RE71R - Competition Tire Pressures - Track and Autoslalom

[j3st3r]

I am only autocrossing, not tracking. Also, wheel and tire width, camber, and surface also matter. I set my pressures based on what the outer shoulder is doing, working the tire to a little above the arrows on the shoulders with RE71's.

For what it's worth, my typical setup:

Wheels: 19x10.5
Tires: 285/35-19
Camber (F): -2.7 degrees
Pressures: 30F / 29R, +/- ~1psi
(Before every run, like DaveW mentioned...)

Reading the tire is always a good idea....

from AutoX event Sunday

 

[racer47]

Reading the tire is always a good idea....

Have you run these in cold weather, like 50s F? If yes, how's it compare to 80s ambient grip?

Is there anything else better in the cold, regardless of 200tw? A7s are not good at 50 F.

 

[blacksheep-1]

just to ball park it, if you are running..say 20 psi cold on a race track, I'd bump it at least 8 psi for an autocross course. Like I said before Hot dictates Cold, not the other way around.

 

[Norm Peterson]

Like I said before Hot dictates Cold, not the other way around.

This ^^^

It wouldn't surprise me one bit to find out that the pressures on the door sticker are accounting for two or three psi pressure rise from cold to operating. 'Cold' is simply the most repeatable condition.


Norm

 

[Bill Pemberton]

Guys, listen to Dave W., as his company SPS ( solo performance.com ) is a main sponsor of Autocross Events Nationwide , though he is super active in the Midwest. He is a mainstay at the Solo Nationals and he does even sell some tires , though not his main focus. He and his family have been involved with Autocrossing for well over 25 years , so good guy to know--- I got my helmet and many other track items from him.

Hopefully AuteauX will respond also , as he runs RE71s and he has been Autocrossing for over 40 years , as well as doing some track time.

 

[AuteauX]

OK Bill, you asked for it.

INTRODUCTION – I have been using Bridgestone RE-71R tires since June 2015 mostly for autocross events around the Midwest including SCCA Solo Nationals. I began using them for a 2008 Audi TT Quattro in 2015 after SCCA changed the rules that eliminated tires like the Hoosier A6/7s from Stock class renaming them Street classes. For Street classes SCCA only allows a tire with minimum of 200 hardness and 7/32 molded tread depth. Interestingly, at the 2014 SCCA Solo Nationals a Bridgestone engineer interviewed me and was interested in the Hoosier tire size I was using. They were in the process of designing a new Extreme Summer tire that became the RE-71R. I later purchased a 2016 Mustang GT competing in SCCA Solos in F Street class. For the Mustang I also use the RE-71Rs for autocross and the occasional track day events.

Since this is a Mustang site, I will focus my experience using the RE-71Rs with my 2016 Mustang GT. The car is a basic with two options, Power Pack and Recaro seats, with weight of 3585 pounds (half tank of gas).

AUTOCROSS and the RE-71Rs – On a 60 second autocross on concrete and a fairly warm day the RE-71Rs requires patience and awareness for the first 30 seconds since the grip will be less. After that first 30 seconds the grip comes in and you will end with a strong run, but likely slower than your next runs. After the 1st run the tires will cool in the grid. If the number of cars in the grid is small the tires will be warm enough for a strong 2nd run. The bigger the grid the tires may cool too much. In that case some of the competitors will cover the tires, which is allowed in SCCA rules. The second run is all out as the tires are at peaking grip. The tires may become too hot for the third run and many competitors cool the tires with water. Some competitors will even change the tires between runs with a fresh set of tires. When the RE-71Rs get too hot they get greasy and less grippy. Just when and how greasy they become is driver and car dependent.

The RE-71Rs are good for about 100 - 150 one-minute autocross runs on concrete depending on the weight of the car, allowed camber, and whether the drive wheels are front, rear or AWD. The tires are directional and can be flipped. After 50 runs, for the Mustang I have to flip the front tires. Street class rules do not allow camber plates and the only negative camber allowed is what you can get as stated in your manufactures Service Manual. Note that after flipping the RE-71Rs it takes 2-3 sixty second autocross runs to “wear shave” the tread back to maximum grip.

Tire goo is an issue with the RE-71Rs as they get hot. They pick up other rubber from the course you are driving on called OPR (other people’s rubber) that greatly impacts grip. It can also be rubber from the RE-71Rs translating across the tread. Whatever, if too much accumulates it effect grip and needs to be removed. Many competitors will have a battery powered scrapper to remove the globs or belts of rubber while in the grid. This requires jacking the car and scrap from the ground or taking the tire off scraping and putting the tires back on. You have to be fast.

TRACK DAY and the RE-71Rs – I have run the Mustang GT with RE-71Rs on several Track Days, SCCA Time Trials, NASA HDPE events and the famous Mustang Round up. Tracks are local Iowa and Nebraska track sites; Raceway Park of the Midlands (2.23 miles), and Motorsports Park Hastings (2.15 mile) both asphalt tracks.

On a warm day (maybe 60-80 degrees) the RE-71Rs will warm and begin maximum grip within ½ lap. The tires are excellent for laps 2 and 3. After that expect the grip to fall off. Just enjoy the rest of the session by improving your lines and marks on the course. After your session, usually there is enough cool down time for the tires that they do not need water or other mitigating cool down methods. Oh, and manage your tire pressures.

Track tire wear for the RE71-Rs is good considering the performance they offer especially if you are running timed events. I have run the 3-day Mustang Round Up with six 20-minute sessions beginning with a set of new tires. After the event the tires were OK for several local autocross events afterwards. I did have to flip the front tires after the Round Up event because of my limited camber. With camber plates you can greatly reduce the edge wear on the front tires.

On the two local tracks I have not had the issue of tire goo or OPR accumulating on the tread.

RE71-Rs are a great Track Tire if you are looking for the great lap time for timed events and you are limited to 200 hardness.

 

[AuteauX]

New Bridgestone RE-71RS ???

r/Autocross post on reddit
https://www.reddit.com/r/Autocross/comments/empyg0/new_tire_re71rs/

Press Release - Need Translation
https://kyodonewsprwire.jp/release/202001075449

Sizes Here
https://tire.bridgestone.co.jp/potenza/re71rs/size.html

 

[JAJ]

And the widest Potenza is - according to the Japanese Bridgestone site - 285/35x19.

 

[Bill Pemberton]

Good reason to go to the TireRack Link on the good ole TMO site, as you will find the Bridgestone RE 71R is available in a 305/19 !

Thanks Auteaux as I thought it would be quite beneficial for others to get a review from someone actually running the RE-71s. Nice write up and it shows why folks like the Bridgestones.

Now if we could get someone to do a similar write up on the BFG Rival 1.5S and the Yokohama A052 , we would have comparison of the current top three Autocross tires, as well as three strong track tires in the 200 TW classification.

 

[DaveW]

I have Yokohama AD052 ready for this season, first event isn't until March

DaveW

 

[Bill Pemberton]

Well, Dave W, we will expect a nice little report from you and I look forward to seeing you ( and Solo Performance Specialties, www.soloperformance.com ) and your Company at some of the Midwest Autocross and Road Racing Events. One of my buddies told me he just got a new helmet from you that was on Sale, so I guess you still have a few in the warehouse?

PS - I gave your decals I put on vinyl magnets to the guy above, so drop me some more when you have time.

 

[Grant 302]

Drifting off topic guys...

Flyhalf started a more general thread on tires.

 

[G-HORCE]

A little input on this topic that might be useful to someone. Due to a faulty pressure gauge, I got a good A/B comparison.

This was Autocross, not track. Sunny, temps in 60’s, on asphalt. RE71Rs, 305 square, at about 50% tread life. Gauge was reading 5 lbs low and didn’t figure that out for 5 runs. Thought it was me. Was actually running 35F/33R and could not find traction. Finally lowered to 30/28 on last run and the difference was pretty significant. Picked up 1.1 secs (50-second run) and the car felt much better. Surprised at a full second difference. I’m tempted to try 28/26 but not sure that’s safe.

 

[Bill Pemberton]

There are a bunch of folks on here that autocross alot , and many either are running RE71-Rs currently or have in the past. I expect some of them will chime in on their experiences , but if you started at those temps you were likely well over 40 lbs hot?

DaveW, Dave_W, Autoeaux, etc. will probably comment on your Bridgestone tire pressures, as all of them have plenty of experience ---- heck AuteauX and DaveW were running in the last Century ,haha!

 

[G-HORCE]

Thanks Bill. No, all pressures above are hot pressures.

 

[Bill Pemberton]

Well, you should be getting comments soon, and the other item you might note ( we do know asphalt pressure can be different than on concrete ) is what was the temperature the night before. Though you mentioned it was in the 60s, if the prior night was in the 30s/40s , the pavement still might have been pretty cool for drivers.

 

[AuteauX]

G-Horse, I might try the 5 psi lower pressures in the dry during an autocross next year. Of course my 16 Mustang GT is stock and I used the higher pressure settings to indirectly add to my spring rates and that seems to work best. It does not hurt to recheck what you think is correct to verify and confirm your settings. Always think outside the box, because truth changes with time!

Now since Bill Pemberton mentioned or implied that I was "OLD" it is time for a little story. Once upon a time, a friend of mine (Ancient 1966 Mustang Shelby GT350H driver) and I co drove a 1994 Camaro at autocross events and I drove the car at some track day events. At one autocross event we noticed that there were significantly more right hand turns than left hand turns in the course. We knew some of the limitations of the GM positraction on right hand turns versus left hand turns so we tried something. We put 50 pounds of pressure in the left rear tire and 25 in the right rear tire. The car handled weirdly, but the right hand turns were great and our autocross times dropped. We won the class, 1 and 2, but I don't remember which one of us ended on top. The point is to always keep your mind open to other ideas about setups; ideas within yourself or others.

 

[Bill Pemberton]

Great Story AuteauX, and it sounds like the Nationals in Salina, Ks. many, many years back. I had a tiny sponsorship from Yokohama and they gave me a set of the new compound rubber donuts they thought might be killer for Nationals. On Day one I was in 3rd in my Formula 350 Firebird ( white of course ) and like you and Don, pressures were one of the few ways to adjust for springs, non adjustable shocks , etc. so pressures often made a big change. I was running 50 lbs in front and in the upper 30s in the rear. I had a slew of drivers running Yokes asking me what I was running , and most of them were Contract Drivers ( meaning they got new tires for both days at the Solo Nationals ). They all thought I was nuts , but on Day 2 the pressure was high and the tire pressures went up , and my placing went down, ha! I trophied , but if I remember correctly it was around 7th or 8th. So the advice from AuteauX to keep your mind open to other ideas is unbelievably true and what better place to get Autocross/Track ideas than TMO!!??

 

[AuteauX]

OK now it time to talk RE71-R tires on the track. I attended the Mustang Roundup X held at Motorsports Park Hastings, Hastings, NE on October 1-4, 2020. The whole week the weather was cool and sunny. Mornings were in the forties and afternoons we were lucky to see 60 degrees. Needless to say, the RE71-Rs preformed nicely at these cool temperatures. Rather than just maybe 3-4 laps of great runs on hot days the tires grip lasted throughout each 20-minute session. Setting initial cold pressures for the RE71-R’s at 30 front and 28 rear gave me final pressures of 37 front and 35 rears upon returning to the pits and what I felt was my optimal pressure from precious track and autocross experiences. Tire wear was acceptable throughout the event. I have included more information about the event on the forum under Mustang roundup at Hastings or quick link here: https://trackmustangsonline.com/threads/mustang-roundup-at-hastings.15581/#post-233052

 

[DaveW]

A little input on this topic that might be useful to someone. Due to a faulty pressure gauge, I got a good A/B comparison.

This was Autocross, not track. Sunny, temps in 60’s, on asphalt. RE71Rs, 305 square, at about 50% tread life. Gauge was reading 5 lbs low and didn’t figure that out for 5 runs. Thought it was me. Was actually running 35F/33R and could not find traction. Finally lowered to 30/28 on last run and the difference was pretty significant. Picked up 1.1 secs (50-second run) and the car felt much better. Surprised at a full second difference. I’m tempted to try 28/26 but not sure that’s safe.

My brain is mushy today, but I would not go too much lower than 30/28. When I ran RE71's, I was usually at 32-34F and 29-30R.

DaveW