MST CMX Scale RTR Scale Rock Crawler w/J4 Body (242mm Wheelbase) (Light Grey)

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Price: $299.99
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The MST CMX RTR is a scale truck designed to deliver a balance of scale performance and incredibly realistic looks. With features that include heavy duty steel CVA front driveshafts and 40° of steering angle, combined with 4 link suspension and a forward mounted battery, the CMX is a scale rig that can hang with the big boys. Read on to discover why the CMX is a great option for both new crawlers looking to have fun on the trail, as well as experienced enthusiasts looking for a new platform for their next project.

A water resistant electronics system combines the XB40 ESC, with the M54-26T motor for a balance of smooth low speed control and top speed that is necessary for technical trails. The electronics package is rounded out with the MST SC-0252MG metal gear servo and a water resistant receiver box that helps to keep things dry in harsh conditions. The system is compatible with 2-3S LiPo batteries and is easy to program by simply swapping the position of the pin jumpers on the ESC. 

The J4 body is included to finish off the package. With all the molded scale details like grill, rear view mirrors, spare tire holder and headlights/tail lights that can fit 5mm LEDs, this great looking body really brings the rig to life and gives it a realistic look on the trail.


  • MST classifies this truck as 1/10 scale, but the wheelbase is shorter and the track width is narrower than 1/10 models from other manufacturers. See specifications below for measurements.
  • The body comes factory painted but must be mounted and scale accessories must be installed before use. Detailed instructions are included.
  • Product photos show body installed, with scale accessories attached. This was done for illustrative purposes only. The body you will receive requires installation and assembly.

Wheelbase: 242mm
Width: 195mm
Gear Ratio: 1:19 ~ 1:42.6
Tire Width/Diameter: 30 x 90mm

Needed to Complete:

  • 7.4V - 11.1V LiPo Battery & Compatible Charger
  • (4) AA Batteries for Transmitter

This product was added to our catalog on May 27, 2021

Verified Owner
Monday, Apr 19 2021 (about a year ago)
MST CMX Scale RTR Scale Rock Crawler w/J4 Body (242mm Wheelbase)
Absolutely love amain. They always ship unbelievably fast and have great customer service. Not to mention there youtube channel has very thorough and honest reviews. So always 5 out of 5 for amain. As far as this mst cmx I bought it to have something a little different than the real common crawlers (trx4, scx10, gen8, etc). The body is very nice, detailed and high quality but the electronics not so much. The slowest it can go is much to quick for a $300 crawler. I was able to replace the esc, motor and pinion with spares from an scx10 and it took care of that but the overall layout just isn’t quite as good as some of the more popular crawlers. For example it’s a little harder to access the motor and transmission. Overall I’m happy with my purchase but I do feel it’s priced a little high. I think $250 would be perfect. I definitely wouldn’t recommend this for your first crawler but if you have all the popular models and want something a little different (and much smaller being a jimny) than it could be for you. Oh and as with just about all rtr crawlers you’ll want to replace the tires if you want some real performance.
Verified Owner
Wednesday, Nov 17 2021 (6 months ago)
MST CMX Scale RTR Scale Rock Crawler w/J4 Body (242mm Wheelbase)
I've had this mst j4 for a couple of weeks and think that the body on the rtr has only one coat of paint. I plan to mask the windows and paint the inside of the body a flat black. The side mirrors and wipers I installed, had to be used with the black two sided tape from an extra kit I accidentally ordered for the inside wheel wells. The rtr had no two sided tape with it. So far the rtr j4 looks to be highly scaled and I will be replacing the rtr with five new mounted
Crawler wheels, and spare tire holder mount, and a roof rack. I also have the metal skid plate and will be installing lights and a chasis mounted servo kit. A winch kit will be installed later. I have yet to use a new battery in it that I have.
Update; The rtr works good despite having to adjust steering linkage for new chasis mounted servo. Also installed inner fenders at the same time. Other parts seem to be lose and will check whole rtr and all of the screws and the chasis.
Update; I bought this instead of the gen8 v2 that was going to replace my gen8 axe that I gave to my brother in law. I will definitely stay with redcat or traxxas since the MST trades detail for non tightening fasteners and screws. I have had to use thread lock on most metal threads when checking rtr out of box. I have built a traxxas kit and the Redcat Wendigo kit. The kit or rtr from MST is too high priced and reminds me of my cheaper Redcat Blackout.
Verified Owner
Saturday, May 15 2021 (about a year ago)
MST CMX Scale RTR Scale Rock Crawler w/J4 Body (242mm Wheelbase)
Great little crawler super scale looking body only downside is foams in the tires
Verified Owner
Tuesday, May 11 2021 (about a year ago)
MST CMX Scale RTR Scale Rock Crawler w/J4 Body (242mm Wheelbase)
Awesome little car!, I have crashed, bashed, jumped and rolled it soo many times and have not yet broken anything. This is my first MST purchase and it definitley wont be the last!. great place, great products thanks Hobby Town!.