Car Classing Information
Need some help deciding in which class your car belongs? There are several resources for determining which class is appropriate.
- Quick Reference of Category Allowances
- "Unofficial" Classifier: scca-classifier.com
- SCCA Solor Rules Handbook: The definitive answer. The Handbook describes each class and the modifications that are allowed. IF IT IS NOT SPECIFICALLY WRITTEN, IT IS NOT ALLOWED. See Appendix A for car classing.
The SCCA may have updates within the year to clarify what mods are allowed. Many other rules for the sport are also covered. The complete list of rules, classes, and guides can be found at SCCA® Solo® Rules
Class overview
Street
Street category vehicles are any that have been in series production within the US in the last 30 years and asides from what is allowed in the rules must be factory stock. This is a good starting place if your car is factory stock.
Typical mods may include:
- One aftermarket sway bar (Front or rear)
- 200tw tires
- Aftermarket wheels the same width, within 1 inch diameter and within 7mm offset as factory
- Aftermarket shocks with factory springs
- Aftermarket catback exhaust
Street Touring
Street touring class caters to folks who have modified there cars and have allowances for braking, suspension and wheel modifications.
Typical mods may include:
- Two aftermarketsway bar
- 200tw tires, maximum width dependant on class
- Aftermarket wheels, maximum width dependant on class
- Coilovers
- Aftermarket exhaust with aftermarket catylitic convertors
- Aftermarket steering wheel
- Aftermarket seats
- Aftermarket brakes
- Camber kits
- ECU tuning
- Factory optional spoilers and lips (Not including manufacturer tuning brands e.g. Ford motorsports, Toyota Racing Division, etc.)
Street Prepared
Street Prepared cars build on the modifications allowed in Street Touring with additional allowances for drivetrain modifications and aero allowances.
Typical mods may include:
- Two aftermarketsway bar
- Any tires(Typically slicks)
- Aftermarket wheels
- Coilovers
- Aftermarket exhaust with aftermarket catylitic convertors
- Aftermarket steering wheel
- Aftermarket seats
- Aftermarket brakes (including drum to disc conversions)
- Camber kits
- Radio and Air Conditioning removal
- Aftermarket clutch and flywheels
- ECU tuning
- Aftermarket spoilers and splitters
Street Modified
Street Modified allows for some of the more extremely modified cars with allowances for engine modifications. These will be some of the most modified cars you'll see that are still able to be street driven.
Typical mods may include:
- Anything that is allowed in Street, Street Touring and Street Prepared
- Any engine block from the same manufacturer
- Engine internal modification
- Addition of forced induction
- Modified bodywork
- Removal of rear seats
- Addition of wings and canards
Prepared
Prepared vehicles use the body of a production vehicle and most are usually dedicated track/race cars.
Typical mods may include:
- Interior removal
- Any tire (typically slicks)
Other modifications depend on preperation level.
Modified
Modified vehicles are full on racecars including, but not limited to custom built chassis.
Spec Class
There are several "spec" classes. This class was created to provide a middle ground between the Street and Street Touring category. Modifications are required and limited to specified parts to keep costs down and provide a level playing ground.
- Solo Spec Coupe (SSC): 2013-2016 FR-S/BRZ cars.
- Club Spec Mustang (CSM): 2005-2009 Mustang GT (S197 chassis)
- Club Spec Miata (CSX): 2006-2015 Miata (NC chassis)
Classic American Muscle & Xtreme Street
The Classic American Muscle (CAM) category is designed for any North American front engined, rear wheel drive car. The ruleset is fairly open to encourage muscle car and pro-touring enthusiasts to participate in autocross.
The Xtreme Street category is designed to attract enthusiasts with creative modifications and little restrictions.
Electrical Vehicle Experimental
The Electrical Vehicle Experimental (EVX) category is an alternative class specifically targeted towards production electric powered vehicles. This ruleset draws from Street and Street Touring with the intention of choosing common-sense allowances to balance streetability and autocross preparation.