knfeparty

Wanted to share an experience. I ordered a new tire/wheelset for my 996. I bought OZ Alleggeritas in 18x8 and 10 and was unable to get 285/30/18 mounted on the fronts due to the sidewall stiffness. I'll report back on the R1-S once I get to drive on them some in September. The 245 width is what I went with for the front with 285 rear.

Mussl Kar

Mounting them yourself? Tire machine type?

knfeparty

Let me clarify: I am out of the country so I ordered them at Tire Rack and they emailed me saying that the 285s wouldn't fit but the 245s would. The only size in between is a 275/35 which is a bit tall anyways.

So maybe it is possible with some serious work but I am pretty sure that the sidewall stiffness of the R1 as compared to A6s is going to prevent some of the ridiculously wide mountings possible with the A6.

balefire

I haven't been thoroughly impressed with the tire installers at Tire Rack.
I bet that an experienced autocross local tire installer could get the 285 BF Goodrich R1 mounted on your front wheels. Sometimes it requires "breaking" them in on a wide wheel, then reinstalling them on a narrow wheel.

knfeparty

I don't doubt that someone experienced in autox mounting might have better luck. That being said, I have been on deployment for 6 months and just wanted some r-comps to be waiting on me when I got back!

PCalhoun

The recommended rim width for the 285/30-18 BFG R1 or R1-S is 10-11". You will be able to squeeze it onto a 1" narrower rim, but to go 2" narrower down to an 8" would seriously compromise the performance and structural integrity of the tire.

On a 986/87, 996/97 w/ 8 & 10" rims the sizes as recommended by Tire Rack are the best solutions, unless you went w/ the 0.4" shorter 265/35-18 on the front, which would alter the rake of the car, but provide a 0.9 more section width than the 245.

Peter Calhoun
Motorsport Manager
BFGoodrich Tires, Inc.
Michelin North America, Inc.

knfeparty

Peter,

Assuming you are the same Peter Calhoun as the 2009 CMod national champion, I have to say thanks a lot for sharing your significant experience. I would love to pick your brain regarding the R1-S; hopefully you can share some info on it here.
Oversized front tires make me a bit uncomfortable from an engineering standpoint regarding structural integrity, but I can't dispute some of the winners at nationals running square setups and squeezing huge front tires on small wheels. I haven't graduated out of the National Tour level (yet!) but if I am not mistaken radical fitments like that are usually done with hoosier A6s, which have much less stiff sidewalls than the R1 and R1-S.

Is the R1-S is intended as a direct competitor for the A6? My understanding from the advertising is that it is still a multi-purpose tire like the R1 that does track days, time trials, and autocross all well but isn't quite as sticky as the A6, but with a softer compound than the original R1.

I look forward to more of your posts, and perhaps we can meet for a drink and tire talk in the future. I will be in Greenville in September visiting my fiance Jackie Branscomb, who starts work at Michelin as a tire performance engineer beginning in September.

AudiOn19s

There have been discussions on this elsewhere, but those BFG's are HUGE for their advertised size.

The R1 / R1-S 285 has almost the same tread patch width as a 315 hoosier (11/5 vs 11.8). Section width is smaller which would work in your favor but you may have run into some inner clearance issues with the tire / suspension if they actually got that 285 to mount on your front wheel. IF it was a True 275 or 285 it would work, that particular tire might have given you fits though.

Andy

CSBM5

I'm still concerned that you'll find you don't want the 245/40 R1S up front -- it's the same diameter as a 275/35, and I think that's too tall with the 285/30 in back plus that additional height coupled with the way the R1 carries its wide section width all the way to the treadface, you might have fender issues too.

I do know the 265/35 R1 will mount on an 8" wheel and work so-so (remember we had these on the ZHP before switching to 245/40 due to fender clearance issues with the 265s).

Maybe Peter will confirm, but from my experience the sidewall stiffness on the R1 is similar to a V710 in that you can't easily pop them on much narrower than spec wheels like you can an A6. If you do get them to mount, getting them to take air can then be the issue, but even then it might actually be dangerous to dramatically deform that sidewall structure on this particular design and depend on it to function properly/not fail.

PCalhoun

Guys,
I'll answer as many questions as I can honestly and accurately; and yes I am the same Peter Calhoun who competed in a Formula Ford and is also a Porsche owner.

The R1-S has the same construction and sizing as our std R1 updated in 2010. The difference is in the compounding to get up to operating temperature quicker. For comparison sake think of it as A6 vs R6 in the Hoosier world or AC vs RC in Good Year's RS line. Obviously the compromise is performance vs wear, but w/ extremely high track temps the std compound may be the preferred choice.

I would no longer think of them as auto-x or road race, as the Hoosier A6 has become the defacto tire if you wish to win at a national level of competition in road racing. The R1-S in many cases has proven to be faster, more consistent over a race distance, and provide superior wear to the perceived mkt leader.

Sidewall stiffness is an interesting one, I have had people tell me we're softer or that we're stiffer. What I can tell you is that our shoulder profile is more square and that section width is the most accurate way to consistently measure the width of the tire and is less suspect to variability among manufacturers than published tread width numbers. The BFG R1 tends to put power down very well also vs. the competition.

For mounting if you are stretching a larger tire onto a narrower rim make sure to use mounting lube, preferably a paste to avoid moisture inside the tire, on both the tire bead, as well as the inner rim bead flange.

Starting pressures are generally higher for the BFG, but that will depend on vehicle weight and the amount of camber as just two examples of contributing factors. Three additional R1-S sizes were released this week: 315/30-17, 225/40-18, 335/30-18.

Rgds
Peter Calhoun
Motorsport Manager
BFGoodrich Tires, Inc.
Michelin North America, Inc.

CSBM5

Peter,

Thanks for your detailed reply -- great information. I look forward to co-driving knfeparty's 996 with the R1-S tires at an autox sometime. I've had a lot of great experience with the regular (and I guess version 1) BFG R1 over the past few years, so I'm anxious to try out the R1-S.

Regards,
Chuck

PCalhoun

R1 Version 1 would have been 2007 until mid-year 2010. For 2010 production date codes earlier than July or Aug are most likely v.1.

V.2 had a compound change that remains current until this day on the std R1. The R1-S formally introduced April 1 is an alternate compound to compliment our line-up for sprint racing, time trails, & auto-x.

PTC

CSBM5

Peter,

Thanks very much for your information.

I'm assuming that the BFG R1 series of tires was designed here in the USA? Greenville? What about the Michelin Pilot Super Sport?

Regards,
Chuck

knfeparty

Well I finally got to run on these. The OZ wheels are great but the lug bolt holes are very small so you have to have a kind of thin socket. Also, the captured hemispherical washers that the lug bolts have get stuck in them when you try to dismount.

245 and 285 widths worked very well. I think I get a bit of rub at full lock backing up, but nothing unacceptable.

The car is now really just a low-flying missile. I was blown away at the grip. On concrete, I was picking up the inside front wheel with no suspension mods except stiffened up konis.

Wear looked pretty normal; I was actually getting rollover on the rears at 44psi hot with a bit more than -2* camber, which is a bit contrary to most alignments people use where they dial out the rear camber. Understeer was not a problem at all but it was a fast course and not a technical one.

HUGE improvement in braking power. Fronts hook up instantly and you can just bury the pedal. Tires were hooking up so well that I was getting brake fade at an autocross with street pads. Need to put the Pagid pads on!

knfeparty