Troubleshooting hot, and eventually desyncing motors

So I have the 5050/5055 sensorless motors from I assume the basic diyeboards belt drive kit. I have them on a 10s right now hooked up to a dickyho ESC, and within a mile or so of running/gunning them they get really hot and start desyncing. The thing is I’m only 155/160 lb. My old hub motors got pretty hot I’d admit but I’d run them for 6-10 miles with no problems in summer weather.

Is it normal for these motors to get super hot? I would’ve assumed since there’s less load on them because of the gearing they’d run cooler than hub motors.

I’m leaning to the problem being with the motors vs the ESC but want to hear what you guys think.

Not much to get from this picture really but here’s my setup. They’re linked to the ABEC 107s

Whats the gear ratio on your drivetrain?

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That pulley looks small for those wheels, iirc the dickyho kit is 15/36. if those are the 270KV motors that might be a bit much for such a large size wheel. I think he does have 180KV versions which would probably be okay at that ratio.

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I haven’t counted :/. I’ll start counting when I get home later today. It might be the 15/36 that came initially with the kit, if those pulleys fit in the ABEC 11s 107mms wheels then I wouldn’t doubt it. Here’s a close-up. They do seem like small pulleys but again I’m new into the belt world. 255mm belts from what I remember

that makes sense to me, especially if the gearing is mismatched. I was talking to another guy that had a similar setup to me and he was fine, but he said had wheels like 30% smaller or something like that. The fix is either smaller motors or bigger pulleys then?

Also, breaks are super weak. I imagine that’s a pretty normal feeling going from hubs to belts with no idler/tensioner right

I’m guessing its 15/36 I could be wrong, I think 13/36 was also an option, but either way with the 107’s your top speed is at/over 40mph. And I’m guessing you’re not getting anywhere close to that due to the heat and inefficiency.

The brakes sucking is a result of high KV and the huge wheels. A higher top speed ratio means less torque, witch is accel and brake torque.

I would check the order if possible to see what you purchased, if not check the ratio and then see if you can make any sense of it based on your speed’s with the eskate calc. Im gonna guess 97mm is the max wheel size you should use with that ratio or jump up to a 40/44 tooth wheel pulley.

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Yup, I counted 35-36 teeth on the wheel side.

Ran some numbers. Gonna go ahead and get a lower kV motor vs a new pulley, be best for top speeds then. Little concerning hitting 32 mph on Cloudwheels if I ever get em but we’ll cross that bridge when we get there.

Thanks guys, appreciate all the help.

As a given, WTB 180 or lower kV 50xx motor.

Well, I’m just gonna bump this thread instead of making a near-duplicate.

I’m having my motor get too hot to touch for more than 2 or 3 seconds after just 10km or so of moderate cruising at ~40kph. Im doing 18-20 wh/km, no stops, moderate hills. Tight or slack chain, no difference, thermal paste to alu mounting plate, no difference except the plate overheats too. The 200A esc gets just barely warm.

Equipment is APS 80100 130kv @ 20s, 130A motor, 60A battery. No temp sensor, vesc tool reads -70C or whatever from the missing wire. Final drive for 70kph, though i haven’t tried to hit that yet due to the heat.

Could that be my setup, or a bum motor?

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This may help, and might be worth adding a temp sensor too


Well yeah cooling is possible, but since this is more motor mass and lower ERPM than my previous build, but has way more heat, i thought something might be up.

I could try one of these to test at least:

Is that adhesive good until at least 100°C? Preferably 125°C

idk cuz VESC needs a thermistor, not a thermocouple. I’ve ordered some 10k NTC thermistors and I’ll glue them on myself

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The thermistor was too big to fit inside the motor without like 3 minutes of effort so i just glued it to the mounting plate right next to the motor shaft, with insulation over it so it won’t get air cooled.

The reading holds steady at 45-50C under moderate riding like before. Maybe i was overreacting?

Don’t use glue. Use epoxy.