Plus size 17" rear tires?

[truegearhead]

Is anyone running wider tires then stock on there 17" twist wheels? I''d like to go to a 265 or something but I don't want to rub.

[Burg Boxster]

I guess the first question would be why? Great deal on tires? Look? or???

Plus sizing in front helps reduce understeer... plus sizing rears will increase understeer (not a desirable thing).

To answer your question though, I don't recall knowing anyone who plus sized the rears for everyday driving. Maybe all around (along w/ fronts) but not rears alone.

[DenverSteve]

Plus sizing generally has more negatives than positives. If you want wider, get new wheels and tires. Otherwise you'll likely spend more money in the long run by wearing out your tires quicker on the stock wheels.

[stephen wilson]

The tire manufacturer will list the recommended wheel widths for a given tire size. I would stay within this range. Whether they rub or not will depend on your wheel offset.

[Pat]

Originally Posted by DenverSteve

Plus sizing generally has more negatives than positives. If you want wider, get new wheels and tires. Otherwise you'll likely spend more money in the long run by wearing out your tires quicker on the stock wheels.

Why would they wear quicker?

[truegearhead]

Wow, I underestimated you all's sensibility. I'll let you know how it goes.

[DenverSteve]

Originally Posted by Pat

Why would they wear quicker?

Tires will cup or bulge if they are too wide or narrow for a wheel. As stated above, tire/wheel sizes are optimized and some deviation is acceptable too much will cause too rapid, and or, uneven wear. Both of which prematurely wear the tires and effect handling.

[Pat]

I agree 100% with that, Steve. However adding just 2 cm to the section width shouldn't be too big of a difference, should it? I realize it may not be ideal, but I doubt it'll really wear that unevenly assuming proper pressure and alignment.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=198

[Topless]

A 285 will fit in the wheel well without rubbing but you will need a 9.5" wide wheel and careful offset/spacer planning. Stock 8.5" rims are essentially maxed out with 255 tires.
http://www.tirerack.com/tires/tires.jsp?tireMake=Kumho&tireModel=Ecsta+XS&sidewall=Blackwall&partnum=84WR7EXS&tab=Specs

[Pat]

Good to know, thanks.

[truegearhead]

Originally Posted by Topless

A 285 will fit in the wheel well without rubbing but you will need a 9.5" wide wheel and careful offset/spacer planning. Stock 8.5" rims are essentially maxed out with 255 tires.
http://www.tirerack.com/tires/tires.jsp?tireMake=Kumho&tireModel=Ecsta+XS&sidewall=Blackwall&partnum=84WR7EXS&tab=Specs

So is it the inside of the wheel well that will rub because it looks like there is plenty of room on the out side

[ReallyDirtyThirty]

I guess the first question would be why?

Because racecar...

[DenverSteve]

If you're worried about inner rubbing, use spacers.

[jmatta]

I have 10" rears et47 with 265/35/18 (no spacer) and needed to tie back the e-brake cable to avoid rubbing. I can mount a 285 on the wheel, but would likely need a spacer to clear the inside strut, so to answer your question; yes, it would rub on the inside.

To the original question; I suppose you have 255/40s presently? Mounting a 265/40 is going to create a taller tire and if you mount a 265/35 on a 17" rim, you will have a shorter tire.

Stick with OEM sizing...

[thstone]

On my stock 17" wheels, I run wider in the fronts (225/45/17 vs stock 205/50/17) in order to reduce understeer and improve initial cornering bite. The wider size/lower aspect ratio also keeps the tire diameter constant.

Keeping the overall tire diameter constant is important because the four-wheel ABS system relies on wheel speed sensors and if the tire diameter changes then the actual wheel speed can be either lower or higher than expected by the ECU and the ABS calculations will be off which may affect proper ABS operation.

In the rears, I run the stock size because increasing the rear width would add understeer and there is no reasonable width increase (265 or 275) that can be combined with a correspding change in aspect ratio to keep the tire diameter nearly constant (265/40 and 275/40 are too tall and 265/35 and 275/35 are too short).

The 285/35/17 is the right answer in terms of matching the stock tire diameter but going 30mm (1.2") wider on the stock 8.5" rear wheel is too much of an increase. Of course, you could just do it (we've all seen worse!) but as Topless said, you really need to go to a larger wheel (9.5") to properly mount a 285.