[Newfie TLR]

I've read a few posts that include some discussions about tire pressures at track days. Here's what I've heard, and have practiced.

First, due to the fact I'm a little on the heavy side (290 ish) I keep max rated pressure in my rubber for street riding (Eg: BT-010's on the TLR @ 42 PSI cold front and rear). If I run less I get some scalloping on the front. This may be due to some other set-up points too, but keeping this pressure seems to reduce it quite a bit.

On the track, here's the rule of thumb I've heard & use:

10% rise in pressure from cold to hot. For example, let's say you have 30 psi cold in the back. When you come off the track from a session, the pressure (now hot, remember) should be 33psi. If you have less, you need to lower the cold pressure a bit. More than 33 when hot and the cold pressure needs to be raised a bit.

I've never been on a wet track, and I've only ever been on the track with Battlax's on the bike, but since I seem to have success with this theory, I'd guess this formula will work for wet tracks, and across all brands of tire.

I'm curious to hear from other people who frequent track days and/or club racers what their rule of thumb is, and if they've ever heard of or tried this formula.

[Pete]

If the track is wet, I stay in the paddock. That's my rule.

[WetShrub]

Originally Posted by Pete

If the track is wet, I stay in the paddock. That's my rule.

I don't pay good money to ride slowly on the race track....plus I suck in the rain. I'm overly cautious.

[Red Rider]

Originally Posted by Pete

If the track is wet, I stay in the paddock. That's my rule.

Same here...not worth it to ride in the rain on a track.

Your theory on pressure is a common one used by a lot of riders. On the track, tire temperature is also important and will dictate what pressure you should be running. Typically, I run anywhere from 29-32 front/rear depending on the conditions.

[freq]

With those low tire pressures on the track (using street tires) the sipes will not be open enough to channel water effectively. Raise the tire pressure (not necessarily to 36/42) to open up the sipes and let them channel water like they where designed to. They will never get up to temp. anyway on a cold wet track.

But I have been wrong in the past.

[freq]

http://www.fireblades.org/forums/showthread.php?t=23190

[freq]

another Active Topic

[Zippy]

I prefer dry conditions, but I don't shy away from wet track riding. You've paid your money, and there is plenty to learn on a wet track. It is just a different traction situation. Just like new tires, or a cold track, or different profiles and brands of tire. The first session in the morning at the track is often far different than it is a couple sessions later. You have to be able to adapt.

With that said, most people are not very interested in riding on a wet track or during rain. The last couple of times I went out, I was one of 5 or 7 people. The other 30+ elected not to go. I got another five sessions of learning time, and became even more confident in the dry.

Another great thing about being OK with riding on a wet track is that you stop worrying too much about the weather reports. You know you'll still get out there and have fun. If the weather turns bad, you can work on smoothness on a basically empty track. See? Even rain clouds have a silver lining.

I kept my tire pressure the same, not knowing any better.

[Newfie TLR]

Originally Posted by Pete

If the track is wet, I stay in the paddock. That's my rule.

I value my bike and hate pain too much to take a chance. If you knew the track had the same degree of dampness all 100%, it would be different. But I'm not good enough to hold the perfect line all the time on every turn, so basically I swallow the cost and wait till another day.

Originally Posted by freq

With those low tire pressures on the track (using street tires)...snip

Freq, this example was just that, an example. Personally I run 36F/38R on the track, the 30 psi example is for easy math. The other Canucks on the board who read my name will understand.......

[Red Rider]

Ask NinerPilot about riding on the track in the rain! I rode all day at Mid-Ohio 5 years ago in a monsoon rain. Sure it was good practice for me for wet riding, but today I'm more interested in extending my braking points and getting on the gas sooner...not good things to work on in the rain!

[02FBlade]

I use to run from a wet track until had a race in the rain. I would run 34/34 in the rain...rain or dots. That will should be enough to get keep the groves separated.

I accutally love racing in the rain..trackday no. Racing yes! Most people are too scraced to push it and are easily past!

[abtech]

Newfie: 10 percent tire growth may be fine for the street, but will never translate into the correct tire temperature for track use. You should see 20% pressure growth on the track from dead cold to fully hot. Regardless of tire brand, this will translate into approximately 170 to 185 degrees fahrenheit which is the target temp for contemporary tire compounds.

[oldgoat]

Originally Posted by Pete

If the track is wet, I stay in the paddock. That's my rule.

Me to

[Newfie TLR]

Originally Posted by abtech

..... approximately 170 to 185 degrees fahrenheit which is the target temp for contemporary tire compounds.

Thanks Pal, I've never seen this before. Last time I was at Grattan, I remember feeling the tire and could only hold my hand on it for a few seconds, but that means it wasn't anywhere those temps. I would have guessed those temperatures would have wrecked street rubber.

Thanks for the info, and needless to say you were one of the people I hoped would add to this thread.

[Fire929blade]

Originally Posted by abtech

Newfie: 10 percent tire growth may be fine for the street, but will never translate into the correct tire temperature for track use. You should see 20% pressure growth on the track from dead cold to fully hot. Regardless of tire brand, this will translate into approximately 170 to 185 degrees fahrenheit which is the target temp for contemporary tire compounds.

The target temp you are telling us about, is this only for race tires or does it apply to normal supersport tires (like Diablos, Pilot Power etc..) as well?

I think I will try to lower the pressure in my tires quite a bit the next time I'm on a track....

[02FBlade]

For dot race tires, dry track I ususally get about a 4lb increase from cold to hot. I run my rears around 33-34 hot. hot front ~34 depending on conditions.

Be sure to check your pressures AFTER you get done w/ a session. Cold pressures are really just a starting point. You may also have to drop a little pressure as the day gets hotter.

Generally I would run a lb or 2 more on a supersport tire...depending on track, temps, tire, bike. I use to run BT12ss at 31/32 cold (+ or - .5lb), which would go up to 34/35 hot. ...I think, been 2 years since I ran any street tires.

A lower the pressure will allow more sidewall flex and produce more heat...heat is good and bad! Too low and you'll over heat'em.

[BushrodW]

Originally Posted by abtech

Newfie: 10 percent tire growth may be fine for the street, but will never translate into the correct tire temperature for track use. You should see 20% pressure growth on the track from dead cold to fully hot. Regardless of tire brand, this will translate into approximately 170 to 185 degrees fahrenheit which is the target temp for contemporary tire compounds.

One of those non-contact infrared thermometers would be a good tool, no?

I believe I've read that taking the temperature of the header pipes is a way to see if the carbs / injector starter valves are in or near or out of synch.

Since it's tire related I can tell SWMBO (She Who Must Be Obeyed) that it's a safety related expenditure! Yes? Of Course!!

BW

[Red Rider]

Originally Posted by BushrodW

One of those non-contact infrared thermometers would be a good tool, no?

I believe I've read that taking the temperature of the header pipes is a way to see if the carbs / injector starter valves are in or near or out of synch.

Since it's tire related I can tell SWMBO (She Who Must Be Obeyed) that it's a safety related expenditure! Yes? Of Course!!

BW

I bought one of these. It works great. I find myself checking the temperature of everything with it!

[roadracer319]

Originally Posted by Pete

If the track is wet, I stay in the paddock. That's my rule.

I'm with him....

[02FBlade]

Nice but not ¢heap!

[abtech]

Originally Posted by 02FBlade

For dot race tires, dry track I ususally get about a 4lb increase from cold to hot. I run my rears around 33-34 hot. hot front ~34 depending on conditions.

Be sure to check your pressures AFTER you get done w/ a session. Cold pressures are really just a starting point. You may also have to drop a little pressure as the day gets hotter.

Generally I would run a lb or 2 more on a supersport tire...depending on track, temps, tire, bike. I use to run BT12ss at 31/32 cold (+ or - .5lb), which would go up to 34/35 hot. ...I think, been 2 years since I ran any street tires.

A lower the pressure will allow more sidewall flex and produce more heat...heat is good and bad! Too low and you'll over heat'em.

"you may also have to drop the pressure as the day gets hotter" ????

As you drop the pressure, the tire growth and temperature will increase. Once you exceed 20% growth, you're going backwards, as the temperature will exceed 200 degrees and the tires will get greasy and not grip at all. You may need to ADD a little pressure as the day gets hotter to compensate for the higher track and ambient temps. The 20% rule applies to slicks, DOTs, DOT Race and everything for track use except rain and street touring tires. Once you exceed 190 degrees, you are wasting your time. It does not vary according to brand, compound or anything else except as noted above due to different carcass construction.

[Red Rider]

Originally Posted by 02FBlade

Nice but not ¢heap!

Those are MSRP prices. You can get them considerably cheaper through various sources. They also have even less expensive ones (~$75). I'll try to find the link to the store I bought mine from and post it.

[Scout]

Wouldn't this be a cheaper solution:

http://scientificsonline.com/product...2=111485172 2