Car Classing Information

Need some help deciding in which class your car belongs? The SCCA Solo Rules Handbook describes each class as well as the modifications that are allowed for your class. The SCCA may have updates within the year to clarify what mods are allowed. Many other rules for the sport are also covered. Try this Link:

2019 SCCA® Solo® Rules - See Appendix A for car classing  

Class overview


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 aftermarketsway 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

Detailed rules for street
Appendix A for Street classing

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.)

Detailed rules for Street Touring
Appendix A for Street Touring classing

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

Detailed rules for Street Prepared
Appendix A for Street Prepared classing

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

Detailed rules for Street Modified
Appendix A for Street Modified classing


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.
Detailed rules for Prepared
Appendix A for Prepared classing


Modified vehicles are full on racecars including, but not limited to custom built chassis.

Detailed rules for Modified
Appendix A for Modified classing

Solo Spec Coupe

Solo Spec Coupe is a spec class for all 2013-2016 FR-S/BRZ cars. This class was created to provide a middle ground between the Street and Street Touring category. Modifications are limited to specified parts to keep costs down and provide a level playing ground.

Detailed rules for Solo Spec Coupe
Appendix A for Solo Spec Coupe classing

Classic American Muscle

The Classic American Muscle 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.

Detailed rules for Classic American Muscle
Appendix A for Classic American Muscle classing