LOL. I just picked up a lightly used set of 19x9s & 19x10s CCW wheels from another member here (I think you may have bought a bunch of the other goodies he was selling) for this reason. Yeah, I have a built C5Z track rat that is considerably faster and cheaper to abuse, but man do I love that M156 singing at full chat and pulling like a freight train. Every now and then I'll do a session or two in the C63 and it is still completely intoxicating. I don't know what it is about that car, but it has imprinted on my psyche and I keep craving it...

 

 

Did the tires overheat?

 

 

^ Any news about Michelin? Are they passing on the blame or helping out?

 

 

I hate to say it, but you probably won't get any help from Michelin or any tire company on something like this. If it was a brand new tire you might have recourse but tire companies especially with their race tires know that these tires will be put to the limit therefore they feel that their customers will know that the abuse they encounter on the track is theirs alone. If I was Michelin I would want to see this tire as a way to make the next model better. What spec is this tire? Is it Mercedes Spec? Porsche Spec?

 

 

 

 

 

Jim,

I didn't see this before. It could have indeed ended up badly... it's a good thing you caught it.

I am indeed tempted to blame this on the narrow rim width for the tire size, not the load rating. For track duty with a 255 front tire on the C63, I'd be looking for a 9.5" rim if it will fit and a 10" for a 265. Porsche uses a 12" rim for a 305 PSC2 and a 9" rim for a 245 on the GT3 which is lighter to boot (especially at the front... but that 305 on the 12" rear gives you an idea of what they think is an appropriate rim size), so if you're going to spend the money on a set of rims for track duty you might as well size them properly.

Someone once told me that the Mercedes MO tires have additional belts / plies or some other type of reinforcement to increase the sidewall stiffness over the identical "regular" tires, and I know that the PSC2 now comes in a 255/35ZR19/XL (96Y) MO1. I don't remember who it was and I have no idea if that is indeed the case, but the fact that the MO tire weighs an extra ~1.5 lbs over the regular one suggests that they may not have been talking out of their butt. You might want to try getting those for the fronts next time - but wider rims would still be a must.

Cheers,
Doug

 

 

 

Have any of you guys tried running the Toyo 888r tyres around a track on your C63's.
Front 245/35ZR19LOAD / SPEED(89Y)
Rear 265/30ZR19LOAD / SPEED93Y
They have a lower load rating. But they are supposed to be a semi slick racing Tyre.

 

 

Yeah, definitely don't want tyre failure.
What is the minimum load rating I should be looking at for front / rear for track use.

 

 

The tire load rating is essentially a result of the tire size and the carcass construction. For any given tire size though, all of them appear to have the same rating (in either the SL or XL categories). All 245/35ZR19 XLs for example appears to have a 93 load rating... can't find any tires that are different. Porsche also uses their own tires with reinforced sidewalls (theirs are N0, N1 etc.) but I don't know what 102Y Trofeo R Mazspeed is thinking of (had one set of those too.. much too expensive and again not ideal for the car). Furthermore, you've never going to find anything even remotely resembling that load range... the 265/45R20 for my ML that I used to tow the old race car with uses 108H tires... that's for a 5200+ lbs curb weight + occupants / cargo + trailer tongue weight. 93 load rating would be sufficient. The OEM 19" 235 fronts only have a load rating of 91 (but they are MO reinforced).

I ran a set of R888s when I first got the C63 but on my 18" rims. At the time it was pretty much the only R-comp that would fit, but after I got familiar and comfortable with the car itself and started pushing it a litle more, they were far from ideal. Even at 245F & 265R they were still too wide for the OEM 8" & 9" rims, and while the 18" in those sizes have a load rating of 93, the car is too heavy for them, you have to run them at too high a pressure for them to provide optimal grip and then you push the tire temps past the optimal window and they get greasy as well... no bueno.

The car is simply too heavy for the grip of a proper R-comp, let alone a race slick... you will either have to over-inflate them or they will always roll under no matter what. The ideal tire would be something like the PCS2s, but in 18s if you haven't changed the front brake rotor diameter. Best bang for the buck would be to buy a set of old C63 18" rims - those are now a dime a dozen (and for track duty you don't care if they are cosmetically challenged for as long as they are not bent or previously repaired) and a set of Nitto NT05s in the OEM 235/40R18 95W XL & 255/35ZR18 94W XL sizes. Load rating is perfect, both the rims and the tires are cheap, and you'll likely have as much grip as you can realistically use on a car like this. Or maybe get a set of aftermarket 18x8.5 or 18x9 F that clear the brake calipers and 18x9.5 or 18x10 R and go with 245/40R18 97W XL & 275/35ZR18 99W XL Nittos. Yes, 18s - not 19s. There is no advantage to 19s over the 18s even if have money to burn.

 

I agree that the Trofeo R is a very pricy tire. I have had good luck with the Porsche spec units for the C63 but as you stated the car is too heavy for optimum track use. But I think it's the best tire for the C63 if you can find the 100y or 102y NO spec tires. I don't see them on tire rack right now, but they seem to come and go. I also agree that the 18s would be a better choice for track use.

 

Doug and Maz - sound advice.

Unfortunately, 18" won't work up front for those of us with the RB 390mm rotors, as mentioned.

Seems we have lots of trade offs with this car, unless we drop significant weight.

 

I'm still shocked that many consider this car for track duty. I've driven my fair share of cars on track (some meant for it, others not) and after driving this car, I wasn't too impressed. Yes it'll get the job done, but its so damn heavy (I am biaised, I have an S2000 track car; 2400lbs). A car this heavy goes through consumables so fast. Not to mention the cooling issues. This is an autobahn car / highway cruiser. For track purposes, ///M cars are the way to go. Dont get my wrong, the C63 is one of the best daily driver but by no means a car meant to see track duty. Keep in mind that I like to do 30-40mins full tilt, not 2-3 laps at 7/10 and then a cool down. Its just not a car suited for my track-driving style.

Not sure I can agree with the above statement of running NT-05s as dedicated track tires but then again, I have not done a lot of research in terms of whats available in this segment.