distance between two pulleys

[farmbj]

Of all the things in life I have learned, measuring the distance between two pulleys is not one of them. I need to find a belt for my flail mower I bought last year. The belts I removed just don't fit, even though they are the exact ones I removed. The belts have been in the sun for a while. Do they shrink? If there is a belt tensioner how much do I add for that?

 

[timcasbolt]

No, they don't shrink. Last time I needed to do that I found an old, really long belt and cut it. Wrapped it around the belt route and measured it up. I 've also done it with a length of 1/2" rope.

 

[Russ from MN]

What I have done with good success is put a belt of the correct width, even just pieces, if you have it in the sheaves, so a tape measure will be measuring the outside length of the belt. Then stretch a flat tape, like a 50 or 100 foot one around the run. This will give you a pretty accurate od measurement, and there are charts online that will convert that to belt size. We did this with our Woods belly mower, ordered a B225 belt online, and it fit.

 

[Mike(NEOhio)]

You can wrap a flexible tape around the pulleys but that's a bit iffy. Look in some belt supplier's catalog. They usually show how to calculate belt length. The length is measured at the pitch line which is between the outer and inner surfaces. Catalogs will have that info.

 

[treeman53]

Maybe I'm misunderstanding, but, if they are the exact ones you removed, and they no longer fit, I would have to assume you are not installing them correctly...

 

[Janicholson]

Of all the things in life I have learned, measuring the distance between two pulleys is not one of them. I need to find a belt for my flail mower I bought last year. The belts I removed just don't fit, even though they are the exact ones I removed. The belts have been in the sun for a while. Do they shrink? If there is a belt tensioner how much do I add for that?

Belts can stretch, but won't shrink enough to make any difference. Belt wear is the most common reason for an incorrect fit. If you gave us a model number, brand, or image our answers would far less generic. I have never seen a V belt drive without some reasonable adjustment system. Jim

 

[Texasmark]

No, they don't shrink. Last time I needed to do that I found an old, really long belt and cut it. Wrapped it around the belt route and measured it up. I 've also done it with a length of 1/2" rope.

And unlike the old belt that may have, probably has, stretched over the years.

 

[Brown David]

A picture of the implement with brand/model and belt routing might be helpful here.

 

[MarkB_MI]

Flail mower belts should be purchased from the manufacturer. I don't know about your mower, but my Mott F6 has a spring-loaded tensioner. The belt is intended to slip if something gets wrapped around the cutter shaft; otherwise something expensive would break.

 

[crsutton81]

Of all the things in life I have learned, measuring the distance between two pulleys is not one of them. I need to find a belt for my flail mower I bought last year. The belts I removed just don't fit, even though they are the exact ones I removed. The belts have been in the sun for a while. Do they shrink? If there is a belt tensioner how much do I add for that?

I have had good luck using a flexible tape like a seamstress style tape measure to measure the needed belt length. Route it around all of the pulleys as the belt would normally run. Typically a belt will not shrink but stretch a bit and some of the stretching lends to the wear from the upper flat part of the Vee being worn off. Usually 1" of slack will allow for tightening capability and allows enough room also to get the new belt installed. Another option to measure with if a tape measure is not handy is a 1/2" diameter rope. Measure the actual rope used once it's determined to be correct.

 

[showcrop]

Besides stretching belts will wear on the sides so that they will ride down further in the pulley.

 

[Jim.ME]

Of all the things in life I have learned, measuring the distance between two pulleys is not one of them. I need to find a belt for my flail mower I bought last year. The belts I removed just don't fit, even though they are the exact ones I removed. The belts have been in the sun for a while. Do they shrink? If there is a belt tensioner how much do I add for that?

Welcome to the forums.

Folks here will do their best to help you, but you need to take a few minutes and explain in a bit more detail. And check back regularly to see the suggestions and give feedback on where you are at as far as progress. If you add your general location to your profile, there might be someone near you or a place someone might be able to direct you to for help.

You posted: "The belts I removed just don't fit, even though they are the exact ones I removed." I understand this as saying, you took a belt off and it doesn't fit when you try to put it back on. That sounds like a problem in what you are doing, not a problem with the belt. I would say the same if you are trying to install a new belt of the same part number in place of the old one. Thus, the need for more detail and clear descriptions.

What brand, and model number, is your flail? What is the part number of the belt you took off and what is the part number of the new belt? Can you take and post, a picture of the belt drive arrangement of your flail?