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Haha glad you are enjoying with the 285 setups. I just installed the Techart lowering springs and Cargraphic valve controller, the valve controller literally changes the car so much and I can stop driving it. Before it feels like the car was missing something and now it’s back. The lowering spring surprisingly didn’t affect the ride quality, to me it feels almost identical to stock (I have SPASM) and the stance is perfect right now. The only bad thing I can think of right now is after lowering the car, the 245 295 setup isn’t that flush anymore. Probably need some spacers or new a set of wheels haha.
It looks great! That's the downside of lowering...it can be a slippery slope once you start adding a couple things here and there.
Could you appreciate any increased understeer with the increase in stagger going from 30-50?
No, I couldn't sense anything there. That said, for my driving on Country Roads in IL, I don't really encounter Understeer much at all. I don't track the car, and our terrain is pretty flat. Thus the roads are mostly on a grid, so my turns are mostly left hand and right hand 90 degree turns, and I don't come in too hot, for various reasons (usually a bit of dust or gravel at intersections, safety for blindfish corners, etc.), more so I come out with high throttle and with some modest oversteer slide - thus the reason for new tires desperately needed at 10K miles.
Also we have a lot of wide sweepers which are fun but wouldn't envoke understeer.
What I did notice is that the steering feel is a decent amount heavier to feather in the long sweepers. Not in a good way, I didn't like it at first, it used to be really light for that, and the heaviness of it made it less fun. I guess I kind of got used to it during the hour plus drive yesterday.
Also in the case of pull from road crown or uneven surfaces, it seemed a little more severe. Both things make sense with wider rear tires.
As with any changes, there are always pros and cons. It looks great and increases grip, which I like.
Just got some 245/295 Goodyear Supercar 3 tires mounted on the CGTS4.0. Looking forward to testing them out next weekend. Hoping for better track tire life than the PS4S.
Just got some 245/295 Goodyear Supercar 3 tires mounted on the CGTS4.0. Looking forward to testing them out next weekend. Hoping for better track tire life than the PS4S.
Did you get them mounted on the stock rims? I'd love to see some close-up pictures. I'm assuming you went with 245/35/20 front and 295/30/20 rear - so if that's not the case let us know. Thanks!
Did you get them mounted on the stock rims? I'd love to see some close-up pictures. I'm assuming you went with 245/35/20 front and 295/30/20 rear - so if that's not the case let us know. Thanks!
Yes 245/35/20 and 295/30/20 on stock rims. Same size as the GT4 SC2 but from the track tires thread people seemed to have good experience with the Supercar 3. I'll snap some pics at some point and post along with my driving impressions.
One thing you notice immediately when you see the pirellis and michelin’s side by side is how stretched the pirellis are. On mine the rim protrudes noticeably, and the sidewalls offer no protection.
One thing you notice immediately when you see the pirellis and michelin’s side by side is how stretched the pirellis are. On mine the rim protrudes noticeably, and the sidewalls offer no protection.
+1. It was quite noticeable when UncleDude and I had our cars side by side. I have Michelins and he has Pirellis.
Hi Ryan, I have a 2021 GTS 4.0 that I bought in July, 20 inch rims; didn't like the PZ4s it came with on track at all (Watkins Glen), so looking to switch to Cup 2s. Read your comment, but wonder what your thoughts are on the potential for understeer with the Front 245/35 - Rear 295/30 set up? I see Michelin makes the OEM size for the rear, 265 / 35, which keeps you closer to the original rolling diameter, so I'm considering that as an option as well. If I go with the 295s in the rear, this lowers the tire to ~27 inches, so rear axis will be lowered by 0.15 inch, while the front axis will be about .14 inches higher with the 245/35s, so slight tilt. My question is: what are your thoughts on choosing between 265 and 295 for the rear, considering all of the above? What are the pros and cons? (Once again, we're talking about 20 inch rims). Thank you and everyone else for providing very useful information in this thread!
Hi Ryan, I have a 2021 GTS 4.0 that I bought in July, 20 inch rims; didn't like the PZ4s it came with on track at all (Watkins Glen), so looking to switch to Cup 2s. Read your comment, but wonder what your thoughts are on the potential for understeer with the Front 245/35 - Rear 295/30 set up? I see Michelin makes the OEM size for the rear, 265 / 35, which keeps you closer to the original rolling diameter, so I'm considering that as an option as well. If I go with the 295s in the rear, this lowers the tire to ~27 inches, so rear axis will be lowered by 0.15 inch, while the front axis will be about .14 inches higher with the 245/35s, so slight tilt. My question is: what are your thoughts on choosing between 265 and 295 for the rear, considering all of the above? What are the pros and cons? (Once again, we're talking about 20 inch rims). Thank you and everyone else for providing very useful information in this thread!
Keeping the factory 20" wheels in place for track use will require some level of compromise as there are far less tire sizes and compounds to work with. There aren't any good track oriented tire options in the factory 235/35-20 // 265/35-20 sizes, and regardless I think we can all agree that this car warrants a bit more rubber. The 245/35-20 // 295/30-20 tire configuration really makes the most sense as they suit the factory 8.5" / 10.5" wheel widths nicely and are available in a few decent tire compounds. While this does open up the stagger a touch more and can induce more understeer, it is still the best solution short of upgrading to a set of 18" or 19" wheels. One of many benefits in switching to aftermarket 18" or 19" wheels is that you can run 9" front wheels to support a variety of 255 and 265 tires which improves turn-in and mitigates understeer when running wider 285, 295, or 305 tires out back.
It would be nice if there were some track oriented compounds available in 255/30-20 // 285/30-20 or 295/30-20 as that wider front tire would help balance things out, but no dice. With that said, even if there were some decent tire options, 255's are not ideal on 8.5" wheels.
You could go one size wider up front (245/35-20) and keep the factory 265/35-20 in the rear to improve front end grip and gain access to Cup 2s, however, I still think the 265's are a bit slim out back on the 10.5" wheels (not to mention the sidewall shape would be pretty different front to rear).
Factory GTS 4.0 Sizes
F. 235/35-20
R. 265/35-20
^ Michelin PS4S (300TW)
Factory GT4/Spyder Sizes * Recommended*
F. 245/35-20
R. 295/30-20
^ Michelin PS4S (300TW), Goodyear Eagle Supercar 3 (220TW), Michelin Pilot Sport Cup 2 (180TW), Dunlop Sport Maxx Race 2 (80TW), Hoosier R7 (40TW)
Alternative
F: 255/30-20
R: 285/30-20
^ Michelin PS4S (300TW)
Alternative
F: 255/30-20
R: 295/30-20
^ Michelin PS4S (300TW)
Alternative
F: 245/35-20
R: 265/35-20
^ Michelin PS4S (300TW), Michelin Pilot Sport Cup 2 (180TW), Pirelli Trofeo R (60TW), Dunlop Sport Maxx Race 2 (80TW), Nankang AR-1 (100TW)
In summary if you want to stick with the factory wheels, 245/35-20 // 295/30-20 is the way to go. You'll just need to work on mitigating understeer through suspension, alignment and tire pressures tweaks. If you are looking for the ultimate wheel and tire solution to reduce weight, decrease running costs, improve grip, broaden tire selection, etc., then an aftermarket set of 18" or 19" wheels is the solution.
A friend picked up his new GTS this weekend. It had Pirelli's. He already ordered Michelins. I thought he was over reacting, but in seeing how stretched the tires are, there's no way i'm living with that either! Just horrible.
A friend picked up his new GTS this weekend. It had Pirelli's. He already ordered Michelins. I thought he was over reacting, but in seeing how stretched the tires are, there's no way i'm living with that either! Just horrible.
They’re pretty stretched but not worth (to me) the cost to change them - still the best tire I’ve ever had LOL. Here’s mine compared to @P-car-Vancouver ’s, and you can see how much more sidewall he’s got. My Michelin winter tires look like his, and the ride is noticeably different.
Factory GT4/Spyder Sizes * Recommended*
F. 245/35-20
R. 295/30-20
^ Michelin PS4S (300TW), Goodyear Eagle Supercar 3 (220TW), Michelin Pilot Sport Cup 2 (180TW), Dunlop Sport Maxx Race 2 (80TW), Hoosier R7 (40TW)
For Street use I'm very happy with 245/295 Yokohama Advan Apex 601 (280tw) on my GTS 4.0 , see post #22 above. Also a good friend has a set of 245/295 Apex 601's on his Cayman S, with approx 75 laps on our local 3 km track, he reports comparable lap times to his last 2 sets of Pilot 4s', and no abnormal wear or chunking.
Gah! I forgot to check the tires that my SA sent, mine just got unloaded with Pirelli's. I heard several folks recently that got Michelin's and I figured it was standard fare...but apparently not. I'll have some 255/40/19 and 285/35/19 Alpin PA4 winters I'll be throwing on shortly. That will be a nicer driving tire than the Pirelli (not to mention the size of the tire is .79" bigger all the way around).
Gah! I forgot to check the tires that my SA sent, mine just got unloaded with Pirelli's. I heard several folks recently that got Michelin's and I figured it was standard fare...but apparently not. I'll have some 255/40/19 and 285/35/19 Alpin PA4 winters I'll be throwing on shortly. That will be a nicer driving tire than the Pirelli (not to mention the size of the tire is .79" bigger all the way around).
give the pirellis a fair chance, other than stretched I'm still not sure what I'm not supposed to like about them, they seem perfectly fine to me in the wet and dry
09-22-2021, 05:54 PM
Also a good friend has a set of 245/295 Apex 601's on his Cayman S, with approx 75 laps on our local 3 km track, he reports comparable lap times to his last 2 sets of Pilot 4s', and no abnormal wear or chunking.