V belt stretching

[ugabulldog]

I checked the tension on my belt, supposed to be 3/8" and it is closer to 3/4". The tension was already adjusted to the max so I could not get it any tighter. Next I checked belt # to make sure it was the right part and it is, (Gates belt). Tractor only has 325 hrs on it, can v belts give that much and need replacing?

 

[Oldpath05]

Take the belt to the parts store and have them measure it and compare it to a new one, might have to go one size smaller.

 

[Texasmark]

I'm going to say it depends on the quality of the belt. Numerous materials used for special applications. I know Kevlar is one material used in glass matts in building boats because of it's strength to weight ratio. V and flat belts are made with it also for that reason, aka resist stretching.

When you pay 35 bucks for a belt you think ought to cost 15 or so, there is a reason for it. I noticed that local parts jobbers usually don't stock the high end belts like come on a lot of big box mowers.....believe that or not.....big box mowers having high end belts. Well they do. Surprised me too.

 

[CincyFlyer]

Most of the time it's not stretch, but wear on the sides of the belt, that make it loose.

 

[Ken Mac]

From my experience with commercial HVAC, I can assure you that any belt will stretch within a short time of installation. Some manufacturers tell you to check tension within 48 hours of installation and again after a week. Only Gates belts do not stretch enough to cause us issues. That's not to say that automotive belts and a/c belts are identical. As was mentioned before, lawn mower belts are some of the better ones out there. None are as good as they once were.

 

[kthompson]

Is it the right width and not just the right length?

 

[Texasmark]

None are as good as they once were.

They must have been something super. For one instance, I bought a new a 2005 DR 52" ProZ that I use for mowing and as a truck and it still has OEM belts. Last year I shot it with some belt dressing because when climbing hills and pulling a trailer, the drive belt started slipping slightly and when full cutting wet rye at 6" the deck would clog and the blade drive belt would slip a little. One of it's jobs is mowing pond banks of 3/1 slope. Since spraying, good to go.

Course these belts have tensioners so their problem is V to V contact.

 

[JRobyn]

My fan/alternator belt stayed at almost exactly the same tension for several years and hundreds of hours and then suddenly loosened dramatically. There was no damage or torn reinforcing strands in it that I could find. I am still searching for an explanation.