Motor Choice for Tiny Truck Challenge Crawler Competition
 

I have two Trucks I am bringing to the Tiny Truck Challenge April 6th in Uwharrie State Park North Carolina: A TRX-4 Sport and a Vaterra Ascender.

Both currently have stock motors,esc, servos and gearing which I am replacing right now.

I have 3 motors which I just bought: Holmes Hobbies Torquemaster Expert 550 21T, Trailmaster 550 21T and Trailmaster 550 27T.

My TRX4 is the heavier of the two trucks. Both trucks are stock gearing. Which motors in each say ye? Im thinking the higher torque 27T motor in the heavier TRX4....and faster motor in the lighter by comparison Ascender?

Or save the Torquemaster Expert 550 21T for my Axial Bomber?

Im running QR1080 ESC in all these trucks.

Thank you for your help in advance guys!

-JT

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

The Tiny Truck Challenge is a great event on some awesome terrain, should be a good time. I'll be out there this weekend to help scout trails for the event. "thumbsup"

As for the motors, I would go Trailmaster 21T in the TRX4 and the 27T in the Ascender. The TRX4 has more room to gear down so going with the faster motor and more gear reduction will get you more torque, better low speed control, better drag brake hold, and cooler running while still maintaining decent wheel speed. Try a 45T spur with a 11 or 12 tooth pinion.

The Ascender, on the other hand, doesn't have the same gearing range so it benefits from the slower motor.

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

my TRX4 is the TRX4 SPORT... in case, by grearing.... Are you simply saying stock Ascenders are geared higher? aka faster, vs lower torque stock fixed gearing in the TRX4 sport?

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

Hey very cool you are going to be out there this weekend -only it might rain! We've been having rain for a MONTH NOW in Carolina. Hopefully by April 6th it will All blow out and we'll have some gorgeous weather. Anyway, my name is John and I'll be running a Metallic Blue Jeep TRX4 and a gunmetal Jeep NuKizer Ascender. Looking forward to seeing you there! Cheers!8)

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

The Sport is geared too high out of the box for my liking but replacing the 39T spur with the 45T spur gets it into a much better range with lower possible ratios. A pinion/spur ratio of 45/12 gives the TRX4 a overall ratio of about 60:1 and can go all the way down to 79:1 with a 9T pinion. Since you said that you were changing gearing along with the other electronics, that is what I would do.

As for the Ascender, the design of low reduction in the axles and high reduction in the transmission is a big source of the torque twist. Gearing it down much more than stock 40ish:1 ratio is just going to amplify the effect. So the slower motor would be the better choice.

In the end, you would have 2 trucks with about the same top end speed but taking different routes to get there.

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

Copy that, go to a 45T Spur for the TRX4. What Spur should I use on the Ascender?

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

Stock spur on the Ascender is fine, a pinion in the 14-16T range is what I usually run.

Re: Motor Choice for Tiny Truck Challenge Crawler Competition
 

Got it! Thanks alot. Should be a fun time! pS... I believe I have a 12T Pinion in my kit for the Ascender.... That would bring the gearing down and help with axle twist.