bmart

Hey all. I have a lot of track miles on two wheels and will be taking a two day class in my 2000 GT in the fall. I'm curious what kind of guidance you would be willing to provide with regard to (cold) track tire pressures. I will be running BF Goodrich street tires in stock sizes, either the g-force Super Sport H-rated on the GT now or G-force Comp-2 A/S on the wagon now. I run 34-35 on the street all of the way around. Thanks a bunch.

JourdanWithaU

iTrader: (39)

Took me a second to realize "two wheels" is a bike.

How do you go about finding pressures for new tires on the bike?

For me, I err on the side of higher pressure. Start high and bleed off until you find the sweet spot. I drove with a stock set-up. With the high sidewalls, lack of camber, and somewhat soft compound, I found that I needed 40psi to keep from rolling over on the sidewall.

With the low grip compounds of those BFGs, you probably won't need so much pressure. But I would start on the high end. Check the wear and the temps when you come in. If the wear and temps aren't right, adjust the pressure accordingly. Go back out, repeat.

In my mind, it's safer to have an over-pressurized tire that holds it's form and slides than a under-pressurized tire that completely deforms and potentially de-beads.

bmart

Thanks for the note. The bike tire pressures vary widely by tire (make and model). I suspect that is the same for car tires. We'll see what folks' responses are.

I run Dunlops on the bikes. They come with some pretty good guidance on hot pressure, off the warmers, not off the track, for consistency's sake.

I was planning on 40PSI cold to start with, so we're aligned there! I am hoping that someone else has run these two models of tire and can suggest something like +5 from street to get me into the ballpark.

Due to the profile of bike tires (with all of that leaning!) lower pressures can provide more grip. Totally useless to this group, but hopefully interesting nonetheless:

Dunlop Q3 is a popular street tire. On the street, a rear tire is generally run at 36-42 PSI cold. I run these on the rear of my track bikes when coaching due to them lasting much longer than race tires. I run my Q3 rear at 35.5 PSI HOT, at ~180F. It is a pretty big difference, in the neighborhood of 10 PSI. Some of the track rear tires are run down into the teens for PSI. It is really something to watch how much they deform for the top level racers.

bmart

There's a front.

JourdanWithaU

iTrader: (39)

Sounds like tires are tires. I'm a set it and forget it person. I run the same pressure on the track and street. But I know people that will be ~28 hot on track and 40 cold on the street.

With something new, tire reading skills are going to play a role and as with almost everything, it will take some trial and error.