What it is: A 35mm stanchion, all-mountain/enduro fork with decent adjustments, plenty of support, and a stiff chassis that suffers from extremely harsh/sticky performance. A coil version is also available.
Thoughts:
I regret that I didn't get many photos of the fork installed on my bike during the ~6 months I used it, so this will be a pretty dry writeup. I'll try to keep it concise, as a result, you can find plenty of photos and other information in other reviews on the internet.
In short, the fork has a few adjustments:
Positive and negative air pressure
LSC
LSR
Ramp Control
The LSC and LSR adjustments are meaningful and wide in range, which is really nice compared to other forks with more granular adjustments. What this ends up meaning is that the fork can support a wide range of rider weights and air pressure settings. I found myself in the upper-middle of the LSR adjustment, for instance, whereas most other forks, I was nearly closed off.
For the +/- air pressure, MRP provides a useful chart that gives you a starting point, but they seem to recommend ~9psi more in the negative than the positive, which is about where I settled. If you pushed it any further, the fork would start to suck into it's travel.
The fork is a very nice appearance, stout 35mm stanchions, and a reasonable weight for what it is. Where the fork really let me down was it's trail performance.
On the Trail
I spent a good deal of time trying to dial in the Ribbon, but I found it to be a very sticky, harsh fork. At the point I tested it, I had tested 5 forks in the previous year and a half, the Ribbon exhibited more stiction and harshness than any of them.
When it first arrived, the stiction was so bad that it would 'notch' through the travel as it compressed, even when I let 50% of the air out and jumped on it, you could feel the stiction, which leads me to believe it was either bushing or seal related.
MRP has excellent customer service, they took it back without question and resized the bushings, then returned it after a week or so. The fork smoothed out considerably, but continued to be stickier and harsher than any other fork I've owned.
During the review period, I swapped routinely between my Fox 34 FIT4 and Sapphire 34 D1, both of which showed a considerably decreased level of arm pump, hand fatigue, and stiction.
The fork is responsive and stands up to it's travel very well, I liked every other aspect of the fork, but the stiction made it a no go for me. I have nerve damage in my left hand which causes stiction in suspension components to be very noticeable, the Ribbon aggravated it more than any other fork has, regardless of settings, but it also failed to track as well.
I know this is in contrast with other reviews on the fork out there, which leads me to believe that there is an issue with my rider weight, bike geometry, or MRP QC that caused it to be stickier than others had experience. As for others, I've talked to friends with the same fork and received similarly mixed reviews, some love it, while a number of others had the same stiction and harsh feel.
I will add that you could blame this on setup, which was implied on a message board I posted about these issues on. I tried numerous setup combinations, bordering on the ridiculous, and in every combination, the fork remained sticky and harsh.
The fork did really well on smooth trails with scattered bigger impacts, it is responsive and remains high in the travel, while blowing off when needed. Where it suffers is on the trails we have in WNC where there is a lot of high speed, eroded, steep, and chunky terrain, the harshness and stiction becomes evident. If you can tolerate this stiction, then the fork will remain responsive and composed through those types of sections, however I could not tolerate the level of stiction and moved on to other options.
So who would I recommend this to?
If you ride a lot of trails that are predominately smooth, with a few big hits or chunky sections throughout, the Ribbon will provide you a really responsive fork that pumps well, is responsive, and stands up to it's travel without diving. If you ride a lot of trail that are chunky all the way down or with a lot of smaller, repeat impacts, then the fork will remain composed, but be harsher than other options on the market.
I expect the harshness comes from bushing stiction, which is possibly bike geometry and rider weight related. I know a lot of lighter riders who get on really well with the fork, but their bikes are more conservative geo bikes.
Comparisons:
vs Fox 34 FIT4: I only include this as a comparison since the Ribbon provides such a wide range of travel adjustments, it can be used on bikes where a 34 was standard. I found the 34 FIT4 to be smoother and with considerably less stiction, along with better small bump compliance, however the Ribbon stands up to it's travel better, with a stiffer chassis, and fewer reliability issues related to the chassis on the 34. A custom tuned 34 FIT4 would outperform a Ribbon for most applications where the 34 is appropriate, but for harder riding, the Ribbon would win out.
vs Cane Creek Helm Air 29: The Helm and Ribbon are similar in many regards, they are both fairly firmly damped, both provide great support, both have a great chassis, and both come from very good brands. The Helm is considerably smoother than the Ribbon, though, and performs better in every way. The main con with the Helm, in comparison, is the lack of adjustment range in the negative air pressure and a slightly more involved travel change procedure, but the feel of the Helm is far superior to the Ribbon.
Pros:
Very responsive, damping seems on point for the most part
Supportive
Negative air valve prevents reliability issues with negative air equalization and provides somewhat useful tuning options
MRP support is some of the best in the industry
Travel changes are relatively easy
Tuning guide is pretty on point for most riding/riders
Wide range of adjustments for most riders
Stands up to it's travel well on bigger hits
Cons:
Very harsh on trail with sustained roughness or chunky terrain
Small bump compliance is mediocre
The stickiest fork I've ever ridden, despite multiple attempts at adjusting it and various settings, and after being sent back to MRP
I'm not sold on Ramp Control compared to tokens (latest version of Ramp Control provides both)
Damper can be noisy, but no more so than most other forks I've used that aren't Fox or RockShox
Chassis stiffness isn't on par with the 36 or Mezzer