Tire pressures with colder temps

Tire pressure is a track condition sensitive adjustment. The temperature usually affects what the track does so I would adjust according to what the track is doing. I know this is fairly broad and vague, but really that is just how it is. If you understand how tire pressure adjustments effect your setup, then it goes a long way to help you figure out the best times, and correct adjustment to make.
 
Simple answer, yes you should be adjusting tire pressures as the temp starts dropping. Usually when the temp starts dropping, the track will start losing a little grip also because moisture will come back up, especially night racing...now this is not always the case at all tracks, some do get faster when moisture comes back up or sits on the track so it really is track dependent like ABR said. Generally you'll use lower air pressures when it is colder out. Also, keep a check on air pressures when you are racing in cold weather, if you set the air at say 5lbs and temp keeps dropping, you'll find that over time just sitting around the air pressure will drop slightly in the tires because of the cold weather, I assume for the same reason that tires gain air sitting in the sun or in hot weather, the air expands with temperature
 
I've never raced dirt, but on asphalt, the general rule was; the hotter the tire gets, the better the grip, to a point. On a hot day, you would have to run harder compound to keep them from getting too hot. On colder days you had to go to softer compound to get them hot. Now I'm talking about the tire compound itself. On asphalt we pretty much kept the tire pressures the same.

I found that sometimes on a slick track, one or two teeth more on the axle could sometimes help. You're getting through the corners slower so a little more acceleration helps.

Watch the air density, that's real important. Cold air means more air getting in the engine and you have to adjust the fuel flow. Cold air means you need more fuel. A 1% change in air density means a 1% change in fuel flow. Going from a .038" to a .039" is just a little over 5% change in flow.

Keep an eye on the clutch slip. Colder air could mean more torque and that would slip the clutch a little more. Just something to keep your eye on.
 
When it's cold we drop pressure quite a bit, especially with the kids. Sometimes run close to half the pressure you would in the summer months on the same track.
 
Thank you for the information. This is for my son who is tuff to get information out of as to what is going on on the track.
 
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