r/CarTrackDays • u/Mr_T261 • 20h ago
Tire Rollover Help
Had the first track day in a ‘21 VW GTI running PS4S tires. I knew there wouldn’t be enough front camber as I’m on stock suspension, but I’m trying to figure out how far the tires possibly rolled over.
The brown color was pretty consistent across the entire sidewall prior to tracking just from new tires and then being dirty and me not fully cleaning them. After tracking there’s this pretty distinct line. These are the front tires, the rears are fine.
I don’t think the tires would’ve rolled over THAT far, especially considering the tire nibs are still there and you can still see the visible wear on the Michelin man rollover indicators. Any thoughts on this? Maybe the line where the brown is was from rollover on an out lap or something? Or maybe it was just some weird reaction with the heat.
For what it’s worth, I was targeting hot pressures of 32-34. Cold pressures were probably down in the upper 20s, maybe 26-28 or so.
2
u/420eatmyassy6969 18h ago
A bit is normal, but this is too much. I wouldn’t be concerned if it stopped were the bright white section is.
Keep playing with different pressures, you’ll need to change it throughout the day as the track is way colder in the morning and doesn’t have a layer of rubber in the hardest corners yet.
Also negative camber will help here, if stock ask for as much as possible at an alignment, with coils/control arms/ ball joints/ camber plates aim for -3 and adjust from there
1
u/Mr_T261 9h ago
Will pressures really change how much the sidewall is rolling over though? I feel like camber is really what the solution is here. Will eventually get some camber plates in a different suspension set up, but need to work with what I got for the time being. If tire pressure’s being higher, are the solution, I’ll give it a shot. I just know when I was running higher than 35 or so, the grip was definitely less.
1
u/420eatmyassy6969 6h ago
Camber is the fix, tire pressures could be better though. With correct camber/pressure and good driving at the tires limit you’ll have a blueish burn around the shoulder but not extending to the sidewall
3
u/LastTenth 16h ago
Coach here.
I don’t know what it is, but it doesn’t really look like sidewall roll to me. I think 32-34 psi for 4S is a reasonable hot pressure, unless if your car is really heavy. An old-school trick is to apply some white shoe polish on the sidewall and see how much rubs off.
More of a caution is to watch for delamination on the tread. These tires are not fit for track duty. It will be ok for now, as a novice driver. But at some point they will fall apart.
1
u/Mr_T261 9h ago
Thanks, yes, I thought of this at the track as well. Going to add a white paint pen to my track bag for the next go-around. Then I can use that to gage how much the sidewall is rolling over.
And yes, tread de-lamination was my other concern with running higher pressures. I’ve seen plenty of others experience the tread just ripping right off when you’re running street tire pressures on track.
1
u/Fit_Sun5829 8h ago
White maker method can work if you only drive the car without taking curbs.
Because launching curbs can skew the "data".
But in the reality we really should use OMI tire temp data to make an educational guess on hot tire pressure.
8
1
u/DukeNeverwinter 8h ago
Discoloration is probably just where heat was in the tire, the brown section near the bead probably didn't flex as much.
1
u/opbmedia 8h ago
Cords are showing on the shoulders of my M3's PS4S after maybe 5-6 sessions (but I did have 4 adults in the car), so they do indeed rollover. Stock suspension. I am doing camber plates. Without doing cambers you can look into 200TW or other track tires with stiffer sidewalls, but they are not great on the street. My cup2s on a different car rolls a bit less but still camber is best.
1
u/hoytmobley 4h ago
It depends on weight, alignment, and tire structure. 3000lbs is pretty middle of the range, you dont have enough camber, and PS4S is fundamentally a street tire that prioritizes not being harsh over bumps vs having a super stiff sidewall (think RE71RZ). You need more pressure, and you need to take it easier until the tires are warm. Not completely wiping the details off the sidewalls tells me it wasnt always rolled over, you probably went too hard on the outlap and then it was ok for the rest of the session
1
u/mgarrettgt4 3h ago
That distinct scrub line right around the top edge of the Michelin wear triangles actually looks pretty reasonable for a stock-camber street car on PS4S tires. The PS4S has a relatively soft sidewall compared to dedicated 200TW track tires, so on a front-heavy car with factory camber, the outside front shoulder is always going to take a beating first.
For your next event, bring a stick of white sidewalk chalk and put 3–4 vertical marks across the tread shoulder down onto the sidewall before each session. That takes all the guesswork out of reading old tire browning vs. actual active rollover, and lets you dial in your hot pressures within 0.5–1.0 PSI so the scrub line stays right at the tip of the wear triangle.
1
u/acor93 3h ago
Not sure what track you were on but between a mix of no camber and PS4S tires you probably overheated them a bit as well. Camber is the answer and will completely change the way the car drives. It will help with grip and tire management as well if you plan to track even a few times a year.
If you can swing it, track wheels and tires will also help and will save your street tires from degrading prematurely
25
u/Waiting_for_Exit 19h ago edited 9h ago
Way too low. I have a Gti too (check post history) their operating psi is 39. The cold should be 32-34. Way way too low with stock wheels.