295/40r21 on 958.1 GTS?
#1
RL Community Team
Rennlist Member
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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.
#2
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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.
#3
RL Community Team
Rennlist Member
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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?
#4
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Try the 285/40-21. Zero rub and very comfortable.
#5
RL Community Team
Rennlist Member
Rennlist Member
Thread Starter
#6
Intermediate
#7
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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
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
Last edited by Norge911; 03-21-2021 at 10:20 AM.
Trending Topics
#8
Intermediate
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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
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
#9
RL Community Team
Rennlist Member
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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...
#10
RL Community Team
Rennlist Member
Rennlist Member
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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.
#11
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
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!
Last edited by BlackPfeffer; 03-23-2021 at 08:59 AM.