While Losi insisted that it was not working on a crawler, a few of us knew, in fact, that it was. Losi finally spilled the beans on their secret project, they’ve created a competition-class 1.9 crawler, appropriately named the Mini Rock Crawler. Let’s take a quick look at what this rig is made of.

As much as they may look the part, the stock wheels are not bead-locks. The 1.9 injection-molded Rock Claws are factory glued to the chrome plastic wheels that feature 12mm hexes. Six screws bolt each bead-lock ring to the wheel. The tires measure 3.75 inch tall, 1.25 inch wide, and have a tread depth of 2.5mm.  

The internal transmission ratio is 7.59:1. With the stock 60 tooth spur gear and 14 tooth pinion, the transmission has an overall ratio of 32.5:1. The ring and pinion in each axle have a ratio of about 2.64:1. This gives the Mini Rock Crawler an overall ratio of 85.96:1. When combined with the 380 motor and new ESC with crawler specific features such as drag brake, the entire driveline is well suited to crawling.  

The MRC uses a 3-link system with steel turnbuckles for lower links and a reinforced composite for the upper 3-link. The lower links attach to the inside of the chassis plates. This helps reduce the chances of the ball ends getting caught as the MRC slides over the rocks.  

The axle assemblies go together clamshell style and house spooled versions of ring and pinion, steel inner axle shafts run from the spool assembly to the wheel axles. The axles measure 106mm from kingpin to kingpin, and 137mm from drive hex to drive hex. The wheel axles accept standard 4mm wheel nuts. 

FIRST TEST HIGHLIGHT

CLIMBING

When pointed uphill, the Mini Crawler will tackle all but the steepest, slickest climbs with relative ease. The compound of the MRC’s injection-molded 1.9 Claw tires isn’t as soft as the 2.2 version of Losi’s Claws in their blue compound, but they did seem to gain traction as the tread surfaces “broke in” on the rocks. When the tires find traction on the steep ascents it will take steady throttle input to allow the MRC to creep up the slope. Even though a stiffer left rear spring comes standard in an effort to combat torque twist, the MRC still exhibits a bit of torque twist. That torque twist combined with the chassis mounted battery can cause the front tires to lift on steep obstacles.  
 

THE LAST WORD

Losi’s new Mini Rock Crawler will no doubt bring an adrenaline shot to the world of 1.9 crawlers and crawlers in general. The MRC has not only given crawling enthusiasts a potent, capable package out of the box, but it has also opened up a few possibilities for whole new classes of crawling.

To see the full article, keep your eye out for the September issue of RC Driver! 

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