New MG Red SH2 for 2024

Regardless of air or track temp, you should be aiming to have the tire come in at a certain lap. For me it’s usually 4-ish laps into the run. This may vary for you depending on the race length or track.

If the tire starts to go away at the end of the run (usually overheating) then you need to drop pressure. If the tire comes in after your target lap, raise pressure.


On that thought… how do you tell, exactly, when a tire has come in to the ideal.

For me, it’s just that after a few laps it feels like it got to temp and is behaving. The tire works and holds as expected and I’m able to go fast. When cold, I feel little bits of push that progressively diminish as tire warms.

I ask because I don’t think I’ve gotten to feel what overheating late in heat feels like. May be a function of hard tires.

My son’s fastest laps are always his last lap or two, almost regardless of length of race. Does the tire coming in correlate to the fastest lap? I also wonder if it just takes him that long to get into a rhythm.

This weekend should be interesting, as Saturday has a high of 70 and Sunday a high of 86.

I did a 22 lap stint last Friday and the tire was “in” on lap 4 but my best was lap 21. So it depends on how long the tire stays in the working temp window. You might nail a lap right when the tire comes in or you might take 15 laps to nail a lap.

Given that I know what pressure you’re running, I would say some of that is why your best laps come at the end. But of course it could be just Blake finding the rhythm late in the run too.

Harder tires will typically come in slower and take longer to over heat. So maybe if you are on hard rental tires vs the Evinco Blues/MG Reds???

Climate where you are matters. We are going to be racing in triple digit temperatures in TX where the asphalt is hot enough to burn bare skin. In those conditions, you can most definitely over cook the tires by the end of the run and have to balance how soon tires come in versus where they fall off.

Also, track layout matters. We have a small club track to liked to run when we were in 206. It put huge amounts of load on the tires and felt like you were always turning. It was also the most physically demanding track my son drove on. We had to run our lowest pressures there to avoid cooking tires by the end of a race. By comparison, we run a couple larger flowing tracks that need more pressure because they just don’t build heat as quickly in the tire over a lap.


Of late I’ve been indoors where it’s cool and the earth doesn’t add heat to the racing surface (which is wood). I have yet to see if overheating is possible, in that to date, the kart just keeps getting faster and faster with more laps. The problem is the longest sessions are only about 15 laps so it’s more about getting to the ideal before the race heat is done.
Someday I will experience greasy hards, but not indoors.

Yes and No…I generally understood what you are saying but more specifically how much adjustment in air pressure is required for say a sunny vs cloudy session, or 70* vs 80*. With the old tire, it didn’t seem to change much but the new tire, 1lb seems to make a difference.