Wheels hit rear caliper

[jlfernan]

Like the title says. Have some ET Wheels Halibrand replicas. 17X10.5. Had the tires mounted today and tried them on the car to see how they look and lo and behold, the rear wheels hit the caliper. I have the standard Mustang calipers that came with the kit. Using a mirror, it appears the wheel is practically sitting on the hub, but it's contacting the caliper. Besides wheel spacers any other suggestions? How much clearance is there normally between the rear wheel and caliper?

[Papa]

Like the title says. Have some ET Wheels Halibrand replicas. 17X10.5. Had the tires mounted today and tried them on the car to see how they look and lo and behold, the rear wheels hit the caliper. I have the standard Mustang calipers that came with the kit. Using a mirror, it appears the wheel is practically sitting on the hub, but it's contacting the caliper. Besides wheel spacers any other suggestions? How much clearance is there normally between the rear wheel and caliper?

What is the backspacing and offset on the ET Halibrand replicas? Here are the specs for the Factory Five 17" Halibrands:

Technical Specifications:
Wheel Set Part Number: 14865
Front Wheel Size (Diameter x width): 17"x 9"
Rear Wheel Size (Diameter x width): 17"x 10.5"
Front Wheel Backspace: 6.00" (24mm Offset)
Rear Wheel Backspace: 6.7" (27mm Offset)
Wheel Lug Pattern: Ford style 5 lug x 4.5" bolt circle
Material: Cast Aluminum
Color: Gun Metal

[jlfernan]

Their website says 6 5/8". I hate when some are fractions, others decimal. For the heck of it I put some 1/16" washers on three of the wheel studs. The passenger side seemed to clear OK, the driver side still scraped a bit.

[Papa]

Their website says 6 5/8". I hate when some are fractions, others decimal.

5/8 = 0.625, so only 0.075" difference; a little more than a 1/16" (0.0625). It could just be the design of the wheel center. Can the ET wheels be clearenced at all? I'm thinking maybe a quick hit with a file or grinder where the contact is happening. You only need to have about 1/16th of an inch between the wheel and the caliper. Also, check to be sure the calipers are centered on the rotor.

[jlfernan]

The problem as I see it is that the distance from the outside edge of the disc, the brake pad and caliper are fixed. there is no way to adjust that that I can see. Until the pads wear in and the caliper moves back, I'm stuck.

[Papa]

I would suggest these:

https://www.amazon.com/trailsport4x4...pacer+1%2F8%22

It doesn't look like my first suggestion will work based on the design of the wheel center. Just be sure you have plenty of thread showing on the studs. If not, get longer studs, too.

[GoDadGo]

If you are going to use spacers, then I would suggest using a Hubcentric Style to better distribute the load; however, they typically are 1/2" thick.

https://lmr.com/item/MM-MMWS4/1994-0...ubcentric-Pair

The big question is do you have enough clearance for our outer fender lip to clear your tires if on your body if scoot them out this far?

As Papa stated, you will need to address the wheel stud length in the process.

https://www.summitracing.com/parts/arp-100-7723

[mikeinatlanta]

I would suggest these:

https://www.amazon.com/trailsport4x4...pacer+1%2F8%22

It doesn't look like my first suggestion will work based on the design of the wheel center. Just be sure you have plenty of thread showing on the studs. If not, get longer studs, too.

Here is your answer.

[jlfernan]

Yea, I think that's the route I'm taking. I've already ordered a set. We think there's too much backspacing on these wheels which is allowing the them to hit the calipers. I'm going to order extended thread lugs for piece of mind.

[hayton55]

Does it matter if the rear axles are the FFR IRS option using the 2015 Mustang IRS? When I researched some of the links for the spacers, they made a special note about ordering 2015-2017 spacers vice 87-04…...

[chopthebass]

I had to use 1/4" wheel spacers with my 15's. I would have had the same problem with my Baer brakes. Problem solved.

[AC Bill]

It's not the backspacing. By the look of where the caliper is hitting the inner wheel spoke, it's the design of the wheel, (when used with your set up). If the spoke was cast with 3/16" less recess, it wouldn't touch at all.

[Richard Oben]

Get Cobra pads, most parts places supply GT pads and they are thicker. Or add a super small spacer or remove some material from the caliper. If it is that close it will take very little to clear. HTH, Richard.

[jlfernan]

I ended up using a 1/8" spacer and that resolved the problem. These wheels are made by Team III and if I understand basckspacing, the FFR wheels have more, which would place the wheel even closer to the caliper. I wonder if if the pads FFR are supplying now are thicker than before. I used these same wheels on my first build with no issues. With this car, I had to screw in the piston on the caliper to get the pads to slide over the disc.

[Papa]

I ended up using a 1/8" spacer and that resolved the problem. These wheels are made by Team III and if I understand basckspacing, the FFR wheels have more, which would place the wheel even closer to the caliper. I wonder if if the pads FFR are supplying now are thicker than before. I used these same wheels on my first build with no issues. With this car, I had to screw in the piston on the caliper to get the pads to slide over the disc.

Back spacing is measured from the bolt flange surface to the back outer edge of the rim. Offset is how far that same bolt flange is from the center-line of the rim. The design of the center section of the wheel compared with the width of the caliper is the issue we are seeing here, but without having the two wheels side-by-side, it's hard to say what the differences are. With a more concave design or a thinner center section, the calipers would likely clear and you wouldn't have a rub.