While exploring the available A/S and Winter tires for the AMG GT55, I discovered a discrepancy between published tire sizes for the 20" wheels. Unfortunately, I believe Tirerack blindly copied the MB "typos" and listed the incorrect 20" tire sizes in its online catalog. I opened a chat session with Tirerack customer service where it was agreed that a 1" difference in the outer diameter between the 20" and 21" tires was very odd. Tirerack has not corrected the sizes and I suspect that is because they are relying upon the tires sizes published in the MBUSA specifications.

Hopefully, a forum member with the RTM - 20" AMG Aero Twin 10-Spoke wheels can confirm the correct tire sizes.


2025 AMG GT Order Guide



Tirerack screen capture.


MBUSA 20" tire specs.

 

^^^Good info
I too would like to learn what UHP AS tires will work

 

There are three choices for the 20" staggered 10.5"/11.0" AMG GT wheels - RTM, RVM, and RVN. The Order Guide shows 295/30-R20 and 305/30-R20 tires for the RTM wheels and 295/35-R20 and 305/35-R20 tires for the RVM and RVN wheels. All of the tire sizes shown in the Order Guide (including the 19" tires) have a nominal outer diameter of 28", except for the tire sizes for the RTM wheels which have a nominal diameter of 27". The chances of this being correct are near zero. I wonder how many tires will have to be returned to Tirerack before they correct the listing. Sadly, the incorrect 20" tire sizes (295/30-R20 & 305/30-R20) have attractive choices for A/S tires.

 

Nothing AS for 21’s, or did I miss it?

 

There are AS tires available in the 295/30-R21 and 305/30-R21 sizes. BUT, there does not seem to be any tires available as a staggered set in the required sizes. I believe both sizes can be mounted on 10.5" or 11.0" rims, but I am certain that the MB engineers would not approve.

 

Anybody had any luck finding compatible all-season or winter tires for the 21" wheels? Coming up short with the online tire dealers...

 

There are 295/30-R21 AS and Winter Tires available. This size can be mounted on both 10.5" and 11" wide wheels. Not sure if MB would approve of using the slightly narrower tires on the rear, but it's a lot safer than trying to drive with the 305/30-R21 Summer tires.

 

I did a lot of research on this and spoke to my dealer as well. Bottom line is there are no all season tires that fit the front and rear 21" wheels (could just put the front size on the rears as another poster mentions, but I don't think I would do that). It's a shame but maybe over time a manufacturer will make them. However, winter tires are available: Michelin Pilot Alpin 5 https://www.michelinman.com/auto/tir...-pilot-alpin-5. They seem to be available at TireRack.com for both front and rear for the 21" wheels. The other option is to buy a second set of 20" rims fitted with winter or all-season tires (plenty of options available for that size). The rims seem to go for about $5k for a set. I personally just decided I won't drive it much this winter, but for next year I'll probably go with one of those two options.

 

I tried to put 295 tires on my previous gen AMG GT, and they were clearly too narrow for the rims and looked horrible. Only replace them with something different but I forget what

 

I have a 2024 AMG GT 55...with the RVM 20inch AMG multi-spoke wheels...they came with Hancock Ventus s1 evo z tires (295/35/20 front and 305/35/20 rear tires)

 

And...I noticed as well...TireRack/Discount Tire had the wrong tire sizes listed (30 profile instead of 35 with the 20 inch wheels).

I just swapped the Hankook's out for Michelin Pilot Sport All Season 4 (295/35/20 front, 305/35/20 rear)....they ride a little bit better (and should last a LOT longer)....

 

I think Tirerack is getting the wrong tire sizes from the Order Guide or some other MB documentation. I reported this to TR months ago, but I think they are too stubborn to change it. Once they ship enough of the wrong tires and have to eat the return shipping cost they will probably fix the website listing.

 

As of today, TireRack no longer has any wheels or wheel/tire packages listed for the GT 55 or 63. The selections are greyed out.