15QR Fork Dropout Concept

I've been developing a 15QR steel fork dropout with some local frame builders for a while. Why? Because most of our customers already have 15QR suspension forks on one of their bikes and it makes sense to re-use front wheels between bikes. Not to mention that thru-axle systems provide excellent steering precision. Since the economy is in the tank, saving money on bike parts is always a good thing.


I just finished off the conceptual design and have teamed up with Paragon Machine Works to prototype the concept. Special thanks to Rick Hunter at Hunter Cycles for design feedback over the last few weeks. The design features 32mm-wide 'hooded' dropouts that accommodate the Rock Shox Maxle 15mm thru-axle. The hoods allow the frame builder to construct various fork geometries easily....as shown this design can be used for 26", 650B and 29" rigid forks. If the frame builder decides to use tapered fork blades, excess dropout material can be easily removed using conventional machining methods.

The Maxle Lite's skewer handle can be easily clocked (to clear the fork leg when tightening) without having to clock the actual nut it attaches to. In this case I was able to eliminate the clocking hardware normally found on Fox forks to keep things simple. I do like the Fox/Shimano system but it is more difficult to source and requires more parts than the Maxle system.

The 15mm axle threads directly into an aluminum nut that is 'keyed' directly into the dropout body. The opposing flat surfaces on the nut will prevent the it from spinning freely when tightening down the axle. On the drive-side, a simple aluminum spacer is used to position the axle perfectly.

Mass Analysis:

Left Dropout Body = 58g
Right Dropout Body = 52g
15mm Keyed Nut = 14g
15mm Spacer = 14g

Total = 136g