I have 18x9 and 18x10s on my Cobra now, with R888s in 265/35R18 and 295/30R18. The R888s were great the first year, okay the second year, and mostly crap the third year. I have maybe 5K miles on them and the grip has gone to shit.
The first problem is the cold. The R888s are summer-only tires, and my Cobra gets parked from late fall until early spring and never gets driven when it's below 50F or so. I live in southern Illinois where the winters are mild (for the midwest), and my garage stays about 20F above ambient, but it occasionally gets down to around freezing in the garage. Even though the car isn't being driven, the cold temps permanently hurt the grip of the R888s. Previously I used to be able to punch it in first gear on a warm day and the car would just hook and go. Now if I punch it in second, it's all over the place and doesn't get traction until third.
The second problem is the tire compound. Prior to the R888s, I had a set of Falken RT615s, which are comparable in tire compound. Their grip also went to shit after a couple years. The RT615s were 200-compound tires and the R888s are 100-compound. Soft rubber designed for competition that doesn't tolerate the cold. At all.
So, what I need are 300-treadwear summer tires that are also not okay for winter driving, but which aren't going to turn into butter if I don't pull the tires and bring them inside when I park the car for the winter.
The next problem is that when shopping for 300ish treadwear tires in 18" sizes, there pretty much aren't any that are Cobra sized. I can get 265s or 275s for the fronts all day, but when looking at 295s or 315s for the rear, I'm looking at pretty much 100-treadwear competition tires. But, if I move up to a 19" wheel, there are a bunch of options in the 300-treadwear range that have suitably sized front and rears available.
Here's what TireRack has for 295/30R18. The only 300-treadwear tire is a Kumho HTR Z III, and that's not exactly a well-rated tire for the 550RWHP+ level.
https://www.tirerack.com/tires/Tire...8&rearWidth=255/&rearRatio=40&rearDiameter=17
When looking at 315/30R18, it's all 200-treadwear or below, so forget that.
https://www.tirerack.com/tires/Tire...8&rearWidth=255/&rearRatio=40&rearDiameter=17
But, when I step up to 19" wheels, there are plenty of options in the 295-325 width that have 300ish treadwear. For example, I just put a set of Firestone Firehawk Indy 500s on my '15 Audi S4 and have been very pleased with the grip and price, and they're available in 275/35R19 ($170) and 325/30R19 ($280) and have a 300+ treadwear.
https://www.tirerack.com/tires/tire...ear=2004&autoModel=Mustang+Cobra&autoModClar=
The Continental Extreme Contact Sport is available in comparable sizes for a bit more money, too. I had a set on my '08 BMW M5 and they were very impressive. So much so that I switched to UHP all-seasons so that the car would have less grip and be more tossable! https://www.tirerack.com/tires/tire...dewall=Blackwall&partnum=03YR9ECSXL&tab=Sizes.
So, where I'm at is trying to figure out which 19" wheels to put on my Cobra. I like the traditional 5-spoke style with the fat spokes. I want to run 19x9 up front and preferably 19x11 in the rear. Tell me why this is a bad idea, and what could go wrong.
The first problem is the cold. The R888s are summer-only tires, and my Cobra gets parked from late fall until early spring and never gets driven when it's below 50F or so. I live in southern Illinois where the winters are mild (for the midwest), and my garage stays about 20F above ambient, but it occasionally gets down to around freezing in the garage. Even though the car isn't being driven, the cold temps permanently hurt the grip of the R888s. Previously I used to be able to punch it in first gear on a warm day and the car would just hook and go. Now if I punch it in second, it's all over the place and doesn't get traction until third.
The second problem is the tire compound. Prior to the R888s, I had a set of Falken RT615s, which are comparable in tire compound. Their grip also went to shit after a couple years. The RT615s were 200-compound tires and the R888s are 100-compound. Soft rubber designed for competition that doesn't tolerate the cold. At all.
So, what I need are 300-treadwear summer tires that are also not okay for winter driving, but which aren't going to turn into butter if I don't pull the tires and bring them inside when I park the car for the winter.
The next problem is that when shopping for 300ish treadwear tires in 18" sizes, there pretty much aren't any that are Cobra sized. I can get 265s or 275s for the fronts all day, but when looking at 295s or 315s for the rear, I'm looking at pretty much 100-treadwear competition tires. But, if I move up to a 19" wheel, there are a bunch of options in the 300-treadwear range that have suitably sized front and rears available.
Here's what TireRack has for 295/30R18. The only 300-treadwear tire is a Kumho HTR Z III, and that's not exactly a well-rated tire for the 550RWHP+ level.
https://www.tirerack.com/tires/Tire...8&rearWidth=255/&rearRatio=40&rearDiameter=17
When looking at 315/30R18, it's all 200-treadwear or below, so forget that.
https://www.tirerack.com/tires/Tire...8&rearWidth=255/&rearRatio=40&rearDiameter=17
But, when I step up to 19" wheels, there are plenty of options in the 295-325 width that have 300ish treadwear. For example, I just put a set of Firestone Firehawk Indy 500s on my '15 Audi S4 and have been very pleased with the grip and price, and they're available in 275/35R19 ($170) and 325/30R19 ($280) and have a 300+ treadwear.
https://www.tirerack.com/tires/tire...ear=2004&autoModel=Mustang+Cobra&autoModClar=
The Continental Extreme Contact Sport is available in comparable sizes for a bit more money, too. I had a set on my '08 BMW M5 and they were very impressive. So much so that I switched to UHP all-seasons so that the car would have less grip and be more tossable! https://www.tirerack.com/tires/tire...dewall=Blackwall&partnum=03YR9ECSXL&tab=Sizes.
So, where I'm at is trying to figure out which 19" wheels to put on my Cobra. I like the traditional 5-spoke style with the fat spokes. I want to run 19x9 up front and preferably 19x11 in the rear. Tell me why this is a bad idea, and what could go wrong.
Last edited: