Most of us are not designing machinery to precisely traverse interdimensional portals into alternate realities. Probably.So an engineering degree is not necessary to pick out most replacement pulleys.
All you really need to know to find an adequate pulley to work with your belt is
2. What size is the pulley? Need help with this? Here's how to Measure Your Pulley
3. How high or low do you want the belt to ride in the groove?
It’s this last one that’s a bit tricky and the reason for this article.
4. Before you chuck out your old, busted v-groove pulley, learn where your belt rides in the groove.
Was your belt sitting at the top, maybe with the belt hanging slightly over the flanges of the pulley?
If so, take a look at the Belts that fit information on your pulley’s page. This section is sorted by belt size, so the largest belt is always listed last. Make sure that that your belt size is the last belt listed in the description.
IF YOU DON’T: When you reassemble your machine, your belt is going to be looser than expected. And then your belt will slip, and you’ll feel like a real loser. Slippage is no joke.
Was your belt sitting around the middle of the groove?
After you’ve narrowed down your options to pulleys that work with your belt, try to choose a pulley that fits *one* of the following attributes
· Pin Diameter is larger than your belt
This will guarantee your belt will not be riding at the top of your pulley because a bigger pin means a larger belt fit into the groove.
Belt Type the Pin is used for
4L/A OR 5L/B
· Pin Diameter matches your belt, and Overpin Diameter is smaller than Outside Diameter
If both are true, then your belt will hit around the middle of the groove
Was your belt touching the center of the pulley?
Then you were probably ripping through belts more often than you’d like. You were also losing a significant amount of power, so no wonder you want a replacement!
The bottom or narrowest part of your belt should never touch the center of a v-groove pulley. Try getting a pulley with a slightly smaller outside diameter instead of matching the one you have.
Here's an example of what NOT to do: See how the bottom of the belt is touching the center of the pulley? And there are gaps between the belt and the sides? This belt will not work in the pulley, and no amount of tensioning will give good results.
Are you feeling a bit more groovy now? I sure am! Use code GROOVY for 10% off your next order! If you still have concerns, please give us a call at 1-800-776-9315, we love tie-dye around here.
 What’s the difference between 4L and A, 5L and B? Belts with “L” are designed for fractional horsepower only. A and B belts are more robust
 Unless there are bananas involved
 Never is always preferred.