[Cameronluster]

I have a 1991 s10 that I order a set of rear 15x10 wheels for…..5.5 backspacing. What size tire is best to use to make sure this fits really well ? I can’t measure anything currently because I have the truck stripped down to the frame and I’m doing a lot of work to it. Just want to make sure they will fit or not so I can’t go ahead and send them back before my time is up. Pictures included.

 

[ExcellenceAuto]

The best thing you can do is set the bed on it, and hang the rear end on the springs. That will tell you if the wheels will even fit when you bolt them on.
Other than this simple mock up, you will have to rely on what others have done and kept a written record of it on the Interwebs.
Hopefully someone here will know.

 

[ericnova72]

What type of tire are you planning to use??
Drag slick, drag radial, ordinary white letter street radial, mud tire, sand tire??

Truck going to be lowered or not lowered??

 

[Cameronluster]

What type of tire are you planning to use??
Drag slick, drag radial, ordinary white letter street radial, mud tire, sand tire??

Truck going to be lowered or not lowered??

It has the Ridetech wishbone suspension installed so it’ll be lowered. Not exactly sure how much since the body isn’t on the frame but I think it’s a 2/3 lower. Now the kicker is, I’m also installing a disc brake kit on the rear end, which actually pushes out the rear wheels roughly 2.5 inches. So gotta factor that and the backspacing in.

 

[ericnova72]

Got a link to that disc brake kit??
I have never seen one that adds that much width??
Normally they add 3/8-1/2" or so per side....

they must weigh a ton to add 2-1/2" to the axle width.

If they add that much to the width of the stock S-10 2wd axle, then you are going to need more backspace on the wheels for sure.

 

[Cameronluster]

It has the Ridetech wishbone suspension installed so it’ll be lowered. Not exactly sure how much since the body isn’t on the frame but I think it’s a 2/3 lower. Now the kicker is, I’m also installing a disc brake kit on the rear end, which actually pushes out the rear wheels roughly 2.5 inches. So gotta factor that and the backspacing in.

Here’s what I have

 

[ericnova72]

I think you are misunderstanding what they mean by 2.75" offset.

That dimension is the distance from the end of the housing where the brake backing plate was bolted, to the wheel mounting face of the axle shaft.
That dimension is used to determine which caliper mounting bracket offset will hang the caliper centered over the rotor blade.....Wilwood uses different caliper bracket offsets to match common components like calipers and brake rotors to different brand axle housings.

The wheels are only going to move out by the thickness of the rotor hat, where it slips on over the lug studs.
Looks like about 3/8" per side to me, looking at the instructions PDF.

You can view all the install instructions and dimensionals from the Summit ad page at their web site.

 

[Cameronluster]

I think you are misunderstanding what they mean by 2.75" offset.

That dimension is the distance from the end of the housing where the brake backing plate was bolted, to the wheel mounting face of the axle shaft.
That dimension is used to determine which caliper mounting bracket offset will hang the caliper centered over the rotor blade.....Wilwood uses different caliper bracket offsets to match common components like calipers and brake rotors to different brand axle housings.

The wheels are only going to move out by the thickness of the rotor hat, where it slips on over the lug studs.
Looks like about 3/8" per side to me, looking at the instructions PDF.

You can view all the install instructions and dimensionals from the Summit ad page at their web site.

so as far and the wheels I have for the back, what size of tire do you recommend for it to clear the best way possible.

 

[ExcellenceAuto]

If it was mine, i would first figure out if the wheel even fits.

Then, see how much room is left over.
For example, a 275 60 15 won't hang out much past the 10 inch rim. But if you have room to spare you could stuff a 305 wide tire in there without a problem on the rim.

So it comes down to how much real estate you have to work with.

Like my cars have 275s on 8 inch wide wheels, but the tire sticks out past the actual 8 inches of wheel a little bit on each side.
So unless somebody has run your exact setup, and can say how much room you have, you need to find a couple more buddies and set that bed on the frame with a bolt or two in it.

If you see that car with tires really stuffed in there you can bet a little trial and error went into it. Or they copied someone who did it before.

 

[ericnova72]

The best bet to find the info you seek without doing a test fit of bed, wheel, and tire yourself.... is a S-10 specific forum.
I don't race an S-10, so I can't give you specific numbers.

I'm assuming there has to be an S-Truck forum on the web somewhere, these trucks are quite popular at the drag races so there should be good interest about what wheel and tire combination fits a stock width axle, frame, and bed tubs. You can then make adjustments for the brake rotor hub thickness if someone hasn't already done it. Wilwood brakes are popular, I'd think it would be a common question on an S-Truck forum.