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PHL33
29-09-2017, 14:19
Mustang RTR GT4, GT4 Career Mode, American Tracks.

Tires are soft slicks. During qualifying on default pressures (1.5 or 1.4 bar), the front's get to 30psi, rears don't exceed 24 psi - which is super strange.
I raised them to 1.8 bar (26psi) cold, which get to about 32-34 psi warm.

When I finished qualifying on sonoma, and entered the race, they rose gradually to nearly 40psi before I even pressed A to start the session. So I had to lower them again to default and the tire pressures got to around 29-31psi during the race.

Anyone else getting vastly different warm tire pressures front vs rear? and is anyone getting different tire pressures on qualifying versus racing? Any tips?

Side note - can we change bar to psi?

Trippul G
29-09-2017, 14:28
I can't be much help other than to say this might get more eyes of people that can help you if posted in General Discussion as opposed to xbox-specific.

And no, unfortunately, it's bar on some screens and psi on others regardless of what you do. Hopefully a patch somewhere along the line will make all units like that consistent.

ironik
29-09-2017, 14:37
Mustang RTR GT4, GT4 Career Mode, American Tracks.

Tires are soft slicks. During qualifying on default pressures (1.5 or 1.4 bar), the front's get to 30psi, rears don't exceed 24 psi - which is super strange.
I raised them to 1.8 bar (26psi) cold, which get to about 32-34 psi warm.

When I finished qualifying on sonoma, and entered the race, they rose gradually to nearly 40psi before I even pressed A to start the session. So I had to lower them again to default and the tire pressures got to around 29-31psi during the race.

Anyone else getting vastly different warm tire pressures front vs rear? and is anyone getting different tire pressures on qualifying versus racing? Any tips?

Side note - can we change bar to psi?

Hi,

The problem is that you talk about pressure but not about temperature : the two are closely dependent.
The pressure rising is normal if the tyres are getting hotter.
I think that the rise you describe just before the start of the race is because of the tyres being warmed.
Once in the race, your tyres temperature might have dropped a bit and as you decreased the pressure before the start, your pressure is lower than during the qualifying.

This is just a wild guess though.

PHL33
29-09-2017, 15:04
Hi,

The problem is that you talk about pressure but not about temperature : the two are closely dependent.
The pressure rising is normal if the tyres are getting hotter.
I think that the rise you describe just before the start of the race is because of the tyres being warmed.
Once in the race, your tyres temperature might have dropped a bit and as you decreased the pressure before the start, your pressure is lower than during the qualifying.

This is just a wild guess though.

That is not the case.

The tire pressure would rise before I even press "start race". I can see it on top of the session menu screen where it shows the driver lineup.


And no, the pressures were not increasing the same in qualifying as they did in the race. The rears did not get above 24psi in qualifying, even after 8 laps, the fronts did get to 31psi quickly. But after 3 laps in racing it was 30psi-ish all around. (Setup - default pressures, soft slick. Rear aero 6. Setup not changed between qualy and race).

Juiced46
29-09-2017, 15:13
In qualifying the tires start out much colder. I have trouble getting them in the green unless I do a full qualifying session.

During a race, I have noticed the tires always start out much warmer.

PHL33
29-09-2017, 15:24
In qualifying the tires start out much colder. I have trouble getting them in the green unless I do a full qualifying session.

During a race, I have noticed the tires always start out much warmer.

True, but after driving 20 mins worth of laps in qualy, my rears never got above 24psi, but my fronts got to 30psi even after 5min. Both pressures are set to the same.

Side note: Doing burnouts in general do not heat up rear tires for some odd reason. Even after 60 sec worth of burnouts it went up maybe 1 psi. Heck, the fronts heated more even lol

Canadian_2Four
29-09-2017, 15:51
True, but after driving 20 mins worth of laps in qualy, my rears never got above 24psi, but my fronts got to 30psi even after 5min. Both pressures are set to the same.

Side note: Doing burnouts in general do not heat up rear tires for some odd reason. Even after 60 sec worth of burnouts it went up maybe 1 psi. Heck, the fronts heated more even lol

Sounds like you need to raise the rear tire pressure then or sometimes putting more downforce on the rear will help this issue, but start with raising the tire pressure in the rear.

Check this out:

https://www.youtube.com/watch?v=GCgGnS5qUWQ&t=608s

Juiced46
29-09-2017, 17:43
True, but after driving 20 mins worth of laps in qualy, my rears never got above 24psi, but my fronts got to 30psi even after 5min. Both pressures are set to the same.

Side note: Doing burnouts in general do not heat up rear tires for some odd reason. Even after 60 sec worth of burnouts it went up maybe 1 psi. Heck, the fronts heated more even lol

Pretty much the same as I am experiencing.

I also experience the same thing with the burnouts. I can do a 60 second standing burnout and the rear tires do not heat up at all. But for some reason the fronts get hotter lol

Juiced46
29-09-2017, 20:29
Just did some testing in Career mode with the Ginetta GT5.

In qualifying, tire temps started out at about 80 degrees. 70 degree track temps. After a 15 minute qualifying session, front temps were about 105-110 rears 100, tire indicators still in blue and car was pretty slippery around the track. This was using Slick tires. This car does not have adjustable downforce.

During the race, tires start out in the green around 140-150, by the end of the race (10 minutes) front tires were 120-125 and rears 115 and turning blue. 70 Degree track temps again.

Tire pressure fluctuated in the front from 31 down to 29psi, rears around 25 down to 23

Casey Ringley
29-09-2017, 20:37
The tire pressure would rise before I even press "start race". I can see it on top of the session menu screen where it shows the driver lineup.

This sounds related to the brake preheating to me. We preheat them to 300C before the start of a race as if you had been working them hard during a formation lap. The heat model must be flowing that energy though the brake-wheel-tire system before you press start race. Physics simulation should probably be paused during this time. How long was it between when the session loaded and when you pressed the button for start race? A greater time of the car stopped with hot brakes would mean more tire pressure increase, if the hypothesis holds up.