How to deal with belt loosening under load?

As per the title, from cold start > 50m into the ride I notice that the belt loosens by a good enough amount for it to pose risk of easily slipping and wearing out the teeth. I’m working on a bracket that will allow me to securely adjust the pulley distances and therefore belt tension but I was wondering if there were any other solutions? I’ve tried idler pulleys and they seem to work well but take some fiddling about.

UPDATE: Machined a new mount with thicker steel and more accurate placement on the trucks, realigned the pulley onto my new wheels, and it seems to work much better - the oscillations in the belt are gone and there have been no slippages!

Yes … Get a better belt

Edit: or a better mount…

Something isn’t right if your belt loosens in 50m…

Time to put the board on the bench

From what I read the belt loosening slightly is rather normal even in industrial application - that’s why they have idler pulleys and such that are adjustable rather than having to adjust the entire mount. Board works fine its just that when braking or accelerating uphill it is on the edge of slipping and sometimes does, the belt itself I trust is of high quality since the same company caters for much more intensive uses. Issue must be with my distancing and such for the mount. Just wondering if there were any creative solutions others might have come up with because that’s what I trust from a collective forum :smiley:

@arfintr most of the HTD5 belts have diagonally overlapping threads in them. I’ve noticed that some belts need to be flipped over to get even wear and this often eliminates any slipping I’ve noticed.This only applies if everything else is lined up and tensioned properly.

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what brand of belt?

Might try a different one.

I have heard people remark some belt brands aren’t as durable.

Lol of course it’s normal… But what YOU describe isn’t … :neutral_face:

The timing belts we use on our builds are automotive grade. they don’t stretch. They don’t. You have an issue with your mount. It needs to be adjusted correctly and tightened properly. If that can’t happen then you need a new mount.

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If it happens every time at 50 meters = Crap-tastic belt

Plain and simple = get a different brand belt

Using Contitech Synchrobelt, but I’m using XL size belt, perhaps switching to wider HTD that seems to be more common would help with more teeth contact, more material taking load, less stretch etc. Might as well since I’ve got new wheels on the way

You might have wobbly gear setup that constantly stretching in and out when it turns. Check your mounting and fitting.

As I said … Something is def wrong with your belt or set up…

Fix the issue…don’t waste your time on a band aid

@arfintr Post some pics, bro! It may be something that we can see right away.

It’s not the belt…They don’t stretch. They tear. That’s it. Nobody makes stretchy timing belts. That would be stupid.

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I noticed my soft wheels deform slightly and allow the pulley to sit at a slight angle as the belt is really tightened, and there are wobbles that move the belt back and forth… when new larger and harder wheels come I can test a ‘tighter’ setup and see if that works

I know this post is old…I have in the past actually noticed belt stretch. It is very minimal though. They are corded but are rubber and when they get dried out they can tear and when they get hot they expand slightly. When I have mine adjusted and add a silicone spray the belt actually seems to tighten from conditioning the rubber.