Tips on setting tire pressures?


(Andres Malovos) #21

Does anyone work off of tire temps?

I usually note track temp, cold tire temp, and then measure tire temp across the face of the tire after runs along with hot PSI. I adjust tire pressure until tire temp across the tire is somewhat even (+/-10 degrees) and it seems to work well. From there I can adjust cold tire pressure for how long of a session is up next, usually dropping pressure so you don’t start losing grip 10 laps into your 16 lap main for example.

(TJ Koyen) #22

I never use temp because usually during an official session we can’t get to the kart in time to get an accurate reading since we have to sit in the scale line or post tech.

(James McMahon) #23

Are you using a pyrometer?

I’ve found it Hard to get actionable information from tire temps. Which is the total opposite to what I expected. IR sensor after you come in isn’t much use, too many variables and live temps are data overload from what I can’t see.

(Andres Malovos) #24

Makes sense after waiting in line after sessions, though I think the trends in tire temp are similar just lower than they would be immediately after a session.

I’ve been using the pyrometer from joes racing.
More than anything it tells you instantly if the tire is over inflated, and seems to eliminate so many variables.

(Aaron Hachmeister) #25

I posted this story on a diferent post, but I don’t feel like retyping everything:

I was at an AiM meeting one time with their rep Roger Caddell (nice guy). One of the things that he brought up was a data set from a family that was having trouble with the handling of their kart, and they couldn’t figure out why. For some reason they had tire temp sensors on, and he noticed through one long, sweeping left turn, the inside rear was getting way too hot. He explained to them how their kart was too stiff and couldn’t lift the inside. They checked the chassis and boom, problem solved: the chassis was tweaked and sat weird if I remember correctly. As he was looking over the data he showed us how much tire temperature changes through even a single turn. By the time that a kart comes back to the pits, it was more dependent on which direction of a turn they had last gone through than the actual setup of the kart.

Just something to think about in the future.

(Andres Malovos) #26

I think those new IR sensors open up a new world of possibilities in terms of the insight that can be actioned. The better the data source the more specific you can tune.

For that it’s worth, I see tire temp variance at each corner. You can see which are loaded more as a general trend over the lap, but not what happens through a single corner. That was impossible for karters until the new era of IR sensors hit the market.

That sounds like a perfect use case for the new IR sensors. I’d be curious to see if they can distinguish tire temp across the face of the tire.

(Davin Roberts Sturdivant) #27

This is what I was talking about why I set off of cold tire pressures, because I can’t get any hot tire temps fast enough to really make a difference during a race day. By the time we get the kart on the stand, the tires will be cold.

(Max) #28

Maybe this deserves an own thread, but my question is related to this discussion. I would liked to learn how to read the tyres and understand the cause of why it looks that way. I’ve read some about graining and blistering, but haven’t really got to grips with how it’s supposed to look when it’s working well. Some pictures along with the thread would be great.

This was interesting, but wasn’t really enough for me to understand.

The basic idea of how the tyre pressure affects the middle structure is quite easy to understand, I think. But the rest of the setup is harder. Then you have the factor of a specific tyre behaving in a certain way as well, ending up with a wear pattern that is not symmetric but is considered normal. Karting is not supposed to be easy, and it’s really not! :laughing:

(Davin Roberts Sturdivant) #29

This link comes right at the right time. I have the hardest time learning how to read tires, so when I have a minute, I’m going to read through this series.

(Eric Gunderson) #30

Reading tires is great, and super helpful to glance at before talking to a driver, or a great reference if you know what to look after you’ve mentally gone through your own kart’s handling.

Out here in CO we’ve worked with the MG/Evinco long enough that I can put my hand on the tire and tell when it’s at proper temp–there’s a narrow window with the tire that it feels super sticky–outside of it the tire is either dry or cold depending on the driver.

(Don Westlie) #31

Still learning…

Just found out why my rear tires were wearing on the inside last week.

(Davin Roberts Sturdivant) #32

And why was that?..

(Don Westlie) #33

Within that “Know Your Kart Tyres: Part 2” column there is talk of coning and the why’s and how’s to fix

(Davin Roberts Sturdivant) #34

Oh, I see. I thought you found something unique that had a story attached. Good deal. :slight_smile:

(Max) #35

Can anyone fill in on the subject?

(James McMahon) #36

Sure, what are you looking for though? Info on tyre pressures?

(Max) #37

I would like to understand how to read the tyre wear and how to use the information, as I wrote in an earlier post.

(TJ Koyen) #38

Basically, the important ones:
Front graining = understeer, add front grip
Rear graining = oversteer, add rear grip
Blistering = kart is binding, lower tire pressure

Tires should be smooth and evenly worn all around after each session.

(Max) #39

Thanks, TJ. But how does good wear, graining and blistering actually look? The link doesn’t actually show how it looks and I haven’t found any good pictures that show it very well.

Would you say that blistering almost always come from binding, or could it be from sliding as well?

(TJ Koyen) #40

Sliding will always yield graining. It’ll look like long rows or waves running the length of the tire. Here’s an old Bridgestone YKC I had laying around the shop that clearly shows that:

Blistering usually only occurs on softer tires. I’ve seen it pretty often on MG Yellows/Evincos. I don’t have a photo of that unfortunately.

Of course there could be some confusion in terminology from one person to another as well. I’ve heard some people refer to blistering and graining as the same thing.