Bent Rims
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2013 C63
Bent Rims
Anyone had issues with bent OEM rims? I didn't feel anything in the steering wheel, just a bit of a rough ride in the seat - nothing substantial. I have my wheels balanced and rotated side to side every 5k miles. While on the balancing machine, I saw a slight out of round condition on 3 of the 4. I took them to a rim specialist where they heated, then using a hydraulic press, bent back into round. After a highway run, I concluded all was well again. Thinking back, I believe I bent them on Highway 680 as I transitioned onto a bridge. I recall feeling a complete suspension bottom out as I hit a major gap or pothole going about 75-80 mph.
Any experimentation with slightly lower pressure to absorb some of those potholes vs transferring all of the impact directly to the rim? Go too low and you risk a pinch flat or more severe rim damage. Curious what others may have experienced or experimented with? I have a 2013 p31 with 18 inch wheels running slightly over sized Micheline Pilot Super Sport front at 245/40 and rear at 265/35. I keep all four tires around 42psi cold.
Any experimentation with slightly lower pressure to absorb some of those potholes vs transferring all of the impact directly to the rim? Go too low and you risk a pinch flat or more severe rim damage. Curious what others may have experienced or experimented with? I have a 2013 p31 with 18 inch wheels running slightly over sized Micheline Pilot Super Sport front at 245/40 and rear at 265/35. I keep all four tires around 42psi cold.
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From: Houston - Clear Lake
C63 coupe, Z3M Roadster garage queen
Sounds like you are doing things exactly right - 18" wheels, insignificantly oversize tires, reasonable tire pressures.
I'm curious - do you have the traditional 5 spoke wheels or the twin-spoke design?
I'm curious - do you have the traditional 5 spoke wheels or the twin-spoke design?
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2013 C63
They are 5 spoke. The out of round bend was on the unsupported (inside) portion of the rim. I was told and did a little research that the factory run out (up and down) should be no more than .030 inch measured with a dial indicator at the bead seat of the rim (tire removed). My 3 were .083 / .091 and .079 and were corrected to .011 / .010 and .009. All are now within the .030 spec. Anyway, was just curious if others had any bent rims or had any opinions on more or less air. If nothing else, it's a good thing to keep in mind as you approach speed bumps or potholes on roads. It's not just the suspension you need to worry about.
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2010 C63 P30
my two fronts were reported to me as being slightly bent last time i took it in for service, but its not enough for me to really notice or pay to fix
I drive fairly careful on bad roads, so I'm just assuming previous owner hit some nasty potholes.
I drive fairly careful on bad roads, so I'm just assuming previous owner hit some nasty potholes.
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I think - just my opinion - part of the reason OEM rims get bent so easily on these cars is the obnoxiously high air pressure MB makes us run - 40+ PSI. Ruins the ride quality, and transfers a lot of the shock to the rims themselves.
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W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, Taycan GTS Sport Turismo, C5 Z06 & IS300 race cars
All other things being equal - it's low air pressure that may cause a rim to bend where a higher tire pressure might not. The lower the pressure, the smaller the "air cushion" between the road surface and the rim, so when you whack a pothole you're that much more likely to completely displace the air in the tire at the point of contact (it is easier for it to move elsewhere in the tire) and have the rim itself hit the pavement. Think of the tire as a closed tube of toothpaste. Is it easier for you to squeeze it in the middle and make your fingers touch when the toothpaste tube is nearly full or when it is half-empty?
Keep your tire pressures at the higher end of the approved range and you won't be botoming out your rims nearly as much, and furthermore you won't run the risk of blowouts at high speed due to the tire overheating (an under-inflated tire flexes and heats up a lot more than an over-inflated one). Think about the Ford Explorer / Firestone recall here - the blowouts resulted from low tire pressures.
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2010 C63 P30
Er - no. It's actually quite the opposite.
All other things being equal - it's low air pressure that may cause a rim to bend where a higher tire pressure might not. The lower the pressure, the smaller the "air cushion" between the road surface and the rim, so when you whack a pothole you're that much more likely to completely displace the air in the tire at the point of contact (it is easier for it to move elsewhere in the tire) and have the rim itself hit the pavement. Think of the tire as a closed tube of toothpaste. Is it easier for you to squeeze it in the middle and make your fingers touch when the toothpaste tube is nearly full or when it is half-empty?
Keep your tire pressures at the higher end of the approved range and you won't be botoming out your rims nearly as much, and furthermore you won't run the risk of blowouts at high speed due to the tire overheating (an under-inflated tire flexes and heats up a lot more than an over-inflated one). Think about the Ford Explorer / Firestone recall here - the blowouts resulted from low tire pressures.
All other things being equal - it's low air pressure that may cause a rim to bend where a higher tire pressure might not. The lower the pressure, the smaller the "air cushion" between the road surface and the rim, so when you whack a pothole you're that much more likely to completely displace the air in the tire at the point of contact (it is easier for it to move elsewhere in the tire) and have the rim itself hit the pavement. Think of the tire as a closed tube of toothpaste. Is it easier for you to squeeze it in the middle and make your fingers touch when the toothpaste tube is nearly full or when it is half-empty?
Keep your tire pressures at the higher end of the approved range and you won't be botoming out your rims nearly as much, and furthermore you won't run the risk of blowouts at high speed due to the tire overheating (an under-inflated tire flexes and heats up a lot more than an over-inflated one). Think about the Ford Explorer / Firestone recall here - the blowouts resulted from low tire pressures.
yup, the ride might not be the greatest but its giving more buffer inside the tire.
i try to just keep mine at an even 40 all around, anything higher and i get too bouncy over bumps (its bad enough as is)
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From: The Great White North
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, Taycan GTS Sport Turismo, C5 Z06 & IS300 race cars
As a rule of thumb, you need minimum cold tire pressures of 40 psi all around on the OEM 18s and 44 psi all around on the OEM 19s on our C63s. OP - 42 psi cold F & R are pretty much spot-on for 18" PSS in those sizes. I suspect you just whacked something nasty. Are you lowered or have after-market suspension bits by any chance? The OEM 18s are not particualrly strong.
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2013 C63
As a rule of thumb, you need minimum cold tire pressures of 40 psi all around on the OEM 18s and 44 psi all around on the OEM 19s on our C63s. OP - 42 psi cold F & R are pretty much spot-on for 18" PSS in those sizes. I suspect you just whacked something nasty. Are you lowered or have after-market suspension bits by any chance? The OEM 18s are not particualrly strong.
