Can a rim using 215's take 225's?

[N-Wing]

I have TSW Nurburgring wheels. The fronts have 215/35 R18's on them. Can I put 225/35 R18's on them?


I ask because my the front tires seems a bit too "thin" such that the rim sticks out just a bit (1/8th inch maybe). The rim is 8" by measurement but offset explained to me at purchase was 18x7.5 w/45. I'm not concerned with performance just the look. I get just a little bit of rubbing if I am turning sharp and hit a bump. Basically none. The car was lowered when I bought it, I believe Bilstiens with Tein springs for a .7" front drop and 1" rear drop.

Thoughts?

 

[docjohn]

I run 235 40 on my front track set on a 7.5 inch wheel.

 

[RYU]

Often times on the NSX issues arise more from tire height secondary to tire width.

I run 215 on the street. 235 for aggressive driving.

 

[docjohn]

ahh I just realized you are talking 18 inch...the wheel will hold the tire but as to rub with a 225/35/18 .....depends on more variables,like wheel type and et.

 

[RYU]

oops on my part too! docjohn and I are really just trying to pad our post counts...

There's a great thread Billy J started on oversized 18 wheels and 225.

 

[N-Wing]

Thanks. I will search for that thread. The wheel is flush so I suspect the width may be ok. Height will remain the same I presume with the same R and the same sidewall percent (I think that's how the numbers work).

 

[nsxtasy]

The fronts have 215/35 R18's on them. Can I put 225/35 R18's on them?

It depends on the tire and on the width of the wheel. Almost all tire manufacturers publish specs, including a range of approved rim widths. You can find these on the tire manufacturer's website and/or the website of tire dealers such as the Tire Rack. For example, as noted on the Tire Rack website, the 215/35-18 size of the Yokohama S.drive is approved by Yokohama for mounting on rims 7.0-8.5" wide, whereas the 225/35-18 size is approved for rims 7.5-9.0" wide. So either size tire can be mounted on rims 7.5-8.5" wide; only 215/35 should be mounted on 18x7, and only 225/35 should be mounted on 18x9.

The width is important because if a tire is mounted on a rim that is wider or narrower than the tire manufacturer's specs, excessive stress and heat can build up in the tire sidewall, possibly leading to a failure (blowout, etc).

The rim is 8" by measurement but offset explained to me at purchase was 18x7.5 w/45.

It sounds like perhaps you are measuring the width based on the outer dimensions. When a rim is specified as 18x7.5, that means it is 7.5" wide at the bead (where the inside edge of the tire sits), as illustrated below. So it is wider than that at the outer edges, typically by anywhere from half an inch to well over an inch. So you might find that the outer dimensions of an 18x7.5 wheel are 8" or more, but it's still considered an 18x7.5 rim, and 7.5" is the width that applies to the manufacturer's spec for approved rim widths. Hope that makes sense.

I get just a little bit of rubbing if I am turning sharp and hit a bump.

If you get a little bit of rubbing with a 215/35-18 tire, you're going to get a lot more with a 225/35-18 tire. Which, along with possible TCS problems, is why most NSXers don't use that front size, except perhaps for track tires (since you don't usually turn the steering wheel to full lock when you're on the racetrack).

 

[Hapa88]

Thanks. I will search for that thread. The wheel is flush so I suspect the width may be ok. Height will remain the same I presume with the same R and the same sidewall percent (I think that's how the numbers work).

No, you're actually incorrect here. The height will increase and overall tire diameter will increase. Basically the entire tire is bigger in every way (width & height). That's because the aspect ratio is a percentage of the width and that represents the sidewall height in millimeters.
215 width * 35% aspect ratio = 75.25 mm sidewall height
225 width * 35% aspect ratio = 78.75 mm sidewall height

This is an awesome calculator to help you see the differences:
http://www.rimsntires.com/specspro.jsp

 

[N-Wing]

The rubbing I get is only up and down, not side to side. I think the car might be able to handle the 225 width but I don't want to effect the tire height (and TCS). In the end, I stuck with the 215's. Wheels are being refinished as we speak. Then we will see what the new sneaks look like.