Aren't there zillions of appliances in the world where stretch to fit is a norm rather than exception? This is NOT exactly rocket science. Heck, I bet rocket might actually be using a stretch to fit belt rather than an automatic tensioner 
stretch to fit drive belts
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I'm not a fan of the concept, but not vehemently against it either.
Back in the day, manufacturing tolerances were such that if you had a multiple belt drive, you had to order a "matched" set from Gates, of belts that had been measured off the assembly line, and were the same operational length.
Their actual length was all over the shop, but they were the same, and held the same(ish) load each.
If they are confident enough in their manufacturing tolerances that they are now saying that the ribbed belts are so uniform that this is possible is a good thing. But it also means that mounting boss locations, pulley sizes and locations have to be more accurate than ever before, as there's no adjuster to provide constant tension and take up the slack.
That last point is where I have the issue. With a spring adjuster, the belt tension is fixed at a design point, which means that bearing and pulley lives can be calculated easily.
Manufacturing tolerances of all of the above mean that the system has to be designed for the "loosest" combination of belt manufactured long, pulleys small, bosses close being able to live a long, slip free life.
Which means that an occasional engine will have the "perfect storm" of short belt, large pulley, boss and mounting pad locations, and have the absolute highest bearing loading in the spectrum, and suffer a "random" early failure.
For AC or the like, I love the idea.
For alternators and water pumps, I'll take some convincing.
Back in the day, manufacturing tolerances were such that if you had a multiple belt drive, you had to order a "matched" set from Gates, of belts that had been measured off the assembly line, and were the same operational length.
Their actual length was all over the shop, but they were the same, and held the same(ish) load each.
If they are confident enough in their manufacturing tolerances that they are now saying that the ribbed belts are so uniform that this is possible is a good thing. But it also means that mounting boss locations, pulley sizes and locations have to be more accurate than ever before, as there's no adjuster to provide constant tension and take up the slack.
That last point is where I have the issue. With a spring adjuster, the belt tension is fixed at a design point, which means that bearing and pulley lives can be calculated easily.
Manufacturing tolerances of all of the above mean that the system has to be designed for the "loosest" combination of belt manufactured long, pulleys small, bosses close being able to live a long, slip free life.
Which means that an occasional engine will have the "perfect storm" of short belt, large pulley, boss and mounting pad locations, and have the absolute highest bearing loading in the spectrum, and suffer a "random" early failure.
For AC or the like, I love the idea.
For alternators and water pumps, I'll take some convincing.
You don't have to cut them off. Use a flat strap, such as ratchet strap to remove them. Thread the strap between the pulley and the belt, slip the strap under the belt and pull. It comes right off and can be reused. Google has pictures, since I have a hard time describing the method.
I thought V belts died off in the 80's, serp belts are miles better.
Sad to see them coming back, GM is using them on there new truck engines for some reason.
I'm guessing to save money.
Sad to see them coming back, GM is using them on there new truck engines for some reason.
I'm guessing to save money.
Originally Posted By: Vikas
Aren't there zillions of appliances in the world where stretch to fit is a norm rather than exception? ...
Sure with just an elastomer but not with fiber reinforced elastomer.
It's a logical step to save the cost of a tensioner and we all know those do tend to be a bit less than perfectly reliable, spinning at unpteen-thousand RPM on a rolling element bearing lubricated only by grease.
Interesting that in the video there are no ribs on that Gates belt, although not sure why they needed them anyway.
Aren't there zillions of appliances in the world where stretch to fit is a norm rather than exception? ...
Sure with just an elastomer but not with fiber reinforced elastomer.
It's a logical step to save the cost of a tensioner and we all know those do tend to be a bit less than perfectly reliable, spinning at unpteen-thousand RPM on a rolling element bearing lubricated only by grease.
Interesting that in the video there are no ribs on that Gates belt, although not sure why they needed them anyway.
I'm glad my car has no belts.
As long as we're going down this road, why not just glue radiator hoses to the nipples and skip the clamps?
I suppose GM is already going down this road with "quick release" fuel clamps that fill with sand and have to be mauled off with a flat edge screwdriver.
/rant
I suppose GM is already going down this road with "quick release" fuel clamps that fill with sand and have to be mauled off with a flat edge screwdriver.
/rant
I would greatly prefer a water pump driven by one of these over one driven by the timing belt.
Originally Posted By: exranger06
You're not supposed to use the tool to remove the belt. The only way to remove the belt is to cut it off. They're one-time use only. The tool is only used to install the belt. And the reason automakers use them is because they can use a machine to install them at the factory, instead of hiring a person to manually install a belt.
In my plant, we have a machine to install the belt..but a human runs it.
You're not supposed to use the tool to remove the belt. The only way to remove the belt is to cut it off. They're one-time use only. The tool is only used to install the belt. And the reason automakers use them is because they can use a machine to install them at the factory, instead of hiring a person to manually install a belt.
In my plant, we have a machine to install the belt..but a human runs it.
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