Vbelt sizes??

TimWafer

Member
What has happened in recent years to vbelt sizes? All my life the size was easy to understand until the last few years. A 4L320 belt was a 1/2" wide A belt 32" long. 4L was to me 4/8" wide or 1/2 " wide. 5L was 5/8" wide or a B belt and so on. The next 2 digits, for example here, 32 was the length or outside circumference.
Now they designate them as A32, Which logically to me would be an A belt, 1/2" wide and 32" long. But NO its 34" long! Why on earth is an A32 actually 34" long? You want an A30 to get one 32" long! You go to buy a belt and you have to know how old the belt is as to how its labeled. Makes zero sense to me. Can anyone enlighten me? Maybe its this new math.
 
"All A,B,C,D belts list the INSIDE circumference measurement after the letter of the v belt part number. Example: A88 has a 88" inner circumference, then you add 2 inches for the A Section (Listed below) to obtain the outer circumference. If you measure the outer circumference, then you would subtract the number of inches based on the section you have (Listed below) to obtain the v belt number. This is also the same for the banded belts. Measure each individual band for banded belts to obtain the correct width.

Examples of how belt numbers are coded per section:

A Section= Add 2" to belt number (Example A88 = 90" Outside Circumference)
B Section= Add 3" to belt number (Example B88 = 91" Outside Circumference)
C Section= Add 4" to belt number (Example C88 = 92" Outside Circumference)
D Section= Add 5" to belt number (Example D105 = 110" Outside Circumference)"


Quoted from: https://www.vbelts4less.com/how-to-measure-v-belts
 
My experience is 100% opposite of yours.

Until recently I had NEVER seen this 4L430, 5L320 crap. It was always A45 or B34. This goes back to my childhood, so it's been like this for decades, nothing new.

How I found out about it is, I needed an A43 belt. Tractor Supply has recently removed the A/B designations on their belts and now only use the "L" designations. I bought a 4L430, and as you can guess, it was too short.
 
Bob you always seem to amaze me with the vast amount of things you know or have worked on and how much you remember. I have worked on a lot of different things too ,but seem to not always remember all those adventures ! lol.
On these belts I have always known if I measured one it never matched up to the actual size, but I never knew there was actually a "system" to it. Now if I can just remember this in the future when I need to use it.
 
Thats strange! I wonder if its different depending on location or what. Ive always seen only the 4L320 type designations around here since I was a kid and Im 61. Didn't matter where you went to buy a belt that's what everyone went by. Now you find belts labeled each way. Older stock ones are the 4L320 type designation and newer ones are the A30 designation. To me the outer circumference is what I would measure a belt by. Inner circumference is pretty vague as the depth of a 1/2" wide belt isn't necessarily 1/2" deep. Not sure how one could even measure the inside circumference. :?
 
There are charts online that explain it and are a lot of help. We needed a new belt for our Woods mower, we took careful measurements and ordered one, and it fit!
 
Two different standards because "L" belts are fractional hp belts while A, B and C are intended for medium HP use, including clutching. L's are generally more flexible. I had to replace my spindle drive belt on my valve refacing machine. an A23 fit, but wouldn't consistently release when the carriage was moved back from the stone. A 3L belt worked, due to the added flex.

One quick explanation here:https://cloudfront.zoro.com/img/zoro_tips/V-Belt_Selection_eZtip.pdf
 
Bob, I have a mower made in New Zealand and the parts manual says the drive belts are C4475 an C6480. Hard to find. A USA supplier sold me a c176 AND A c255. He says they will fit. I have not put them on yet, but hope when the season comes they will fit. What do you think?
 
(quoted from post at 10:51:06 02/14/20) Two different standards because "L" belts are fractional hp belts while A, B and C are intended for medium HP use, including clutching. L's are generally more flexible. I had to replace my spindle drive belt on my valve refacing machine. an A23 fit, but wouldn't consistently release when the carriage was moved back from the stone. A 3L belt worked, due to the added flex.

One quick explanation here:https://cloudfront.zoro.com/img/zoro_tips/V-Belt_Selection_eZtip.pdf

A 3L belt isn't an "A" belt. It's a 3/8" width, and an A belt is a 1/2" width. The narrower belt would be more flexible.

I don't buy the fractional/medium HP explanation either, because upon closer inspection, ALL the belts at Tractor Supply are marked with BOTH sizing standards. I have in front of me an A&I Products "B43K 5L460K" the K indicating Kevlar fiber in the belting.
 

I see now , well sort of anyways. Must be around where I live, everyone just commonly used the fractional HP system then.

In reference to the chart, I dont understand yet the "belt inside length" column. For 4L it says 170-4000. What the heck does that mean.

Also I never had much luck with the string around the pulley measurement it mentions. I usually try a broken or cut belt that's too long, mark it and measure that. For example I needed a belt for a small grain auger. I measured it with my broken belt method and got 32". I just measured it with a string and got just under 29". The string goes to the bottom of the groove and even adding 2" for the A belt inside measurement system it would come up being an inch too short.
 
I went into a parts store one time to get a belt for a woodworking machine. I gave the guy the width and length of the belt and they couldn't help me because
they couldn't enter into their computer the make and model car it went on.
 
To accurately measure a belt you need to at least have enough good pieces of belt to fill the sheaves, then pull a flat tape, (100 ft.)around the run. If the belt is worn you have to add a little to get outside length, but that got us real close.
 
Bob has it correct. those are industrial size numbers. I worked at a bearing supply house for a year or so, and had to learn that system. The bearing guys can't look them up by application, but walk in & give them a number like that and you'll get exactly what you want.
 
I went into the local hardware store last night and they have a whole wall in their back room with v belts hanging on it. We looked over the array of belts there and studied them for at least 20 minutes. I noticed that all the packages or wrappers actually list the actual outside circumference (OC) often in very small type somewhere on them. The belts themselves however do not. Some of these belts were obviously older than others as the store has been in business since 1943 .

Looking at all these belts I made the following observations.

Using a 65" OC belt 1/2" wide as an example size to compare.

Some are labeled 4L650 and actually say industrial belt next to that.

Some are just labeled 4L650

Some are labeled A63

Some are labeled A63/4L650

Some had a K after the designation which presumably means Kevlar

Some are labeled 6865 (these were Gates green belts)

Most of the newer looking stock had either the A63 or A63/4L650 designation.

I guess my only real question at this point is why the A63 type designation would go by the approximate inside circumference (IC) of the belt rather than the actual OC. The IC seems to be hard if not impossible to accurately measure either on the belt or the pulleys. Why add 2" to the designation of an A belt to get the actual size. That designation seems to defy all logic in my mind.Yet it seems to be what is dominate now. I must be missing something.
:?
 
I just bought a replacement for an early 1980's Ford MOCO requiring a 55" belt...forget the exact nomenclature. Belt I received had a letter followed by 51.
Upon receiving it I too thought it was the wrong belt but comparing to the old one it was the exact fit. Have no idea as to the current mixup.
 
I have a set of "V" gauge quick check that I use....

I never guess as to the profile of the "belt"

Bob..
cvphoto5256.jpg


cvphoto5257.jpg
 
?
Bob, I have a mower made in New Zealand and the parts
manual says the drive belts are C4475 an C6480. Hard to
find. A USA supplier sold me a c176 AND A c255.?

4475 in Millimeters equals 176.18 inches.
6480mm = 255?

They should work.
 

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