Roys07GT

Having an issue with both rear tires rubbing after Cobra Jet Drag Spring installation, running Race Star 15x8 with Mickey Thompson 275/60/15 drag radials. It's fine just driving around, it's when launching at the drag strip, I can see marks on both tires from hitting the fenders.

This is not a daily driver, drive 8 miles 1 way to the track and the occasional local car show.

I have done some research but not much out there, anyone else have this setup? Anyone experience a similar issue and get a resolution? I can try a shorter tire but don't want to invest if the issue will just continue.

Norm Peterson

Got pictures? Sounds like the wheels have the wrong offset if both fenders are getting hit.


Still on the stock rear springs and shocks?


Norm

Roys07GT

The wheels are RaceStar 15x8 direct drill, specifically for Mustangs, although the tires do stick out slightly.

CobraJet Drag Springs and new OEM rear shocks installed this spring. That's the last change and the reason for the rubbing. When launching at the Drag Strip it's rubbing.

Couple pictures:

Norm Peterson

Drilled for what year(s) of Mustang? This matters, as the OE offsets for the SN95 wheels are significantly lower than the OE offsets for the S197. SN95 wheels on an S197 will make the tires crowd the sheetmetal on both sides.


If these are your wheels
http://www.americanmuscle.com/racestar-15x8-0511.html
then the offset is only +19, which is a small offset even for the SN95's.

My 18 x 11 wheels (not the tires) hardly stick out as far as yours. Even though they're three whole inches wider. FWIW, I get zero rubbing (285/35's).






Norm

Roys07GT

Those are the Wheels. I contacted AM yesterday via web chat, they haven't heard of anyone having this issue. I guess it's time to invest in some better quality Wheels. I may try the Mickey's P275/50R15, they are a little shorter, to see if this helps in the short term.

I really appreciate your feedback Norm!

Roys07GT

The resolution was basically to ditch the 15x8 Race Star wheels in favor of the 15x10 wheels. As Norm had stated it was the back spacing or offset that was causing them to stick out.

For reference so anyone else looking into this setup here are the parts that are working (Copy & Paste from Summit orders):
RCE-92-510154DP - 15x10 Race Star Wheels
SDA-555-8114 - Steeda Rear Sway Bar relocation brackets (so the 15x10 fit)
FMS-M-5300-RA - Cobra Jet Springs
MTT-3754R - Mickey Thompson ET Street Radials (they fit the 10" wide wheels no worries)

Scott2

Glad you got it figured out!

You may want to consider 3" studs?

I was able to stuff 325/50/15 MT ET Street Radials on my car with 10x15 Race Stars with a little smoke and mirrors (shortened differential) shown here aired out.