Monster Truck Madness – Questions about Dual Motors

Hey gang and Happy Thursday! I received a couple questions last week from a long time reader and I’ve been meaning to talk about one of the topics for awhile but didn’t know how to slip it into a column, so this is the perfect chance. These questions come courtesy of “The Trail Rat”.

I am getting into radio control monster truck racing mostly in the sport mod and Pro Mod class eventually maybe mega truck. I’m looking for any information or video or website that can help me to learn about racing in general mostly the tuning like I know the shocks can be tuned gear ratio 4 links and weight balance?

Congrats on deciding to get involved racing a monster truck! Now as for the question(s), there’s a lot there. I’ll focus on the shocks part.

For those who are unaware of the difference between Sport and Pro mod classes, while the rules differ slightly from club to club, in general Sport Mod is stricter on battery rules and limits racers to brushed motors only. Typically 2S and somewhere in the 17t range. Pro Mod is more open, with big power and higher voltage.

There are various chassis out there, so tuning a lightweight Axial SMT10 versus a heavier Losi LMT will obviously be different. A good rule of thumb I use is that I start out with 30 weight oil and start adjusting from there. Given you are just starting to race, I dunno that I’d recommend you go out and get crazy with swapping springs and other things (though you can if you want!), I’d keep the variable limited to just the oil at first. Or maybe keep the oil at 30 weight but experiment with 2 hole and 3 hole piston shocks. Whatever you do, try and only change one thing at a time to better understand what you like and don’t.

But hey- if you want to get crazy and build a custom Frankenstein shock absorber using various manufacturer parts, oils, and springs then talk to the monster truck shock man- Jeremy of Taurus R/C Monster Truck Racing. His trucks land like butter and he is constantly tinkering trying to find the perfect shock setup. Send him a message and he will give you the lowdown!

Let me make a recommendation to you that is NOT shock related though- get a set of JConcepts Renegade tires and Slam-Tech closed cell foams. You will eliminate tire bounce. The difference from open cell to closed cell foam on a monster truck is so pronounced that it almost makes it handle like a new truck!

On sport mod is it worth it to use two brushed motors on an smt 10 or just one.

Ah yes, this is the topic I had been wanting to weigh in on. The Axial SMT10 comes standard with one motor. Those wanting more power could simply just upgrade it to a brushless system. Racers who were limited to brushed motors, usually with a turn limit of 17, could not do this. A lot of racing clubs allow a max of two motors to accommodate Clod Busters, so in following the established rules racers started adding a second motor by way of a twin motor mount plate.

This REALLY changes the feel of a brushed SMT10. Whereas with a single brushed motor the trucks are down on torque, two of them provides a massive upgrade. So much so, that it almost feels like driving a pro-mod with them. The trucks are quicker and faster, but also trickier to handle.

I’ve hesitated on switching my Sport Mod trucks over to twin motor for the latter reason- the trucks are just easier to drive with a single powerplant and I’ve won a good deal of races by keeping my truck smooth and in control. This past year though, as more and more competitors are going to twin motor, I find myself being outgunned and losing races because of it.

I ordered some twin motor plates from eBay and plan to upgrade soon, and when I do I’ll discuss it here. I plan to use two JConcepts Silent Speed 17t motors and a Hobby Wing 1080 ESC.

Ok Trail Rat, I hope this info helps ya! If you have a question(s) that you’d like answered here, shoot an e-mail to doug@bigsquidrc dot com.

Until next time, keep it on all 4’s!