5 things to check when buying used race tires: Your guide to buying “Scrubs”
There are two words often said when buying Racing tires. Stickers and Scrubs. Stickers are new tires, named for the stickers and labels manufacturers put on before shipping them. Scrubs are used tires, and may be bought from individuals, race teams, wholesalers, etc.
If you are on a tight budget, a good deal on a set of scrubs may allow you to be reasonably competitive at a fraction the cost of new. On the other side of that coin, a bad deal may leave you underwhelmed with expensive lawn ornaments. Whether you’re trying to race and win on a budget, or just want R-Compound tires to play in HPDE sessions this guide should help you navigate the market so you can maximize your chances of scoring with scrubs.
5) Date Codes:
Reading date codes: Almost Every tire related post on this blog has included checking tire date codes… because it is both easy to find and very important. Race Tires are not wine and should not be allowed to age as such. I Have head from both Maxxis and Toyo Tires that a fresh, unused tire will not have any degradation in performance for 1-2 years if it has not had it’s first heat cycle. However, once the tire has had it’s first heat cycle, I have seen performance drop-off if it is not used up within a year.
Once most racing tires begin to approach and get beyond 5 years of age, I would tread very carefully and have second thoughts about driving on them at speed. Certain tires like Toyo RA1’s have a reputation of working for a very long time… my 7 year old RA1’s get me around the track in the rain but didn’t seem all that competitive (I’m happy to blame them for the poor finishing position in my last rain race)
4) Heat Cycles
A heat cycle is when a tire goes from ambient temperature to operating temperature, and back to ambient. Each session on track counts as a new heat cycle to a tire. Different tires will have their own “useful life”. Typically a tire is competitive for a short number of Heat Cycles, is good for practice for a bunch more, then becomes useless after a few more (If it wasn’t corded by then).
Tires like Toyo RR’s are known for being pretty competitive until around 12 heat cycles, and have a reputation of being decent to practice on until around 20. Hoosier SM7’s are known for being competitive for about 7 Heat Cycles. Before choosing a tire, check how many heat cycles they can sustain. If a tire is only good for a few cycles, it may be best to look for a different compound.
Heat Cycles are the biggest concern when buying scrubs, as you are at the mercy of the seller’s honesty. There is no easy way to see how many heat cycles a tire really has. Many racers will add hash marks to a sidewall to identify Heat Cycles but it may not be accurate.
3) Reading wear
Make sure you thoroughly inspect any used tire before purchasing. Look carefully for flat spots (can typically be spotted when grooves in the tires disappear or get shallower). Flat spots don’t mean instant death for a tire, but can be a pain if they’re deep. Look for uneven wear. You can mount a tire opposite way that it was with the previous owner, but if it’s very close to cording, you may not get a lot of life from it. Just before a tire starts cording on the shoulder I usually see little areas beginning to look like they’re peeling.
Tire storage is similar to Heat Cycles, as you’re at the mercy of the previous owner. Race tires shouldn’t really see temps below freezing, especially if they are mounted to a vehicle. If a car on race tires is moved when temps are below freezing, they may crack and should be tossed. In the Best case scenario for any long term storage, tires should be placed in bags and kept from freezing. Kept in controlled temperature is okay. Simply removed from the car but allowed to freeze may be acceptable but is not ideal.
Most racing tires use the same tire sizing scale as your normal street tires (Some Non-DOT tires come in sizes measured in other ways). When choosing a tire size, know that race tire manufacturers are sometimes very conservative on their width markings. If your current street tire sizes (let’s say a 245/45) jjjust fit without rubbing, a Hoosier A7 245/45 with the same size stampings may end up being significantly wider.
If you are able to use a tire common in popular classes, you may have a MUCH better chance of finding an easy, cheap source of tires. 205/50/15 is used across many classes that run in my area (Spec Miata, Spec E30, Honda Challenge).
If you are racing and need R-Compound racing tires, scrubs may a great way to keep your running costs as low as possible. If you are looking for scrubs because you want to use them for HPDE and Track Days, know that the cost of running race tires may be a bit higher than the initial sticker price makes them seem. With limited heat-cycle lives R-Compounds (especially used ones) will need to be mounted and unmounted often, creating significant expense if you don’t have access to a machine. Most Race Tires are slicks, so it is a good idea to bring an extra set of treaded tires for rain days, which could add more expense.