GL550: 235/R18 Winter tires?
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Junior Member
Joined: Jul 2020
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2008 GL550 (X164)
GL550: 235/R18 Winter tires?
I recently bought a used 2008 GL550 and with it came a full set of winter wheels 235/65 R18. (For summer I have the standard 295/40 R21).
Since tread is pretty low I want to buy new winter tires and figured that the smallest recommended size is 265/60 R18 for GL450 (for the GL550 its even 265/55 R19).
So I was wondering:
Why should the GL550 have 19inch instead of 18inch?
Are brake rotors different? As far as I can see in parts shops it seems that the same OEM rotors fit the GL450 and GL550.
Is there any good reason not to have 235ers instead of 265ers?
With the narrower 235ers snow handling should even improve (of course handling on dry roads would be a bit worse with the narrower tires).
Cheers
Sebastian
Since tread is pretty low I want to buy new winter tires and figured that the smallest recommended size is 265/60 R18 for GL450 (for the GL550 its even 265/55 R19).
So I was wondering:
Why should the GL550 have 19inch instead of 18inch?
Are brake rotors different? As far as I can see in parts shops it seems that the same OEM rotors fit the GL450 and GL550.
Is there any good reason not to have 235ers instead of 265ers?
With the narrower 235ers snow handling should even improve (of course handling on dry roads would be a bit worse with the narrower tires).
Cheers
Sebastian
Senior Member
Joined: May 2013
Posts: 437
Likes: 84
From: Espoo, Finland
2012 GL 350
For winter tires, you want two things:
1. The biggest sidewall that will still clear the brakes. You want that extra sidewall so that in the spring when the freeze-thaw has done a number on the roads, you can survive pothole strikes that would kill lower profile tires.
2. The narrowest tire that will support the weight of the vehicle. Narrow tires work better in the snow than wide tires. That allows the car to press the snow away rather than ride up on top of it. Look at a winter rally car next time you get a chance - they almost look silly how narrow the tires are. Tire width is about weight and heat. You can put more heat into a narrow tire in the winter because the ambiant temperatures are lower and will keep the tread from overheating.
What that translates to for a 550 I don't know, but hopefully that helps in your decision process.
1. The biggest sidewall that will still clear the brakes. You want that extra sidewall so that in the spring when the freeze-thaw has done a number on the roads, you can survive pothole strikes that would kill lower profile tires.
2. The narrowest tire that will support the weight of the vehicle. Narrow tires work better in the snow than wide tires. That allows the car to press the snow away rather than ride up on top of it. Look at a winter rally car next time you get a chance - they almost look silly how narrow the tires are. Tire width is about weight and heat. You can put more heat into a narrow tire in the winter because the ambiant temperatures are lower and will keep the tread from overheating.
What that translates to for a 550 I don't know, but hopefully that helps in your decision process.
Member
Joined: Apr 2014
Posts: 177
Likes: 45
From: Florida
X166 GL550
The reason why MB recommend R19 for the GL550 is because the car is a little wider than the GL450 and the wheel offset for the GL550 is 56mm. Both the GL450 and GL550 weight the same (GVWR 6944 lbs).
The 18" tire has a bigger sidewall (6.3") than the 19" tire (5.7") Diameter and width are the same.
The 18" tire has a bigger sidewall (6.3") than the 19" tire (5.7") Diameter and width are the same.
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