SL/R231: tire cupping both front inside edges
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Junior Member
Joined: Dec 2025
Posts: 19
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2011 R350, 2025 GLA, 2018 SL450
tire cupping both front inside edges
I'm looking at a '16 sl450 with 24k miles. it has a wub wub and seems like excessive tire noise from the front with no vibration. I put it on my lift and both tires are slightly cupped at about 2" intervals every other tread block around both inner edges just slightly visible . contisportcontact ssr tires with alot of tread. looks like oe suspension no apparent leaks and feels well damped not ably to get any wiggles out of the suspension on the lift either. car tracks nice and straight and steering feels solid, not twitchey or heavy.
Is there any known common cause for this with the r231 chassis? my gut says a wee bit too much toe out is the issue.
If the alignment is corrected will the wub wub go away eventually? or will I need to replace the tires to get rid of it.
What are good target lignment numbers to not have this happen?
Thanks all!
Is there any known common cause for this with the r231 chassis? my gut says a wee bit too much toe out is the issue.
If the alignment is corrected will the wub wub go away eventually? or will I need to replace the tires to get rid of it.
What are good target lignment numbers to not have this happen?
Thanks all!
Last edited by weeblebiker; Apr 29, 2026 at 10:25 PM.
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AMG GTC Roadster, E63s Ed.1, M8 Comp. Coupe
Not sure about the cupping but SL's (R129, R230, R231) are subject to inner tire wear on the rears (but not the fronts). That is with proper alignment. This can be easily fixed by just adding 2PSI cold on the rear tires. But that is wear and not cupping. I assume your SL has springs with adaptive dampers instead of the ABC active suspension.
If the dampers and suspension look good I would just get new tires. Those tires mentioned are crappy run flats anyways. I would get rid of those anyway and then get some Michelin performance rubber instead.
If the dampers and suspension look good I would just get new tires. Those tires mentioned are crappy run flats anyways. I would get rid of those anyway and then get some Michelin performance rubber instead.
Thread Starter
Junior Member
Joined: Dec 2025
Posts: 19
Likes: 4
2011 R350, 2025 GLA, 2018 SL450
I passed on the car and told the dealer about the issue: loud tire noise and a wub wub and seeing scalloping on the inside edge that I was pretty shure was toe out.
