Need help for proper tensioning of pulley belt

I’ve been looking around the forum but couldn’t find a good answer for this: I can’t quite seem to get the belt tension right, either it’s too loose or too tight. My wheels are 90mm and my mount is too small to put an islet on without breaking or hitting something. Any suggestions would be appreciated!!

I’m using torqueboards 36t and 16t pulleys with a 12mm belt. If someone can give me an idea for an idler that works too I just don’t have a lot of space really to work with.

Just use bearings for an idler if you want one. You can run the belt right on the back of a bearing

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I tried mocking it up but I couldn’t seem to get it to fit without the wheel pulley hitting the bearings.

Posting photos of it would be helpful

Ok, Uploading…

Don’t really have too much space to work with

I have 2 bearings and tried to put a bolt and nut on but the nut hits the motor and if I move the motor back any more the tension becomes really tight and it forces the motor.

Correct me if I’ve misunderstood, are you taking the belt off, moving the motor a mm or two then putting the belt back on to see what the tension is?

No I’m just trying to figure out where to place the idler since I don’t have a lot of room

What does your wheel-side pulley look like? Do you have a photo of it?

When I get home I can post a photo.

Ooh jheeze so that’s what islet is lol. My bad :joy:

In order to incorporate a pulley into your mount, you will need a much longer belt. I would recommend laying everything out and tracing it onto your motor mount ie. Take the wheel off lay it flat on the center point of the mount, trace the shape with a sharpie. Do the same for the wheel pulley, the motor, and the drive gear. The next step is to find out if there is actually enough clearance for a bearing then you can measure out where to place it.

Another option is to do what @Deckoz did. His is the most clever I’ve seen

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Yes, there is a photo of Deckoz’s in the other thread and it’s also the best I’ve seen. He uses the motor mount bolts as idler pulley axles. Genius

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With that size belt 265 and that mount, there’s no way to make an idler work there just hasn’t the room.


so how do i get the right tension

here is a side view: