Car Classing Guide

One of the best parts about Autocross is the ability to bring literally any car and be able to compete against cars of similar performance. Cars fit into classes based on their performance level. Determining what class your car fits into is simple if it’s completely stock like it left the showroom… but can get complicated quickly once you start adding aftermarket performance upgrades. Even things you might think are minor & common tweaks can be enough to bump you into a modified class.

If you’re new to the sport, then we recommend you start out in our Novice class. It’s a great program and means you don’t have to worry about classing your car until you’ve been to a few events.

All of the rules regarding which cars fit into which classes, and what modifications are allowed, can be found on the SCCA’s website here – Solo Cars and Rules. Remember that the rules state what you can modify on your car. If it’s not specifically mentioned… it’s not allowed. As you proceed deeper into the classing categories, more and more modifications are allowed.

Even after looking at the rules, it’s easy to be confused. There are more than 40 classes. If you’re struggling to figure it out, feel free to ask in the forums.

SCCA Autocross classes fall in to one of several high-level categories based on the modifications done to the vehicle:

Classing Categories

Street – This is the base set of classes for cars with no or minimal aftermarket modifications. There are 10 street classes. There tend to be many questions about whether or not a car qualifies as Street so at the bottom of this page is additional detail on what is and is not street.
Street Touring – This category provides for a much broader array of modifications for wheel size, suspension and braking and unlike the Street classes, allow for engine and other drive-line modifications. There are 6 ST classes.
Street Prepared – This category expands what is allowed from Street & Street Touring. Cars that have had quite a bit of modification, but that you’d still consider tuned street cars would fall in here. There are 7 SP classes however beginning in 2017, we will be combining all SP cars into single PAX class.
Street Modified – Even more modification is allowed here. At this point you’re beginning to approach the limit of what anyone would reasonably drive on the road. There are 3 SM classes, however beginning in 2017, we will be combining all Street Mod cars into single PAX class.
Prepared – These cars have the original engine and body type of a production car, but have been significantly modified for racing and are often not street legal. There are 7 prepared classes.
Modified – These are essentially pure race cars. There are 7 modified classes, however beginning in 2017, we will be combining all Mod cars into single PAX class.
Kart – Loads of fun… Teeny weeny package. There is 1 adult kart class and 3 classes for kids and teens.
Classic American Muscle – The name pretty much says it all. The SCCA’s version of “Goodguys” with all kinds of old-school, big-block action. Definitely the coolest class. There are 3 CAM classes.
For classes that begin with the letters A-H, you’ll typically hear them pronounced like “C Street” or “F Street Prepared”. Otherwise you’ll usually hear classes pronounced with their letter abbreviations like “STU” or “SMF”. Classic American Muscle is pronounced simply as the word “cam”.

UPDATE FOR 2017: Due to low numbers in the higher preped classes, we will be combining all Street Mod classes into a single class, Street Prepared into a single class & Modified into a single class. Cars running will be ranked in class according to their base class PAX values. This will allow the handful of cars that may show up in these classes to have someone to run against. We’re keeping Prepared as separate classes because XP has solid attendance.

In addition to these nationally sanctioned categories, CCR offers the following supplemental regional classes:

Regional Supplemental Classes

  • Pro – Experience levels can vary quite a bit at the regional level so for drivers who are ready to up the competition level, we offer Pro class. Pros will compete against each other based on their PAX times calculated from their normal base car class. Pro is further divided into Pro Street Tire and Pro Race Tire depending on the type of tire your base car class would allow. Separate event and season ending trophies are awarded for both PST and PRT.
  • Ladies – PAX class open to female participants. You will be competing on PAX Time based on your base class against everyone else in class.
  • Masters– PAX class open to participants 60 years and older. You will be competing on PAX Time based on your base class against everyone else in class.
  • Novice – An introduction to the sport. This class is open to anyone in their first year of autocoross. For all the details… check out Novice Class.
  • Rookie – This class is open to anyone who has 3 days of experience with CCR via either Novice class or Novice school during the year. It will only be run for the last 6 events of the season. You will be competing on PAX Time based on your base class against the other Rookie participants. This class will need a minimum of 5 events for a season trophy and there will be 1 points drop.
  • Seat Time Only – Not really a class… but if you just want to drive and not worry about competing, you can just go with STO.

Is My Car In Street Class?

This question comes up a lot when people start autocross and often drivers are surprised that their car which has been lightly modified does not qualify for Street and gets pushed into a higher class. Here’s an general overview of what’s allowed in Street. There are some nuances in the full ruleset… this is intended only as a first-round of guidance. Note that statements about “OEM or not” depend on what was standard or optional equipment on the vehicle in the year it was produced. Just because a part did not come as standard doesn’t disqualify from street as long as the car is presented in a configuration that could have been ordered from the factory. If an optional part was only offered as part of a larger options package… then the entire options package must be implemented.

  • Pretty much anything done to the engine or drivetrain that didn’t come from the factory is not allowed. You can remove or replace the air filter with a non-stock one but you can’t modify the intake. Cold Air Intakes are not allowed if they’re not OEM.
  • You can change the wheels, however they must be within +/-1″ in diameter and +/-7mm in offset from a standard wheel for the car. The width cannot be different from standard. Note that if there were optional wheels that came on the vehicle in the year it was produced, you can use that as a baseline even if those wheels were not purchased with the car. However again, if those optional wheels were part of a larger options package only, then you can only use those as a baseline if all of the items in that options package are also done to the car.
  • Any tire is allowed at any size you can fit on wheels that meet the rules above, as long as they are DOT approved for highway use, have a 200TW or higher rating, and an original minimum tread depth of 7/32″. No race slicks
  • You’re allowed to change the exhaust system only from the last catalytic converter back (“Cat-Back”). If you’re car came with a dual outlet exhaust system, you can change to a single along as the place where it exits at the rear is the same as a stock location.
  • You are allowed to add, remove or swap either the front or the rear swaybar, not both.
  • You can change the shocks, but not the springs. No aftermarket coilovers. The car can not be lowered.
  • You can change the brake pads to non-OEM, but rotors, calipers and lines have to remain OEM
  • Things that the manufacturer intended to be alterable using stock equipment is generally allowed. You can for example adjust camber and toe as long it’s using the stock adjustment mechanisms. You can disable traction control.
  • Any type of non-standard aero parts are not allowed so no aftermarket wings or spoilers

If you still have questions, the full rule book is at Solo Cars and Rules. Look for section 13 about Street Classing. You can ask more specific questions in the forums as well.

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