Am planning for next year's track season and need some sage tire advice. Have no class restrictions to consider.

I feel that I've pretty well maxed out my lap times on my 205 section RA1's. Feel that my 205 section tires are at the limit in sweepers and chicanes. Will converting to 215 or even 225 (if I have to) materially improve my lap times? I am reluctant to push the engine power route very far for fear of reducing my reliability. Great dual purpose car.

Any experience based advice is appreciated.

John Petrich in Seattle

 

i, too, believed that the 205 RA-1's were too skinny and short. i switched to 225/40/17 Hoosier R6's. i love them. excellent grip under accelleration, braking and turning. predictable enough at the "break loose" point if you have some experience. i don't know what wheel size you are running, but tire selection is really limited for the MINI. in the 17" RA-1, only the 205's have a high enough load rating (they have a reinforced sidewall).

 

(Mr ?) Bean,

Appreciate the input. Just what I was asking. Tried to keep my post short, but my track goal is to get as much grip in the corners as possible so I can maintain the momentum for the straight aways.

It looks like new rims and larger section track tires are in my future.

Could we continue the conversation via email(preferably) or PM? I have a number of mundane questions that might not be too interesting for this forum's readers. My email address is: petrich@u.washington.edu I'll start with a PM to you.

Any other advice?

John Petrich in Seattle

 

the best is a light 15 inch wheel with 225... Best grip light weight and the cheapest tire size.
It's the way to go..
Plus if you chose to upgrade your brakes wilwood makes a kit that fits 15's
It's much faster in the corners!

 

Petrich,

I, for one, am interested in your mundane questions as well as the answers that will go along with them. If you feel them appropriate to post, please do!

mb

 

+1

 

by popular request, here is my message to john. warning, this might get long.....
John: i'd be happy to share w/ you my experience and thinking as to how i
arrived at my current setup.
1. i already had the 13" TCE/Willwood bbk so i was committed to 17" track
wheels. the rest of my setup, when i went w/ track-only wheels and tires:
Spax coilovers, RDR camber plates, Alta PSRS, M7 USS, RDR lower rear control
arms, 19mm rear sway bar. front camber -2.5*, slight toe in, rear
camber -1.5*, zero toe. i don't remember exactly what my caster was after
installing the PSRS.
2. i chose SSR type C-RS wheels. 17"X 7.5". while not inexpensive, they
provided the size and weight that i was looking for. (they were way cheaper
than my HRE street wheels! how's that for rationalization?)
3. i went w/ 205/40/17 RA1's. i wanted the toyo's so that i could get some
experience on a forgiving r-comp before going to a true (more unpredictable)
slick. this is the only size that worked. while much faster than street
rubber, the narrow section limited traction under braking ansd cornering.
in addition, combined w/ the short height, promoted a lot of wheelspin
exiting corners (and i have lsd).
4. after my first weekend w/ these tires, i was looking for a replacement.
i stumbled across the fact that Hoosier introduced a 225/40/17. a perfect
size IMO. prevoiusly they only had a 225/45 which i thought was a little
tall for the torque that i had available at the time (totally stock motor)
and i wasn't sure that they would fit my ride height. the 225/40's are a
perfect fit on my car. i have to run a 5mm spacer up front (even w/ my
street wheels) to clear my coils on the inside w/ -2.5* camber.
5. i ran the RA1's for most of thr next weekend and switched to the
Hoosiers foe the final session so i could get one proper heat cycle on them.
by the end of the session i was much (2-3 sec) faster and the car felt much
more stable, particularly under braking.
6. with this much more rubber, i have gone to much more agressive track
pads (willwood poly h's up front and porterfield R4 in the rear). my car
can now stop stupid fast. my last instructor before i started running solo
said, "that's not a car.....it's a set of brakes w/ a motor attatched."
7. i corded my firsr set after 3 weekends plus the one earlier session.
not great, not bad. i look at it as the cost of doing business.

misc thoughts......don't dismiss the option of 15" wheels. RSR (the
grand-am team) switched to 15's w/ better results. this is the size
recommended by DMH and LDG. TCE ansd Texas Speedwerks both offer nice brake
upgrades foe 15" wheels. i have never looked at thr sizes available in 15",
but it cannot be worse than the choicw in 16" or 17". i went w/ 13" rotors,
because it looked so much better under my 18" HRE's! i love the brakes on
the track, but there exists good smaller options. my first instructor (a
MINI driver) uses Nitto NT-1's. he is still a little quicker than me and
likes these tires. he is running 17" wheels to fit his JCW brakes.

i've run about twelve weekends in my MINI at Sebring, Homestead and Moroso.
i'm a solo qualified driver w/ plenty of room to improve. at least i don't
feel that anything on my car is "holding me back". i drive pretty
aggessively and have a lot of fun. we have 6 So. Florida track junkies who
get to the track pretty often. i'm the old man in the crowd, but the young
guns can't catch me yet. here is a little video from my last session in the
advanced group.
http://s166.photobucket.com/albums/u103/beaner2147/?action=view&current=PBOCSebring.flv

good luck.

 

I run ra1 205s. I have about 70 track days fwiw.

Narrower tires are more predictable which means you can spend more time closer to the limit. If you are really running that 5-6% slip angle on a perfect line, using the whole track everywhere, then your skill level is up to a wider tire.

The next question is whether you can really go faster. You'll corner faster with a wider tire. You'll accelerate more slowly with more weight (but you can get smaller wheels and actually save weight). You'll also have more air resistance with wider tires which will matter at high speeds. The mini is already so aerodynamic....

I can imagine going to 225s sometime but the 205s don't seem to be my limiting factor right now.

Don't go to wider lower profile tires because everyone else is.

 

John,

You make a lot of sense. I'm certainly not at the point where my tires are the sole limiting factor. In some situations, the tires are limiting, and in other situations, the limits are because of me. Probably the majority are me.

I am not committed to the larger section tires. Just finished a track day on the remnants of this year's 205 section RA1's and just love 'em. Was talking to some friends who drive with larger section tires and they are pleased with them. One driver in particular is leading the points chase in the NASA Time Trials, and he's using 225 section tires. He is quite an accomplished driver, and might be one who can take advantage of those tires.

How is your car prepared? Lowered? Aftermarket suspension? Engine work? Alignment settings?

Regards,
John Petrich in Seattle

 

I really wish I had something to add here, but being as I just went from a 225/45-16 soft street tire to used 205/45-16 Kuhmo Escata 700 this past weekend I can't add much but sit back and learn.

One thing I did note is the overall gearing changed with the smaller tire. A turn I was able to carry 2nd to exit now has me doing a quick shift before entry so I can exit properly in 3rd.



Looking at the map above these are the changes I made after going to a smaller tire. Running CCW exiting Big Bend in 4th reqires a down shift to 3rd for the uphill right turn entering the Rattlesnake complex. The track levels out as one enters the slow speed left. A quick downshift to 2nd pulls the car around but can provoke wheelspin if not smooth on the throttle. With the larger tires I was able to remain in 2nd through the downhill off camber Wagon Wheel section. Once past the 2nd apex of this dual apex corner I'd shift up to third with the larger tires. Now with the smaller tires I shift up to 3rd in the very short straight exiting the slow 2nd corner. At this point I'm just over the sweet spot of 3500 RPM where my engine comes to life. I carry that through the uphill exit of Wagon Wheel and now shift to 4th as I crest the hill leading down to the turn in point for the sphincter tightening Richochet. However this creates a slight conundrum. Previously I would reach about 7500 RPM before breaking and downshifting to 3rd for Little Bend. Now I'm bouncing off the 8000 RPM limit about 3/4's down the straight. Going to 5th for a split second would help but would require two downshifts before the turn. If I was racing and going for it all I'd play with tire sizes to find the best balance between grip and gearing. Since I'm not I just breathe off the throttle some and coast the last bit to the braking zone.

Hope that offers another way to think about what size tires to use.

 

The discussion is on section width with tire size as a seperate variable. However, your point, and the point made by others is that section width and tire size must be considered together when looking at the overall performance package. I'm quickly getting lost.

Measured tire temps of my 205 section tires at the last track day and am favorably impressed with the balance, front to rear, tire pressure, and overall alignment. Am starting to think that maybe I should leave things alone and learn to drive. Gnatster's comments about 7K+ RPM's are a stark contrast with my less aggressive driving style, limited to 6500 RPM's.

John Petrich in Seattle

 

can you provide a link as to where you found the 225/40/17s size tires?

Thank you.

 

i bought my first set through the tire vendor at the track. since it was an odd and new size, i ordered them before the event. i bought my next set from an SCCA racer w/ one heat cycle on them. Tire Rack has them on their site. Hoosier R6's and, i believe, A6's.

 

i've run about twelve weekends in my MINI at Sebring, Homestead and Moroso.
i'm a solo qualified driver w/ plenty of room to improve. at least i don't
feel that anything on my car is "holding me back". i drive pretty
aggessively and have a lot of fun. we have 6 So. Florida track junkies who
get to the track pretty often. i'm the old man in the crowd, but the young
guns can't catch me yet. here is a little video from my last session in the
advanced group.
http://s166.photobucket.com/albums/u103/beaner2147/?action=view&current=PBOCSebring.flv

good luck.[/quote]

Very informative posts here. Rather refreshing actually! LOL That was one great vid. proof that being smooth and consistant = great laps. I lost count of how many cars you reeled in, well done! I did notice that you never passed another MINI? Nor did I ever see you get passed? That had to be a major ego adjustment for several of those drivers who finnaly had to point you by after several brake checks on your part.

I have a friend who gave me some used tires(80-90% left) to try my 1st r compound track days on. 1st set Hoosier 225/40/15 (kosie k1) real change at CMP from my street tires! Took some adjustments on my driving style for sure. No real issues when they broke loose as it was smooth not abrupt. Toasted left front (pre-quaffie) and had to go back to the BFG G sports 215/40/17's on 15lb Enkeis that I run on the street, still fast but not as controlled.

2nd will be the 205/45/15 Toyo Proxes R1s that I will be mounting this week, and will be running at LTGP on 12/3 at Wicks track day. Lots of new factors may skew the comparison now that I have several upgrades to the car. 227whp -190tq vs 185whp -163tq / header, quaffie etc. We shall see.....

Any constructive thought of what to expect would be appreciated (DMH has not found this thread yet! )

Tim

 

Any constructive thought of what to expect would be appreciated.
Tim[/quote]

with all that new found hp/tq, there will be a learning curve! from where did you find/purchase these increases? oh, no.....i didn't just ask that question...the MINI can hang w/ some serious hp cars. here is a clip from my first event (at Homestead) in the solo/instructor group. faster cars and better drivers. MINI still does pretty well. http://s166.photobucket.com/albums/u...071125-001.flv

the Lotus Exige that i spend much time chasing is owned/driven by a former MCS owner/driver.

if you feel that the car is holding you back, upgrade......if you can't get the car to its limit, spend on more DE's......then upgrade.....go fast, be safe and have fun....

p.s. i didn't pass any MINI's in the previous vid because i started in front of them and they couldn't catch me! score one for the old guys!

 

Having Waylon as a friend can get expensive! LOL Since he has a shop in ATL now, give him a shout and come spend a few days and a few$$ ! List of tweaks is kinda long, guess I need to jot it all down. We sort of got ahead of my mod plan due to other things wearing out. Car was pretty strong before / very strong now. Some of the story...
http://atlantaminis.proboards32.com/...ead=1194579985

I have done several DEs and have turned into a bit of a track junkie over the last couple of years. I have been very fortunate to have some extremely good instuctors and always try to learn as much as possible from each one. Old guys like us can still learn! And have a lot of fun doing it! LOL
I've been working on that lerning curve with the latest mods and it is like driving a different car for sure, the car has stayed ahead of the driver in capabilites most all of the way.

Thx again for the vids!

Tim

 

TLMCS05,
Did you swap the factory LSD for the quaife??? If so, was there a noticeable improvement?? I've got an '06 w/ stock LSD, and I'm ust trying to find out the advantages of the quaife over stock LSD. Thanks.

 

Did not have LSD. Not sure if the upgrade would be worth it or not. Others may have a better answer for that.

 

Oops. I dropepd out of this thread. I have a GP, so all the JCW everything and a little lighter. This includes the stiffest jcw shocks and the car is a fair amount lower than a normal mcs. I had to put camber plates in front or I was cording tires in one day in the front (so two days from $800 worth of tires. ouch). With the camber plates and 2.5 degrees of camber in front I'm doing a lot better on wear and the car is a lot faster. I also added the h-sport 22mm sway bar in back and went to 1/8" out in front and 0 toe in back. With all of this stuff, the car rotates almost too easily. I don't feel like I'm bouncing around in the corners, so I'm not sure if stiffer shocks would actually help. (relatively) soft = more grip. Hard = less roll and less geometry change, less grip.

If I wait that extra 1/2 second before getting on the power, wheel spin is a lot less and I actually exit faster. And, it's a lot cheaper. I can't afford $2-400 a day for just tires.

 

LSD is very worth it coming out of corners and up any low gear hills (NHIS).
I only have the stock LSD, so I can't comment on the quaife. I could go for something more aggressive. With my current suspension I can rotate as fast as I want going into low speed corners, and more lock coming out would not be a bad thing.