JD101b

What is the largest tire (height and width) you can fit on a GLS550 on the stock 21 inch wheels?

Promo Bob

Hi
i wouldn't know on 21s, but i can tell you 305/40/22s fit, and that's the max. Bigger will rub(in front@).You can try those online calculators "will they fit" to kinda estimate and compare. I'd say maybe a 275-285 45 21 will fit allright.
Hope that helps.

cheers,
Bob

threeMBs

Theoretically, the largest tire that can fit stock's 21x10 wheel and have no clearance issues on GLS is 305/45-21. However, since there's no tire in that size (nor 295/45-21) the largest (tallest) tire is 285/45-21 which is narrower than stock (295/40-21) but almost an inch taller.

SVDNN

We have 315/40 R21 on the stock GLS550 21 x10in wheels. Got tired of the the wife curb-rashing the wheels. Work very well for intended purpose.
All good except would be challenge to place snow chains (low profile)...not enough clearance.
Really wish there was a 305/40 option but no tire exists in that size.

You could probably get away with a 305/35 R21 on the 10in wheel but it is an inch smaller diameter and obviously thinner side wall.
Doubt the 315/35 would fit on the 10in wheel due to the smaller side wall compared 315/40
Hope that helps