Tire prep is the part of dirt karting where the most money gets spent and the most nonsense gets talked. This page does two things. It tells you what we actually stock, and it lays out the variables that decide what you do with it. It does not tell you what to soak, for how long, or what number to shoot for on the durometer. Those answers depend on your track, your class, your tire and the night, and anybody handing you a universal recipe in print is guessing.
What we stock
These are the prep products we carry. We are describing them in category terms only. For how any one of them behaves, what it is suited to, or how anyone runs it, call the shop.
- Acrysol — tire prep
- Burris PRP — tire prep from Burris
- Hot Lap II — tire prep
- HTR IN — tire prep from the HTR line
- HTR PRP — tire prep from the HTR line
- HTR SSP — tire prep from the HTR line
- Black Sand — tire prep
- Prep oil by the gallon — for anyone buying in volume
- Maxxis HT3 tire sets — tires
All of it is at tires, wheels and prep. If you are trying to work out which of these fits what you are doing, that is a phone conversation, not a web page: 864-269-8947.
Check your rules before you use any of it
This comes first, not last, because it is the part that ends weekends.
Tire rules vary by track and by sanctioning body. Some tracks allow prep broadly. Some allow it only in certain classes. Some ban it outright. Some spec a single tire and check it. Some tech tires with a durometer at a stated temperature, some use a chemical sniffer, some pull tires at random after the feature, and some do all of that on the same night. A prep that is completely legal at one track on Friday can get you disqualified sixty miles away on Saturday.
Selling you a product is not the same as telling you it is legal where you race. We cannot know your track's rules, and they change. Read your track's posted tire rules and your sanctioning body's rulebook, and if the wording is ambiguous, ask the tech official before the race rather than after. "The guy at the kart shop said" has never won a protest.
Track condition is what you are actually preparing for
Prep is not a quality ladder where more is better. It is a match to a surface that changes across a night. The same set that was right in hot laps can be wrong by the feature.
Tacky
Early in the night, moisture still in the track, plenty of bite. The surface gives you grip, so you are generally not looking to the tire for all of it. Karts tend to be freer to drive and the problem is often too much forward bite on entry rather than too little.
Rubbered up
Heavy classes have laid rubber into the racing line. Grip is high but it is concentrated in a narrow lane, and what works on the bottom may be useless a lane up. Setup and prep decisions here have to account for where you can actually run.
Dry slick
Moisture is gone, the surface has gone hard and polished, and grip falls off. This is where tire choices show up most obviously and where most of the prep conversation lives. It is also where an over-prepped tire can hurt you, not just help you.
Cushion
Loose material pushed up off the racing surface, usually toward the top. Running the cushion is a different problem than running a slick bottom, and a setup and tire package aimed at one is rarely aimed at the other.
The takeaway is that you cannot pick a prep in your shop on Wednesday and be certain about Saturday. Watch the classes ahead of you. Talk to people who ran the earlier heats. Have more than one option in the trailer.
Cutting versus rolling
These are two different operations and they get confused constantly.
Cutting is machining the tire. You put it on a tire cutter and remove rubber, changing the diameter, the profile, or both. It is how you get a specific stagger number, how you true a tire that is out of round, and how you shape a contact patch. It is permanent. You cannot put rubber back on.
Rolling is working the tire under pressure on a roller, generally as part of the prep process. It is about how the tire and the prep are treated, not about removing material.
They serve different purposes and are not substitutes for each other. We do both as services: Cut Tire and Prep / Roll Tire. If you do not have a cutter or a roller, or you would rather have it done right than learn on a set you paid for, that is what those are there for.
Stagger and how cutting fits into setup
Cutting is a setup tool, not just maintenance. Stagger — the circumference difference between the right rear and the left rear — is a primary handling adjustment on a dirt kart, and cutting is how you set it precisely instead of hunting through the pile for a tire that happens to measure right.
Measure with a stagger tape at the pressure you are going to run, not at whatever the tire happens to be sitting at. Write down what you ran and what the kart did. A notebook is worth more than another gallon of prep.
Durometer is how you check, not how you decide
A durometer gauge measures the hardness of the rubber. It is the tool you use to see where a tire actually is, to see whether a tire is changing over time, and to keep some record of what you have.
Two things worth knowing about using one:
- Readings move with temperature. A tire read in a cold trailer and the same tire read in the sun will not give you the same number. If you are going to track readings, take them under conditions you can repeat.
- Readings move with where and how you press. Same spot, same pressure, same technique, every time, or the numbers mean nothing.
A durometer tells you what a tire is. It does not tell you what it should be. That target is a function of your class, your track and your conditions, and it is not something we are going to print a number for.
Handle it like the chemical it is
Tire prep is solvent-based chemistry. Read the label and the safety data sheet on whatever you buy. Gloves, ventilation, away from ignition sources, and stored where kids and pets cannot get to it. Follow the manufacturer's instructions on the container over anything you heard in the pits.
Questions
If you want to talk through what fits your track, your class and your tire, call the shop at 864-269-8947. We would rather spend ten minutes on the phone than have you buy something that does not fit what you are doing.