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That wear looks fantastic for 30 cycles. Usually at that point I have to ditch my cup 2's due to being cycled out. I am on AR1's now. Will see how long they last.
That wear looks fantastic for 30 cycles. Usually at that point I have to ditch my cup 2's due to being cycled out. I am on AR1's now. Will see how long they last.
Actually the photo was taken at about 20 heat cycles, but I ran the tires for another 10 heat cycles and they still had good grip. You're right about the Cup 2's--they have a very short heat cycle life.
Tire Temperatures is the only tool to evaluate proper hot tire pressure. Suspension setup influences tire temperatures especially if the setup is understeering, hot front tires. Driver's input can cause overheating front tires. If the car understeers and the driver does not feel it, then the driver cranks more steering input and the tired overheat instead of waiting to go to full throttle on exit. Very complex is the challenge
Tire Temperatures is the only tool to evaluate proper hot tire pressure. Suspension setup influences tire temperatures especially if the setup is understeering, hot front tires. Driver's input can cause overheating front tires. If the car understeers and the driver does not feel it, then the driver cranks more steering input and the tired overheat instead of waiting to go to full throttle on exit. Very complex is the challenge
I was at the track yesterday (Club Motorsports in Tamworth, NH) and got some tire temperature data. I had an assistant waiting in the hot pits with a pyrometer, so we were able to get some data within a minute or so of coming off the track from a hot lap. That's the best we can do for getting hot temperature data on the tires.
The spread of temperatures from the inside edge to the outside edge of each tire was fairly uniform. The rear tires measured about 180 degrees (F) on the inside edge, tapering smoothly to about 160 degrees on the outside edge. The front tires were about 10 degrees cooler, but there was the same spread of about 20 degrees from inside edge to outside edge. The track surface temperature yesterday was about 120 degrees. I think the temperature spread on the tires is more important than the actual temperatures because the tires are already cooling off from the time I was on the track to the time we were able to measure data. This data was with hot tire pressures of 28 psi front and 30 psi rear.
So, I'm not sure the pyrometer data points to a "smoking gun" for the uneven tire wear unless somebody sees it differently. After many heat cycles, the wear is pretty uniform on the inside and outside shoulders of all 4 tires but far more worn down around the circumference of the tires just to the outside of center. It's the same on all 4 tires. The tires feel fine on the track so the only concern is the shortened tire life from the uneven wear.
You have (significantly, and too) low static negative camber as per comps and the tire manufacturer recs, you have visually accelerated wear and heat on the outside - and yet temps are hotter inside? I am confused, but interested to hear how you run this to ground.
PS - I have a new set of AR1 ready to go on, will post any observations if I think they may be helpful. Have been running NT-01 exclusively.
I've run many sets of AR1s on a Honda S2000 and on a 991.1 GT3. I had a similar wear pattern as you did. I never figured out why it does that. I don't think it's camber related. I was running -3.7 camber in the front on the S2000 and still had this wear pattern.
I also found them to have great longevity for the grip. It's a very fast tire and relatively cheap.
I was at the track yesterday (Club Motorsports in Tamworth, NH) and got some tire temperature data. I had an assistant waiting in the hot pits with a pyrometer, so we were able to get some data within a minute or so of coming off the track from a hot lap. That's the best we can do for getting hot temperature data on the tires.
The spread of temperatures from the inside edge to the outside edge of each tire was fairly uniform. The rear tires measured about 180 degrees (F) on the inside edge, tapering smoothly to about 160 degrees on the outside edge. The front tires were about 10 degrees cooler, but there was the same spread of about 20 degrees from inside edge to outside edge. The track surface temperature yesterday was about 120 degrees. I think the temperature spread on the tires is more important than the actual temperatures because the tires are already cooling off from the time I was on the track to the time we were able to measure data. This data was with hot tire pressures of 28 psi front and 30 psi rear.
So, I'm not sure the pyrometer data points to a "smoking gun" for the uneven tire wear unless somebody sees it differently. After many heat cycles, the wear is pretty uniform on the inside and outside shoulders of all 4 tires but far more worn down around the circumference of the tires just to the outside of center. It's the same on all 4 tires. The tires feel fine on the track so the only concern is the shortened tire life from the uneven wear.
Are you using an infrared pyrometer measuring tire surface temperature? This is an inaccurate measurement device because do not know the size or shape of the view image.
The temperature probe that penetrates 1/4 inch below tire surface is the best measurement of actual tire temperature, a pin point in time.
Infrared measurement is not a pin point in time and highly inaccurate of measurement vs actual.
I've got about 18 heat cycles on the AR-1's and wanted to provide some feedback and show the wear.
I used them the first 2.5 days at Watkins Glen during 75F temps and the second 1.5 days in 100F temps. The tires felt slightly greasier in the 100F temps but they were completely predictable and they managed the abuse really well. The wear is clean and no part of the tire got overheated.
They are definitely faster tires than something like the Cup 2. Cup2's are not happy once they get that hot, you end up fighting the car based on my experience. The AR1 was very happy on the track. They offer a very controllable slip at the limit. Extremely predictable. Best of all, they are WAY cheaper than something like the Cup2.
The sidewalls are VERY strong. This meant I was going out at 20psi cold and by mid session it was at the target pressure of about 28psi. They build heat quickly. I had no problems rolling over on the sidewall too much like you would with low psi on a Cup2. In fact I damaged the sidewall of a Cup2 because I ran it too hard too quickly while I was warming up the car.
Regarding the con's, the same thing that makes them awesome on the track takes away some of the joys of driving on the street. If you watched the other video I posted, they are very loud on the highway. Constant hum. Stiff sidewall so you feel everything. I want to say they balance out difficulty. First time I got them installed the ride was pretty smooth, very little steering shake. Now that I have some time on these tires, they have moved around on the wheels. Even after having them rebalanced there is a good amount of steering shake. Maybe they used too much grease to mount the tire due to the stiff sidewalls? Either way I am not sure I am coming back to this tire if I continue driving to the track. Hope to get a few more days out of these!
I've started using Nanking AR-1's as track tires this season. Now that I've accumulated a good number of track miles, I'm seeing some strange wear patterns on these tires. Take a look at the circled areas in this photo and note how much more they are worn down than the rest of the tire:
This wear pattern appears along the entire circumference of the tire and it's the same on all 4 tires, front and rear. The outside of the tire is on the right side of the photo, so you can see the deepest wear is offset somewhat to the outside from center. I've tried different inflation pressures and I'm currently running hot pressures of 28 psi front and 30 psi rear.
Other info: The car is a 997.1 GT3. It's primarily a track car that only gets driven on the street to get to and from the track. The alignment specs are:
-2.6 deg front camber
0 front toe
8.0 deg front caster
-2.3 deg rear camber
0.2 deg rear toe-in per side
I have relatively new Motion Control 2-way adjustable coilovers with pretty stiff springs (700# front, 900# rear) and the suspension has all semi-solid monoball joints.
Otherwise the tire grip is very good and holds up very well with accumulation of heat cycles. However, the deep wear that you see in the photo ultimately limits the tire life. The inside and outside shoulders show much less wear.
I was thinking this kind of wear could be caused by overinflation, but I've been trying progressively lower pressures and it doesn't seem to make much difference.
So, what could be causing this strange wear? Should I try even lower pressures?
Yep, thats just how they wear. You can't do anything about it.
I also believe the AR-1's are very sensitive to lower temperatures when driven on the street; what I mean is that I had "abnormal" inner shoulder wear and I believe it was due to not putting enough air in the tire after my last track session and then driving home. I had to replace my front AR-1's and added tpms sensors at the same time which allowed me to keep an eye on pressures on the way home from the track and I was able to keep 32 psi in them for the trip home and had MUCH less "abnormal" wear. I found it interesting that the pressures did not quickly after a track session but they fell quickly once I started driving on the street. I just add 5 psi before I leave the track and the check again when I get gas and have to add more then.
I can't imagine how my wear would be if I were running at 28 hot - I run 32 hot front and 33 hot rear in a 981 Cayman S.
AR-1 wear after about 3,400 street & track miles, 6 track days, Florida. Got money's worth. Rear up top, front below. Replacing with CR-S now. Will do a set of AR-1 again no question.
^ Are they heat cycled out? How is the inside shoulder wear with all of the street miles? What's your rear camber setting?
I'm generally curious how many street miles I can get on my rears with -2.0 camber before the inner shoulder starts cording. Figure I'll heat cycle out the tires before this happens, but curious regardless.
What tire pressure are folks running on the street? On track I'll keep them at 30-32 psi HOT for all four tires but driving home from the track I run the PSI similar to street tires - 33-35 psi in the front, 35-40 psi in the rear.
^ Are they heat cycled out? How is the inside shoulder wear with all of the street miles? What's your rear camber setting?
I'm generally curious how many street miles I can get on my rears with -2.0 camber before the inner shoulder starts cording. Figure I'll heat cycle out the tires before this happens, but curious regardless.
What tire pressure are folks running on the street? On track I'll keep them at 30-32 psi HOT for all four tires but driving home from the track I run the PSI similar to street tires - 33-35 psi in the front, 35-40 psi in the rear.
This is on a 997.1 C2S.
Yes, rears are toast. Fronts can't be too far behind, but loss of rear traction dominates.
-2.1 rear camber. No issue with inner shoulder wear. Always run vehicle spec pressures on the street, or thereabouts.
07-08-2022, 06:08 AM
