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I’ve been going to a local track for the past 2 years with this C8. The first year was with the PS4S and last year with Sport Cup 2 tires, and never had problems. This year, I switched to 18 inch MRR wheels and Nankang AR1 tires. The wheels have TPMS.
Today was my first event with these wheels and tires. As I left the house, the traction control light came on twice, even though I was light throttle and low speed. On the highway, the cruise control wouldn’t stay engaged, even though no lights or warnings turned on.
Now, at the track. In Track-Race 1 mode, it felt like an incredible amount of intervention from the PTM, almost like the engine wasn’t getting enough fuel. I switched to Race 2 mode and it wasn’t as bad, but it still happened under acceleration. When I used Race 2 with the PS4S, I could feel the tires slipping and I had to make the corrections, but I never felt the tires getting loose today. Once the tires built up some heat and pressure, then the car felt more normal, but still had the occasional stutter under acceleration.
Since I never felt the tires getting loose, I’m wondering if this is something separate from the new wheel/tire setup. However, I would expect a check-engine light or traction control light to come on. I’ll watch the video tomorrow to see if I missed any lights and I’ll check for any codes as well.
These issues are not caused by wheels, but rather by tire diameter specs. I'm surprised you did not mention the most important information: what are your tire sizes? : )
I think my diameters are the same as others running these wheels, but nobody is reporting the problems I'm seemg.
The issue is the tire sizes not having the front/rear size differential the system expects. That setup is nearly identical in diameter front to rear -- 25.6" / 25.4". In stock config the rear tires are 5.4% or 1.4" taller -- 25.8" / 27.2".
You can run that setup, but you'll need to turn everything off. Otherwise PTM assumes you have constant rear tire slippage due to the smaller diameter and will constantly intervene.
Man im sure some of the track Gurus will help out but for sure nothing to do with the wheels. something must be off , settings? traction etc i wish i knew, please share the info if you get down to the problem this way others dont have to deal with it. Here's a link to one of our clients in Japan taking on the track.
Man im sure some of the track Gurus will help out but for sure nothing to do with the wheels. something must be off , settings? traction etc i wish i knew, please share the info if you get down to the problem this way others dont have to deal with it. Here's a link to one of our clients in Japan taking on the track.
The wheels are perfect Carlos, he just didnt consider tire height when he selected his tire sizes.
I had the same thing with my first event with the 18 inch wheels. PLayed around with it and I have to hit Z mode twice and go to Race 1 to take care of the issue. No problems since.
Race 2 turns off TC and stability control, but your engine output will still be limited to available traction as calculated by PTM. It should work fine in your case.
@Carlos@mrrwheels Your wheels look great and it didn’t make sense to me that they would cause the problem. When I did my research, I never saw anyone mention the front/rear ratio needing to be the same as the stock sizes, and I didn’t think of it myself. Maybe add a comment to your webpage to inform buyers. You don’t have to dictate a size, but inform them of the ratio requirement, to keep the PTM happy.
@Carlos@mrrwheels Your wheels look great and it didn’t make sense to me that they would cause the problem. When I did my research, I never saw anyone mention the front/rear ratio needing to be the same as the stock sizes, and I didn’t think of it myself. Maybe add a comment to your webpage to inform buyers. You don’t have to dictate a size, but inform them of the ratio requirement, to keep the PTM happy.
That said, I think it still falls on the consumer to figure out which tires are the right fitment for your car. You can't just fit any tire with the right width, after all. If you fit a very tall tire, you could have even damaged your car or broken your fender, which I think would be on you. APEX makes a great fitment guide, but they are an exception. Most other wheel manufacturers either don't provide any info, or they keep their recommendations close to their chest as a sales tool.
@Carlos@mrrwheels Your wheels look great and it didn’t make sense to me that they would cause the problem. When I did my research, I never saw anyone mention the front/rear ratio needing to be the same as the stock sizes, and I didn’t think of it myself. Maybe add a comment to your webpage to inform buyers. You don’t have to dictate a size, but inform them of the ratio requirement, to keep the PTM happy.
Every performance car for the last decade that has traction control needs you to keep front to rear tire sizing in the same ratio to stock.
@Carlos@mrrwheels Your wheels look great and it didn’t make sense to me that they would cause the problem. When I did my research, I never saw anyone mention the front/rear ratio needing to be the same as the stock sizes, and I didn’t think of it myself. Maybe add a comment to your webpage to inform buyers. You don’t have to dictate a size, but inform them of the ratio requirement, to keep the PTM happy.
Noted for sure and thanks again. send some pics buddy lol
Cars I've tracked before either didn't have traction control or it could be turned off. I thought Race 2 disabled the these features, but apparently not.
not an issue if traction control and stability off. need to get proper tire diameter sizing. the rear needs to be bigger. I ran into the same problem in c8 z06 and rear ccb pads overheated and fade in less than 3 miles on track
04-10-2024, 11:02 PM
18 inch track wheels - issues
