parsecnc4

I am struggling with a dilema in changing out my tires and would like some recommendations from those who have gone down this road before....

Should I opt for 265/35/18 (standard size used with 18" Speedline rears) or go with 285/30/18 simply for the extra width and possibly meatier looks? I am sticking with 225/40/18 on the fronts since moving up to 245/35/18 would seem a bit wide for the fronts, while maintaining rolling diameter delta to a minimum.

P.S. I am not too worried about understeer issues, for my car is rarely driven to 6/10ths of its capability in Los Angeles traffic.

Flachbau

235 fronts and 285 rears look best by far ... and handling is not compromised in fact improved IMO.

kleinbbc2

285/30/18

parsecnc4

Would it be 235/35 or 235/40? I fear the rolling diameter differences would be too great on 235/40 with 285/30 rear. Here are my observations on rolling diameter:

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STOCK
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225/40 = ~25"
265/35 = ~25.3"

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OPTION 1
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225/40 = ~25"
285/30 = ~24.7"

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OPTION 2*
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235/40 = ~25.4"
285/30 = ~24.7"

* The F-R diameter delta is ~0.7" and I am a bit concerned that it would alter the overall weight balance of the car.

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OPTION 3**
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245/35 = ~24.8"
285/30 = ~24.7"

** This setup matches the closest in overall diameter if 285/30 were to be used. However, 245/35 in front might be an overkill and not ideal for the 8" wheel width.

Flachbau

235/40 285/35 ... forget the new math ... feels reeeeeal good seat of the pants!

dholling13

Going with a thirty series tire in the rear could cost you a bent wheel; even at 6/10's

SA Mike

Drew doesn't the profile(ie. 30) number represent a percentage of the width of the tire. Meaning that a tire with a 30 profile with a 285 width will be almost the same as a 35 profile with a 265 width, as far as height of sidewall. I think someone acutally told me it was a percentage of the width.

emilios

How about fitting 295/30's at the back? Would they fit? I'm finding it hard not to wheelspin during hard/spirited acceleration with the 285/30 Pirelli P zero Rosso's and i'm thinking of changing to Michelin Pilot Sport 2's. Any suggestions/recommendations anyone?

dholling13

Mike one could make that argument but the profile is still providing less cushion for street use.

SA Mike

Can't be any lower than what I have on now. The stock Pirelli P Zeros (35/265) that are on the car now are ultra low. When the tire has some sort of tire shine on it, it almost looks like it's flat.

jeff91C2T

I chased this a while back....Tirerack has a good explanation. But here's a break down;

Sec % of Sec Aspect Ratio
Width Width (Profile)
(baseline) 225 0.45 101.25
245 0.4 98
285 0.3 85.5
265 0.35 92.75
275 0.4 110
295 0.35 103.25
315 0.35 110.25

The question on if 295's will fit....never tried but it would be close. You have to factor in tire diameter as much as you do width. The driver on tire size (width and dia) is on the forward inner edge of the tire where it is against the trailing arm. This is at an angle so it's not just crosscar but fore/aft as well. You can take your hand and run it along the inside surface and feel the gap. With 285/30's I have just enough room to get my fingers between tire and trailing arm.

cobalt

I am running MPS2's 235/40 and 295/30 Rolling dia was 25.4" front and 25" rear. The 295's are a tight fit leaving about .400" clearance between the trailing arm and tire and also to the lip. So you are .300 larger in rolling Dia in the fronts which is equivalent to wear.

The 235 fronts do feel heavier on the steering, do tramline a little and are more fatiguing on long drives (over 300 Miles). Although when pushing the car hard they are a definite benefit.

I went over the tire sizes with my local tire expert and although Mark says they work he recommended staying away from the 235/285 combo. Although he said I had to do the 235 with the 295. I can't tell you what to go with but these are just opinions and Mark knows his stuff too and has experience. So Good Luck.

One other point is although the MPS2's work in these sizes each manufacturer sizes vary for like sizes.

SA Mike

So that being said what is the down side to going with 285/30s in the rear and leavind the front stock size?

kimo964

Anthony, can you verify your front tire size. You mentioned it was 235/35 in a previous post. I want to go the 235/295 set up after I wear the PZeros down. Thanks

cobalt

I ran 225/285 S02's prior to the current tires. Like MPS2's far better but steering was lighter with the 225

I apologize if I posted wrong info. Sometimes I have a brain fart. Can you tell me what thread and I will correct it.

Correct size is 235/40 they don't make a 235/35 in the MPS2's