Wormhole

How many people run this setup? Do you feel it's pushing the limit with the larger tire? Do they bulge too much? This would be with a race tire.

Any feedback is appreciated.

red9four4

i would think thats about the limit

Danno

The distorted tread won't help much over a narrower tire. My 255/40-17 tire on 17x10.5" rim sticks much, much better than my sorry attempt at a 275/40-17 on a 17x9.5" rim. The 275/40-17 has moved onto a 17x11.5" wheel and gets the best support possible. Remember bigger needs more support...

Jfrahm

I have 9" Design 90's on the back of my cabrio with the stock 245 tire size. The rim lip sticks out too much, just like 225's on 8" D90's. This leads to curb damage. I have a pair of 255's in the garage but I was thinking of going to 265's instead, but I think 265's would be pushing it. I think 275's would be too wide for the rim, but that really depends on the manufacturer as section width varies.

-Joel.

Luke

I would think a 265 would be nice. Most of us wear 245/45's on 8" wheels, and there are roughly 25mm in an " .... so if you gain an inch of wheel width, i would think 20mm +/- a couple would sit nicely.

Z-man

According to a recent tri-region tire tech (Michelin Pilot Sport Cups were discussed by a Michelin rep), it's all about maxing out your rim width. IE: if you have 8' rims, 245's are the biggest you can fit. If you have 9's, go with the 275's.

Maxing out the rim will mean the tire has a slight 'trapezoidal' shape, which will enable greater spread of the tread. See discussion on the Racing/DE forums regarding this: Stefang explains it better than I do:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=10;t=000943" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=10;t=000943</a>

Mike Buck

Also remember, width has a lot to do with the specific brand of tire you are looking at. For example, a "225" yokohama will be just as wide as a "245" Toyo. Look at the specs TireRack gives on their site and you'll see what I mean. What you need to find is a "wide" 245 tire for a 9" rim.

Wormhole

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">According to a recent tri-region tire tech (Michelin Pilot Sport Cups were discussed by a Michelin rep), it's all about maxing out your rim width. IE: if you have 8' rims, 245's are the biggest you can fit. If you have 9's, go with the 275's. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I was considering going to the tire tech, but thought it would turn out to be a Michelin promo, but now I wish I had.

From what I have gathered so far, mounting a wider tire will not necessarily yield more traction, on the same size rim. Tire Rack explains a tire mounted on a narrow rim would be narrower than if the same size tire were mounted on a wide rim.
As Z-man pointed out the trapezoidal shape will produce as much contact patch. And obviously lower weight and better sidewall stability, then a wider tire that bulges.

Also interesting, a larger wheel requires a larger rim width for the same tire size. Danno’s example somewhat illustrates that with his 17’s, and lower aspect ratio. A 15X6 and 18X8 can both run 225’s as an industry standard.
Tire rack refers to the industry standard as the “Measuring Rim Width” to meet dimensional targets. All of their calculations are based on the measuring rim width, which makes it difficult to see how changes in tire section width would change from rim width, relative to the tire manufacturer.

I’m probably going to stick with the manufactures recommendations. In this case 265 for a measuring rim width of 16X9.

Thanks for all the help.

DangerIsland

Danno: what are your thoughts on going beyond 275 on an 11" rim? This would be for street use. Any benefit at all?