Rear Axle: 3/8-inch Threaded x 135mm

The center tread features ramped leading edges to improve acceleration and sipes to create a smooth transition when leaning the bike

Nylon fibers have a flat profile

adjustable flex base w/ five inserts

Surly 24-pack Rack Black Compatio_Enriched Rear Axle: 3/8-inch Threaded xA traditional style Porteur rack that mounts securely to mid blade and crown eyelets of Surly forks, making it compatible with fat bike and 29+ wheels. Mounts to mid blade and crown eyelet Safety Mounting hardware is included Compatible with Surly forks that use crown mounted braze ons and mid blade fork eyelets Not recommended for use with forks that have single mounting point in the fork crown