After breaking-in the XTM 24.7 engine using a heat-cycling method, I.. .blah blah, you honestly don't care to hear the details, do you? You want to know how it tore up the track, shot dirt rooster tails ten feet high, and I don't blame you. So let's cut to the chase! I tested and practiced at our favorite local track, Revelation Raceway (www.revrace.com) to put the Mammoth ST through its paces.

Acceleration and Speed: The Mammoth ST's considerable mass is easily overcome by its low gearing and strong XTM 24.7 engine. Pull a handful of throttle, and the ST shoots away quickly with all four tires clawing at the ground. A few seconds later, you'll hear it pop into second-gear on its way to a 49.5 mph top speed. Its initial acceleration runs were strong, but after a few tanks at the track the truck began to bog considerably in spite of a good tune, which meant that the clutch shoes were beginning to overheat. Keep an eye on the clutch, scuff it regularly and you'll have the ST accelerating strongly every time.
Rating: 8/9

Braking: Much to my surprise, the little Hitec HS-311 standard servo provides more than enough yank to bring the Mammoth ST to screeching halt. The truck's dual disk brake setup works brilliantly with the standard servo, which has much less torque than a "race" type high torque servo. The Mammoth continued to brake well and nearly lock the wheels up after extended run times, which translates into an excellent braking rating, although I did notice the brakes begin to fade slightly after a 10 minute track session.
Rating: 9.5

Low-Speed Handling: For a truck of its size and weight, the Mammoth ST is fairly nimble through tight infield sections but its stock servo doesn't seem to have the yank required to keep the tires pointed in the right direction. Having seen XTM sponsored driver Jeff Guest wheel his truck around the same track, I'm confident that the Mammoth ST is more than capable of cutting tight lines with any truck on the market. My truck, however, pushes and drives wide arcing lines unless you drive with lots of brake taps to bring the rear end around slower, tighter turns.
Rating: 7.5

High-Speed Handling: As the truck picks up steam, the steering becomes less and less responsive, again due to the stock steering servo's lack of torque. Although the Mammoth ST is extremely stable at high speeds, and soaks up surface imperfections without getting upset, handling at higher speeds becomes numb as the steering servo loses its fight to steer the big wheels and tires in the desired direction. The ST's chassis is highly capable of carving up highspeed chicanes and timing sections, but in its stock form its wheels straighten out and you must drive with lots of brake to get the rear end pointed in the right direction. High marks for high-speed stability, lower marks for its inability to turn and keep tight lines at those speeds.
Rating: 8

Rough-Track Handling: The Mammoth ST's extended chassis and suspension design gives the truck a very stable, plush ride over even the most rutted surfaces. As Revelation's track surface became more rutted over the weekend, the Mammoth ST never seemed to notice. The truck comes with 100wt shock oil from the factory, but I followed an XTM employee's recommendation and refilled the shocks with 45wt oil for track use. The truck's wide tires and wide suspension makes the Mammoth ST highly stable even on rutted surfaces.
Rating: 9

Jumping: Jumping the Mammoth ST is a breeze; simply line up the truck, pull the throttle, and make any mid-air corrections necessary. It's as simple as that. My Mammoth ST jumps straight and true, and its in-air attitude is easily corrected with a tap of the brakes or a throttle jab. The truck lands with stability and soaks up even the biggest air you can throw at it.
Rating: 10


Wrenching Maintenance: Working on the Mammoth ST is similar to working on a 1/8 buggy, which means you can tear the diff cases open and access the diffs fairly easily. I'd like to see hex-head screws rather than the Phillips-head screws included in the kit, but that's getting picky. One thing you cannot avoid before running your Mammoth ST, however, is adding thread-lock to ALL metal-to-metal joints. After only two tanks, my Mammoth ST had nearly shaken itself apart and I was convinced that I had broken the truck. All four differential outdrive cup setscrews had loosened, and two of the four engine mount bolts loosened and were unthreaded before I caught them. Take the time to go over your truck, apply thread-lock liquid, and you'll keep everything in once piece.
Rating: 7

Wear and Tear: Other than the threadlock problems on the metal-to-metal connections, my Mammoth ST held up well and broke no chassis parts during testing. I did have some issues with radio gear, however, as the steering servo actually melted during radar testing. XTM reps say that the ST's updated and upgraded differentials and driveshafts will easily withstand the stock engine's power, and they were correct. I jumped the truck and purposefully landed with the throttle pinned to see how durable the drivetrain really is, and it never once hiccupped or chipped a gear tooth. Overall the truck seems very durable in its stock form; throw in a race-caliber steering servo, and it should be bulletproof.
Rating: 8.5

Tuning: The ST offers plenty of tuning options out of the box. Its threaded oil- filled shocks are easy to adjust, and several shock mounting positions increase its adjustability. The steering plate offers three Ackerman settings, and you can add or remove swaybars to alter its bump handling capabilities. I'd like to see a center diff standard in place of the included 2-speed tranny, but XTM does plan to offer a standard center differential as an option for racers. And although Pro-Line's popular 40-series Maxx Bowtie tires will mount to the ST's wheels, you must use XTM's wheels due to the truck's 17mm drive hexes.
Rating: 8.5

Conclusion: XTM's Mammoth ST is an excellent way to get into "Unlimited" or "Outlaw" monstertruck racing at an unbelievably low price. Like most RTR vehicles that are claimed "racers," there are some components you'll want to upgrade before hitting the track; most notably its radio gear. Beginners will get plenty of use out of the stock Hitec radio gear and steering servo, but those of you who plan to club race competitively will want more. The truck's handling is solid in stock form but becomes a totally different monster with racing components installed. When you factor in the potential cost associated with building up a buggy conversion to enter the outlaw MT class the Mammoth ST's performance and amazing price makes it a strong contender at the hobby shop counter and at the racetrack.