I'm hoping someone can help me sort out my backspacing confusion.

Here's the deal, I have a MII front suspension with a 60" hub to hub measurement. I have an Explorer rear with a 59-1/2" hub to hub measurement.

In a perfect world, if I go with a 8" wide rim, what should my backspacing be for both the front and rear? How about if I go with 9" wide wheels? Will 9" wide wheels even fit up front? How much room should I leave myself between the wheel lip and the fender lip?

Since I'm not made of money and I can't afford to have custom wheels made, I'm going to have to "make up the difference" with wheel spacers in the rear.

Please enlighten me with you experiences so I can sort this out.

Thanks for your help - Brad

 

Brad,

Only you can determine how much back space you need on your wheels. Depending on how low your truck is the backspace can vary. On a higher truck the wheels can be spaced out closer to the fender edge instead of going up under the fender. In my own opinion, tires and wheels look better brought out close to the edge of the fender, but not past. And be careful here, because when you add a tire the bulge of the tire will protrude some past the wheel edge. This is my personal opinion. but I don't like wide wheels on the front because it makes the truck steer harder and they try to steer themselves on some of those highways where the big trucks have created ruts in the asphalt, so I never use more than a 7 inch wide wheel up front.

This is how I usually go about determining wheel spacing. I have about 12 different wheels of varying width and pattern stored in my garage. I find one that fits the pattern and is the closest to the width I want. Then I use that for my benchmark to determine exactly what I need. I measure the spacing on the wheel both front and back and go from there. You may not have 12 wheels in your garage, but surely you must have some wheels to start with. Just pick one...hope this helps.

Vern

 

svooom-
I've been told to allow min. of 1/2" between the tire and both the bed side panel and the fender lip. That seems to be cutting it pretty close to me. On the rear of my 56 I have 6" from the wheel mounting surface to the bed side panel and 5" from the mounting surface to the fender lip or a total of 11". If I leave 3/4" clearance on each side I can go with a 9 1/2" wide tire and either a 7" or 8" wheel width. Assuming I use an 8" wheel I will have 3/4" of tire past my rim (9 1/2"-8"/2). So my backspace can be calculated by taking the 6" dim from the mounting surface to the bed side panel and subtracting the 3/4" min clearance and the 3/4" of tire past the rim to equal a 4 1/2" backspace (mounting surface to back edge of rim). This probably is as clear as mud. You might try some of the wheel manufacturers websites (www.billetspecialties.com) as many of them have diagrams of how to figure backspacing. Also the tire manufacturers websites have tire profile dimensions. Hope I haven't confused you more. Good luck. 56Fun

 

The rearend article at the top says you need 3.5" or less backspacing. That is cutting it close on my 1950 F-3. There might have 0.5" clearance between the inner wheel well and the P215/70R15 tire mounted on a 6" wide wheel with a 3.5" backspacing. The only reason I have this particular wheel is because it is what was available at the salvage yard. I am going to use a 3.25" backspacing on the rear for piece of mind. I think I will keep that tire and backspacing for the front and use one of the rear wheels as a spare.

 

I was going to post the same question "How to figure backspacing...etc" until I read this post. My question would be 'Is there an industry standard in manufacturing wheels with various back spacing, that is, are they made in 1" increments or 1/2" - such as 3", 3 1/2", and so forth.

 

Gramps,

Yes, but depending on the width of the wheels there is a minimum and maximum backspace. When I bought a set of wheels from Pete Paulsen a few years ago, I found that I could not get exactly the backspacing I wanted. I ended up with a compromise. As I remember, the minimum allowable spacing to the front was two inches, so the maximum backspace on a six inch wheel would be 4 inches. And, remember a six inch wheel is really seven inches wide from lip to lip. The measured width is from bead-to-bead and does not include the 1/2 inch lip on either side. I learned this the hard way...

Vern

 

My 56 has an MII IFS and a 59-9" rear end. My rims are 8" wide with 3.25 backspace on the front and 9.5 wide with 3.0 backspace on the rear. I have about 1" clearance from the inside wall of the tire to the bed wall in the rear. and the front turns lock to lock with no clearance issues.
I think you can go with 3.25 backspace on 8" rims for both front and rear. You'll like the alignment of the tire outer wall and the fender skirts too.
Hope this helps.

 

Good information - thanks for the reply.

Grumpy-

 

Brad

Avoid spacers if at all possible. They are dangerous in my opinion. I've seen them work loose too many times. Wheels that need a babysitter is not a good thing.

 

I ASSUME THAT IF THE ORIGINAL REAR IS ABOUT 61 1/2" THAT I WOULD WANT TO REDUCE THE BACKSPACING APPROX. 3/4" FROM WHAT YOU HAVE TO ACHIEVE SIMILAR CLEARANCE THAT YOU STATE ABOVE. CORRECT? DID YOUR "59-9" REALLY MEAN 59 1/2? OR?

 

I think He meant he has a 1959 9" rear end, presumably from a truck to retain the 5 on 5 1/2" wheel pattern

???

Glack

 

That makes sense!!
Grumpy (getting senile I guess)