BLKROKT

Who's running this size in the rear? I'm looking at streetable R-comps in this size (stepping up from my MPSS 275/30-19's, also a very hard-to-find size), and the only thing I'm seeing out there are Pirelli PZero Corsas. Anyone running these? Not my first choice, but people seem to like them ok, and I don't have many choices.

Alternately the MPSC2 ZP's (run flats) come in this size, but then I would have to run a non-ZP on the front which doesn't sound like a particularly good idea.

Any other suggestions? Reminder, in a 285/30-19 only thanks.

BLKROKT

Also the Dunlop Sport Maxx Race comes in the right sizes if anyone has any experience with them either

zcct04

No good suggestions, but I'd think that mixing runflats and standards would create unpleasant handling problems. The sidewall flex is effectively part of your spring rate, and I would assume that the sidewalls on the runflats are much more rigid than a standard tire.

BLKROKT

Yeah exactly what I was thinking. One less choice.

Diabolis

The Dunlop Sport Maxx Race came as OEM rubber on the track-equipped C63 BS cars. They're MO tires and have a higher load rating than the rest, which means you can safely run lower pressures...

P.S. The MPSS is really not a good track tire... so the difference to a proper R-comp like the Dunlops would be night and day.

BLKROKT

Thanks Diabolis. I've read some poor reviews on the Dunlops on heavy cars, which has me leaning towards the Pirelli's (which are also the same XL load rated at 98Y). Any opinions either way? Those appear to be my only real choices unless you have any other ideas.

zcct04

Other ideas . . . like a set of 18" track tires?

BLKROKT

Can't. I'm stuck with 19's because of my huge brakes.

zcct04

Ha - you and the Donald bragging about your big "stuff." :-)

I forgot about your brakes - that's a definite show-stopper for 18's.

Diabolis

Sorry - no first-hand experience with the Dunlops and no other suggestions in 285/30-19s. The P Zero Corsas are probably your safest bet. Can you actually squeeze in a 285 in the rear without rubbing?

BLKROKT

I couldn't resist... yeah, the 285's will fit fine. If they rub then I'll just bend/cut stuff.

Diabolis

I'm wondering if we can roll the rear fenders a little... I guess what I really mean is stretch them a bit as there isn't a lip to begin with. For as long as it doesn't require a respray or you might as well cut and put flares. Anyone done it yet? Any volunteers?

BLKROKT

That's exactly what I'm talking about. Now that I'm lowered, my 275's just fit. Rolling that rear lip and maybe a little stretch is all it will take for the 285's to clear. If I wanted to go 295's it'll require metal to be added and paint etc. I'm not there yet. I just want something to get me through the first half of this season. THEN we will see if we want to do flares or not - real metal ones. I like what Kriston did to his. Nothing too drastic, a little bit of metal added and a spray, and he can clear 295's I think.

Phil Chow

BLKROKT, if you're looking to run 18s...

Look into some 18" TE37 or 18" Rays G25s. I'veh eard the G25s clear one brake size higher, and I know the 18" TE37s will clear.

For example, 18" TE37s clear the 380MM BREMBOs on M3s. Usually 18s only clear 350MM.

I've cleared 350MM BREMBOs on 17" TE37s. So, I'm willing to bet that the 390MM should clear the 18" setup.

Mazspeed

Wow 285 is streching it. I am running a 265 trofeo r. They seem to run wide, I am not so sure a 285 trofeo r will fit at that size. If you have any questions on that tire, let me know.

Diabolis

Yup... I just orderd a set of Trofeo Rs in 245/35-19 F & 265/30-19 R that should properly fit my rims. The 265 rears look to be exactly the same width as the 275/30-19 MPSS, which already run on the wider side. I'm also thinking that a 285 R-comp will require some fender pulling. Unfortunately we still have snow on the ground, and I'm desperately tryign to finish building a race car for ChumpCar racing (the season starts in two weeks) so the C63 likely won't see any track duty for a couple more months.

Mazspeed - have you run the tires yet? How do you like them? What pressures are you running? Any differences before and after heat-cycling them? And, do you have & use a pyrometer by any chance and if yes, what temperatures are you seeing?

BLKROKT

Dunlop Sport Maxx Race are the winners. 80TW vs 60TW, and a full 10/32 tread vs the 6/32 on the PZeros is what sealed it. I need them to last long enough to get me to the track afterall.

Going to try and shove a 285/30-19 back there. The tire has a very square profile. Although I'm only going from a 275/30 (MPSS) to a 285/30, the tire is a full 0.5" wider, and about 0.25" taller. Will post up results along the way of what had to be done to get them to fit....

Mazspeed

I have run them and I like them. A lot. I think right now on the street I am running around F37 R38.5 and it seems to be the right balance on a 80 degree day. You can get around 30-40 heat cycles out of the tire. Sadly I don't have a pyrometer. Like any other race oriented tire, you want to warm it up completely before going for it, or else you might chunk them, but I have seen some good abuse out of them from media day testing and even some of the lesser experienced guys had not chunked them. For a light weight tire, it's surprisingly resilient.

Mazspeed

Very soft sidewall. I would not recommend. Especially if you're pushing widths.

zcct04

Dilemma - to shave or not to shave. Tire Rack says:
Sport Maxx Race tires are molded with approximately 8/32" of tread depth in their grooves and are left unshaved for use on damp tracks. While the tires do not require shaving for dry track use, their durability and lap time performance will improve if shaved to approximately 4/32" deep tread to begin competitive road racing/track use in dry conditions, however this will sacrifice significant treadlife.

Diabolis

Many years ago when I was younger, fitter, more entusiastic and I used to run Toyo RA1s, my experience was that all other things being equal shaved they lasted about 2x as long and were easily 2 seconds a lap faster than unshaved ones because there wasn't nearly as much tread squrm and they didn't heat up nearly as much. I always had two sets - one with full tread that I drove to and from the track on and that I could use as wets or spares, and one shaved to 4/32 (right to the point where the lateral grooves disappeared) for dry use that I towed with the car on a little custom-made tire trailer and swapped at the track.

I think generally it depends a lot on the design of the tire. I am told the R888s for example don't seem to benefit nearly as much from shaving due to the tread design.

Furthermore, if you're going to be driving on them to and from the the track, I'd opt on the safe side and leave them with full tread. On the street, cold R-comps (by cold I mean street driving temperatures) are already considerably worse in terms of dry grip than, say, a 10-year-old 740 treadwear all-season grand touring tire. Add a little bit of water in the mix, and in the wet you have about as much grip as a bucket of wet eels (think skating rink here). That would by far be my biggest concern if I were driving to and from the track on them.

BLKROKT

Yep. Thanks for all your feedback guys. Past the point of no return now. The Dunlop Sport Maxx Race get here tomorrow, and we're going to try and cram them on later this week before I head up to the Glen this weekend for a 2-day event. Will post updates along the way. I'm thinking I may be running with ugly banged-up rear fenders for a few days... we'll see...

zcct04

Nuttin' we cain't fix with a big enuf hammer! Good luck!
Looking fwd to your feedback next week.

Diabolis

Good luck with the Dunlops and let us know how you make out!

And, if you have no choice but to roll and/or stretch the fenders and don't want to use a big enuf hammer, this is the tool that you'll need: http://www.eastwood.com/ew-fender-ro...struction.html.

Mazspeed

Let us know how it goes. May I suggest going 1 to 1.5 psi more than you were normally going to go with them depending on temp and track conditions.