luciano136

Wondering if anyone runs this size successfully on their GTS? Stock is 295/35r21 or 275/45/20. Looks like 275/45/20 is 29.7" diameter, 295/40/21 is 30.3", so not that much more but obviously wider. I read there may be some slight rubbing but not sure if that was GTS specific or just 958 in general. Having some extra sidewall would be nice for light offroading.

bernoulli

Not a GTS owner but I just swapped out the tires on my 958.1 Turbo to 295/40R21s (Continental DWS 06 Plus). I had slight rubbing at the lower suspension level when the steering was at full lock but bumping it up to “normal” level eliminated it. The extra sidewall makes a big difference in ride quality. The only downside I’ve seen so far is a one MPG decrease with about 600 miles on the tires.

luciano136

Thanks for the info! Unless something is different on the GTS, I'm guessing it may rub too much since it drops lower than the CTT if I'm not mistaken?

Norge911

Try the 285/40-21. Zero rub and very comfortable.

luciano136

Oh, nice! And they actually have an all-season that's severe snow rated in that size. Vredestein Quatrac Pro. No need for a second set of wheels that way.

CWCTT

I've read this on another thread. Now do you at set the wheel size setting down to 20 inches in order to get a more accurate reading on your speedometer?

Norge911

No, the interesting part is that OEM 20” comes with 275/45 and diameter is about 29.9 pending on brand while the 21” comes with 295/35 which have a diameter of 29.1. Larger rim have smaller diameter tire.


also, speed sensor is on output shaft on transmission so speed is a calculated value based on engine rpm and gear. This is what your speedometer reads.
therefore, tire revolution will change with change in tire size and not the traveling speed.

the 285/40-21 tire diameter is 30.1 so only 0.2” larger than the 20” OEM size

CWCTT

Thanks, the Continentals that were included in my recently purchased 15' Turbo are still in very good condition with a lot tread life left. When they wear out, I'll definitely go with 285/40-21 afterwards as I'm in NYC and the roads are horrible out here.

lml999

A 285 width tire is going to be more of a snow plow than tire! If you spend any significant time driving in real snow, you're going to want to drop to a 19" or even 18" wheel and a narrower tire...

luciano136

I honestly don't know if tire width still makes that much of a difference? In the old days, narrow tires were for sure better but tire compound also wasn't that good. Granted it's no 285 but I've been driving in all kinds of snow with moderate all-seasons and 255s with no issues. The amount of time I need to drive through deep snow is very limited; typically very small sections of unplowed road.

BlackPfeffer

I run the Conti 295/40ZR21 on 2015 CTT. Slight rub on driver side at full turn. The outside edge of the tire rubs the liner below the grill opening of the front cooler. The extra sidewall is so worth it. The slight rub is nothing compared to fixing two bent rims!