Almost all Chromag frames are made from quality 4130 chromoly steel tubing. Chromoly is an abbreviation for chromium-molybdenum indicating the materials that the steel is alloyed with.

The added chromium helps increase the steels hardenability and also provide some corrosion resistance.
The molybdenum helps to increase the toughness of the steel.

It has a high tensile strength but is also malleable which is what gives our frames their notorious ride quality and feel. Chromoly is often used when more strength is required than that of mild carbon steel.

It falls under the AISI (American Iron & Steel Institute) 41XX designations which is where the “41” comes from. The “30” indicates it contains approximately 0.30% carbon by weight.

Chromoly is much stronger than traditional 1020 steel and it has a higher strength to weight ratio and high tensile strength, which means we can use less material and achieve a product that can withstand the abuse that riders love to throw at it.

Hub Spacing // Boost 148mm (Axle, hanger and modular dropouts included of course!)
Headset // 44-56 Semi Integrated
Seat Clamp Size // 35mm
Seatpost Size // 31.6mm
BB // 73mm Threaded
Wheel Size // 29"
Recommended Fork Travel // 140mm (±10mm)
Builder // Chris Dekerf

Head Tube Badge

Your bike is special. The head tube badge is the finishing touch so we’ve always made a point of taking the time to do something interesting with it. Our head tube badges have changed over the years and are an indication of the time each bike was made. Whether it’s a cast bronze, or polished stainless steel, water cut aluminum or a 3D CNC carving, each one represents our commitment to detail.

Dropouts

The Surface Voyager features our unique sliding dropout system, which makes running single speed a breeze (if you're so inclined), even with disc brakes.

The rest is as you'd expect from Chromag, 12x148mm spacing, compatible with our traditional axle and all boost hubs.

Yokel

Our ‘Yokel’ design is a small machined junction on the chainstay that helps accommodate both tire clearance and chainring clearance. Our first versions were huge CNC yokes that bridged the entire front end of the chainstays. Over time we refined this to minimize weight by arranging our chainstay layout asymmetrically and reducing the yoke to a minimal size. It’s one of our most unique frame features and has been copied by other frame makers.

Chain Stay Protector

All Chromags now ship with our injection moulded chain stay protector to help keep the paint fresh and the noise low. These have an adhesive applied, but also slot for zip ties if they come unstuck years down the line, or if you want to apply it to another frame.