MRP hail from Colorado, USA, and started out making chain guides. After licensing the White Brothers brand for a while, they dropped it in 2013 and acquired the Canadian manufacturer Elka for shocks and started branding their suspension also under the MRP name. They now make forks and shocks for different applications, and also upgrade parts for 3rd party forks like the Ramp Control system.
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EDIT 27.11.2023: Further ride impressions added to the conclusion after 3000 km.
What is the Ribbon SL?
The Ribbon is MRP's trail fork with 35mm stanchions. They also have the 32mm, and older design, Loop series of forks, of which the Loop TR is also available in similar travel numbers as the Ribbon SL. The SL is essentially a lightened version of the standard Ribbon, and only available in internally adjustable 110-130mm travel, 29", tapered steerer, 46mm and 51mm offsets and 15x110mm boost spacing. Minimum brake disc size is 180mm, so no XC / Weight Weenie love here either. This makes the Ribbon SL MRP's "Light trail" or "Downcountry" fork: Afterall, who likes flexy 32mm stanchions any more?
The Ribbon SL shares many, but not all features with the standard Ribbon air. The ChocoLUXE internals are there as are the Norglide PTFE coated bushings, Outcast reversed fork arch, PSST pressure release valves on the lower legs and a similar low-pressure IFP style damper.
They have removed the RampControl from the SL and 8 clicks of low speed compression and 16 clicks of high speed rebound adjustments are available on the damper. Air spring progression is adjusted with tokens, similar to Fox or Rockshox, that screw into the air spring top cap. The air spring is the same FullFill dual chamber air spring as in the normal Ribbon.
These changes and features combined with the shortened stroke and bolt-in through axle has allowed MRP to make a fork, which weighs around 1800g or 4lbs. I weighed mine with the axle and an uncut steerer at 1816g. For comparison, a 130mm Fox 34 weighs around 1780g, so the difference is negligible and the Ribbon is much stiffer.
Ribbon SL features
As mentioned before SL does not mean the fork is just a more basic version of the normal Ribbon, but rather clearly a light weight version with some omissions to save weight, while retaining similar performance to the normal Ribbon. Like all manufacturers, MRP seem to love their slogans and abbreviations, so I will cover them here:
- ChocoLUXE = Special seal material, which MRP claim a 37% reduction in friction vs. the first Ribbon forks, which to be honest, were notoriously harsh and sticky.
- Norglide = A brand name of Saint-Gobain for the special PTFE coated metal slide bushings.
- Outcast = MRP's reversed fork arch, which is claimed to gather less mud than traditional designs
- PSST = Pressure release valves on the lower legs
- RampControl = Adjustable air valve, which acts partly as a volume spacer and partly also changes mid-stroke support
- Huck Puck = MRP's name for tokens / volume spacers, specific to the Ribbon SL
- FulFill = Independent positive and negative air chambers
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| HuckPuck tokens screw into the air spring top cap |
MRP offer a 1-year (ROW) and 2-year (EU) warranty on their Ribbon forks. The fork retails for approximately 970EUR in Europe, so much cheaper than a Fox 34 and about the same as a Pike Ultimate.
Performance out of the box / before a service
MRP states that all of their suspension products are assembled in Colorado and 100% dyno tested, so you should have very little performance difference between samples.
Out-of-the-box the fork feels a little bit sticky, and much worse than a factory fresh Rockshox or Fox fork. The difference in stiffness when compared to a Fox 34 SC is immediately apparent and the Ribbon feels more like a Pike when it comes to lateral support and especially braking feel with no wobble or flex.
I'm running 5.8bar / 85psi in my positive chamber and 5.7bar / 83psi in the negative and one HuckPuck token. At these setting the fork feels a bit stiff in a parking lot test, but is surprisingly active over small bumps and even bigger bumps. I was easily getting full travel, but no harsh bottom outs, so based on that I'd say the fork is a bit more eager to use full travel than my Fox forks are. I thought I needed to do more testing with another token, but as-is, the fork felt like it could ride higher in its travel.
The FulFill system was also VERY sensitive to too much pressure in the negative chamber. Add too much, and the fork will suck down about 10mm into the travel and dive badly. MRP recommend more pressure in the negative chamber, but I find it makes the fork too eager to use all travel. The sweet spot seems to be equal pressure in both chambers or ever so slightly less in the negative.
Successive big hits is where MRP's damper struggles. Despite having rebound dialed as fast as possible with out the fork feeling bouncy or harsh, the fork still packs on successive big hits. I thought there was quite a bit of low speed compression damping from the factory,
which mostly results in the fork really opening up during faster paced
riding as long as the hits are small enough or not coming in too quick succession. However, the issue turned out to be something else than the damper!
Service
MRP have released good instructions on their website on how to service the Ribbon forks. One thing, which clearly stands out from the "Big 2" is that absolutely ALL parts are available as spares, even single stanchions, should you need one.
No special tools are required for a basic lower leg service, but MRP recommend you use their special tool, which is just a machined-down rebound adjuster, to keep the damper shaft from rotating when you remove the foot nut.
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| Rebound adjuster removed with the MRP tool still attached |
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| Removing the rebound adjuster. The red tool is used to keep the rebound needled from unthreading from the damper. A pair of pliers could also be used as long as you don't damage the adjuster. |
Upon opening the fork I was surprised to find no oil dripping from the lowers. It turned out my sample had GREASE in the lowers from the factory with maybe a hint of oil in the mix. This was very disappointing as MRP clearly state in their service instructions to use 15ml of 10Wt oil in each leg and only to grease the wiper seals. Later I have been informed the bath oil quantity has been increased to 20ml / leg.
The MRP foam rings are also much thinner than Fox or Rockshox, black and clearly absorb less oil. Based on this I would in no circumstances recommend exceeding the recommended 30-50h lower leg service interval. The springs on the wipers are also not very strong and the wipers feel quite hard to the touch.
Another problem I have had with the fork is stuckdown. The correct way to fill the FulFill air spring is to fill the positive chamber to the desired pressure, and then the negative to equal or max. +10% pressure, so in my case positive 85psi and negative 85-93psi. However, as soon as I filled the negative chamber the fork would suck down by about 5mm, and this would gradually get worse as I rode, up to a point where the fork would be sucked down into the travel by 15mm. As soon as I let air out of the negative chamber, the fork will return to full length and once filled again, suck down by about 5mm. This would be acceptable, but after 2 hours of riding and a few big hits the fork will again be stuck down 10-20mm. This is incredibly frustrating and a BIG problem with a fork that only has 130mm to offer in the first place. This problem was not 100% fixed with an air spring service and after sending a claim to MRP they responded promptly and supplied a new air spring seal kit free-of-charge.
The stuckdown problem got so bad that I could not ride the fork. When the new seal kit arrived I proceeded to install it and while taking the fork apart I discovered a little oily residue around the air spring top cap. The problem turned out to be a slightly split top cap o-ring! This was letting pressure out of the positive chamber and as the positive pressure decreases, the ratio between the positive and negative pressure becomes negative, and this leads to the negative pressure sucking the fork down into its travel.
MRP supplied a new air spring seal kit, but for some reason it does not come with the top cap o-ring 29x2.0, but I was able to fix it temporarily with a 22x2.0 o-ring from a generic o-ring set.. The new o-ring is the same thickness as the MRP seal, 2.0mm, but has a slightly smaller ID. I was still able to stretch it over the top cap assembly without issue, but turns out it would not hold pressure for more than a few rides. Ultimately a special order 28x2.0 o-ring fixed the issue.
Ramp Control in the Ribbon SL
As mentioned above, the Ribbon SL does not come with Ramp Control. This is due to the fact that at 130mm, there is 105mm of space between the top of the air piston and top cap, but at 110mm this is naturally shortened to only 85mm, which is not enough to fit the RC cartridge. It requires 95mm of free space on top of the piston, so I will likely see if it can be fitted to my 130mm fork to increase adjustability.
Conclusion
The fork feels MUCH better after the first service, which I should have done before installing the fork but thought the problems with factory assembly that plague Fox would not be an issue with MRP. This was clearly not the case, and I recommend a lower leg service no matter which fork you get new.
The stuckdown issue and the split o-ring could have been caused by a mistake in assembly or even a material issue in the o-ring, so it’s not worth it to speculate. MRP quickly stepped up to fix the issue and this is what counts.
Post service the fork is VERY supple over small chatter and bumps, but still struggles a bit with bigger hits. It feels like the damper can’t keep up as the fork is pushed deeper into the travel, which makes it difficult to hold a line over very rough sections. However, I have the fork installed on a hardtail that I rarely take on very rough trails, so this isn’t a huge issue for me. To he honest the Fox 34SC and the FIT4 damper are not that different in this regard. The new GRIP2 or the Rockshox Charger still easily out perform MRP.
The Ribbon chassis works beautifully and is stiff enough for the 130mm of travel on offer. It feels composed and supportive when pushing watts uphill with little unwanted feedback. The finish also seems to last well and the quality and feel overall are what you would expect at this price point.
Given you are willing to give the fork some love from the box, the Ribbon SL will perform just as well as any other high-end fork. The price is similar to a Pike Ultimate and much cheaper than a Fox 34, so if you like the looks, adjustability and aftermarket support then the Ribbon SL is the perfect fork for you! If you prefer a fit-and-forget solution and always have your forks serviced by a specialist the a Pike is likely a better choice.
Further impression
I now have about 3000 km of riding on the Ribbon. I have serviced the fork several times, including a full rebuild and damper oil change and I think I've finally come across a working fork! My damper started to show signs of air ingestion in the form of gargling and swooshing noises probably after about 2000km of riding, so did a full rebuild and seal change. I should have done this earlier! The factory seals were all completely hardened and I had a persistent leak from the negative chamber which was fixed with a new seal kit.
Bleeding the damper was surprisingly easy with a 20 ml plastic syringe from a drug store, which fit the tapered bleed screw hole on the damper perfectly. I used Motorex 2.5 Wt oil in the damper and it seems to work much better than the OE oil. I may try a 5 WT oil next time for a bit more low speed compression support, but the damper is no longer overwhelmed by repeated hits like it was before.
Overall the fork is nice and plush again and I'm running it with 80 PSI in the positive and 85 PSI in the negative chamber.
Overall I give the Ribbon SL a score of 3.75/5 and “recommended with reservations”
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