I had the Roush 18x10 wheels all the way around with 275/40/18 wheels.

One of my wheels got bent and instead of replacing one Roush I plan on replacing all four wheels with a cheaper brand so I can avoid the expense of having to replace another Roush wheel down the road.

Now comes the delimma. I have heard of problems with Mustangs that have 18x10 wheels rubbing BADLY.
Mine did NOT do this but I know that I am going to have to be careful not to run into this problem.

So my question is this. With this size tire: 275/40ZR18.
What is a good size wheel to put on the back and front?
Keep in mind I don't really want to stagger them.
I do not mind getting a smaller wheel but I still want 18's.
What would be a good 18 to fit on these tires? and what offset and backspacing would I need?

If I do get 18x10's all the way around again... I do realize I will have to get the same offset on the wheels. But will I have to get the same backspacing as well? If so I am in trouble because I called ROUSH and they said they did not know... and could not get the backspacing for this wheel.

 

That is bizarre that they would say this. I'm suspecting either an inexperienced tech or just lousy customer service.

Backspacing is a function of offset and wheel width. There's no reason the tech should have said "I don't know." Two wheels of the same width with the same offset will have virtually identical backspacing. The only variable should be the construction of the wheel lip, but that's not going to change offset figures by much.

Here's a nice conversion calculator that graphically demonstrates changes on wheel/tire parameters. If you punch in an 18"x10" wheel with the Roush offset, it will give you backspacing. You could also just measure (or confirm) it with the wheel you have off (it is off?). http://www.wheelsmaster.com/rt_specs.jsp

Best,
-j

 

Post #26


Norm

 

So I take it I could go with a 18x9.5 as long as I had a 45mm offset.

What about a 18x9? Would that fit this size tire or no? If so what kind of offset would I need for it?

 

I'm running 275's on 18x9's. They fit, but feel kind of mushy in the corners. If I was to do it over again, I'd do 275/40/18's on 18x9.5's or 285/40/18's on 18x10's. Both would give enough sidewall support while allowing plenty of grip

 

I'm running 285/40/18 in the summer on 18 x9.5 45 mm offset rims front and rear. No rubbing before the car was lowered. Slight rubbing on the left front on full lock after lowering.

 

I too am running 275/40/18s on 9.5 and I'm lowered and have no scrubbing issues. I drove on a very curvy road in eastern N.C. a couple of weeks ago and the cornering was fantastic.

 

285/35/19 on 19x10 +50 front and rear here. No rubbing anywhere, but not lowered. YET.

 

The biggest tires I've ever seen installed on all four corners were 305s on a FR500C on display.

I can't remember the aspect ratio but they looked awesome!

 

There's a guy that posted in the appearance section a while back that has 295 section tires on 22" rims up front with no rubbing. He's at stock height, though.