Cruiser-bike Adapter for Unisky Fluid Trainer

thingiverse

There doesn't seem to be a category for "Sports and _Indoors_"... . We don't want to risk the gym right now -- although thanks to our idiot Governor we could -- so I ordered a Unisky brand fluid trainer to round out our home exercise options. It's designed to fit bikes with quick-release skewers, but I didn't want to set it up for my mountain bike so I adapted it to work with my wife's restored antique cruiser. Just print two of these adapters and slip them over the axle studs, follow the Unisky installation instructions, and get pedaling! (They'll likely work with most brands of stationary-bike trainer stands.) The axle studs on my wife's old bike are fairly long; I used the 3_8ths_adapter.stl version. Looking at photos of new bikes online, there may not always be enough exposed stud to use that, so you could try 3_8ths_adapter_with_nut.stl which includes relief to fit over a nut (_not_ tested). I printed in HIPS 'cause I like working with it. Nylon or similar would likely be "best" because it's less brittle, but they're really just shims and I doubt it matters much. I tried to make them as "beefy" as possible. You can adjust dimensions in the .scad file: /* dimensions for bike */ include_nut=0;//set to 1 to include relief for a nut, 0 for no nut bolt_d=3/8*25.4; //sized for 3/8-inch dia nut_t=1/4*25.4;//thickness of nut (sized for 3/8) nut_d=21/32*25.4;//dia of nut across points (sized for 3/8) /* dimensions related to trainer */ sk_h=15.5;//skewer-nut overall height shoulder_h=7; shoulder_d=19; cone_h=sk_h-shoulder_h; cone_min_d=13.75; cone_max_d=19; /* arbitrary dimensions for adapter */ iface_thk=5; //thickness of flange between trainer and bike iface_d=25; // diameter of flange between trainer and bike