hansamg

2012 coupe , stock 18 wheels. ( 8in wide frt and 9in wide Rr) 1. I like the blizzak LM-32 , what do you think about 235/40 frt ( 25.4 O.D. which is stock size) and 255/40 rear (26 in O.D. -stock tire is 25in. ) that 255 is the shortest tire for the rear without using the same front tire size on the back. I have had many snow tires and I know skinny is good but I,ve run "wide" Blizzaks with great result. The difference in width here is 3/4 in. for the rear. If I use the front frt size on the rear they'll be stretched a bit. Tire wear has been even across the summer tires so I don't care about rotation. I don't run snows down to bald, I replace at about 4-5/32nd's . I have a 4WD truck with Blizzaks, I just want to be able to run the AMG in the cold weather and have some grip and be able to handle a couple inches of snow.
2. TPMS - are the Schrader TPMS ,433 MHz the exact same unit whether I buy from tirerack , dealer or other internet dealer ?

hansamg

Anyone have a comment on rear tire height being one inch taller than stock summer tires? don't care about having "wide" snow ties , I've donei t before.

Diabolis

If you've done it before and you don't care about having snow tires that are too wide to provide optimal grip on a 450+ hp car, why do you care about the height? What are you really asking here - whether it's going to rub or whether you'll end up in a ditch? What difference does any of it make if you've already made up your mind about what you think is fine?

I am constantly amazed to see people like you that will spend $90K on a car and are too cheap to buy a proper set of winter wheels and tires. If you can't afford to properly equip and maintain the car, why did you buy it in the first place?

As for the TPMS sensors, for post-facelift cars it depends on the VIN of the car. The 433 MHz frequency is correct, but the coding is different for some of the later cars and there are different TPMS sensors. There was a discussion on the board (in the C63 forum) a few months ago about TPMS sensors.

hansamg

Thanks for replying. Difference in tread width is < 1 inch between the rears and the skinny alternative. Have you stretched 225/40 's over the stock front and rear wheels ? My situation is I own a pair of 18in take-off stock AMG wheels , I figured out the sensor , it is Schrader part # 8214, sometimes listed as S8214 or 28214. They are the 433 Mhz and supposedly will require no re-learn- just drive. I used to be anti sensor, til the ones on this AMG saved me in an early morning at the end of the driveway, I returned home , grabbed my truck and went off to make good $$ on my shift. Had I been flatted on the highway I probably would have missed my start of shift.
I have had many skinny Blizzaks on other autos, my needs for the C63 are just to give me a tire for a few inches snow, ice , and a softer compound for winter driving.
I just need to know if the one inch in the rear will rub. I also prefer not to stretch a skinny so much that the wheel surface is even more exposed to curb rash.
In the past I have always bought the WS 50,60,70 supersoft and sticky ice tires. I call a performance-winter tire an oxymoron, but here my needs are simpler.

Diabolis

The issue that you're likely to encounter is that the wider the tire, the lower the pressure it exerts on the road surface per square inch. In the winter and in snow you want to maximize the grip so a narrower tire is obviously better, but all other things being equal, I would probably put a 245/40-18 rear instead if you have the option (it's fine on a 9" rim). I don't know if you have an LSD, but with 255s on the back and without an LSD things do get pretty interesting when you try to get moving from a stop. A couple of bags of sand or kitty litter in the trunk might help. The larger overall diameter is not going to affect anything.

AFAIK the TPMS sensors were changed on the face-lift cars -- the non-P31 vehicles now do not use discrete TPMS sensors but instead rely on the ABS system to detect if a wheel is spinning faster than the other (indicating a flat). The P31 cars do use discrete TPMS sensors, but these were changed from previous years. Schrader TPMS sensors for a 2011 C63 sedan did not work on my 2013 P31 Coupe. Same 433 MHz frequency but the MB part numbers were different. The car will re-learn the new sensors automatically, so if you're driving for 15 minutes and you get the "no TPMS sensor detected" message you've got the wrong ones. Best bet is to call the dealer, give them your VIN and get them to give you the correct MB part number for the sensors for your specific car, and then cross-reference that against Schrader and see if they'll work. I had to buy a set of OEM MB sensors from the dealer, but to my great surprise they were actually cheaper than the aftermarket Schrader sensors that the Tire Rack and other retailers sell.

hansamg

Diabolis thanks for helping. So you think NO problem in a 1in taller rear tire regarding wheel well clearance. I don;t follow threads about plus sized tires/wheels here, so it's not on the tip of my tongue. I fully appreciate the physics of PSI. I've had alot of seat time in Formula 2000 and sedans at the limit.. I am not looking for the ideal ice racer, just the ability to have a flexible tire at cold temps with nice open shoulder blocks. I'll review the dimensions of the available 18's. I have the standard diff. and no PP . I don't care about rotating year to year, beside if they are directional and a staggered setup there's not alot of rotating that can be done. Once I run about 1/2 of a snow tires tread away , I replace them.
Now regarding the TPMS , you have given me some great data. I have 2012 coupe with no PP and the normal diff. I will call the dealer and maybe even pull a tire to see the model # of my current sensor. I ordered the Schrader tpms x 4 last night prior to reading your reply ( -Amazon $63 ea. they are returnable if incorrect).
Thanks again,

hansamg

Dealer got MB part # 0009057200 via my VIN and a general 2012 search. Schrader crosses that part # to their # S8214.....which seems to go with most 2010 and up MB vehicles.

Diabolis

The 1" taller tire overall would be 0.5" (12.5mm) closer to the top of the fender well, which is considerably less than what most people that use lowering springs drop their cars by (20-25mm). Seeing as it's on the rear, it won't affect the speedo accuracy either, and finally, pretty much every car manufacturer builds their cars and OEM wheels so that you could fit snow chains over them with no rubbing, so I don't see any problems from a functional perspective if your rear tire is 1" larger in overall diameter. It might affect airflow under the car at 100mph or possibly if you're carrying 500lbs of load in the trunk, but nothing that you would encounter in daily driving in winter.

The TPMS sensor part numbers are exactly the same ones that my car uses (2013 C63 coupe), so they're likely the right ones for your car as well. FYI, the old TPMS part number that DIDN'T WORK on my car was 000 905 4100.

Cheers,
Doug