Flat bars, fat knobbies, and a full chrome finishing kit.

The 4130 All-Road Flat Bar is the simple one. Steel frame, upright bars, 650b wheels on 2.1" Vittoria Barzo tires, and a 10-speed drivetrain with nothing to charge and nothing to pair.

It looks like the mountain bikes people actually want to be riding again — chrome cockpit, steel tubes, big rubber — and it's built to a spec that keeps the price where it belongs.

Simple on purpose

Every decision on this bike went the same direction: fewer things to go wrong, fewer things to pay for.

Completely external cable routing. No fishing housing through a frame, no internal guides to rattle, no removing a bottom bracket to chase a cable. Every line is right there where you can see it, adjust it, and replace it. It's the difference between a twenty-minute job and an afternoon.

68mm BSA threaded bottom bracket, square taper cranks, 27.2mm seatpost, 31.8mm bar clamp. Standards with decades of parts behind them, available anywhere, serviceable by anyone.

Long, low, and slack

Long chainstays, a slack front end, and a low bottom bracket. Every number here is doing the same job.

• 450mm chainstays across every size. Long rear center puts your weight further forward between the wheels, which means the bike tracks straight on loose surfaces and stays planted when it's loaded with bags.
• 70.5° to 71.5° head angle. Slack by gravel standards. The front wheel leads rather than darts, so washboard and gravel don't push the bars around.
• 75mm bottom bracket drop. Low. Your weight sits below the axles, which is what makes a bike feel confident in corners and on off-camber dirt.
• 45mm fork offset across every size — consistent steering feel from XS to L.

The result is a bike that's calm. It won't feel twitchy on a fire road descent, it won't wander when you're riding no-handed, and it won't fight you when the surface changes under you mid-corner.

Flat bars change the bike

630mm wide with 25mm of rise, on a 31.8mm clamp.

Wide bars give you leverage — more control over the front wheel on loose ground, and more confidence when the surface gets rough. The rise brings your hands up, which opens your back angle and takes weight off your wrists on a long day.

And you can see. An upright position on a bike you're riding through traffic, on a canal path, or down a dirt road you've never been on is worth more than the aerodynamics you're giving up.

650b x 2.1", and room for more

Every build ships on 650b wheels with Vittoria Barzo 2.1" knobby tires — real off-road tread on real volume, at pressures low enough to take the edge off anything.

The frame has room well beyond that:

That's genuine mountain bike clearance on a steel gravel frame. Run the Barzos for dirt, or build a 700c wheelset with something fast for commuting and have two bikes.

10-speed, and it's enough

A MicroShift Advent X 1x10 drivetrain with an 11–46T cassette and a 40T narrow-wide chainring up front.

Advent X was designed for exactly this kind of bike — a wide-range 1x that's built tough, shifts under load, and costs a fraction of what a 12-speed does to replace when the cassette wears out. The clutch keeps the chain quiet on rough ground, and the narrow-wide ring holds it on without a guide.

418% of range from an 11–46 means a climbing gear for loaded dirt and enough at the top for a fast flat section. More speeds would give you smaller steps between gears. They wouldn't give you more range, and they'd cost more every time you replaced a chain.

UDH

Universal Derailleur Hanger, so a replacement is available at virtually any shop anywhere in the world. No proprietary part to track down after a crash on a trip, and a clear path to modern drivetrains if you ever want to change direction.

Hydraulic disc brakes

Flat mount hydraulic discs with 160mm rotors front and rear. Not cable-actuated — proper sealed hydraulics, which on a bike carrying weight down a loose descent is the difference between modulating and hoping.

Thru-axles front and rear: 12x100mm and 12x142mm, with sealed bearing hubs.

Size Recommendations

Sizes overlap on purpose. If you fall between two, the smaller size gives a more nimble, upright fit and the larger one stretches you out. Full numbers — reach, stack, standover, and wheelbase for every size — are on our geometry chart.

Complete Component Spec

Frame & Fork

• 4130 Chromoly steel frame, UDH dropouts, 12x142mm thru-axle
• 4130 Chromoly steel fork, 12x100mm thru-axle
• 68mm BSA threaded bottom bracket shell
• Completely external cable routing
• Headset: SBC 1-1/8" threadless, steel

Drivetrain

• Shifter: MicroShift Advent X, 1x10
• Rear derailleur: MicroShift Advent X, 10-speed
• Cassette: 11–46T, 10-speed
• Crankset: SBC 40T narrow-wide, aluminum, square taper
• Chain: 10-speed

Brakes

• Hydraulic disc, flat mount, 160mm rotors front and rear

Wheels & Tires

• Rims: 650b double-wall, 32h
• Spokes: Stainless steel, 14 gauge
• Front hub: 12x100mm thru-axle, sealed bearings
• Rear hub: 12x142mm thru-axle, sealed bearings
• Tires: Vittoria Barzo, 650b x 2.1"

Cockpit

• Handlebar: SBC low rise aluminum — 630mm width, 25mm rise, 31.8mm clamp
• Stem: SBC 3D-forged alloy, 31.8mm clamp
• Grips: 135mm TPE
• Seatpost: SBC aluminum, 27.2mm x 350mm
• Saddle: PU pad with microfiber cover and steel rails
• Pedals: Nylon flat pedals, included

Max Tire Clearance

• 650b / 27.5": up to 2.4" (60mm)
• 700c / 29": up to 2.25" (57mm)

Want to get technical? Full Geo / Specs here.