DR.ZOIDBERG

Hey Guys
Need new tyres on my Boxster. I am currently running the following

Front -

225/40/18 Bridgestone Potenza S-03

Rear -

285/30/18 Bridgestone Potenza S-03


Is this the correct way? Just that my rear tyres look smaller and theres a bigger gap from the tyre to the body due to the different profile. Looks good having a big meaty tyre on the rear but the gap from the tyre to the body makes it look a little funny. Still running standard suspension and shocks and the car has not be lowered.

Reason I am looking at new tyres is the left hand side rear tyre which fel apart last night. It decided to de-tread itself which a rope like tread from the tyre wrapping itself around my break etc - approx 2-3m long (The tread came off the tyre in a rope like form and wrapped it self around my break). Tyres are 4 years old but have only done 18,654km. Is this normal? or did I get a dodgy tyre?

Hope someone can point me in the right direction or tell me if this is the way to go.

Ta
Zoidy

EPWilson

The stock tire sizes for the 99 Boxster with 18" wheels is 225/40-18 front and 265/35-18 rear (per TireRack.com). With the stock sizes, the rear side wall would be 92.75, but the tires you have it's 85.5. The shorter side wall would make the rear look smaller with the bigger fender gap (assuming you have stock width wheels).

Byprodriver

Shorter tire lowers overall gear ratio for quicker acceleration also so you have to choose which you would rather have.

Ray S

On a stock suspension you are only going to increase understeer with that combo.

Personally, I like that way the car drives with a 235/40 front and a 265/35 rear tire.

To answer your second question, I would not say it's normal for a tire to shed its tread after 11,000 miles.

Try some Michelin Pilot Sports next time, it's a great tire for the Boxster IMHO.

DR.ZOIDBERG

Hi
What I meant was, the gap from the wheel arch to the tyre is bigger, sorry didnt mean the wheels are in too deep.

They are different wheels from Standard, think they are 10" on rear

So should I still the to 30 profile on the rears? or can I go different?

Ray S

I think you missed his point. The diameter of a 265/35 combo is 25.3" (642.62 mm), while the diameter of a 285/30 combo is 24.73" (628.14 mm). So it may look smaller in your wheel well because it is indeed smaller.

As others have indicated this could improve acceleration slightly by effectively lowering your gear ratio, but I don't think it's going to do you any favors in the handling department paired with a 225 tire up front.

FWIW, both a 265 or the 285 will work just fine on a 10" wheel.

smshirk

You will like the look of 275 35s on the rear better, as it fills out the rear much better than the 285 30. As previously mentioned 265 35 is the stock size.

Byprodriver

Changing 285/30 to a 275/35 with 2.5 litres will feel like you are starting off in 2nd gear.

Ray S

I'm not sure it will be that bad, but he will effectively make his gearing taller by going to 275's.

Really, if he wants to fill out the wheel wells better he'd be better served working on the suspension instead of changing the wheel diameters.

DR.ZOIDBERG

I am thinking of staying with

225/40/18 Fronts

285/30/18 Rears

as I dont want to make my car any slower.

Guess I will just have to save and work on the suspension to lower the car etc

Byprodriver

I think you will be happier going that route. I bought a 996 wheel & tire package from a dealer with 285/30 in anticipation of my built 3.6 engine & loved the extra torque multiplication for my 3.2 but it was not worth the understeer it caused so I went back to 265/35/18. If you don't want to lower with springs (stiffer) you could go with 265/40/18 but it is noticeablly harder to engage the clutch due to reduced torque multiplication.

DR.ZOIDBERG

So can I go -

Front 225/40/18 (Dont want to change these as they are still in good condition)

Rear 265/40/18

My car is a 1999 Boxster 2.5 Triptronic

or should I stick to the Front 225/40/18 - Rear 285/30/18

DR.ZOIDBERG

Here is some photos of my current setup

Fronts - 225/40/18

Rears - 285/30/18

Stick with these sizes and lower the car or change Rear tyre size?

Edit - Just been speaking to the tyre shop and he has recommended some Hankook Evo 295/30/18. Will a 295 tyre fit? Tyre shop seems pretty confident they will. Anyone know?