Paragon Machine Works Debuts Sweet Belt Drive Quick Release Dropouts
Paragon Machine Works is testing a “quick release” rocker dropout design for belt drive bikes. Typically, you’d need some sort of tension bolts to push the dropouts away from the bike to create tension in the belt, much the same as with chain-driven singlespeed bikes.
The new design is basically it’s a rocker dropout, but instead of using the threaded bolts to create tension, a quick release lever on the backside pulls things back as it closes.
The toggle clamp is attached to a turnbuckle bolt that allows fine adjustments to get the tension set properly and equally on both sides. On the driveside pic above, it’s closed, which pulls the axle rearward to the preset tension. You’d then clamp the skewer to secure everything into place and go ride.
Yes, it’s the combination of pressure from the skewer and the turnbuckle screws holding the wheel in position. PMW’s CAD designer Jeff Whinney says it only works with a 142×12 axle because the thinner 135×10 QR skewer wouldn’t be strong enough. It’s using Shimano’s e-Thru rear axle, but with a custom titanium nut engraved with their skull logo.
Pic, video and more details below…
Open, the axle slides forward and creates slack in the belt. Unthread the axle and you should be able to wrestle the belt loose for simpler wheel removal (compared to pulling out your multitool to loosen tension bolts and loosing axle nuts). Besides saving a bit of time, it maintains your tension settings during wheels changes, offering something like set-it-and-forget-it.
If you’re ordering a custom bike with dreams of belt drives spinning in your head, might want to ask your builder about these.
Looks like it got cut short, but you get the idea.