22 replies to this topic

[bmarshall1]

Grrr....most post didn't save.

My name is Tom, two (too).

All of the above. Pressure, pressure increase, wear patterns...especially differences between tires. Not that perfectly even pressure growth is NOT the goal, but if something is wildly different, and I had a handling problem that'd be where I'd start. Lap time rules, though. As Saul has said in other threads...."If flipping a brake pad backwards is faster, well....then do that!" So, faster is as faster does.

So, if you've got a corner that's growing 9psi, and everything else is +6....and you've got a handling problem that's related to that corner...then maybe a change is in order (cross or arb) to take some pressure off that tire.

I've taken to recording my tire pressures on my windshield through the day (hot and cold in different colors). I find it really handy to be able to just stare at the car, and see the patterns in pressures over a day's sessions while trying to decide what to do.

When I check tire pressure, they are all within 1-2 lbs, which I had always assumed to be 'normal'.  Let's say for instance I get a +9 vs a +6, that's tells me that tire is working harder/sliding more?  Then what does that tell me, to adjust something in the set-up, or perhaps driving style.  I also assume it matters if F/R and/or Dominate/Non-Dominate side.

 

What Toyo hot pressure should I be shooting for

[Tom Sager]

Tom - in follow up, what do you use to gauge set up and adjustment instead of temps? Pressure increase, wear patterns, lap times...

Disclaimer, I'm not a chassis engineer.

 

Assuming you arrive at the track with an initial setup that is at least "good" you can tweak after every session.  I think the answer somewhat relies on what tools, available surface and confidence you have in making adjustments.   I don't like messing with rear tow/camber at the track as it's a PITA to get right. With slotted rear arms now though you can slot them just enough to give you maybe .3 or so degrees of adjustment and that will allow for a quick camber add or delete per wheel depending on your static setting.  To me that's the best feature of slotted arms, practical and quick adjustment without worrying about screwing up the toe.  

 

Give the car what it wants. If it's loose in one direction or pushing in one direction, cross adjustment can help and you can even do that without scales.  If it's loose both directions you can add camber (slots), reduce some air pressure, reduce some ride height if you aren't already max low or even disconnect the rear sway bar.  I ran a race this year with rear bar disconnected in the dry.  Car was loose on Saturday, had nowhere to go with camber and ride height so I nixed the rear bar and son of a gun the car was quite good. 

 

On more than one occasion at the track I've wanted to add front camber, had no flat surface to use, limited time but had a camber gauge.  Jacked up car, measured camber on jack stand, OK it's telling me 8 degrees.  Adjusted until I saw 8.4 or something like that.  Lowered the car.  Checked and tweaked toe and off you go.

[Steve Scheifler]

Regarding real-time logging with IR sensors, that’s a little different for the same reason you shouldn’t use an IR temp gun in the pits. Surface temps are extremely dynamic and you can certainly learn things from them if logged in real time, but the idea of using a probe that reads subsurface temps in the pits is that they change more slowly near the carcass. While far from perfect even in hot from a lap, they are stable enough to identify large problems and trends like a hot center reading suggests overinflation or low center indicating the opposite, and yes too much or too little camber before tire wear shows it IF you take into account what you know about the car and the track. Like a lot of things one standalone set of data isn’t necessarily meaningful without context but as you learn about your car and the tracks you run they can be somewhat useful. Then when you’re confident with things you will probably find them of little interest unless something doesn’t feel right.