Sportwerks offers its 1/8-scale Mayhem buggy in two trim levels. There's the "almost ready to run" Mayhem Pro that omits radio gear and is available with or without a .21 engine and pipe, and there's the Mayhem RTR, which is reviewed here. We know what you're thinking: the Pro must have all the best features, and the RTR is without frills but has a budget radio. Wrong! The Mayhem RTR comes with a massive shaft-start .26 engine, and Sportwerks didn't skimp on the features. A heavy-duty, 3mm, hard-anodized aluminum chassis, pivot-ball suspension, sealed diffs and swanky JR XR3i FM radio gear are all standard! It's a compelling combo of racing stuff (high-end radio gear and fully adjustable, equipped chassis) and play-friendly features (shaft starting and the supersized powerplant). It looks equally ready for race action and backyard blasting.

CHASSIS. The quality of the chassis usually gives a good indication of a car’s overall quality and how raceworthy it is. The Mayhem’s chassis is a high-quality piece made of 6061 T6 3mm aluminum-alloy stock that’s hard-anodized with a scrape- resistant satin-gray finish. All the screw holes have been countersunk, or, as is the case with the engine-mount screw holes, have been routed out to ensure a smooth underside.

Aluminum-alloy, 3mm stock front and rear braces run from the bulkheads to the center of the chassis plate, and molded-plastic mudguards that conform tightly to the body to keep out debris and protect the pipe and radio gear are attached to the chassis’ sides. A front bumper protects the front inner hingepin mounts and overlaps the front of the chassis to protect it. All the fasteners are strong, hardened hex screws.

The radio tray is made of aluminum and is connected to the chassis with molded standoffs. The steering servo comes mounted in a laydown position for a lower CG. The radio gear is in an easy-to-access, low-profile hinged box that has enough room to hold a receiver of average size, a dry-cell holder, or a 5-cell hump pack and the associated wiring. The battery switch is installed and has a protective silicone cover, and it’s away from the edge of the chassis to prevent you from accidentally switching it off.

The included Sportwerks .26 is a potent powerhouse that’s factory-rated at 2.75hp. Three carb inserts are included so you can tune its powerband to match your track.	The Sportwerks Mayhem has a 125cc fuel tank with internal baffles that help to minimize fuel foaming; a drainage groove is molded in the top to funnel away spilt fuel when you refuel.	The pivot-ball steering system uses clever screw-on retainers instead of threaded inserts. Caster can be set by using shims to reposition the upper arms.

DRIVETRAIN. Like the chassis, the drivetrain is packed with race-oriented features. The sealed center differential has a 46-tooth machined-steel spur gear with hardened-steel spider gears, and it comes filled with 5,000WT silicone fluid. The front and rear outdrives are keyed to vented-steel brake discs. The brake linkage is color-coded, and front/rear brake bias can easily be adjusted without tools. An aluminum plate on top of the center diff mount keeps the diff running true and also supports the brake levers. Dogbones transfer power from the center diff to the front and rear sealed bevel-gear diffs. The sealed front diff comes with 5,000WT silicone fluid. The steel front diff yokes mate with rebuildable universal driveshafts. The rear is set up in the same way as the front, but the diff is filled with 1,000WT fluid for less restricted action. All the rotating parts ride on rubber-sealed ball bearings.

ENGINE AND ACCESSORIES. The engine is a Sportwerks .26 rated at 2.75hp.Three carb inserts are included to cope with varied track conditions. Carb inserts restrict the flow of air into the carb to alter how quickly the engine revs. A 6.5mm insert is supplied for slippery tracks on which wheelspin should be minimized. The installed 7.5mm insert is for good midrange power on medium-traction surfaces, and the 9mm insert is for high-traction tracks on which you can really put the power down.

The engine is finished in black and has a large, blue-anodized 10-fin heat-sink head. Instead of a pull-starter, the backplate has a hex insert to accommodate a hand-held starter unit.

An aluminum flywheel with a 3-shoe clutch is attached to the integrated pilot shaft. The steel clutch bell is fitted with a 13-tooth pinion. Additional clutch bells in several sizes are available.

Exhaust duties are handled by a one-piece Sportwerks tuned pipe/header unit. Made of aluminum and sporting silicone gaskets and steel springs, this is a race-quality pipe and not just a muffler.

The 125cc fuel tank has internal baffles to minimize fuel sloshing and give consistent fuel delivery. A fuel drainage groove is molded in the top of the tank, and it’s connected to a short piece of tubing that safely drains spilt fuel out though a hole in the chassis plate and under the car. This, combined with the screw-on splashguard, should effectively keep excess fuel away from fuel-sensitive parts such as the brake pads. A high-volume blue-anodized fuel filter comes in the accessory bag, but it isn’t installed.

The center diff comes with a sturdy, 46-tooth, machined-steel spur gear. The dual-disc brakes provide plenty of stopping power.

SUSPENSION AND STEERING. Suspension and steering. The Mayhem uses a mix of pivot-ball and hingepin suspension designs. Up front, the plastic steering blocks pivot on large, 14.6mm pivot balls that are hard-anodized for durability; 1mm to 1.5mm shims inserted between the pivot-ball shanks and the upper and lower arms make quick camber changes possible without setup tools. The heavy-duty upper and lower arms ride on large, 4mm hingepins on their inner mounts. Snap-on shims in front of and behind the upper arms make it easy to adjust front caster. In the front and rear, the lower arms have machined-aluminum pivot plates that are guaranteed not to break. In the rear, the lower arms pivot on 4mm hingepins, but they have hingepin-mounted upright hubs to carry the axles. The camber links are made of 5mm-thick tie rods. There’s a lot of adjustability here: on the uprights, there are two holes and four inner holes plus two lower hingepin holes to allow roll-center adjustment, and well shims allow the wheelbase to be made 5mm longer or shorter. Swaybars come installed on the front and the rear to minimize body roll in the sweepers.

The shocks have threaded, hard-anodized bodies and 3.5mm shafts and are filled with 30WT fluid. Threaded shock collars are not included. Instead, you get an array of clip-on shock-preload spacers. The shock towers are made of 3mm 7075-T6 aluminum stock. The front tower has four upper shock-mounting holes to go with the two lower holes on the front lower arms; the rear tower has six upper holes and three lower holes on the rear arms. This should be more than enough for most people to get dialed on any track.

The steering is a typical bushed-bellcrank design with a built-in adjustable servo-saver. The drag link and upper plate are made of machined aluminum. The steering turnbuckles are 4mm thick and easy to adjust.

BODY, WHEELS AND TIRES. The Mayhem body looks pretty good with its four-color paint scheme. It comes trimmed and mounted and with the window decals in place. Soft, mini-pin tires with foam inserts are mounted on white dish wheels.

 LIKES
 • High-quality parts.
 • Very good out-of-box handling.
 • Strong engine.
 • Excellent RTR radio.

 DISLIKES
 • Shock bodies are threaded, but threaded collars are  an option.
 • No center universals.
 • Some screws weren’t thread-locked.

THE VERDICT
The Sportwerks Mayhem RTR is billed as a race-ready RTR, and it is. It’s durable, it has features that will give most other RTRs an inferiority complex, and it’s backed by very good factory support. At about $550, it’s also very good value, especially when you consider that it comes with an excellent FM computer radio, a .26 engine, an aluminum pipe and a shaft starter. Its out-of-the-box performance is very forgiving—neutral handling with some push—but you can tune the suspension to be as aggressive as you like by using the many shock-mounting positions, roll-center settings and camber, caster and wheelbase adjustments. And don’t forget the many carb inserts for engine tuning. It’s fair to say that the Mayhem is a racer in RTR clothing.