The Momsen R355 Gravel is a full carbon frame resembling a road bike but shaped to accommodate a variety of wheel and tyres sizes to take the bike beyond the confines of tar.
The frame comes with a number of practical touches to make long distance adventures somewhat easier. There is provision for three water bottle mounts. Two inside the front triangle and one on the outside of the downtube. There are also mounts for racks and bags on the seatpost and rear axle.
The R355 gravel borrows technology from the mountain bike world. The axles size comes straight out of mountain biking with a 142 mm rear thru axle and 100 mm front thru axle. This allows the R355 to fit a variety of wheel sizes including 700 X 50C, 27.5 X 2.10, and 29 X 2.10.
When first looking at the centimetre sizing, I was a bit confused by how small the range appeared. However, its is best to ignore that and look to the S/M/L/XL sizing for a better representation. For example, I'm usually a 58 or 59 on road bike measurements but I fit reasonably comfortably on the 54 (Large) R355 frame although one size up would probably have been the sweet spot.
The Momsen R355 arrives perfectly ready to get stuck in, with a well thought out selection of parts. There are no components that are subpar or necessitate an upgrade, except perhaps a tubeless conversion if your conditions require it.
Originally developed for cyclocross racing, SRAM’s single chainring Force1 drivetrain has proven to be versatile across many cycling disciplines including gravel. The Momsen R355 features a SRAM Force crankset, derailleur, and hydraulic brakes/levers. The X1 cassette is borrowed from SRAM’s mountain biking catalogue while the chain has been sourced from KMC. Momsen have elected to go with a 40 tooth chainring and a 10-42 cassette range. The disc brakes are SRAM Force hydraulic with 160mm rotors front and back.
The wheelset is Stan’s NoTubes gravel specific ZTR Grail MK3 rims laced with Sapim Force spokes to Neo hubs wrapped in Clement X’Plor MSO 40c tyres. The bike arrives with tubes and this is how I tested it, without suffering any punctures or pinch flats.
The cockpit consists of Momsen branded parts. Most interesting is the carbon seatpost which is ovalised near the top to add flexibility to the post. On the large frame the stem is 90 mm with a 44 cm flared handlebars wrapped in shock absorbing bar tape.
Momsen R355 Specifications:
- FrameCarbon Gravel Plus 142 x 12MM Rear Thru-Axle, Internal Cable Routing, Dropper Post Compatibility, Rear Flatmount for disc
- ForkFull Carbon, Carbon Steerer, 100 x 12MM Thru-Axle, Disc Only, Flat Mount
- HeadsetMomsen Integrated, Angular Contact Bearing
- CranksetSram Force1 24MM XSYNC 40T (170MM – XS, S) (172.5MM – M, L) (175MM – XL)
- Rear DerailleurSram Force1 Type 2.1 Long Cage
- ShiftersSram Force1 HRD 11-Speed Rear Only
- CassetteSram XG 1180 10-42T
- BrakesSRAM Force1 Disc
- RotorsSRAM CLX, 6 Bolt, 160MM Front and Rear
- Bottom BracketSram Pressfit GXP Road 86.5/WA91.5
- RimsStan’s ZTR Grail MK3 28H / 32H
- SpokesSapim Force Black
- Front HubStan’s NEO 28H 12 x 100
- Rear HubStan’s NEO 32H 142 x 12
- TyresClement X’Plor MSO 60TPI 700x40c Folding Bead
- Tubes700x40c, Presta Value
- HandlebarsMomsen Gravel, Oversize 31.88MM, 40CM (XS) 42CM (S, M) 44CM (L, XL)
- GripsAnti-Slip, Shockproof Tape
- StemMomsen 3D Forged Alloy, Oversize 31.8MM, 7 Degree Rise, 80MM (XS, S) 90MM (M,L) 100MM (XL)
- SaddleMomsen Custom, Cromo Rail, Embossed Graphics
- SeatpostMomsen Carbon 27.2MM Comfort / 350MM
- Seat BinderAlloy 31.8MM CNC Groove
- SizesXS (48CM), S (50CM), M (52CM), L (54CM), XL (56CM)
- Weight (Large)8.6 kgs
Models and pricing
The above build is currently the only model in the R355 range. The recommend retail price is R52,500. If that's a bit rich for your taste, Momsen also have an aluminium GP300 gravel bike with a modest build retailing for R17,500.
On the trail
I tested the Momsen R355 on a variety of terrain including gravel roads, tar, urban greenbelts, single track, and even the odd mountain bike rock garden.
As is to be expected, the R355 excels on gravel and broken roads. The direct road bike feel coupled with a comfortable geometry and large tyres certainly enhances the experience of disappearing down a farm road.
Putting the power down and surging forward feels great on the Momsen R355 but the rigid frame design does mean some harsh impacts without any suspension to soak them up. The flexible carbon seat post actually worked. I could feel it moving underneath me when I hit big holes but it was never was uncomfortable or distracting. While the large 40c tyres worked tirelessly to soak up a decent amount of chatter and corrugations. Having recently ridden around the dirt roads of L'Agulhas on a road bike with 25c tyres, I can attest to the gain in comfort and traction that larger tyres bring.
The R355 is no slouch on the tar either, making switching between the road and dirt seamless and natural. I tested the bike on my regular road group ride around the Cape Peninsula. On tar, the bike feels like a road bike. The geometry made for a comfortable ride without impacting on performance. I even enjoyed the flared handlebars. The larger tyres do add a bit of weight, and a touch of extra drag is noticeable. The low gear range only hindered my progress on the steeper descents which I found myself approaching with much more confidence on the 40c wide tyres (and a higher cadence). There was little compromise on the climbs with the range of the mountain bike cassette. The R355 is a viable road bike for those riding for fun and fitness, and if you really don't want both a road and gravel bike, the R355 can go a long way to being your road bike. Throw on some skinnier slick tyres and I have no doubts that the bike will be even better suited for the job.
The bike’s handling is predictable and stable. The flared drops proved to be the safest place for your hands on rougher terrain. This did mean that the back wheel can get a bit sideways with your weight far forward, just something to be mindful of when grabbing the brakes. The Clement X’Plor tyres give good grip and I was pleasantly surprised at their resilience when bashed into sharp rocks.
This sense of adventure carries over to more technical riding on what is usually considered mountain biking territory. Much like riding on gravel roads, the Momsen R355 breathed new life into my midweek mountain bike route. (For those familiar with the Cape Town southern suburbs trail network, via the Constantia Greenbelts up Constantia Nek, back down through Newlands Forest, and back to the Greenbelts via the Cork Tree Trail). Riding the R355 on these familiar trails presented new challenges and required different line choices that transformed the experience. Perfect if you’re looking to switch up your riding but not the trails.
On the R355, I managed to largely keep up pace, if not go faster, than my mountain biking companions. However, on fast and loose gravel descents where the robust tyres and coddling suspension of the mountain bikes show their worth in speed and stability. The R355 or at least I, fell apart in rock gardens and rooty sections. I found myself understanding why some gravel bikes come fitted with a dropper seatpost. Its worth keeping your expectations in check, it is a gravel bike after all and while it's perfectly adapted to mountain dirt roads and smoother single track, in most rider's hands, it is not a mountain bike.
In the end
The Momsen R355 is the ideal companion with which to explore the countryside. While it shines on gravel roads, the versatility means that you can get away with using it as a road bike and even on less technical mountain bike excursions. The component selection is spot on, matching the abilities of the light sturdy frame.