Tire prepping

Anyone ever seen or heard of people using prep? I’ve always thought that was just oval guys that did it, but I heard through the grapevine that people were doing it at my local track and winning races. L0206 and yamaha classes. Just curious to see what you guys think on the subject

I’ve seen some local club racers doing it in 206 in sprint years ago, but that team has since left, so the sport is better without that.

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I agree! Its cheating! I wish my track had a way to test tires. Hell as of right now we do our own tech! They give us a checklist sheet and we turn it in for a sticker :rofl:.

Do you think that there would be any real benefit in prepping Bridgestone YLC tires in a yamaha or 206 class? I cant see it honestly. last weekend I was hopping because I had so much grip. But the same 3 or 4 people were at the front an entire second faster than the rest of us. My own engine builder told me that they were prepping and that’s coming from a very reputable source

Jeez. Sounds like a game you don’t want to play. Unless you do.

I think you need to get clarity from your race officials. If it’s legal, well yes. You would have to, pretty much.

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It’s unilaterally illegal on pavement/sprint tracks.
Dirt is a whole other (contentious) story.


All the rules say is that there is no prepping allowed at the track. Doesnt say you cant do it at home

Lol Yeah I know, I’ve helped prep some dirt tires before. My buddy runs dirt and is always prepping

Yup its illegal in sprint karting no matter where it’s done. I believe you can test with a durometer, but I’ve never seen it done by tech. I suspect just the idea of testing as you enter the grid would clear up any bad actors.

I’ve been told you can tell a new tire might have been prepped if the tire whiskers (vent spews) look wilted or melted(or cut off). I have also seen new tires on the grid with an usual sheen and hand prints that I suspected were prepped(but I don’t know for sure). If that driver puts down their best qualifying lap on lap 1 or 2 and the rest of the field puts it down in lap 4 or 5, I’d be suspicious. Good luck. It’s only fun if the racing is fair.

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If the racing is competitive and tyres aren’t being tested then it would be a surprise to me if their wasn’t widespread use of tyre softener.

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That sounds like the spirit of the rule is being broken.

I think you either run with tire prep or go have a conversation with the race director. Or both.

Triple check your rulebook regarding its legality. I know at Dousman it was legal for a long time, as long as you didn’t do it at the track. Not sure the rule there now. It was a huge problem several years ago for a few seasons even in WKA national competition, before they started using tire sniffers.

On a YLC you will definitely see an advantage prepping the tire and making it softer. There’s dozens of different kinds of prep and different usages for it. The dirt guys do almost all their tuning with different preps and tire compounds. A YLC is hard enough that you could get benefit out of softening it, you’ll just have to compensate with some chassis adjustments to keep it from over-gripping. When we were doing it at club level (legally), we built a hot box in our garage powered by a drill to rotate the tires while they soaked up prep internally.

It’s a whole other ballgame and requires a complete other set of tuning knowledge. My thought would be from a learning standpoint it would be better to optimize your current chassis setup and knowledge base on traditional kart tuning and driving first. When you’re looking for those last couple tenths and you REALLY want to win a club race, maybe consider the positives and negatives of prepping then. And keep in mind, that it’s illegal at all other levels of sprint racing, so any knowledge or time you spend learning about prepping to win club races, will be time wasted if you ever decide to move up to higher levels of racing where all that knowledge is useless.

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I may say something this weekend when I go practice.

Im gonna dope my practice set tonight and see if they are faster than my race set in practice tmrw. Then I’ll know for sure if that’s what is making them faster

Thank you for that info tj! I may try prepping my practice set and run two sessions back to back with my race set first. And see if it’s faster. I’m sure it wont be with setup I have now

I was told it is terrible for the track surface? Is this true or scaremongering?

We are absolutely not allowed to use it at the track. I believe they have the means of taking tyres to be tested chemically.

Badger allowed it before they added the extension. Supposedly the softener was bad for the asphalt they were using in the extension but I don’t really buy it. The track was tearing up even with MG Red’s and YLC’s that weren’t treated, so I think they were just covering their asses in case of that scenario, so that the paving company couldn’t say “well your tire softener chemicals ruined the asphalt.”

I’ve run treated YLC’s before, the most noticeable difference was at the start of a race. When the tires were cold the treated tires seemed to be much grippier from the start, as opposed to sliding around for a while. Biggest difference was in a race when it was like 45 degrees out. My kart felt so planted compared to the others who looked like they were sliding around so much more.

If you’re racing where I think you’re racing, none of the front runners in either 206 class are doping. I can’t say for Yamaha.

Hopping at the track I’m thinking of isn’t going to be from too much grip, it’s from bad lines or bad setup combined with the track surface imperfections.

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Yep I am! Lol. I know some people are or were doping in yamaha. A dude I work with is friends with a guy who is helping a guy racing with us, not sure what class because he wint tell me. Anyway they have been inside prepping. The only two places I really hop are in turn one on the occasion and the hard right hander before the front straightaway. That corner needs resurfaced big time! I hopped so bad through there that I bruised a rib, took over a month to heal

I used to think that pain was bruised ribs, until one time it was so bad I went to the doctor and had x-rays, 5 cracked, with 4 healed, ribs. You should get an x-ray, just for safety’s sake.