Matched Motors on MOA rig

[Colgout]

I am having some thought on Motor for MOA rigs. At the moment, it seems everyone is running speed matched pair motors (identical) on their MOA rig.

Has anyone try running different motor on front and rear?

I was thinking these 2 motors work quite differently, the rear one for drag brake, and the front one to find traction.

If the front end uses a smooth motor like 5 slot one so with its smooth start up it will allow a smooth dig action and should make difficult climb a bit easier.

At the rear a big 3 slot 10mm Comm with XX stiff spring to provide strong drag brake.

I am keen to try as currently on my Pro rig, I have 2 HH torquemaster 35T and I have a HH crawlmaster 16T armature so if I swap out the front 3 slots with a 5 slots, I can sort of speed match them using my lousy motor checker by adjusting the timing... Even they are out by a small bit, it does not really matter I guess as long as the front is slightly faster.

Has anyone try this before? How does it goes?

[Charlie-III]

I have not tried what you're suggesting, but I have done "mismatched" motors.
-Different winds front vs. rear
-Same winds but different mfgr's

I didn't do it for a performance gain, I did it because I had killed a motor and did a "quick fix".

Interesting idea you're looking at though.

[winnerone23]

Wouldn't a smaller pinion in the rear do the same thing or similar to what ur talking bout?

[ittybitty]

He seems to be more focused on enhancing the characteristics we "want" from each motor like nice smooth low speed from the front and strong drag from the rear. With the combo he's talking about he'd get the desired effect, but most likely you'd have too much trouble getting both motors to react the same. There's just too much of a difference between those two motors to have them start together...react to full throttle input the same...etc.

You can tune the motors you already have to enhance the characteristics you're looking for. For instance...running a set of stiffer springs and different brushes out back "can" increase the effectiveness of the drag brake although this is not the "best" way to do achieve stronger drag brake.

Really though...your best bet is to drop what ever ESC's you're running and go to the BRSL's or wait for the new smaller version to come out. You can do so much more fine tuning with these speed controls compared to the others. If you want the rear brake to LOCK UP...they'll take care of that and as far as smooth low speed control...it doesn't get much better than with these

[EddieO]

If it worked....John or I would sell it as a combo....it doesn't, hence why its not offered. I've had some people run like a 35t in the front and 40t in the rear....also some have done 4 mag front/2 mag rear with decent success....but still to much variance in the motors to be optimal.

Later EddieO

[bigstu]

I know a couple guys that used to run 35t in the front adn 45t in the rear.
Worked OK, but if there was an instance you wanted some more rear drive speed, you wern't going to get it.
Just like EddieO said.
Buy a set of matched motors, two speed controllers, a mixing 3+ channel radio, enjoy.
When I built my XR 10 I spent the money to buy a 4pk and haven't regretted it for one second. And Eddie's motors have been motovating them for a while now.

[JohnRobHolmes]

I say give it a shot, won't hurt to try. Don't think its been tested, but so much of a setup is driver preference and popularity. Years back we tested skewed arms and drivers hated them because of low drag. Fast forward a few years and rigs were so light that five slot and 1/2 skewed arms were good enough without Holmes hold. What isn't good today may be great tomorrow.

What you will find is that your rear starts up later and has more brake, just like you are expecting. You can eliminate rear push if you set the front five percent faster in rpm or have a radio with mixing.

combos I have built:
Faster wind fronts
Thinner web fronts
Smaller comm front
Lay down or p94 front and standup rear
Four mag front two mag rear
Fb9 mag front fb12 rear
1/2 skew front
Full skew front 1/2skew rear (nice combo actually)
Advanced timing front, the plain Jane version.

Obviously the trend is smoother and faster front, except the smaller web front pair which was for sand drags to keep it pulling straight. Smaller web three slot starts up at higher speed, not an easy thing to overcome or drive with on the front of a crawler.

The vast majority of people want matched motors. The precision between motors isn't so critical, I could throw almost any two identical build motors together and tune them front and rear with simply timing, spring, and hood tweaks. I've even snuck sets to team drivers that were on opposite ends of the batch "quality". The top competitive drivers in the world can't even tell which motor is the good one with proper speed matching that biases the front at least one to three percent faster, so we stopped going beyond the basic vitals unless specifically asked for. Happy to pick some reluctance matched arms and field matched cans, but I would be lying to say it has proven an advantage besides having a blueprinted set.

On the subject of matching, there are but a few critical ways to have podium winning quality. First and foremost, ensure the comms are of equal size if possible. Easy on a new set. Equal Brush length is next, a gimme on new motors. A quick zero timing speed check in both directions will reveal which motor is faster and suitable for front install. On used motors this will generally be the smaller comm. Break in the pair with proper rotations, tweak hoods if needed, then set timing with equal or front speed bias. Rarely is spring tension tweaked, but springs on the edges of batch variance will screw with speed, and motor pairs with unequal wear can be quick tuned by reducing tension to increase speed on a lagging motor.

One element of matching is startup. We can ignore the can and magnet on 540s, tolerance is tight in relation to other forces. An epoxy balanced motor is extremely predictable and offers smooth and consistent startup. Drill balanced motors become unbalanced in detent force and positional dependent, only capable of absolutely predictable starting with full pitch skewing. Keeping to epoxy balance is far superior in this regard.



Try unmatched and see how you like your unique idea. Some people absolutely love unmatched sets.

[Colgout]

thanks for the info, john. good to hear some other drivers had wanted something similar before.

i will give it a try after this week comp. i will use your crawlmaster 16t at the front and torquemaster 35t at the rear. the two cans and end bell are from a matched pair. so i would expect the front being slightly faster which i don't mind.

i do have a lousy motor checker so i can speed matched them if needed. but i like the idea of front being faster (like od/ud in 2.2s rig). my 4pl will also allow a 20% overdrive for rear esc if needed to even the speed.

[Manning]

I've been running laydown brushes in the front, and standup in the rear for years. Everything else about the motors are the same.