Rear tire clearance

<table id="post8788679" class="tborder" align="center" border="0" cellpadding="6" cellspacing="0" width="100%"><tbody><tr valign="top"><td class="alt1" id="td_post_8788679" style="border-right: 1px solid #e5e5e5"> I'm narrowing a 9" Ford rear end to put under my 56 Chevy 4 dr station wagon. I'll be setting the car up with a 4 link and coilover suspension. The wheels are 12" wide x 15" with MT 16.5 x 15" cheater slicks.
How much tire clearance should I build into the car? Wheel well side and frame inside clearance as well. I'm thinking of 3 to 4" all the way around in case I ever want to change rear wheel and tires to another larger size.
Any ideas will be appreciated. I am doing all the work myself in my home shop so no issues with dealing with a 2'nd party to do the work.
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If you ask me, 4 inches to the inside of your fender lip will make it look like you narrowed the rear to much. Your tire will grow in height during the burnout but will not really get much wider on squat.
There are chassis builders on this site and they may chime in to let you know how they set theirs up. What kind of power plant do you have to need a wider tire than that anyhow ?

 

I always build the car with the wheels and tires that are being used on the vehicle, if there is likely to be an optional set of wheels you need them so as not to incure any suprises! Wayne

 

x2 on using the wheels and tires it will run during the build. since you got a 4 bar you must be using a panhard bar also, so having a bunch of extra clearance is not necessary.

 

4" is way overkill.

 

So, how much bigger of a tire might you want to move to ?
If you set it up 4" back from the fender openings it will look like ass from every angle.
You could build your wheel well 8" over size to accommodate the future wheels , that way the car wouldn't need to be touched. You'll need an even narrower rear end though.

 

If you can fit your fingers between the body and the tire, you're good.Bill ORourke from the roadster shop showed me this years ago, works.

 

Yea...4"....it'll look like one of two things -
1. The car is gonna fall over.
2. The guy that cut the rear axle housing cut too much.

Pick a wheel and tire and build to that. If you change things at a later date, then change everything required at that time.
Hell...keep a second axle housing around handy..!

Mike

 

This!!! Any more room looks like a mistake to me.

 

This what i was taught because your tire will grow in height -not width during motion, & yep, use the tires/wheels you're going to use when setting up the rear

 

If you widen the inner side of the fenderwells and extra 4" or as suggested 8", you would also have to narrow the frame and suspension points the same amount. This will adversely effect the handling unless you never plan on driving the car in anything but a straight line.
The narrower the spring base the more tippy the car will be in a turn.
To illustrate the problem grab a long steel bar and hold it very close in the center and let the ends rotate and then try to stop it. Next try it with your hands out wide.

 

I agree with the finger width or just a touch more but not much, my off topic truck is pretty close to where my fingers join my hand. The only thing you will need to worry about is getting the tire on and off, with a 4 link you should be able to drop the shock and lower it down.