[Marco Falcone]

Need new tires on my ‘18 2SS Convertible.

Currently has Michelin PS4S ZP/Run-flats; 285/30 front and 305/30 rears. (On 20” MRR FS01 wheels.)

Tire shop is telling me the 285/30 isn’t available from any of his distributors, and he is recommending Michelin PS4S ZF’s in 285/35 for the front and 305/30’s in the rear.

Says there would no discernible difference. Car is also getting an alignment.
Shop has been around for over 40 years.

Anyone know of any possible issues with that minor profile difference set-up?

Thanks!

[tbair64]

I believe there is a member that has 35 aspect ratio tires on his car. I believe they fit but very close to the strut

[arpad_m]

I have 35 AR tires, 285/35 front and 305/35 rear, see below.

You'll be fine just as the tire guy said, since 285/35 is only 0.7% taller than the 245/40 stockers.

With that said, know that while 285/35 does fit, the tire will be close to the strut perch and will very slightly rub on the wheel liner at full outside lock. I live with this because I don't spend much time in full lock, but wanted to let you know.

[Curr]

Do you have Mag Ride?

My '17 50th SS 'vert did, and I put 285/35's on the front and they rubbed a little too often for me, so I switched to 275/35 and everything was fine.

These were BFG Comp 2 A/S+ on MRR 1LE rep wheels.

[arpad_m]

Originally Posted by Curr

Do you have Mag Ride?

My '17 50th SS 'vert did, and I put 285/35's on the front and they rubbed a little too often for me, so I switched to 275/35 and everything was fine.

These were BFG Comp 2 A/S+ on MRR 1LE rep wheels.

Yes, I do have MRC. These are OEM 1LE wheels with a different offset than what MRR uses on their replicas, and the rubbing is almost negligible.

I'm sure 275/35 or 285/30 would be better, but I got a great deal on the wheel+tire combo, and don't want to throw or give perfectly good PS4S tires away.

[Marco Falcone]

Thanks for this info.

And yes, I have MRC.

Any concerns the different profile front/rear, 35’s in front and 30’s in the rear?

The combo my tire guy can get is 285 35 front, 305 30 rear.

Again, thank you!

[tbair64]

For me the 285 35 paired with the 305 30 would not look right as the sidewall height on the front is taller than the rear. When I see this it always looks like the tires are on the wrong end of the car. But thats just me being picky.

[arpad_m]

Originally Posted by Marco Falcone

Thanks for this info.

And yes, I have MRC.

Any concerns the different profile front/rear, 35’s in front and 30’s in the rear?

The combo my tire guy can get is 285 35 front, 305 30 rear.

Again, thank you!

You're welcome

Yes, you can use 285/35 fronts and 305/30 rears, the aggregate difference front to rear will fall in the other direction, but small enough in magnitude not to mess with the car.

Two other adverse effects are that you'll change the rake by making fronts taller than rears (unlike the stock setup), and as tbair64 said, front sidewall height will be more (by 0.3" specifically), but IMO neither is significant enough to cause any harm beyond a bit of visual weirdness, only noticed by those in the know anyway.

Again, do watch out for rubbing in front, you have MRR wheels and they probably come with a +23 offset in front, so your tires will be set in by an extra 3 mm compared to mine. If you add 3 or 5 mm spacers, you can eliminate this as well.

[Msquared]

A 285/35/20 will be 27.9" tall in front, and the 305/30/20 rear will only be 27.2" tall. That's going to look kind of goofy. I wouldn't do it. At one time, I had a C4 with a taller tire up front, but the difference was on 0.4". It still looked goofy to me, and I couldn't unsee that issue.

I'm not sure what PS4S "ZF" is. You don't want run-flats (ZP): you just want the regular PS4S. Tire Rack has two different versions of that tire (not sure what the differences are) in stock. Your installer should be able to get them. If he can't, you need a different installer. For as much as these are going to cost, there's no way in hell I'd settle for the wrong size tire up front.

[WhiteMale]

Its going to visually front and rear look bad. It'll work but will look bad I would not do that.

[Marco Falcone]

Thanks everyone for the advice.

I’m going to get regular/non run-flat PS4S in matching profile size; 285/30 20 and 305/30 20.

The run-flat option was what was causing the issue.

Shop will have them in next week.

[arpad_m]

Originally Posted by Marco Falcone

Thanks everyone for the advice.

I’m going to get regular/non run-flat PS4S in matching profile size; 285/30 20 and 305/30 20.

The run-flat option was what was causing the issue.

Shop will have them in next week.

You made the best possible decision (note to self: don't assume that if someone already has aftermarket runflats, they wouldn't consider normal tires)