Not another tire thread...
 

Question about sizes for you tire experts out there :D

Looking at different tires to replace my current Continentals. Mine are Sportcontact 2's, 265/35/19 rears and 235/35/19 fronts. Some of the options coming up on tirerack.com are showing 265/30/19 rears with the same 235/35/19 fronts.

Questions:

1) Is having the different sidewall sizes between front and rear a "normal" and ok thing to do?
2) Does it look "right" having a thicker sidewall at the front/lower at the back?
2) Does it make any difference in the handling?
3) With the 19" wheels I'm using, what other size tires could I look at using? The wheels are Porsche 911 Carrera S "Sport Design" type.

Any help/advice is greatly appreciated!

Cheers, Gord.

That sidewall height number is actually a ratio of sidewall height to tire width. So the back will naturally be lower due to the fact that the tire is wider.

For instance, I'm buying some new tires for OEM 18's today. Fronts are 225/40 while the back are 265/35.

FWIW, I am most likely getting Kumho Ecsta ASX. If not those then likely some Bridgestone Pole Position 960AS. It rains a weeeee bit around here at times.

Yeah, I see what you're saying...but the tires that are on there right now have the same sidewall size, 35 front and rear.

Any other answers to my questions folks?

Cheers, Gord.

The tires you have on the rear now are the wrong size.. the 265/30 is correct. The tires you have in the back now are adversely effecting the handling of the car, because they have a larger diameter then is ideal.

Marc

:eek:

Thanks for the reply. Really?? The tires that are on there right now came with the car. It was the previous owner who put those wheels/tires on there. He told me that the Continentals in that configuration was all he ever used.

Tirerack.com does recommend those (35 sidewall, f/r) also for the 19" rims. It was only after I saw some other owners have used the 265/30 set up on their wheels that I checked tirerack again.

Interesting..totally confused now, but interesting stuff lol.

Cheers, Gord.

Squeak,

I agree with schwank & mdex. My 99 has 225/40ZR18 on the front and 265/35RR18 on the rear. Not sure about the difference with 19" wheels though, but it does make sense that the middle number for the rears would be less than the front due to the wider tire. Perhaps Grizzly and Bmus can chime in, I think they both have 19's...

Nick

Grizzly, Bmus...any input guys?

Also, those that do have 19's, what tires are you putting on your wheels? A friend of mine swears by General Exclaim UHP's and my neighbor has Kumho Ecsta's on his 19's...anyone recommend them? Seen them on tirerack.com and the price is very competitive.

I'm just slightly concerned about the whole "don't drive below 45 degrees on these tires" that I keep reading. I know when I lived in Germany, where we had some pretty bad winters, I had "summer" tires on my BMW and never used winter tires. When it snowed, I just drove steady and never had any problems at all. When it was icy, I didn't drive!

It doesn't tend to get "nasty" around here in Little Rock, (overnight lows are getting down about high 30's - low 40's right now) and my financial advisor (she who must be obeyed) has told me that two sets of wheels and tires "ain't gonna happen!" so a set of winter wheels/tires probably ain't in the future. I need to get new tires pretty soon, so does anyone use "summer" tires all year round? Is it just plain crazy to do so? Any help/advice is greatly appreciated. :D

Cheers, Gord.

I have 19s, you need 265/30/19 rears and 235/35/19 fronts. Don't use summer only tires in temps less than mid to high 30s, mid 40s are better. In any snow and ice summer tires are scary!

As others have noted you can used summer only tires down to the mid 30s but don't expect them to stop or corner well. That means brake early, no tailgaiting and slow down for corners. The downside is that you have littlke margin if there is a problem. If it is cold and wet stay home!

Yeah, if it does get too cold/ice/snow, I won't be taking the Boxster out at all...I'll use my wife's Jeep ;) In the three years I've lived here, we've only had one bad ice storm and a small amount of snow that's usually gone in a couple of days.

Anyone got any recommendations (or not) on the Kumho Ecsta's and General Exclaim UHP tires?

Cheers, Gord.

Squeak,

I have Kumho's on the Benz and I have been really happy with them.

I spoke to djomlas last night and he recently put Kumho's on his Boxster and he is really pleased with them as well.

I think Unklekraker also has Kumhos on his Box. Maybe one of them can chime in...

Hope this helps,

Nick

Thanks Nick, much appreciated mate :)

Cheers, Gord.

Aspect ratio
 

The number in question is the relationship of sidewall height to tread width. An aspect ratio of 35 means that the sidewall height is 35% of the tread width. Knowing that, it's easy enough to calculate the actual height of the sidewall in any unit one desires...