SOMA - JAWBONE B-TYPE FRAME

The Jawbone B-Type frame is the perfect platform to build your dream drop bar mountain touring and bike packing rig. While it is still game for riding gravel and singletrack, it is in its element when packed up for your next adventure.

• Tange Prestige heat-treated butted CrMo steel; butted CrMo rear end
• IRD Broski Sliding Dropouts allows for running derailleurs as well as geared hubs like Rohloff. You can also convert it to single speed if your derailleur conks out on a ride. (Stock dropout insert is for 135mm QR. 142 x 12mm Thru-Axle inserts available separately)
• IS disc brake mounts on rear
• Front derailleur compatible (bottom pull)
• Rear rack and fender eyelets
• Two sets of bottle cage bosses; one set of cargo cage bosses on downtube
• 44mm headtube: Fits 1-1/8" steerer tubes and tapered steerer tubes with a headset swap
• 27.2mm post size/28.6mm frt. der. size/29.8mm seat collar, 73mm bottom bracket (English threads)
• Tire Width Range: 27.5 x 47mm to 2.6” / 700c x 38mm to 29 x 2.25”
• Sizes: 650b only: 50cm, 52cm. 700c: 54cm, 56cm, 58cm, 61cm, 64cm

SPECIFICATIONS AND RECOMMENDATIONS

FRAME

Headset for optional 1-1/8" matching fork: SHIS: ZS44/28.6 | ZS44/30). If running a tapered steerer fork, get an EC44 lower cup
Front derailleur: 28.6mm ID, bottom pull
Seatpost: 27.2mm
Seat collar: 29.8 or 30.0mm (not included)
Rear hub spacing: 135mm
Brakes: Disc (IS mount 160mm rotor)
Bottom bracket shell: 73mm wide, English threads
Max.Tire Clearance: 29 x 2.25 and 27.5(650b) x 2.5". On size 50cm and 52cm, we recommend not using tires more than 27.5 x 2.2 to reduce toe overlap issues
Chainring clearance: Mountain 1x and 2x, Shimano GRX 2x 48/31
Guides for full length cable housing
Water bottle bosses: On seat tube and under down tube
Cargo cage Bosses (Three-pack mounts): One set on down tube.
Rack and Fender mounts: Two at dropout
Max. weight with rider and load: 270 lbs/122 kg.
Acceptable fork lengths: 417-425mm
Acceptable fork rake: 44mm - 50mm

FORK

Axle to crown: 420mm
Rake: 50mm
Steerer length: 300mm
Hub compatibility: 100mm QR
Four sets of three-pack mounts at 45 degree angles.
Inside/outside leg pannier rack boss
Rack and Fender mounts: Two at fork end