Category Objective

The purpose of the Xtreme (XA/XB) Category is to attract automobile enthusiasts interested in autocross events with street vehicles using minimal rules that allow for creative modifications with limited restrictions. This category is intended to appeal to regional/local competitors who would like to compete with a modified car on street tires but would otherwise be classed in high-prep race tire categories.

This class, unlike many other classes, is relatively unrestricted. Any modification is typically allowed unless specifically stated otherwise in the rules. This is unlike other classes that disallow any modification unless otherwise specified in the rules.

Eligible Vehicles

• Must be an automobile or truck (e.g., pickup, SUV) manufactured for road use and legal to drive on US roads. Non-US models are allowed and right-hand-drive steering is permitted.
• Must be licensed & insured
• Must include all road-going components such as lights, wipers, interior, heater, etc
• Must comply with these sections of the SCCA® National Solo® Rules
  • Section 3, Vehicles
  • Appendix I, Sound Measurement Procedures
• EXCLUDED: Acura NSX; Audi R8; Ferrari (all); Ford GT; Lamborghini (all); Lotus 7 (all including clones); McLaren (all); Porsche 911 (all w/liquid-cooled engines)

Subclasses

Your subclass should be highlighted

• Xtreme Street A - Import and domestic sports sedans and coupes
• Xtreme Street B - Lightweight import and domestic sports cars
• Xtreme Street Unlimited - High Performance vehicles with minimal restrictions

• Must have OE or OE-equivalent windshield. Side and rear glass must be in the original location if original for the vehicle. Windshields, side, and rear glass may be replaced with polycarbonate (e.g., Lexan®). Windshields must have a minimum thickness of 3/16" (0.1875 in.). Vehicles using polycarbonate windshields must add 150lbs to their minimum weight.
• Dashboard may be modified or replaced but must be "finished" and cover the original area.
• Headliner may be replaced or removed.
• Interior panels (e.g., door panels, kick panels) forward of the B pillar (driver and front passenger area) may be replaced, not removed, with an upholstered or finished panel of any material.
• The area behind the B pillar may have panels and carpet removed. Exposed metal interior surfaces must be painted.
• Front seat(s) may be modified or replaced. Rear seat(s) may be replaced, modified, or removed. Unless originally equipped as a center seat vehicle the driver’s seating area must not cross the vehicle’s longitudinal centerline and must not intrude into the original rear seat area.
• Exterior body panels may be modified or replaced in the original locations.
• Frame and Unibody may be modified or replaced to support allowed modifications. Subframes may be modified or replaced. Vehicle wheelbase may not be changed except for small changes resulting from the allowed replacement of suspension components or modification of suspension designs.
• Fender liners and inner fenders may be modified, replaced, or removed.
• Fuel tank/cell may be modified or replaced and must be separated from the driver/passenger(s) as originally manufactured or by a metal panel/ bulkhead if the OE structure is modified. Fuel must not vent into the driver/passenger compartment directly or indirectly.
• Body electrical system components and wiring are unrestricted.

• Components, lines, hoses, and method of attachment are NOT restricted

• Components, lines, hoses, and method of attachment are NOT restricted

• DOT tires with a UTQG Treadwear Grade of 200 or higher
  • EXCLUDED: Kumho Ecsta V720 ACR; Michelin Pilot Sport Cup 2 and Pilot Sport Cup 2 ZP

XA
• AWD: 3180
• RWD: 2930
• FWD: 2680
XB
• AWD: 2480
• RWD: 2330
• FWD: 2180
XS
• Average tire width of 275 and less: 2680
• Average tire width greater than 275: 2830

• Components (internal and external) are unrestricted

• A front splitter, air dam, spoiler, canards, and vertical members (e.g., fences, endplates) may be added below the top of the bumper (measured at the highest front most point of the bodywork). Components may extend a maximum of 6.0" (152.4 mm) from the front bodywork/ fascia as viewed from above. The aerodynamic surface may not extend rearward past the centerline of the front axle.
• A rear diffuser may be added but the aerodynamic surface may not extend forward past the vertical centerline of the rear wheels and may not extend rearward more than 6" from the original body, as viewed from above.
• A rear spoiler may be added but may not extend more than 10.0" from the original body nor beyond the perimeter of the body as viewed from above. When adding a rear spoiler or wing competitors may add either a wing or a spoiler. Not both.
• A rear wing may be added, removed, or modified. Endplates are allowed. No portion of the wing or its components may be more than 6.0" forward of the rear axle or more than 6.0" beyond the rear most portion of the bodywork. For sedans, coupes, and trucks no part of the wing or its components may extend more than 10.0" above the roofline. For hatchbacks, wagons, and SUVs no part of the wing or its components may extend more than 14.0" above the roofline.
• No part of the wing may extend beyond the OE vehicle width as defined by the outermost portion of the OE bodywork including mirrors, door handles, rub strips and trim. The maximum number of non-OE wing elements is two (2). The total surface area of rear wings shall not exceed 8.0 sq. ft. as calculated per the Wing Area Computation in Section 12 of the Solo Rulebook. Except for standard parts, wings designed to be adjustable while the car is in motion must be locked in a single position.
• All off-the-shelf commercially available wings, splitters, air dams, and diffusers that are vehicle model specific and installed per the directions are permitted with the following exclusions: