2017 GLC 43 - downsizing 20" tires to 275 and 245?
There are literally zero options for all-season tires in that size, besides the very expensive goodyears
But if I downsized to 275/40R20 and 245/45R20, all my options open up. Looks like the diameter of each would only be 0.3 inches smaller.
Has anybody done that? Any potential issues with this idea?
USA here in case that matters




Your cars computer and safety systems, including auto transmission and 4Matic system may be voided.
Speed on dash may be higher, or lower, based on revolutions as well. MB spends $$$$$ in deciding tyre size - you might be better off buying 19” or 18” rims designed for the GLC, with correct ET and offset and buy cheaper tyres from a larger manuf range.
You could dump runflats and fit non run flats, several companies sell them.
I cannot believe there is only ONE tyre left in the USA that meets GLC specs.
Good luck, consider different rim sizes, just be careful re your transmission, etc.
Your cars computer and safety systems, including auto transmission and 4Matic system may be voided.
Speed on dash may be higher, or lower, based on revolutions as well. MB spends $$$$$ in deciding tyre size - you might be better off buying 19” or 18” rims designed for the GLC, with correct ET and offset and buy cheaper tyres from a larger manuf range.
You could dump runflats and fit non run flats, several companies sell them.
I cannot believe there is only ONE tyre left in the USA that meets GLC specs.
Good luck, consider different rim sizes, just be careful re your transmission, etc.
Also another poster on the mercedes subreddit put the downsize option, and linked a picture. It's hard to tell any difference from stock: https://www.reddit.com/r/mercedes/co...nge_tire_size/
I can't really tell any noticeable difference in appearance from stock.
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Last edited by I_love_ICE; Apr 5, 2022 at 11:19 AM.
Tire is Not Available for Your Vehicle
This tire isn't available in sizes 255/45R20 - 285/40R20 for your 2017 Mercedes-Benz GLC43 AMG SUV Standard Tires.
Total price I paid for front and rear (255/45/20 and 285/40/20) was $1465.87. It'll cost me an additional $100-125 to have them installed at a PepBoys or some place like that.
Can't wait to get rid of these awful run-flats!




Thanks for the quick response, glad to hear you are happy with them! Just got off the phone with Tire Rack and am ready to order. My bad with the name!, yes I meant the CrossClimate2's. I noticed they have 285/45/R20 and 255/50/R20 with a higher aspect ratio, it calculates out to about 1" higher sidewall, do you think that might be too high? Looking for more sidewall 'cause our roads here really suck! My truck rides better... Nice ride Tim, tires look good, like the color, ended up with Cardinal red this time, last two cars where Lunar Blue.
Last edited by bsaz; Apr 18, 2022 at 06:49 PM.
Thanks for the quick response, glad to hear you are happy with them! Just got off the phone with Tire Rack and am ready to order. My bad with the name!, yes I meant the CrossClimate2's. I noticed they have 285/45/R20 and 255/50/R20 with a higher aspect ratio, it calculates out to about 1" higher sidewall, do you think that might be too high? Looking for more sidewall 'cause our roads here really suck! My truck rides better... Nice ride Tim, tires look good, like the color, ended up with Cardinal red this time, last two card where Lunar Blue.












Just had the new tires installed yesterday, could tell a difference right-a-way, better "ride" not as choppy/harsh. Our roads suck sooo bad, they maintain to stagecoach level! Can't attest to handling performance, haven't taken any "high speed open road" trips yet. will let U know. I am curious what psi folks are using for the non-run flats? Discount Tire used 39/42 psi same as the door jam numbers.





