Shinigami

Hey guys

I think I'll be changing tires during my next service interval (another 4000km's to go).

Currently, I've got 225/40 R18's on the front, and 245/35 R18's on the rear. Standard Mercedes furnished PZERO ROSSO's...

I came to the conclusion (after your recommendations), that the PS2's are the way forward. However, whilst I can find 225/40 for the front, I cannot find any 245/35 for the rear rims...

However, I DID find the following PS2 tires:
245/40 & 255/35

I understand the first ones are thicker (i.e. more space between the outer edge and the inner portion), whilst the second set is wider.

Is there any problems going for either of these two? Would there be a problem with the 40's rubbing against the wheel well due to their larger diameter? What about the 255's, will they overhang too much from the rim, or would it even be impossible to fit them?

If either of them CAN be fitted without a problem, which one would you recommend? I guess the wider ones would provide better traction?

The cost difference is only about $30 for the pair.

ClayJ

According to the Tirerack's published specs the Overall Diameter on your OEM Rosso's is 25.1 inches front and 24.7 inches rear.

The PS2 in 225/40/18 has an O.D. of 25.1 inches - perfect fit on the fronts.

In the rear, the PS2 at 245/40/18 has an O.D. of 25.7 inches -- a difference of a whole inch (25mm), which is just too much of a difference IMO.

The PS2 at 255/35/18 has an O.D. of 25.2 inches -- still a half-inch (13mm), and still too much of a difference in Overall Diameter IMO....

I found PS2's in size 245/35/18 with an O.D. of 24.8 inches -- an almost perfect match in O.D. Now my file is 6 months old -- but are you sure that you cannot get the PS2's in 245/35/18?

Shinigami

Sorry, I'm a bit confused.

In the first part in italics, you mention the difference being too small, and then in the second part, where the difference is even smaller, you mention it being too much? I think I'm misreading something here, but I guess the 255's should do ok, as a 13mm difference is quite insignificant...

Probably a bit more gas consumption, but that's it?

Overhere, it seems like PS2's are not easy to come by, and I found one online store with very good prices. They however did not have the 245/35's... I can look around, but I might end up paying $100 more to just have 245/35's, and I'm not sure if that's really worth it if the 255/35's fit?

Saaz

Shini, a few thousand miles ago, I put on the exact tires you're thinking about, and they seem to work fine. I had the same problem - 245/35 seems to be a little harder size to find.

The tire place I went to (Butler, btw, great place) said they'd put 255s on another SLK, and they fit fine, and asked if I was ok with that. Before giving them the ok, I checked Tire Rack (and double-checked just now) to compare PS2s in 245/35 and 255/35. Clay's right that the diameter is larger, but I haven't noticed any rubbing or other problems. They look like a perfect fit on the rims, not bulging out or anything. The only other notable difference is the revolutions per mile, and that only amounts to about 1.5% difference, so I figure my speedometer will be off 1.5% - no big deal. (Sorry officer, see, I've got these larger tires... I didn't realize I was going 140mph, I thought I was only going 138. )

Shinigami

Yeah, well... 1.3% difference, big deal. Speed cameras have a 5kph margin for error, and besides, speedometers are always generous in that you're most likely doing 78mph then 80...

Thanks for the info, keep it coming. I think I'll settle for 255's. Probably buy them a few months from now.

Ynot

Get the 255's, the only problem I see is it might rub the inner fender but since Saaz has it before and didn't rub, I would take his word for it. And the other problem as Saaz mentioned, your speedo will be off by 1-2% but that's about the same as if you get aftermarket wheels.

Easty

I have 255's yoko ES100 on. no problems here

the width doesn't make a huge difference 10mm either way. the
wall height though can vary alot and I'd try to get a match.

if front is 225/40 wall = 90mm

a 245/40 rear wall = 98mm

a 255/35 rear wall = 89.2mm

with 18's wheel they'll never scrub the arches just by altering the
wall height of the tire unles you go dramatically out of scope.

Shinigami

Okie dokie. Yeah, I have the standard multispoke 18" rims you get with the non 030 SLK 55 AMG. I'm gonna end up taking the 255's I guess. I think it might look a bit better due to them being slightly wider too. The original tires are anything but wide =\

JBRhee

Hey Shini,

How did you decide on the PS2s? I'm probably going to need new tires in a couple thousand miles, but there're so many different types of tires out there. I don't know what to get and I wanted to try something different than the pirelli's. Do you know what type of tire I'd have to buy to get the smoothest ride possible? I know Michelline Pilot Sports are smooth, but are they better than the original pirellis?

Have you considered the pirelli PZero Neros?

ldye

You can go to TireRack's web site and compare all the tires for the SLK. I think they rated best ride and noise comfort to Dunlops. Not a great fan of that brand but it may be one I try when I need replacement.

trompazo

I run 265/35-18s on 9" rear rims with no problems.

I will be trying a 245/35-18 on the front to see if it rubs. It does fit on the car, no problems, but I didn't try driving it to see if there is any rubbing when the suspension is compressed.

JBRhee

That's a lot of cars you have, Trompazo. Do you take up a whole block to park those cars?

trompazo

No, but they take up my whole warehouse. Soon I'll be setting up a ramps attached to my hoist so I can stack cars on top ot either other and double my space.

JBRhee

Unbelievable!

Shinigami

Well, in the end, I ended up replacing my current tires with the same ones (this was last year) using MO's... (I didn't like the idea of the tire size being different).

Today I made a new order, and by chance they had PS2's with 245/35's for the rear, and not only that, but the PS2's were MO's (both front and rear!), so I took 2 of each.

Baby's gonna get some new shoes in a week or so

Let's hope the PS2's are a little bit quieter, the PZERO's can be kinda loud at times on some types of tarmac...

Shinigami

Got my car back with the PS2's, and they seem pretty good. I think they're considerably quiter then the PZEro's, and the grip seemed really good in the corners.

I hope they will do ok in the rain and on cold roads in winter.

alroumi

Congrats on the new PS2's good choice.