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+--- Thread: Attn: Hoosier R6/A6 users (/showthread.php?tid=2177)
- Mike Thomas #828 - 04-28-2010
For your edification:
Tire Break-In Procedure
Proper break-in will not affect initial performance but will increase the competitive life of the tire.
The procedure can be broken down into phases.
1st phase: The initial run heat cycle
2nd phase: The length of the time the tire is allowed to "cure"
R6 Roadrace: The first laps for the tire are critical for setting up the durability and competitive life. The first session should consist of no more than 10-15 minutes of running. The early part of the session should be run at an easy pace, with the speed gradually increased until the end of the session. The final lap should be run at the fastest possible speed. The intent is to achieve maximum tire temperature on the last lap. At this point the car should be brought in and the tires allowed to cool at a normal rate.
During the initial run-in process, the inflation pressure should be 3-5 psi higher than you would normally use. The best progression would have the driver taking 4-7 laps to accomplish this break-in. Each lap should be approximately 7-10 seconds per lap faster than the previous lap. The goal is to have the tire temperature as high as possible on the last lap without "shocking" the tire during the warm-up laps. In essence, no wheelspin, late braking, or sliding. The last lap should be at, or very close, to the maximum possible.
After completing the initial heat cycle detailed above, the length of time the tire is allowed to rest out of service is possibly most important. The barest minimum for this process to be beneficial is 24 hours (not "the next day"). Any less than this is a waste of time. The best situation would allow a week before using the tire again. The tires should be removed from the vehicle while they cure, or the vehicle lifted to remove its weight from resting on the tires.
Proper tire management is a difficult process. The payoff is greatly increased competitive tire life.
A6 Autocross: For autocrossing, the A6 does not need the same break-in procedure as the R6. The A6 needs a minimal scuff-in session before the first autocross run. This "session" can comprise of simply driving around the event site at minimal speeds on the A6 set of tires. By scrubbing off the newness of the tread (only minimal or no shine remaining) prior to your first competitive run, the A6 tires will be more consistent in handling, grip and responsiveness on the first run. If this is not completed, running on un-scuffed A6 tires on your first run may result in the tires not gripping properly, or feeling like they "skate" over the course surface. It is acceptable to run 3 - 5 psi higher when scuffing in a new set of A6 tires, but be sure to reset them to the correct operating pressures before your first autocross run. As you compile autocross runs on your new A6 tires, they should become more consistent in run times.
Tire Pressure Recommendations for Competition
Traditionally, Hoosier tires have often required higher pressures than other brands. This has changed with the A6/R6.
Roadrace/Track Applications
Vehicle
Weight
Recommended
Hot Pressure
Cold
Pressure
1800-2200 lbs
34-37+
26-31
2200-2600 lbs
35-38+
27-32
2600-3000 lbs
37-41+
27-32
over 3000 lbs
38-43+
27-33
+ Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
One characteristic of the tires is the tendency to "skate" initially (when inflation pressures are correct). It is important to resist lowering the pressure to attempt to eliminate this feeling. Dropping the pressure too far may improve the "feel" of the tire however it will also lower the performance and increase the wear rate.
Autocross Applications
For autocross applications, your starting pressure for the first run should be within 1-2 psi of the recommended hot pressures shown above. After the first run and each subsequent run, keep resetting the pressures back to your target hot pressures before taking the next run. This way your tires are at the proper pressure during the bulk of every run you take.
Tire Temperature Recommendations
For best performance the expected temperature range will vary from track to track. Generally, optimum traction will be generated when the pit lane temps show 180-200 degrees for the R6 in Roadrace applications, and 140-150 degrees for the A6 in an Autocross application.
Chassis Setup Recommendations
For optimum performance the tires will require around 3 degrees of negative camber. There will be a trade-off in maximum performance to maximize wear. Generally 1/2 degree less than optimum will result in the best compromise for wear and speed. Less than 2.5 degrees can result in excessive wear on the shoulder junction.
The tires should offer better performance with spring/shock rates that are higher than previous brands you may have run.
Things to Consider
These tires are molded to their designed tread depth. They do not require shaving to be prepared for competition use. Shaving the tire further will not improve performance. It is not recommended that they be altered in this manner.
Due to extremely light construction, the Hoosier tires have a much lower polar moment than many other radial tires. This translates to a very low rotational mass, which is a good thing for performance applications. The down side to this feature is that the tires don't resist "spikes" in braking force as well as a heavier tire might. As a result, there is a tendency for drivers to "flatspot" a tire the first time really getting to the limit. Vehicles equipped with ABS will benefit from its use. If you do not use ABS, it is recommended that you make an effort to minimize stabbing the brakes until you have some experience with the feel of the tire under hard braking.
The light construction also provides less protection from impact damage and punctures. Off-course excursions or running over debris on the track will likely result in tire damage.
These tires are not directional or asymmetrical. Once some wear has occurred it may be desirable to flip the tire on the wheel so a "fresh" shoulder now faces outward in order to even out the wear and maximize tire life.
Following the recommended break-in procedure will require a lot of planning to make it work. The benefits to doing it right include greatly increased tire life as well as more consistent performance and durability under stress.
The Hoosier D.O.T. Radial tires are extremely good in dry conditions, however they don't make very good wet weather tires. Having dedicated rain tires available will be necessary for your team to be properly prepared. Hoosier makes a D.O.T.-approved wet tire called the D.O.T. Radial Wet that has been proven to be superior at full tread depth in steady "wet" conditions. This tire can also be shaved to partial tread depth for use as an intermediate wet tire.
- 997S22 - 04-28-2010
Mike Thomas #828 wrote:
Quote:Roadrace/Track ApplicationsI know this is from Hoosier web site, but you will get around the track much more quickly with lower, not higher pressures. Some say tires may last a little longer with higher pressures, but what's your goal - traction and lap times or longer lasting tires? You decide - I let air out and really enjoy it.
Vehicle
Weight
Recommended
Hot Pressure
Cold
Pressure
1800-2200 lbs
34-37+
26-31
2200-2600 lbs
35-38+
27-32
2600-3000 lbs
37-41+
27-32
over 3000 lbs
38-43+
27-33
+ Higher pressures will improve the performance capability but will require a more sensitive feel to take advantage of the increase.
- geza - 04-30-2010
+1 for lower pressures. For those driving neutral handling, front engined cars (944,928?), Phoenix Performance recommends starting at 26-22.
- 997S22 - 04-30-2010
OK, you didn't hear it from me because it is a "racing secret" - probably old enough no longer "secret" - for 997 cars 32-33 F / 35 R Hot. Any time they get 38 psi or higher they start to get greasy and slide. This was way different from what others had told me, so I snuck up on it, cutting my prior 36/38 Hot settings 1 psi per session. WOW! Glad I tried lower psi's and I am not going back!
Cold starting temps depend on weather and your driving - for me usually 7-8 lbs. less and take it easy 1st lap until they warm up. Tuesday at WG it was 34 degrees out for 1st session so I tried 30/30 cold thinking they wouldn't warm up much - last half of session tires were sliding - checked them and they had gone up to 40F / 43 R so next time I will start lower even when it's really cold out.
- bobt993 - 04-30-2010
Sorry, but I don't agree. Not so much a racing secret from my experience. We had a NASA race two weeks ago at Summit and I started pressure slightly higher ending at 40psi and set a track record in race 1(25min race), then broke it again in race 2 (40min race). Part of it is car setup and driving style. My car has been setup by a pro driver/coach for more even loading and rolling the slow speeds. Because of this, the car remains very much at the limit before the apex and continuing to track out. I would still suggest targeting a 38 to 40 psi hot temp on cars between 2800 and 3100 lbs. I have spoken with a lot of racers and some Grand Am guys that show up at our races and have not been told otherwise. Your car setup and style may just be more confident with the temps.
- Mike Thomas #828 - 04-30-2010
Can you guys speak to the break in and curing process..that is what intrigued me the most about this article.
At a 3 day DE... lets say you do the breakin procedure first run group of first day...take them off..use another set for the rest of that day and day 2....Is it too soon to use the hoosiers on day 3 without sacrificing the longer life gained by proper curing?
- bobt993 - 04-30-2010
Mike 24hrs and they are good to go. Use them on day2. I have to be honest and say I don't do this at all. I typically run a set of stickers (new never run) for my qualifying session and then race on that set the same day. Longevity is not important to me as being fast for at least one lap in qualifying (new tires have a couple of magic laps that a half a second better than the rest of the tire life). 1st place is 2 free tires from Hoosier and up to 4 a weekend. Fortunately this has been paying off. I am only having to buy a couple of tires a year now with the support from Hoosier. Hawk also provides brake pad coupons, but I recently switched to Pagid and will not go back to Hawk.
- 997S22 - 04-30-2010
bobt993 wrote:
Quote:Sorry, but I don't agree. Not so much a racing secret from my experience. We had a NASA race two weeks ago at Summit and I started pressure slightly higher ending at 40psi and set a track record in race 1(25min race), then broke it again in race 2 (40min race). Part of it is car setup and driving style. My car has been setup by a pro driver/coach for more even loading and rolling the slow speeds. Because of this, the car remains very much at the limit before the apex and continuing to track out. I would still suggest targeting a 38 to 40 psi hot temp on cars between 2800 and 3100 lbs. I have spoken with a lot of racers and some Grand Am guys that show up at our races and have not been told otherwise. Your car setup and style may just be more confident with the temps.
You are clearly a successful and experienced driver with a well set up car to to be able to set 2 track records. Your response however wasn't clear on whether you have tested both higher and lower pressures to reach this conclusion, or were you able to reach this conclusion without any experimentation? Perhaps your record would have been even faster with lower pressures - hard to tell without testing. I've tested and am sticking to lower pressures, maybe with some more experience it will help me challenge your records. If you have tested a range of higher and lower pressures it would be great if you could share how the higher and lower pressures impacted handling and lap times.
In any event congratulautions on the records, that's great!
- bobt993 - 04-30-2010
I would suggest some tire testing. Go out cold 12 psi under your target of 40psi. Do 3 laps very consistently. Mark your lap times on your DAS system. pull in, check temps and measure your tire temps all 4 corners. This is hard to do in a DE and that is why race practice or test/tune days are much better with open passing. If your still low go out again. Repeat.
My response was really to say I would not advise recommending to others to run lower temps, especially a driver just starting out on R or slicks. Your more experienced and have a better skill set than someone new that could get in trouble with a car stepping out. I mentioned you have become confident with a certain setup. Just verify your results with a pyrometer and DAS to be certain that lower pressures are optimal. I would suggest some car setup may change that along with higher spring rates.
Start with the factory specs and get used to what should be optimal, then develop what works for you knowing your car setup inside out. I wasted a lot of time possibly years driving the car the way it was (wrong), until I spent the money properly on pro coaching. That set the car up correctly and changed my driving style to more curving and less forcing the car around the track.
I am not touting my accomplishment, but rather enforcing that if everything is dialed in the numbers should work. Answering your question about how did I know what worked. My fast lap(2) were lap 3 in race 1 and I ran higher temps (2 lbs) to get to speed quickly (middle of lap 1), then maintain a lead for the short sprint. Fast lap in race 2 was lap 18 (2nd from last) and that was done in traffic while battling for 1st. Ironically, I took 2nd, but was squeezing time each lap on P1 who finished 7/10th a second ahead. My pressures were at 40 because that is how they measured from testing for both race situations and track temps and when I came in from cool down (39psi, minus 1 lb). I am not even that good at setup. Larry Herman is much better at sweating the details. It may be years before I can really know the car, but tire I do understand now having run a bunch of combinations.
- 997S22 - 05-01-2010
Thanks for the explanation. I note and share your caution about advising others to use certain pressures, especially newer drivers. My goal was simply to share some information that was shared with me that I found helpful and thought may benefit other RTR members - I think that is one of the best reasons for these forums. Other RTR members should start with Hoosier's recommendations, but if they decide to cautiously experiment with other psi's they may find lower pressures deliver more grip, but our set ups are all different...
The recommendations were shared with me last year by an individual involved in preparing cars for Grand-AM, IMSA,Porsche Club Racing and DE . Their on-track testing of the optimal set up for Hoosier R6's was done with pro drivers running several laps at each of various pressures and found the best lap times came with lower pressures. The best lap time results were not consistent with the psi's that gave the best tire wear or most even tire temps. My friend said to me, "do you want even tire temps or the best lap time?" These findings were used by winning cars in last year's club racing. Like your situation, was it the car, the driver, the tire pressures? Likely the combination of everything coming together.
I had been told by many experienced drivers that Hoosiers had to be kept between 38 & 40 psi hot, so I was skeptical of this new recommendation. I asked around and it seemed most hadn't tried lower pressures and were so concerned and cautious that I was hesitant to even test dropping my pressures 5-7 psi as the friend had recommended. Then as I indicated earlier, I decided to test into it cautiously, dropping just 1 psi at a time, testing 2-3 pressures per session over a number of track sessions doing several laps at each pressure. I was sharing the car with my son that day and we both had 5 sessions so we had plenty of opportunity to test each pressure. After we got down to the recommended pressures, we were both certain the car had much more grip with lower pressures, but to be sure it wasn't because the track was warming up or some other variable we then started testing increasing the pressures again. With just 2-3 psi added back in we both noticed the grip deteriorate, so ever since we keep them lower. In our experience , for our car 38 psi seems to be the "break point" - at 38 psi or higher the tires slide much more than below that.
I had this same discussion 2 weeks ago with a fellow I was parked next to in the Lime Rock paddock. He tried lowering the hot pressures for the Hoosiers on his track prepped Evo from 38 to 35 and told me his data aquisition system showed his lap times in the next session improved by 2 seconds.
Again, if you or others don't want to try psi's outside the standard 38-40 psi recommendation that's fine, just sharing some information and experience that I thought might be helpful to other RTR members who are interested.