96redLT4

Looking to replace all 4 on my stock 05 C2S. Have decided on the Michelin PSS. Wheels are stock 19 inch lobster claws.Should I opt for the 305 instead of the stock 295? They are already so dang wide...Any issues with rubbing? Thanks in advance.
Jim

user 72902

11.5 rims take 305's and 11.0 takes 295 so it would depend on your rim but wider = more grip.

user 72902

I run 305's without rubbing issues.

USMC_DS1

I have 11.5" Champion wheels in back with MPSS 305's. No rubbing.

96redLT4

Rims are stock. How do I know if they are 11 or 11.5? Per Tirerack they say 305 should fit where 295 are now and just looking, price delta is only 10 bucks/tire. Seems like a no brainer I guess.

J

LexVan

Look at the numbers by your valve stem.

808c2s

305 will also fit 11" rims, but Porsche uses 305's with 11.5" rims.

wc11

I'm running 305's.
No issues.

Coincident

Substituted my Michelin 295 for 305 on my 997.1 2S. No problems at all but also very little difference if any in feel or handling. Did look slightly more aggressive.

PhilD

I have 305/30R19 at the rear on 11" wide rims (52mm ET) and they fit perfectly. I increased the fronts to 245/35R19 on 8.5" wide rims (45mm ET) to help balance out the understeer. I'm running H&R lowering springs, no clearance issues at all at the rear, occasional very light rubbing at the front when at full lock and on an uneven surface.

As already mentioned I doubt you can really notice much difference between 295 and 305. In theory, more rear traction will increase under steer, which is why I went with 245 at the front to cancel any increase in under steer.

As an aside, I recently switched to a GT3 adjustable rear sway bar and now have some over steer. I have it on the middle setting, so may try the softer setting. If that isn't enough I'll go a little stiffer at the front.

One other thing to consider is unsprung weight, a wider tire will add a few lbs to each corner. Not a fast amount, but there will be an impact on performance, albeit it may not be noticeable.

96redLT4

Great info! Thanks LexVan and all. My rims show 11, 8 on the front. Maybe I'll try the 305s though.
Jim

mdrums

Softening the rear will give it more grip and can make car understeer even more.So if you are under steering you can either stiffen rear bar or soften front bar...or both. You will have to test and see which combo works best for your car, driving style and track.

PhilD

Thanks. Agreed, but I have some over steer now since going to the stiffer at the rear, which is why I was going to try a little softer at the rear. If that isn't enough I'll get a front adjustable bar and go a little firmer at the front. I prefer a pretty much neutrally balanced car for the street, I know a little under steer is preferred by some and is easier to recover from, I just like it more neutral.

I'm not going to do anything until I replace my motor mounts as I know they are shot so that may make a little difference to the feel when replaced.

Perk10

I have also been contemplating using 305's on my stock S wheels (lobster's)... I like the wider look in the rear but now that I've added an 18mm rear spacer, I am not sure if the 305's would be TOO wide.. Nice to know that they fit, though.

red996

Is your car lowered? If it's lowered or your even thinking about lowering it stick with 295. On the street I found no difference between 295 and 305 with Bridgestone Potenza RE050A. Michelins might be wider between sizes. I would look at the tire overall width spec!

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