I have been running Direzza I and II's for a bit but am now ready to get a set of R-compound tires.

Has anyone here been running R-compounds on the track for extended sessions, around 20-25 minutes? What are your experiences and suggestions?

I am currently running with NASA in their time trial groups.

Thanks!

 

What size wheels will you use?

What suspension are you running?

What alignment? Do you have enough front negative camber? If not then get some adjustable front camber plates (see Waymotorsports.com) so that you can run at least -2.4 degrees or you will not be able to make full use of any tire on a track.

For R compound tires on a track you don't want the softest rubber for the fastest laptime, you want something that will last and handle the heat and wear of lapping.

What is you budget?

15" wheels will give you a decent selection of tires that are light and don't weigh or cost as much as with larger diameter sizes. You can fit 15x8" rims on an R53 but larger JCW brakes will require larger wheels.
For Durable R Compound tires- (100 treadwear or less)
Toyo R888 lots of sizes, not a bad choice, can be run on the street to events.
Toyo Proxes RA1 limited sizes
Hoosier R6 lots of sizes but also higher prices, cannot be run on the street
Yokohama Advan A048 Medium Hard compound
Nitto NT01 has sizes that will fit, should be OK

For Extreme Summer tire
BF Goodrich Rival 200 treadwear
Has sizes that will fit, can be run on the street and will be durable
Not as costly as R compound tires, you give up a little time but it can work on a budget. Better than either Bridgestone RE11A or Dunlop Direzza ZII.

 

Minihune - I am running KW Varient 2 coilovers with the h-sport adjustable sway bar and adjustable rear control arms. Wheels are 15x7 team dynamics pro race 1.2 with 15mm spacers.

Camber plates are next on my list, I'm not sure I realized how critical that front camber is.

The size I have been looking at are 205/50's. The tires I had been looking at we're the Nittos NT01's and the Toyo Proxes RA1's.

Between those tires am I splitting hairs on the performance on the track?

 

How competitive are you looking at being? The Hoosier A6 will handle shorter sessions (20 minutes) on a mini but they'll wear a lot faster than a R6 will. My recommendation would be the BFGoodrich R1-S.

Keep in mind the r-comps allow you to brake much much later but make sure your brakes are up to the task. R-Comps tax the brakes significantly more than street tires. If you're not running brake ducting now is probably a good time to start.

 

OK,

For track use you need to look at the big picture-

Determine your budget for each year/season.

Tires and brake pads are wear items.

Maintenance is stepped up to prevent trouble:
Brake fluid with higher temp tolerances
Full synthetic Oil changed more frequently
Coolant Flushed and filled regularly
Brake pads that handle heat better/ stock rotors OK of you can get cryo treated rotors, avoid drilled but slotted OK.
Brake ducts are good
Replace Supercharger belt each year
Keep your air filter clean

Dump all the extra weight you are allowed to.

Front camber- OEM is about -0.5 degrees. Using any performance tire on the track with this little front camber will cause excessive build up of heat on one part of the tread (usually the outer treads). In order to use the tire better you need more negative camber, how much depends on which track and how sharp the turns are.

I did this experiment once on a track lapping session (15 mintutes) using newish Michelin Pilot Sport Cup 205/50-15 on stock 15" MINI wheels run on an MCS with upgraded suspension vs a stock MC. I checked wear and tire temperatures right after the session and the MCS tires did well while the
MC tires were worn and much more uneven on the tread temps. Both drivers were doing about the same lap times.

Your alignment can be-
Front camber- as much negative as you can, -2.0 to -2.4 is OK to start
Front toe- zero
Rear camber- about 1 degree less negative than the fronts or about -1.2 degrees
Rear toe- 1/8" toe in.
Once you take tire temperatures you will know if you need to make adjustments. Use a probe style pyrometer, not an Infrared one.

For camber plates, try contacting Way at Waymotorsports.com, you want adjustable not fixed and ones that will fit your KW coilovers.

As far as Toyo RA1 vs Nitto NT01,
this was posted on Renntrack.com comparing those same tires-
"The tires are very similar, in fact the compounds between the NT-01, RA-1 are identical and everyone knows the RA-1's were more liked than the R888, which still has a similar compound. The sidewall characteristics are just very different. Toyo owns Nitto BTW so they certainly share DNA.

The difference is that the R888's are designed to run from full tread down, where the RA-1 was meant to be shaved or run full tread in rain and the NT-01 is already very low tread depth. The R888's so far have not responded to shaving as well as the RA-1 and clearly do not have the capacity to match the times full tread with less contact patch. The NT-01 is going to be a better tire new because it doesn't have much tread at all. For the money, it's hands down the best tire out there.

I have looked around for some A/B same day testing and only found a 1 (maybe two) in which both cases the drivers preferred the NT-01. Most people run R888's because they work better on the street (notably rain). But the shortcomings of the R888 are evident by the fact that Toyo has re-released the RA-1 (which sucks full tread without rain)

Really I think Toyo/Nitto have all of the bases covered, though not in one tire. The RA-1 is for the club racer who can shave a set and race and keep some sets full tread for rain. The R888 is for the guy who drives on the street and on the track and is the best all around tire and the NT-01 is for the track day guy who has an extra set of tires/wheels for the street but hasn't started buying R6's (or see's that it really makes no sense to)."

So are you using this set of wheels for track only and pack them in your MINI, using street tires to get to the event?

If so, then Nitto NT01 (no need to shave)
205/50-15 about $162 each, fits 5.5-7.5" rims, 23" tire diameter
225/45-15 about $181 each, fits 7.0-8.5" rims, 23" tire diameter

Summitracing.com has free shipping on orders over $99
205/50-15 $166 each
225/45-15 $176 each

While the 205/50-15 will fit your 15x7 wheel perfectly, you get more rubber and it will still fit OK using 225/45-15, you may add a little weight. Tire diameter is equal for lowered gearing. Personally I like the 225/45-15 for wider treadwidth and lower sidewall.

 

I love my Toyo RA-1s. I run 225/45/15. I do not do competitive track days so I am not worried about the absolutely fastest tire. The RA-1s seem to have a good balance of grip, wear, and a good tolerance for pressures. I don't even bother shaving them. Camber plates are a must. Even with Camber plates I still kill the outer edge of the outside tire. I also agree with the suggestion for brake ducts, especially with 15" rims. I get about 20-25 20 minute sessions out of a set.

 

If you've got your NASA TT License, I'm betting you're watching other cars just as much as your own. I learned early on that copying others is a great way to find what works for you. Check out your competition. If I were in your shoes (and I have been before) I'd try both tires and pick the ones you like best. After all, there's nothing more enjoyable that burning up tires at the track.

My personal preference is Hoosier R6's but I've run NT01's, R888's and Kuhmo's. I had a used set of A6's once but never quite got comfortable.

 

Hey Tim,

I have been watching others (which is the ideal), the trick is there are no other advanced drivers in Mini's. The Rocky Mountain Region is dominated by M3's, so it is a completely different platform.

With my Mods's I am currently in TTD, but after this winter may be jumping up to TTC, followed by GTS2 if things go right.

Thanks for your input on the tires!

 

Minihune - always educational, and never any shortcuts. Thanks mate.

Cheers,

Charlie