stands useless while I wait.

Id like to be able to order wheels ahead of time and install the brake kit when I have the wheels sitting here ready to go on.

[GVDobler]

You can do all the measuring now. Check with supplier, but the big brake will probably put the WMS (wheel Mounting Surface) out about 1/2 to 3/4 inches on each side.

The backspace of the OEM rims were 3.75, so a backspace of between 4 1/4 to 4 1/2 inches would put the inside rim at the same location.

The 20 inchers you plan to use should have no issue with being able to clear the calipers of disc brakes, however the width and tire size may be an issue.

There is an excellent article in either Hot Rod or Super Chevy called " Size Does Matter" that explains it all very well. Check there websites if you don't subscribe.

There are too many variables, how lowered is it, what suspension, etc..

I would think you would want to measure for yourself before placing an order. Imagine the wait if you have to send it all back and order a different size. Restock fees??

[JWG]

You are right GVDobler, great advice. Thank you!

[GVDobler]

Take a look at this website.

https://www.rsracing.com/tech-wheel.html

The article I mentioned is "Size Matters" in the Super Chevy Sept 2014 issue.

[LVPhotos]

This is a Nitto 420S. 255/40/20. 28" tall and 10" wide. 8.5-10" rim. I run Nitto 555's 295/45/18 at 28.4 tall and 11.5 wide. Makes contact with inner tubs when there is a side to side shift if I don't air up. I would run this size tire if I had 20s and not a staggered rim/tire. My rims are 4.5" backspace with a 70-72 rear.

http://www.nittotire.com/passenger-t...ruck-suv-tire/

here is my rear tire...

[JWG]

Originally Posted by LVPhotos

rims are 4.5" backspace with a 70-72 rear.

What's the differences between my '65
Rear end and a 70-72 rear end?

[GVDobler]

Somewhere about then they widened the rear by about 1 1/2" I just can't tell you the exact year.