I just purchased my 2004 Xtype about a month ago. The guy I purchased them from said he put size 50s on the car because the 40s always looked flat. Here is spec: Bridgestone HP550 225/50R17. I hate to replace them because they only have 7K on them and the guys spent almost a grand to put them on.

The problem is that when I make a sharp turn and take off fast the tires rub. Then, the other day I pulled into a parking lot fast because of oncoming traffic, I hid a large dip line in the pavement and the car sounded like it bottomed out a little. What I found was the metal that is normally bent under the wheel well, was pulled out and I had to pay $100 to have a dent guy put it back with little evidence that it happened. That really made me upset. from what I can tell the 50s are only about 1" bigger than the 40s. How can they be rubbing? I have seen guys in the forum go from 17 wheels to 18" wheels, but they don't rub.

Help!! what should I do?

 

well first off, you should locate where your tires are rubbing. If they are at the outer part of the fender you could have your fenders shaved or rolled from a body shop. If the overall rolling diameter is just to big then you might need smaller tires. I went from a 16" wheel to an 18" wheel but the important thing is to keep the same overall rolling diameter. I was running 205/55/16 then I had to go with lower profile tires to keep the same or near the same diameter 225/40/18.

 

Jaggyx is on the money. It is very important on the X to keep rolling circumference the same on all four corners. and match the rolling circumference of the original factory tires. You can easily do that using a tire calculator like this one:

http://www.1010tires.com/TireSizeCalculator.asp

Also, is important to have front rolling circumference match the rears. If more than 15% out the ABS, traction control, etc. will interpret that as wheel slip.

On the tire rub - are the wheels stock, or aftermarket? If aftermarket, the offset sounds like it is wrong.

 

Stevetech beat me to the question about the wheels and offset. That could be your problem. I have 225/45 17's with nary a rub on aftermarket 17's.

Also from the events you describe, perhaps your shocks are shot or springs are sagging?

BTW, I just fit a set of Goodyear Eagle GT's in the size mentioned above and I'm very happy with them. Stick like glue, didn't break the bank. I'm not a Goodyear fan but I like these.

 

Thanks guys! The wheels are stock 17" 7 spoke. I just had them repainted and they are beautiful. I think they are called Caymans. So, if somebody get's 18 wheels, they just get lower profile tires?
The shocks should be find at 36K miles. I hate to get rid of the tires, they look so good on the car. But I don't want any rubbing AND I want to enjoy the sportiness of the car.
Besides the tires are quite and the previous owner paid almost a grand for them.

 

Check your inner fender liners, sometimes the edges can come loose and deflect enough to make tire contact. A few screws or even cable ties in a pinch can get the inner liner back out of the way.

Perhaps your issue with the big dip/bump was just an unfortunate situation where the road was just bad and it would have done that to any car. Even though you only have 36k mi, the car is still 6 years old, maybe it sat for awhile or it could have a leaking shock. I would at least get under there and take a peek around.

As for the 18's, yes you need to keep close to the same total overall size when you upsize a wheel, so you would get a lower profile tire to keep the diameter the same.

 

225/50/17 is about 4.5/10ths of an inch to tall. Maybe a tire shop will give you a trade in value for a set of 225/45/17s (the proper size) and you can keep your Caymens.