Rough ride , what size rim?
Last edited by Mmr1; Nov 28, 2024 at 03:29 PM.




Plus there are other TR Calculators out on the web, no doubt at Tire Rack's website, and so on.




19 inch rims on a GLK350 were probably standard with 235/50R19 tires. If the 17 inch rims don’t interfere with the front brake calipers, then 235/60R17 tires should fit with better ride, no rubbing, and less than 1 MPH speedometer error as long as the offset of the new rims is the same as the stock ones.
Check all this with your tire and rim dealer to be certain.




https://www.wheel-size.com/size/merc...m-glk-350--302
Of course, you have to work out offset and total tire diameter and width, if you stray from the stock combinations. But the options you'll see at that link should give you a really good baseline.
FWIW, when I got my current GLE 19" wheels, I test-fitted them to determine the proper spacers to install (by measuring the distance from the sidewall to the fender lip, at the likely contact points). And yes, my GLK's ride quality improved significantly going from the stock 20" "sport wheels" to the 19" GLE wheels. No doubt going to 17" or 18" will make a bigger difference, which can only be a good thing for Chicago streets.




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Last edited by Silver Shadow; Dec 1, 2024 at 05:00 PM.








If you change tires, the Michelin Primacy Touring A/S is a very compliant tire that absorbs road imperfections well. It’s all season, but it’s not 3 Peak Mountain/Snowflake rated like the Cross Climate tires.
I guess it would be unfair to say it rides a little tougher than before, mainly because I've also replaced the OE worn out shocks with Bilstein B4, which are going to be a little stiffer than stock anyway.
OP, if new tires are too stiff/rough for your liking, double-check the PSI and adjust accordingly. Also should be aware that in sub-freezing temps, most rubber compounds will stiffen up and result in a somewhat tough ride. Unless you get dedicated snow tires which are made from a different compound entirely, that's just the nature of the beast.
The review that included them mentioned that they're stiffer than the other snow tires tested, and that the tread produces a "noticeable growl". I know the tread pattern is similar to the Z-rated "summer-only tires" I used to run on my "hot" BMW, and they weren't close to quiet tires. Doesn't sound like the ones you got are the best bet for a quiet tire.
Also, the size you selected results in a 1" reduction in the height of the tire (half an inch less ground clearance). You could have opted for a tire with a taller sidewall (with a sidewall ratio of 70 or even 75), though of course your handling would suffer (not that you're going to be tracking the car with snow tires). ;-)
FWIW, I had a (nearly new) set of 20" all-season tires on my GLK last winter, and got to experience some snowy, icy roads in Maine. The car did so well that I was getting pretty bored with the whole thing - until I drove my granddaughter's FWD Toyota Corolla... it was a white-knuckle experience. The true "snow tires" I've used in the past are noisier than all-season tires, and honestly I've never felt they worked much (if any) better in snow.




Last edited by Silver Shadow; Dec 4, 2024 at 08:17 PM.
The new tires are 235/65/17 and the originals are 235/60/19. Since the width of two are the same, the sidewalls are calculated at width (in mm) times profile (in %). That means that the sidewalls on the 17" tires are only 5% taller than the sidewalls on the 19" tires (235mm x 5% is just under 12mm, or 1/2" taller). Times two (top and bottom sidewalls) leave the 17" tires 1" shorter than the 19" tires.




Should we spend a whole 60 seconds using it?

Orig: 235 / 60 / 19
New: 235 / 65 / 17
... result:
Inner Clearance:8.35mm less
Outer Position:extend by 4.35mm
Diameter difference:-1.07" (-3.70%) <----
... confirmation of @habbyguy !!
Okay, let's spend a few more seconds checking other possibilities :
New: 235 / 70 / 17
... result:
Inner Clearance:8.35mm less
Outer Position:extend by 4.35mm
Diameter difference:-0.15" (-0.50%) <----
New: 235 / 75 / 17
... result:
Inner Clearance:8.35mm less
Outer Position:extend by 4.35mm
Diameter difference:0.78" (2.51%) <----
Seems the "70" would have been a better (closest to original diameter) choice.
Last edited by calder-cay; Dec 4, 2024 at 11:49 PM.




