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Old 11-29-2012, 10:30 PM
Motorized Bicycle Elite Member
Join Date: Jul 2010
Location: CA
Posts: 1,754
Default Re: V belt, How buy?

Originally Posted by Nehmo View Post
I still haven't found a correct-size belt. The local AutoZone goes down to 23". I need a V-belt, type A, 19.5" inside circumference.
Nylon string didn't work - too much slip.
I'm riding the bike around, and I'll try OReilly (again) tomorrow.
From Measure Twice

Note as Tool Maker said "The length of the belt is listed at the gauge line, which is about .100 below the top surface of the belt."

You want not the inside, but the top outside measurement. The inside measure is what I started out and made that error before as well. There is quite a difference and it would not be long enough if someone at a store gets a match unknowingly for length when you offer inside and the specification is for the outside measure.

I don't really know any easy conversion between the two, so it would be best to get the top edge of the pulleys that is the full length.

I have an equation to get the length of a belt that is good to fit between two pulleys given the diameter of the two pulleys, the diameter of the two shaft bores, and the distance between the centers of the two shaft bores. I heard of this from help at Grainger. I knew I could do this myself but without the use of this nifty mathematical constant, I would have used trigonometry and way more steps figuring it out. Should you or others already know of it or would like to know how it is done, I’ll post it.

I got a Gates belt from the Kragen Auto Parts store near me and I had already check at the Gates site directly and some other sites too. Kragen ordered it and had it in 1 day. You may see the site for Gates.

I got one that is as short as 18 inches just fyi.


The info on the 6818 gave this from Gate Website:

Product ID

Part #
4L180K, 6818

Product Description


Category Hierarchy
Industrial Power Transmission -> Light Duty V-Belts -> PoweRatedŽ V-Belts -> 2 or 4L Section, P.N. Series 8423
Automotive -> Belts -> PoweRatedŽ Belts

Product Images

Product Features

Category Name Description These green belts are an alternative to conventional light-duty belts, with high performance construction delivering more horsepower, less stretch and providing longer service life.

Features Advantages Aramid Tensile Cords combine limited stretch with extraordinary strength and durability.
Meets RMA oil and heat resistant standards.
Bareback construction for smooth clutching on shock loaded, backside-idler driven equipment.
PoweRated belts transmit more hp than conventional utility belts, up to 17 hp.
Gives outstanding performance on drives with backside idlers.
Green Flex-Weave cover resists heat, oil and cracking.
Superior performance on clutching and backside idler drives.
NOTE: Can be substituted for equivalent sizes of Truflex V-Belts.

Markets/Applications PoweRated belts are suitable for outdoor power equipment, appliances and industrial applications where FHP belts are typically used.

Belt / Sprocket Specifications
Effective Length (in) 18.17

Effective Length (mm) 462

Outside Circumference (in) 18

Outside Circumference (mm) 457

Recommended Sheaves Light-Duty Sheaves-Bored-to-Size
Light-Duty Sheaves-Variable Pitch
Light-Duty Sheaves-Bushed

Top Width (in) .5

Top Width (mm) 13

Customer Pack 1.0

Standard Pack 120

Product Attributes
Section 4L

Weight (Lbs.) .11

Datasheet References

Safety and Usage Disclaimer
Attached Images
File Type: jpg IMG13631-20121129-2037.JPG (396.8 KB, 15 views)
File Type: jpg IMG13632-20121129-2037.JPG (347.7 KB, 13 views)
File Type: jpg IMG13635-20121129-2039.JPG (350.0 KB, 12 views)
File Type: jpg IMG13636-20121129-2040.JPG (289.9 KB, 14 views)

Last edited by MEASURE TWICE; 11-29-2012 at 11:51 PM. Reason: Changed link for Power Rated Brand for Gates Web Page
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