Ever notice two "same size" belts don't ride the pulleys the same?

[JohnDawson738 1]

I always assumed if two belts had the same published dimensions they'd behave the same. Then I had two aftermarket belts for what should have been the same OEM replacement, and one clearly rode higher in the pulley than the other.
That sent me down the rabbit hole comparing OEM cross references ( https://www.amazon.com/Mower-197253-Replacement-Husqvarna-Craftsman/dp/B0949K1453) before ordering another one.
Has anyone else actually seen this, or am I overthinking it?

[T-Mo-(Moderator) 4,870]

Most people only sized belts based on width, i.e. 1/2, 5/8, etc., and length.  There is also another measurement to consider, the groove angle.  That angle on the belt will dictate how well it fits into the groove on the pulley and whether or not it will give long life.  Another is the belt material, the cheaper belts will wear out faster due to inferior belt material.

[WHX?? 57,270]

Yes I have seen it and Yes you may be overthinking it. Any new belt has to "break in" to the pulley.

I generally buy the blue Husky ones from TSC and I always buy one either side and run the one that fits the best. Being careful not to run them in as the ones that don't fit get taken back. Also any new belt will leave some "belt dust" from run in. Blue dust in the case of Huskies. 

Edited 7 hours ago by WHX??

[ebinmaine 79,463]

40 minutes ago, JohnDawson738 said:

overthinking

 

You're not overthinking it. This has been an industry issue for decades.

Standards can vary slightly from company to company but also if they are using outside vendors to produce their products.

 

Even amongst the top-tier manufacturers like Gates, manufacturing methods dictated that if you needed two or more belts for the same system, you had to order a MATCHED SET to guarantee proper fit.

 

 

 

[WHX?? 57,270]

One thing I have learned is of all the things you can buy/order online nowadays belts is not one of them. Guaranteed it's going to be like the proverbial box of chocolates. 

I have a wall of them to prove this. I suspect it's due to what EB said coupled with someone stuffing the wrong size into your box. Some even the belt just labeled wrong. 

11 minutes ago, ebinmaine said:

Standards can vary slightly from company to company

I also generally don't go by part numbers Just the belt length and type. (3L, 4L, 5L) etc. 

One (ok a couple) of the files I lean on heavily when replacing a belt. 

Get the WH part number and cross to length. Then go to farm & barn, power center, big box or where ever and shop on length. Belts_Mower_spindle_and_drive_belt_charts.pdf

WH LENGTH and WIDTH BELT LIST.txt

[Ed Kennell 46,445]

36 minutes ago, WHX?? said:

Yes I have seen it and Yes you may be overthinking it. Any new belt has to "break in" to the pulley.

I generally buy the blue Husky ones from TSC and I always buy one either side and run the one that fits the best. Being careful not to run them in as the ones that don't fit get taken back. Also any new belt will leave some "belt dust" from run in. Blue dust in the case of Huskies. 

                                                   and    to the 

[ri702bill 12,367]

33 minutes ago, ebinmaine said:

Even amongst the top-tier manufacturers like Gates, manufacturing methods dictated that if you needed two or more belts for the same system, you had to order a MATCHED SET to guarantee proper fit.

The exact issue when replacing the two 3/8" wide captured drive belts on a 1960's gear drive deck. Older Chrysler product cars had a matched set for the AC compressor - not exactly inexpensive...

[Handy Don 16,878]

2 hours ago, ri702bill said:

The exact issue when replacing the two 3/8" wide captured drive belts on a 1960's gear drive deck. Older Chrysler product cars had a matched set for the AC compressor - not exactly inexpensive...

The $$ for “matched” was too much for me. I bought four, found the best pair, then returned the other two. 

[gwest_ca-(File Mod) 12,319]

You may not find matched belts anymore. 

Back in the day belts were cut from a wide blank the length of each belt. As two or more belts were cut off those next to each other were tagged as matched. The best they could do.

As technology improved they were able to make belts to more exacting tolerances so the "matched belts" was abandoned.

I don't know when that happened but in 1970 matched belts were tagged as such.

[Handy Don 16,878]

35 minutes ago, gwest_ca said:

You may not find matched belts anymore. 

 

I get it. Stocking pairs, when pairs are not being ordered, is a loss for a business. 

Every SKU (stock keeping unit) represents overhead!

[ri702bill 12,367]

Yup - Marketing 101.... If you have to pay someone to dust off the dormant merchandise on the shelf (unless it is seasonal & you have the room) it is better to let it reside at the Supplier's warehouse than taking up space where a fast moving item can be displayed. Think Buggy Whips, 6 volt car headlights, Poodle Skirts & touchup paint for Big Box Store tractors... On the other hand, Elbow Grease, Muffler Bearings, Blue Steam, & Corvair water pumps are never on display... 

[ebinmaine 79,463]

1 hour ago, gwest_ca said:

I don't know when that happened but in 1970 matched belts were tagged as such

 

 

I started selling Auto Parts in 1992. 

Matched pair was still happening then.  

 

 

 

13 minutes ago, ri702bill said:

Muffler Bearings

 

We used to use that too until in the mid 1990s Mercedes started using a multi piece exhaust isolator. 

It was, in essence,  a flippin muffler bearing!