Timing Belt Pulley Off Center

I bought this 15T timing belt pulley from Enertion (Looks like a standard McMaster Carr part or something) and it doesn’t seem to be true. I’ll link the video below. Is this normal?

Dont mind the bolt as a set screw. It was temporary.

it’s a little bit hard to see where the problems is, something definitely looks a little bit wobbly.

maybe remove the belt, the screw and position the camera directly in front of the pulley. sometimes the flange is what is wobbling because it gets made off center.

the bulky flange itself is milled on a lathe, so it’s hard to figure how the would be not a perfect centered circle.

how di you mount the pulley onto the shaft? is it possible there is an issue with the way it’s mounted.

It’s definitely wobbling. When I tighten the belt it actually shifts the motor mount laterally and the same spot every rotation. I can’t see how it could be a mounting issue considering such a tight tolerance between the shaft and pulley. I’ll try to take another video today.

do you think you might have a slightly warped motor shaft? I would think its more likely the pulley is warped than the motor shaft.

nevermind. After watching that video repeatedly until my eyes crossed, it really looks like your motor pulley is somehow malformed.

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My observation is that the Enertion pulleys are not 100% snug around the 8mm shaft and needs enough shaft to get the outer circlip on.

The benefit of this is its easier to take on and off and will not get stuck as easy.

I do notice more ringing sounds as the pulley can sometimes vibrate against the shaft.

With a proper keyway it seems to be okay without the outer circlip but finicky about the keyway.

By comparison the DIY pulleys are snug so even the pulley extends beyond the end of the shaft it stays aligned.

Downside is 100% snug design can get stuck and need to be pried off.

naw mine are super snug and are just a little hard to take off. The diy pulleys are perfect and very well made.

that’s super weird…

I have three enertion pulleys, and have used them on 3 different motors with no problem- maybe you got a defective one.

You not using the key?

Maybe the shaft has moved slightly into the 3mm wide cutout for the key. I suggest getting some 1.5-1.6mm steel plate and hammering it into the keyway, that will push the shaft back into the correct position.

Send it back and get a new one. You’re probably wasting your time trying to find out what’s wrong.

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If you have some digital calibers, you could measure the wall thickness of the pulley too… that would tell you if it changes thickness at different points on the pulley.

The difference in the offset of the pulley is way more than any clearance inside. I guess I’ll just cut my losses. I was hoping I could just get a new one.

This statement couldn’t be more wrong! My warranty doesn’t cover products that ‘might’ be faulty

Every product is different and some faults are obvious, I’ve sold well over 2000 pulleys and never seen or heard of them being eccentric. So I need to establish what the real issue is. It could be faulty, it could be installed incorrectly.

Let it be clear: If you buy enertion products that have manufacturing faults you can have them replaced within 600 days under warranty. Here’s our T&C’s

But first we need to establish what the fault is if people just send stuff back to me without first trying to find out what a problem is - well that is wasting time & money - personally I don’t have the spare time to troubleshoot everyone’s issues one-by-one here on my bench. The cost of postage to send this item back probably costs more than the item, if I get it back and test it without any fault found the customer then has to pay freight to get it sent back again.

That back & forth process wastes my time & the customers time & money.

The quickest/best process when you have a faulty enertion product

  1. Post about it online, with detailed video & pictures, to explain what the fault is.
  2. Allowing myself and the community to help diagnose the fault. (This also builds a huge online resource of troubleshooting & diagnostic content so others in the future can learn how to better diagnose faults)
  3. If fault is found product will be replaced under warranty NOTE: Depending on the value & repairability of a product I may just send a new one out without it being first returned, but I will only do this once I’m convinced it has a manufacturing fault - so as a claimant wanting products replaced under warranty simply prove they are faulty and you get a replacement.

So @stuxtruth has done exactly the right thing, that is making a post about it first! - At this stage however, I’m still not 100% convinced it’s faulty. So once I get the proof I need, like a measurement using calipers, or some other irrefutable evidence proving the fault is due to the manufacturing of the pulley & not bad installation - I will continue to ask questions. If its faulty ill send you a new one.

I know this sounds trivial for an inexpensive item, but it’s a process and we must do it.


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I’ll send you a new one free of charge under warranty!

please ‘buy’ this ‘free’ item http://www.enertionboards.com/how-to-build-eboard/postage-charge/ write a note saying what you need to have sent “15t piulley”

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Sorry. Not trying to be a dick. But I just looked at the image again. The one with 9.77mm measure. The caliper is positioned above the keyway slot. Is there a reason your measurement is taken at that point. Is the inside tooth of caliper firmly seated on the wall inside the pulley?

It was right in front of it I tried to measure the shallowest side vs. The deepest side. The caliper was NOT in the keyway.

The change in distance is not as drastic on those two sides though.