As one of the big names in climbing, Mammut‘s gear has been tested everywhere from the French Alps to unnamed scrambles in Nevada; the Swiss company’s Rime Pro belay jacket is as versatile as just about any that I’ve seen. After putting it through its paces, it’s time to see how well the Rime Pro holds up in harsh mountain conditions.
Mammut Rime Pro Belay Jacket Features:
- Pertex® Endurance material with coating and strategic reinforcement
- Wide cut
- Adjustable and helmet-compatible hood
- Articulated elbows
- Velcro cuffs
- 2 side pockets with zips
- 1 front zip pocket
- Chin protection
- 2 Powermesh inner pockets
- 2-way front zip
- Available in 5 colorways
- MSRP: $219
Rime Versus Sweat and Grime
A warm synthetic jacket is an essential component of any gear closet – with the newest slate of synthetic insulation, jackets are performing better and better. The Rime Pro is loaded up with a proprietary synthetic insulation called Ajungilak OTI Climate. I wasn’t able to find a great deal of information about this technology, so I’ll just note a few observations. The Rime Pro is pleasantly puffy, but still svelte enough to not encumber your movements. Like any quality synthetic insulation, the Ajungilak feels deliciously soft within the jacket although it doesn’t compress especially well. However, we can expect the Rime Pro to breathe well when things get toasty and to put up with foul weather at the same time. It’s a fairly heavy, warm piece so it can be easy to heat up quickly in the Rime Pro.
As a belay jacket, the Rime Pro has a few classic features that any cold-weather belay slaves out there will appreciate. First off, there’s an obligatory two-way zip; when the jacket was brand new the zipper was pretty tough to initiate but it’s broken in nicely after a month’s use. The Rime has two zippered hand pockets and a Napoleon pocket; those hand pockets are lined with a warm, fleecy material which makes them a constant temptation for anyone on belay. The fully-adjustable hood is generously sized to accommodate a variety of helmets and the peak is reinforced to stand up to wind. I found the hood easy to adjust for a good fit, but I’d like to see bigger pulls for ease of use. The same applies to the hem adjustments which work well in general but are tough to grab, even with light gloves.
Now for the jacket itself – Mammut built the Rime Pro out of two weights of fabric, Pertex Quantum on the main body and Pertex’s Endurance nylon reinforcing the head, shoulders and arms with a more durable weave. The Endurance is only lightly water-resistant (1000mm) but it defies even strong winds when layered properly. What’s more remarkable, though, is the extraordinary softness of this fabric – Pertex wove together pixie hairs and rarest spider silk to create an absurdly soft-handle fabric that feels wonderful next to skin, even when you’re sweaty, and slides easily over layers. By the way, this property coupled with the synthetic insulation’s moderate compression make the Rime Pro a delightful pillow when you head back to the tent.
I tested a Medium jacket and it fit my 5’11”, 180lb. frame very well. As a belay jacket it’s not really technical in the sense that you would climb with it – it’s cut rather generously so you can slap it over a hardshell, but range-of-motion is quite middling. Raise your arms and the main body travels with them; that said, I still enjoyed a lot of activities like Nordic skiing where the range-of-motion was more than adequate.
Two odd points – while Mammut’s Swiss heritage lends itself to expectations of quality construction, I noted a number of loose threads throughout the jacket, but especially on the softer torso fabric. Secondly, the synthetic insulation likes to leak through the seams on the front of the jacket – this manifests itself in little strands of stretchy thread poking through the seams which are invisible to all but the person wearing the jacket.

The Good
- Fantastic fabric with extraordinarily soft handle
- Fleece-lined pockets are warm and inviting
- The jacket is cut rommy enough to go over a hardshell
- Light waterproofing only on key areas reduces weight
The Bad
- Loose threads throughout fabric
- Synthetic insulation is making its way through seams
The Bottom Line
Mammut has been producing top-notch gear for a long time now and the Rime Pro has a lot to live up to. It’s not one of their premiere pieces of outerwear but it’s still highly functional. I was pleased with how well the Ajungilak insulation handled heat and perspiration when I started getting aerobic, but I thought quality control was somewhat lacking due to the loose threads. On the whole, it’s a great jacket for climbers and hikers alike who need a fairly heavy, warm synthetic addition to their gear closet.
Buy now: Available from Backcountry.com