Breaking and shredding belts ..?

So I broke a belt last week and today after a couple miles my belt literally skinned itself …not sure why think the alignment might be it but not sure … also the motor shaft keeps coming outa flusher withe the can…wtf help please lol these belts are expensive xD

you running dual or single?

give us a pic of skinned belt and motor(s)/mount(s) setup(s)

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Just had this happen to my single drive, 6374 motor last week. What thickness is the belt that got shredded? For me, I ran a single 9mm belt that got over-torqued when going uphill and got shredded. Upgrading to a 15mm belt now… Edit: My drivetrain is slightly misaligned so that may have also contributed to the shredding.

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Single 6374 motor on torqueboards v4 mount kit

12mm belt ya mine shredded going up hill…well just after a hill… but it was making grinding noise for a bit today only did a couple miles on it…not sure what the noise it

you definately did a number on that belt.

k, so i’ve notice everyone (almost everyone) whose been shredding belts have had a large motor and small belt (9mm).

I think if guys are running these large motors especially on single setups they should consider a belt upgrade to 15mm at minimum.


well iv only 12mm pulleys and 12mm belts are what im using i think but am not sure that its alignment…along with the dodgy motor shaft

can you rotate 2nd pic and put a space in between pics. looks like it is a bit mis aligned

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having trouble rotating it lol

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your belt is pulling motor towards the wheel pulley.

ya i was having trouble rotating and having pic stay rotated.

take motor mount off and lay it on flat surface

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its the alignment ya…i hate alignment lol so hard get right

if it is single, the torque always destroy the belt unless u go slow. U will need nice idler or go dual. even with 15mm, belt life is short. it is just inevitable out come. also buy belt from ebay in bulk it is way cheaper and save shipping cost. I always buy 275 270 265 5 of each. wich is about 3dollar per belt from same seller.

I just noticed your belt dosen’t have fiber over the little bumps. but mine has. maybe the belt is faulty or bad quality.

As I know how much is to make small sync belt I’m not sure why they listed so expensive on 'merican or eu sites.

place like aliexpress you can buy 10 for $20. it just takes time to come over from china

How sharp are the edges of your pulleys? Do they feel sharp or not? On my first build I shredded one belt a week, it was so frustrating. I recognized that both pulleys have quite sharp edges and when I took a close up picture of the motor pulley compared to a proper one I was shocked. Never had problems with belts on other pulleys so far, my first pulleys were a joke.

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The answer is to @stormboard1 but what @rich is showing is a worn pulley. A worn pulley will destroy belts. I found this out too. If you have a small size motor pulley they wear out faster than a larger tooth one.

After I discovered this I switched to much lower KV motors so I could run a larger motor pulley and smaller wheel pulley to get to the same top speed range. The pulleys last much longer and I have not broke a belt since I changed to that setup. Currently runing 140kv 12s with 18/36 gearing on 97mm wheels.


In case it is a worn pulley, switch to steel. They last allot longer.


True, but I wanted to point out differences in NEW pulleys. Both in the pic are 15T pulleys, the “worn” was used for 2 months only but the surface on each teeth was tiny and sharp from the beginning. You can see the tiny edge instead of a surface compared to the left pulley.

And as @telnoi mentioned steel pulley for president!

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You must need:

  • 15 mm pulley
  • 15 teeth and up (less destroys belt)
  • Made of Steel
  • With two flanges (thin edge)
  • No overhang

Extra (but not required):

  • 200 kv motor or less
  • Idler
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Fresh pulley but 14t steel one… belts are from beltinonline. .

Don’t want to start any argument, but it looks exactly like heavy wear I have seen on low tooth aluminum pulleys. They can wear out in less then a month.

I’m sure the like new tooth profile is the blue area.

And a couple of my worn 12 tooths. They had thick teeth when new.


ill take a pic of it tomorow