Surly Thru-Axles are low-profile, bolted Thru-Axles are specifically designed for use with Surly thru-axle compatible frames. Offered in several sizes, for both front and rear wheels. 12x142 Rear Thru Axle: - Fits: Midnight Special and MDS Dropout bikes including Instigator, Legacy Karate Monkey & Legacy Krampus. 12x142/148 Rear Thru Axle: - Designed for frames with Surly Gnot Boost spacing (145mm), capable of working with 142 or 148mm rear hubs - Fits: Karate Monkey, Krampus, Troll, Ogre, ECR 12x177 Rear Thru Axle: - Fits: Wednesday 12x197 Rear Thru Axle: - Fits: Ice Cream Truck, Big Fat Dummy 12x100 Front Thru Axle: - Fits: Midnight Special 15x110 Front Thru Axle: - Fits: Karate Monkey, Krampus 15x150 Front Thru Axle: - Fits: Wednesday, Ice Cream Truck, Big Fat Dummy