Motor timing with new gearing

[farrerzack]

My current setup is using a sk3 6364 213 kv motor on 6s batteries. I originally was using the stock 9mm gearing kit from torquebaords (which I believe was using 14t/44t). I recently upgraded to an 11mm belt kit, also from torqueboards which almost certainly has a 36t wheel pulley and a slightly larger motor pulley. The new belt is awesome, but I definitely noticed that the motor struggled much more at lower speeds (as expected, it has been geared up) while also getting much hotter. What confused me is that the top speed has not risen but actually seems to have gone down slightly. Because of all of this, I lowered the timing setting on my esc, which seems to have helped somewhat with the heat issue and the low speed problems. My top speed hasn't gone up though, and it still feels lacking in the top end.

My question is whether I should adjust my timing more or look into either a lower kv motor or a smaller rear pulley. I know a lot of people seem to use the 192 kv or even lower motors, but I've also seen people using 245 and 280 Kv motors just fine which leaves me confused as to why it seems my motor is struggling in the torque area. Any insight is welcome,
Zack

 

[torqueboards]

11mm belts and/or 15mm belts are much more responsive but do have added resistance because of the added width. I feel this affects the easiness of 9mm going up to speed more. I haven't verified but I've noticed.

With higher gearing/torque, your lower end speed should be easier and shouldn't be struggling as much.

From what I've noticed heat is a result of an inefficient setup for your "purpose".

What type of grade hills are you climbing? Are you kicking off?

What's your current gearing ratio and pulley teeth with the 11mm belts?

You can also put your motor timing to the highest setting at least I do. Acceleration I bring down to a lower setting.

 

[farrerzack]

I do have some relatively steep hills around me, but even riding on flat level ground seems slower even still. I do always kick off, what I had noticed was that even after the initial kick off (which I get up to a reasonable speed), the motor stutters and even stalls when accelerating hard. This is something that I hadn't experienced beforehand. And I believe the current ratio is 12 teeth on the motor pulley/44 teeth on the wheel pulley

 

[torqueboards]

I'd check the motors, connections and possibly the ESC.

Doesn't look like a normal issue with the mechanical parts.

 

[mccloed]

What esc are you using?

 

[farrerzack]

I'm using an alien 150 amp 8s esc

 

[sl33py]

Uh oh, there's been some consistent issues with alien ESC's. Where are you located? If you are in Seattle (we do have hills) i'd be happy to let you test with a spare ESC!

 

[farrerzack]

Trust me, I know all about alien esc problems. This is my second one (the first one totally blew up and actually almost caused a fire) and a few months back the internal BEC died for no apparent reason and it is now run off of an external one. I live in NH though, so hardly close lol. I'm going to try switching back to the older gearing ratio today to see if that resolves any of the problems

 

[torqueboards]

Trust me, I know all about alien esc problems. This is my second one (the first one totally blew up and actually almost caused a fire) and a few months back the internal BEC died for no apparent reason and it is now run off of an external one. I live in NH though, so hardly close lol. I'm going to try switching back to the older gearing ratio today to see if that resolves any of the problems

Let us know if that fixes it. Possibly other things would be loose ESC signal wire connection, bad/low controller batteries, no ferrite ring on esc signal wire (causing interference), motor disconnected?, loose connector on motor wires?, esc settings, handheld controller settings changed by accident?

 

[farrerzack]

After some inspection, I think I've pinpointed the cause of all of this trouble. I have disassembled my motor and it seems that the skirt bearing has been damaged at some point and is no longer smooth at all. Unfortunately, that bearing size(38mm x 25mm x 7mm) seems to be a very rare part. Other than hobbykings own bearing kit for the motor, no other bearing provider seems to sell ones with these dimensions, although they sell tons of bearings with an OD of 37mm instead of 38mm. So I guess I'm stuck ordering the bearing kits all the way from HK.

On another note, I am considering upgrading to a 6374 motor with a lower Kv. What would be the most ideal Kv motor for good low end torque but still having plenty of top end speed? And does that extra length on the can make much of a difference?