On-One’s steel Rujo is a budget gravel bike from the UK-based bargain bike retailer Planet X. Built from 'aerospace grade' chromoly DN6 steel, the Rujo is specced with an eye on the price although you're still getting a SRAM 1x drivetrain, hydro brakes, and a Fulcrum wheelset.
It's one of the best gravel bikes we've tested too and proves you don’t need a fancy spec, low weight, or a stack of money to create an addictively smooth and stealthily rapid all-rounder that’s as versatile as it is awesome value.
Design and geometry
If you’re wondering what DN6 steel is, the name originally appeared on On-One single-speed MTB frames in the late 90s. In a dig at the fancy names given to in-house tube sets by other brands, they labeled theirs with the postcode of their Doncaster, South Yorkshire, UK warehouse. And while the composition and design has changed with various far eastern frame vendors over the years, the name has stuck.
On the Rujo it’s a 4130 steel alloy with slim triple-butted, round section main tubes. These join a neatly tapered head tube with swollen ends for a 1.25in bottom race and 1.125in top race and to the back end with a plate. The snaking chain stay has machined bolt-through dropouts with a flat brake mount and separate fender and rack eyelets. The slim, swerving seat stays have upper rack mounts and there’s a fender bolt on the arched bridge.
You also get a conventional bottle mount on the seat tube and under the downtube with a triple bolt mount on top of the downtube. There’s an accessory/bag mount on top of the top tube behind the headset too. The bottom bracket is threaded, cables/hoses are held externally using small slotted shoes for zip ties or plastic clips.
Even with the plated chain stay tire space is adequate rather than amazing at 700 x 43mm or 650 x 55mm. Seatpost size is 27.2mm with a rear-facing slot so keep an eye on potential corrosion from rear wheel spray over time. While I don’t have an exact frame weight the Rujo is around 500g heavier than the titanium-framed Planet-X Tempest and a kilo heavier than the carbon-frame On-One Free Ranger, but as you’ll see there’s more to speed than a number on the scales. It's available in dark red if you'd prefer too.
The standard front fork is a full carbon Selcof ‘All Road’ fork with mudguard mounts and internal brake hose routing but you can select a RockShox Ruby 40mm suspension fork for a bargain price of $571.50 / £450 (normal RRP $843 / £780).
Geometry uses a ‘middling for gravel’ 71-degree head angle a relatively steep 74-degree seat angle with a slightly sloped 546mm top tube, short 130mm head tube, and 525mm seat tube on my medium-sized sample. Chainstays are 425mm on all sizes and bottom bracket drop is 70mm, with a wheelbase of 1020mm. One thing that's easy to overlook until you're lying in a heap at some stop lights after getting tangled up in a trackstand or during a tight turn is that there's no toe overlap if you're running mudguards. Like I said previously, this is a properly practical bike, not just a peach to ride.
Components and build
On-One only currently offers the Rujo in a complete Rival 1 11-speed single-ring build with a selection of Selcof alloy finishing kit, with basic bar tape. You can choose different stem and bar sizes though and there are a handful of saddle options on the pull-down ‘custom’ menu. Standard wheel spec is Fulcrum 900 gravel wheels with steel-edged, innertubed Panaracer Comet 38mm tires. I switched to Hutchinson Touareg tubeless tires ($71.12 / £56 upcharge) and set them up with $11.63 / £10.99 worth of Barbieri valves to maximize float and puncture proofing. Building to order in Rotherham, South Yorkshire, and then delivering direct means pricing is very competitive and allows the alterations mentioned but build time can add a few days to your order. You won’t get all the potential benefits of buying from your local bike shop either.
Ride, handling and performance
There are all sorts of myths and legends attributed to the ride of a steel frame, but the truth is there’s also a fair amount of art in actually making that happen. The Rujo proves that doesn’t necessarily mean extruding, bending, or otherwise torturing the tubes into shapes you can ask people to pay extra for. Neither does it have to mean oversizing, gusseting, or a frame build back story that reads like the label of a vintage Italian wine or pair of hipster jeans.
By keeping the tubes slim and round, without the stressors/reinforcements needed for internal cable routing On-One delivers one of the most delicious riding bikes I’ve ever had the pleasure of testing. At over 10kg for the complete bike, it isn’t the fastest out of the blocks, but it soon turns that ‘should have changed down a gear for that corner’ into an inexorably growing surge of speed. A speed that it hoards with remarkable stubbornness up extended climbs or spreads or stutter roots on singletrack as lighter/stiffer bikes stall and fall behind. The power smoothing compliance that makes it feel like you’re pedaling a slightly elliptical chain ring means traction is excellent and feet don’t get blown out of pedals or turned numb on rocky descents.
This lazily unstoppable velocity had us creating comparisons to old auto gearbox Jaguars driven by sheepskin-coated gangsters in 70s crime series. The damped frame and silent Fulcrum freehub all contributed to the limousine feel and while we probably would fit a chain stay protector if it was ours, it never slapped or chipped during testing. And that wasn’t because we avoided the nasty line options. In fact, I’d often take them deliberately just to hear the damage being done to other riders trying to follow. That’s because the Tai Chi like ability of the steel to mute impacts makes a real difference when you’re slamming rims into unseen edges and it’s one of the most forgiving, flat-out night ride bikes I’ve used. That also makes the restricted tire room much less of an issue than it would be on other bikes, although I did spend some time on 650 x 47mm WTB mud tires on really sloppy sessions.
Despite its almost insolent, languorous approach to moving watts to the wheels, it consistently turned in some startling stats on Strava. It put serious hurt into group rides too and it was soon christened the ‘Flywheel Mobile’ by our northern gravel test team. While it certainly caused a shift in my normal impatient riding style in terms of when I expected to pull away, Tom at On-One has somehow managed to keep it feeling enjoyable dynamic rather than dull and docile in handling terms. Yes it’s grippy rather than sticky - especially when I added the tubeless Hutchinson tires but turn-in is keen and really exploits its ability to hold a line and momentum.
With a longer reach than seat tube height, low head tube, and a 100mm stem as standard, the Rujo gives a ‘classic’ bike fit for long, efficient miles too. Not quite ‘race’ but definitely not a sit-up and beg ‘sportive’ style that instantly neuters your need for speed. The slightly sloping top tube and slim tubes also mean plenty of bag space in the mainframe if you like your luggage between your legs. While the bar tape doesn’t have any fancy tapered edges or texture and dents/cuts quite easily the cockpit feels fine. The saddle is a lot more comfortable than we expected from its basic plastic looks too and I’ve sat on the same for a six-day African gravel epic with zero complaints. Mudguard and rack mounts mean it’s equally happy taking whatever you need for work or utility in between multi-day expeditions, gravel epics, or just chasing MTBs down the woods. The fact you get a complete bike for less than some top-end steel frames that may not ride as well as the Rujo only adds to the undeniable value and underdog charisma too.
I met Tom the designer from On-One when I picked the test bike up from their HQ in Rotherham along with their titanium and carbon bikes for another project, He’s a very modest, quiet chap but he handed it over with a knowing smile and let me know that the Rujo was the bike he picked as his personal ride from a very broad range of options.
Having ridden it myself now I totally understand why. Yes it’s heavy, but the way it eases that weight up to speed and then turns it into flywheel-like momentum is truly remarkable. Its smoothness, silence, and surefooted traction are outstanding too, but there’s still enough sprung charisma and liveliness in the handling to make it a total joy to ride. And the fact I rode it way more than I needed for test purposes while other much more expensive carbon, steel, and titanium bikes hung on the workshop wall is probably the most telling thing I can say about the Rujo. I’m already plotting how to hold onto it for longer so I can see what carbon wheels, seatpost, and fancier tape add to the mix, but even as it comes it’s a truly wonderful, versatile bargain I’m not hesitant at all about giving five stars to.
Tech spec: On-One Rujo
- Discipline: Gravel, road, bike packing, touring
- Price: $1,670.24 / £1,566.98 as tested (currently $1,587.49 / £1,499.99 with tubed Panaracer tires)
- Head angle: 71 degrees
- Frame material: 6061 alloy
- Fork material: Carbon fibre monocoque
- Size: S, M (tested), L, XL
- Wheels: Fulcrum Rapid Red wheels
- Tires: Hutchinson Tuareg tubeless 700 x 40mm tires
- Drivetrain: SRAM Rival 11-speed rear mech, shifter, 11-42T cassette, and 42T chainset with threaded GXP bottom bracket
- Brakes: SRAM Rival 1 hydraulic disc brakes with 160mm front and rear rotors
- Bar: Selcof Sterrato 420mm flared gravel bar
- Stem: Selcof Zeta 6061 Alloy Stem 100mm
- Seat post: Selcof alloy 350 x 27.2mm seat post
- Saddle: San Marco Monza Start Saddle
- Size: S, M (tested), L, XL
- Weight: 10.5kg (size M)