Anyone using these? Supposed to be low stretch and designed for supercharged applications. Not that I can find the size I need anywhere, or even anyone that stocks the RPM. Gates says that most distributors wont have them in their database and need to special order. The standard version of the K120891 that I use is OE on 15.0L diesels, so I don't think they are too concerned about high RPM/stretch. But the catalog does list an RPM version in this size.
RPM belt sizes

 

Longest 8-rib is 108.8 so that won't work for most of the guys here (I use a K081124HD). 6-rib guys may be in luck though.

I am wondering if the RPM is a re-engineered Green Stripe Micro-V since they are no longer available? Product descriptions are similar:

From 2012 catalog:

Green Stripe® Micro-V AT® Belts
Long wearing fiber-loaded stocks with greater load-carrying capacity designed for demanding, heavy-service drives.
Desogned for replacing original belts on serpentine drives and other heavy-duty V-ribbed belt applications.
• Special belt constructions eliminate belt noise, reduce tension loss and solve problem drive
applications.
• Extra heavy-duty construction resists cracking and wear.
• Precision ground to assure optimum belt-to-pulley fit.
• Special formation process for precise dimensional control.
• Reinforced with stretch-resistant, thermally active polyester tensile members.
• Meets or exceeds SAE J1459 specifications.

From 2016 catalog:

Racing Performance Muscle (RPM) Belts
Specially-engineered to deliver optimum boost from supercharged engines, these belts feature the most advanced
technology.

• Nylon-fiber reinforced undercord
• High-modulus, low stretch aramid or polyester cord
• Advanced, exact-fit, precision-ground belt profile
• Strict OEM dimensional tolerances
• Two layers of adhesion for increased durability
These features result in lower heat, noise, vibration, and belt slip, for increased durability,
improved power transmission, and unsurpassed boost.

 

I can’t even find the 108.8

I have a K081088hd now.

 

You maggie guys and your short belts.

Yea, it seems the 1088 is elusive. The longest one I saw listed on O'Reilly was 0922 and was $131. You can buy a few green belts for that. I was thinking it would be more in the $50-60 range.

 

Managed to find one from ZPE in California. Think it was something like $103 plus shipping. Will see how it does. Regular version of this belt is too tight and next size up gives too much tensioner action, so either way I have to move an idler. Mounting plate is looking like Swiss cheese already and I'm right at the corner already, so looks like I am going to have to rework it.
RPM Sell Sheet

Will have to make another video when I receive it. This was an 8 rib though.

 

Is switching over to a cog belt an option?

 

Cog may be looking for more trouble on the street. As long as I can keep a belt on I think I will be OK. New belt stayed put beating on it today. Tensioner is probably wound up about 70% with engine off. Was 50% before. Must have been hitting the stop at times on the unwind end before as well, because there was a shiny spot on it.

Did have to do some welding to add onto the plate so I could move the one idler up. Still a b***h to get the belt on. I also improved pulley alignment somewhat. Although a little twist in the belt seemed to help previously....not that it is good for the idler/tensioner pulley bearings.