Small stones in belts

Not sure about the category but this seems fitting enough.
I have very small stones in my belts from riding off-road.
Should I leave these in or get them out?
Leaving them in might put more wear on the motor pulley, getting them out might damage the belt a bit more?
Im not that sure.


I think leaving them in will probably wear out the belt even faster than if you were to take them out

I’d also just advise you to buy a new set of belts and carry them in your ride bag for when these ones break

There have been a couple belts of mine that I got stones in, removed, and they lasted a long time, but yours look pretty worn already.


This ^^
Part of the reason why people use belts, very easy to repair.


After riding a few miles home on one motor before I always carry spares with me


get the rocks out of your pulleys. leaving them in there will damage the belts and pulleys more. if you have spurs in pulleys as a result of the rocks you can use a razor to shave them off or a tiny file if you have one.

but i learned over the course of years that belts and off road aren’t the best combo. belts are no doubt pretty standard for street builds but off road is better served by chains or gears if you’re going to be doing it all the time.


Picking rocks is a hobby of mine.


Ok, cool, thanks everyone.

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Yeah I agree, you can break belts in 0.5 seconds if you hit just the right consistency of sandy dirt too, ask me how I know :roll_eyes:


Takes less time to order new ones then to remove rocks.

Someone should do some science to see if they have a great affect.

I would wager that it would put a lot more wear on both the pulley and the belt

Affected or not, it’s incredibly annoying to ride with, you can usually hear clicking and feel resistance


Lacroix does sell these belt guards. It’s a bit of an expensive solution to the issue, you could go gear drives instead which would also solve it. But I’ve seen evidence in their face book group that the guards so actually work quite well against stones.


Here’s my science from years of sciencing belts. first the rock digs into the pulley groove and fucks it up a bit, then the belt tooth starts to fray where it hits the rock and then a crack will appear on the outside of the belt and while all of that is happening the pulley is being forced to at least attempt to reposition itself, and if you have press fits with offset bearings then your wheel is going to start clicking while the belt misaligns it. if you have precision aluminum pulleys then the groove won’t partially heal itself like nylon or some other plastics would, and if you’re lucky enough to have a bearing directly beneath the belt surface and not offset or missing completely then you’ll do more damage to the pulley as the belt presses the rock in even harder and the belt will snap faster.


True but I’ve seen a few people having problems with gears, supposedly the case is not that sturdy.
Plus, they’re like 700 bucks or something?

I’ve heard that about the Lacroix ones too

Good news though I think the BN AT drives should have a hypertruck mount soon?

“in progress” I think

I’d love to make the Lacroix a bit more offroady, all those great patches of tarmac around here are connected by strips of rough gravel and traily surfaces.

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@SeanHacker & his aptly named board “RockSlut” are actually our resident experts on this topic.


Here is a 3D printed PETG pulley with just shy of 1,000 miles on it. Pavement only, but with plenty of stones & gravel on it.

The rocks embed themselves in the relatively soft pulley. I’ve picked out probably 30-40 tiny rocks, and you can see the witness marks if you zoom in. The belt makes a squeaky pulsating noise when there are rocks in there.

The belts broke every 400-500 miles. Interesting that the belts appear to be from a wider roll and broke in the same spot. Makes me think it wasn’t actually the rocks that caused the failure.

Leaving rocks in certainly messes up the pulleys and probably puts undue stress on the belts. I try to remove them whenever I notice it.

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Definitely not. Takes less than 5 seconds to pick those out and saves the wait time from ordering and shipping time. I’ve picked more rocks than shown in these pics and had the belts last a year afterwards.

Doesn’t take science. Rocks rubbing against metal repeatedly creates wear and divots in the pulleys.

Grab some extra belts and keep them in your backpack. Worry about picking the rocks out later. And get gear drives from now on. :kissing_heart:

I use my dab tool to pick rocks out.


Expert unfortunately. Ugh…

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I picked the stones out yesterday evening and I noticed slight dimples let’s call them on the motor pulleys.
The other thing is, I have a spare set of belts but I’d have to take a wrench with me to get the axle nut off to get the new belt on.
I can’t get the belts over the big ass tires.
This means I’d have to take a bag of sorts on a ride which I don’t want to do but I guess it’s better than walking and / or having no braking power.

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