You’ve probably noticed that the suspension fork market has been dominated by two big players for a long time now. RockShox and Fox have the lion’s share of the OEM market sewn up, so the vast majority of every bike you’re likely to buy will come fitted with one of these two brands’ forks. That doesn’t mean they’re the only players on the field though. Colorado based MRP (Mountain Racing Products) have had suspension forks in their range for a few years now, but to get one you’ll almost certainly be buying it aftermarket (though mine came stock as an option on a bike from fellow Colorado-based brand, Guerrilla Gravity).
I’ve got a Ribbon 29er fork here from MRP. It’s got 35mm legs, Boost spacing, can accommodate Plus sized tyres and is adjustable in travel from 160mm down to 120mm in 10mm increments, by the mechanically minded, with basic tools, at home, with supplied spacers. Mine is set to 150mm of travel. Offset is 51mm, though a 46mm offset can be special-ordered. There’s a big array of adjustment available on the Ribbon – what MRP call the ‘Fulfill’ air spring, which features independently adjustable positive and negative pressure. Of course, there’s rebound damping, as well as low speed compression damping, and also an air-based ‘Ramp Control’ cartridge to increase end-stroke progressivity. Unlike Fox and RockShox, the Ribbon doesn’t have a bladder-based damper but instead a low-pressure internal floating piston is used; MRP say this is for greater reliability and easier maintenance.
As well as the Fulfill air spring and Ramp Control cartridge, there’s a couple of other little features that stand out on the Ribbon. First, the Psst valves: these are nifty little additions that allow air that becomes trapped in the lowers to be relieved without having to slide a zip-tie inside the leg. This is a nice feature and especially handy when changing altitude (which is why some DH forks feature similar valves, to account for the big changes in elevation). Second, the ‘backwards’ arch. The Ribbon features an arch with the weight-saving reliefs in the front of the arch, rather than the back. This makes sense as it doesn’t fill up with (heavy!) mud this way. It also looks unusual.
Set up was easy enough, though different than the usual suspects Fox and RockShox, which have automatically adjusting negative air pressure. Contrastingly, the Ribbon has two separate air valves – one for positive pressure, one for negative air pressure, which means you can set it up for firmer or more supple feel off the top of the stroke. I followed the guidelines for my weight and put in 75 psi in the positive chamber and chose the upper-end of the allowable pressure in the negative chamber (MRP recommend a maximum of 10 PSI more) by setting that at 85 psi, which is intended to increase suppleness. If I wanted a less-supple top-stroke, I’d put in negative air pressure to match the positive pressure, or anywhere in between.
The Ramp Control’s approach to controlling end-stroke is very usable because there is no need to swap tokens at home. It does operate slightly differently than tokens, in that the ramp-up happens later in the stroke, though I have to admit this wasn’t super-noticeable to me. What was noticeable is that because it can be adjusted on the trail, it’s possible to experiment over certain drops and terrain and easily find your preferred setting. And if I knew I was riding a trail with bigger drops and features, I’d simply wind in a few more clicks of Ramp Control. It’s worth noting the ramp up cartridge is available as an aftermarket upgrade to many forks, such as Fox 34s and 36s, and Rockshox Pikes and Lyriks, for $229.
As for the low speed compression, I tried it in various setting and preferred the lighter end of the scale, though dialled on a bit more when running less pressure.
I tried a number of different combinations of air pressure and Ramp Control. For example, 10 PSI more than recommended for my weight in the positive chamber without any Ramp Control provides a linear feeling fork, with still enough bottom-out resistance, and the fork rode taller when heading down really steep stuff. Conversely, less pressure with more Ramp Control yields more traction on flatter tracks, but some diving, with the ramp control kicking in off drops. In short, the Ribbon is hyper-adjustable and adaptable for different riders and different locations, which is great for riders who have the patience for making small adjustments and noting what happens. This easy adaptability is what sets the Ribbon apart from the usual suspects and is something that tech-minded riders who like to make sure their set-up is optimal will appreciate.
While the Ribbon started every bit as slippery smooth as a Pike or a Fox 36, there was one niggle; after a few weeks of riding the fork got noticeable sticky. Admittedly those few weeks were in extremely dusty Californian-summer conditions, and added up to about 55 hours of riding, which is beyond MRP’s (and RockShox’ and Fox’s) recommended lower leg service interval. I got sore hands and noticed my front wheel getting kicked about. I called MRP and they suggested I test something by turning the bike upside down. If that made the fork more supple, then the grabbiness was likely due to it needing an oil change. After turning it upside down for a couple of minutes, the fork did indeed get much smoother, but I didn’t have the time to drop the legs off and service the fork. Instead, I unthreaded the Psst valves and dropped a little fork oil in there. That did the trick – the fork was back to being slippery smooth again and I haven’t touched it since. Yes, dropping the legs off and changing the splash oil properly is on my list…
On another note, MRP also offer the Ribbon in coil spring option. I’m hopeful a coil spring kit will arrive for the fork soon, and if so I’ll report back about how that goes. On paper it promises to be a good combination, with the Ramp Control taking care of end-stroke bottom-out control.
In conclusion, the Ribbon is a high-quality suspension fork that performs on par with the industry giants but includes some additional performance features, so if you’re building a custom bike, or otherwise in need of replacing your existing long travel burly-ish fork, the MRP Ribbon should be on your list. And if you like to dial in the performance of your suspension and to have multiple options to go about that, then I reckon the Ribbon has some meaningful performance tuning benefits that place it out ahead of the others.
Distributed by: Wide Open
Words & Images: Carl Patton
Originally printed in Issue 87 of the NZ Mountain Biker