Buster – A Scratch Built 2.2 Text & photos by Jay Kopycinski

A couple of years ago Mike Wetzler showed up at a Phoenix area competition with a near stock TLT. Granted, the little crawlers weren’t nearly what they are today, but he got spanked on the rocks. After that, this Mesa, Arizona crawler went back to the garage and put together his own custom chassis. What you see here though is his third and current rig that was completed in the Fall of 2006. He calls it Buster. Mike started with a custom "pan-car" chassis that uses front and rear suspension pods. It is designed so there is no up/down travel, only articulation. Rotational flex is dampened with a pair of Associated RC10L Macros up front and RC12L Micros in the rear. Wheelbase measures in at 12 3/8” to be USRCCA legal.

The chassis and transmission are integrated based on an idea inspired by F-1 cars. Mike used a combination of Kydex, G-10 fiberglass, aluminum, and carbon fiber sheet to build his chassis and various component mounts. Inside sits a homebrew 6.5:1 transmission combined with a transfer case that disconnects the tranny drive running to the rear axle and locks rear axle rotation to allow for front drive only. The tranny is fabricated from an array of Traxxas Stampede, Revo, and Associated RC10GT parts with a few bike parts thrown in. This was Mike’s second custom transmission design and he’s got a third undergoing test in the rig now.

From there power gets to Tamiya TLT axles via stock length Stampede slider shafts with steel u-joints at the axles and lighter plastic Jato ones at the transmission. The axle differentials are mechanically locked by a simple method. With the diff asembly open, he removed one of the spider gears from the internal y-piece and placed it between the two remaining spider gears. This stops the diff action, is reversible, and avoids the mess of using epoxy. Mike says he’s tried numerous methods of locking the diff, only to have them break loose internally. Additionally, the axle stub shaft cups have been modified for improved turning radius.     Mike wanted to optimize front approach angle and clearance so built his own behind-the-axle (BTA) steering setup. A cut piece of carbon fiber sheet serves as the draglink to connect the GPM blue aluminum knuckles on the front axle. The rear steering is locked out with a set of turnbuckles tied to the axle housing.

To maintain precise directional control on the rocks, a Hitec 5998TG servo running on a 5.4V 10amp voltage regulator handles steering chores and an 85MG is used to shift the transfer case.     The wheels on Buster are back-narrowed RPM Revolvers wrapped with Proline Moab 2.2 tires. Lower COG is obtained with about 4 oz. of weight in each front tire and traction is improved with coned front foams and star-cut rear foams. Underneath, Mike keeps the chassis sliding over obstacles with the use of a skid pan made from roll-up cutting board material that runs from the tranny skid back to the rear axle tube. Topping everything off is a Losi XX buggy body with a cool paint job sprayed down by the owner, and throughout the rig you’ll find plenty of custom touches and anodized aluminum hardware.

Mike’s rig gets its juice from an 8-cell Intellect 1400mah 2/3A pack and sends it through a Novak Super Rooster (sitting under a custom bash guard) to an Integy 55t lathe armature and can with Orion V2 endbell (58/17 spur/pinion gearing). As an alternate, Mike runs a Mamba 25 ESC and a GWS 1020kv park flier brushless motor (60/16 gearing). All power connections are made with Deans plugs and wires, and the routing and clean layout is impressive. A Futaba 3PDF/R133 radio set provides three channel command for throttle, steering, and rear drive disengagement.

Buster is always in flux. Mike makes steady changes to this 2.2 to keep up with our evolving hobby. After all, it was competition that drove him to look for a path to improvement. Mike’s built one sweet crawler and you can follow his ongoing changes in his build thread on this site. Build Thread can be found by clicking here.