Re: ALL belts are uneven, dress them

> Graham Motzing Wrote:

> -------------------------------------------------------

> like that one time i ended up with an egg-shaped sprocket and couldn't

> figure out why my chain would get loose-tight-loose-tight.

Drill out a tomos sprocket to fit a sachs, not quite exactly centered, and then proceed to wonder what is causing the engine to surge not thinking once about the chain...

Re: ALL belts are uneven, dress them

Totally normal JBOT /

Last night one of my newer belts that I cut ate itself. I know why.

I had cut out a hump on the top of the belt as an experiment, and I shouldn't have done that. This dayco belt relied on the top piece to keep it together. It peeled away and then the shredding began. I was somehow still rolling even with a 1/8 strand of the original belt. But of course it finally gave up.

So in the future, I will continue to dress belts for minimum variance in width, but I'm not going to touch the top.

Re: ALL belts are uneven, dress them

DONT TOUCH THAT! Ha

Re: ALL belts are uneven, dress them

crazy wayne says:

Kevlar belts with proper angles to work with variators

https://www.mopedarmy.com/forums/file.php/7/89164/Archivio_Files_MONTAGGIO_DIM_CINGHIE_001.pdf

Re: ALL belts are uneven, dress them

Totally normal JBOT /

Tell crazy Wayne that I have no interest in his way. I must find my own path. I chart these waters alone, buoyed by the fact that a mistake does not mean a failure, for it is a portal to another higher state of consciousness.

Don't fuck with that shit or I'll stick ya

Re: ALL belts are uneven, dress them

I still buy the cheapest shyte belts I can find for their lovely super soft wear fast but grip like heck rubber. 1/4 the cost of Dayco or Gates (etc)

Re: ALL belts are uneven, dress them

How aggressive have you gotten with this? Mostly just truing belts to spec or making shit work that shouldn't? Kinda considering trying a belt that's 1 3/16" on top and narrowing it down to 3/4"-7/8" range.

I'm in a bit of a no man's land for finding a belt that takes full advantage of the overrange pulley on derbi. I'm a bit jealous of hobbits and adjusting belt tension by moving wheel. 1228v255 is just a hair too loose so it likes to flip and the flatreed belts sit down in rear a fair bit. Needa find something in the upper 25" ish long range by roughly 3/4 wide. Like 640-650mm outer circumference, 17-20mm thick at top

Trying to find the arbitrary differences between different manufacturers of the same size belt quantified on the internet is kinda fuckin silly, lol. These are the choices I make

Re: ALL belts are uneven, dress them

Totally normal JBOT /

You can go as hard as you want.

Just have to be careful to keep it all even and have the angles right.

Re: ALL belts are uneven, dress them

What the heck. This is rad.

Re: ALL belts are uneven, dress them

Fuck yea proof of concept. Took a 1 3/16 belt down to about 3/4, basically cut 10mm off. This belt is kinda fucky now but I've got a feel for how to do it better next time, I feel better about getting some other sizes to experiment with. Adding some pulleys to the jig would be dope. Used a utility knife for the cut and then just pulling it thru jig a bunch to tryn reset that angle.

20211121_141817-COLLAGE.jpg
20211121_141904-COLLAGE.jpg

Jbot did you make those angle pieces on the mill or are those available somewhere? I just did angle bevel on the skilsaw so definitely some precision to be gained

IMG_20211121_134337.jpg

Re: ALL belts are uneven, dress them

Totally normal JBOT /

I cut on my mill but eyeballed the angles.

The way to do this really right is with a motorized machine with 2 pulleys and an adjustable V it has to slide thru. An adjustable bearing on the top edge forces the belt into the sandpaper V again with adjustable tension. I’ve been wanting to make it but have been much too lazy

You should make it

Re: ALL belts are uneven, dress them

Totally normal JBOT /

The key is measuring the belt consistently across the top with a digital caliper. You have to get a real feel for it since it’s kinda squishy. I do multiple attempts and try to use the same caliper pressure and technique. I mark the belts width at as many places as I find that are high. Then take them down to a median width, or go to the size of the lowest width you find. If you put the belt onto a bike with perfect pulley cheeks, you can see the thicker areas raise higher in the front and that’s a high spot to mark. If your pulleys are bent this doesn’t work.

With a motorized machine with real time adjustable pushing into the V you wouldn’t even have to measure.

Re: ALL belts are uneven, dress them

I remember this when it was originally posted in 2019. Only a Libra would ever think of or try something like this. Kudos my man.

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