DIY Free Motion Bike Training Rollers
Introduction: DIY Free Motion Bike Training Rollers
This project got started a while ago with a rainy day and the urge to go for a ride. I took a look at how some other people on youtube, and here on instructables, put together their rollers for inspiration and started from there.
I wanted to make this project with off-the-shelf components where I could and not have to struggle cutting things perfectly round or getting too complicated with construction. I was also intrigued with the free motion idea (putting the roller frame on rollers itself). Others have accomplished this with wooden tracks and skateboard wheels, but I wanted to see if I could make a one-piece system with the free-motion mechanism integral to the frame. From there my spools and spring idea came to life (outlined below). I don't have anything to compare it to (this is the first rollers I have ever ridden), but the mechanism seems to work fine so far. The final thing I wanted to accomplish with this project was to find an easy way to make drive belts from old inner tubes. First, I had plenty around, and second, I didn't want to be bound to commercial drive bands. So far the old tubes are working fine.
I'll take you through the steps I went through below and provide some thoughts on build options where I have them.
Step 1: Motion Return Mechanism
This is a description of the free motion part of the project (see image). It works fairly well and lets the frame roll back and forth and doesn't require a track to roll in.
Step 2: Frame
I made my frame from 2x4's, but others have used hardwood. Make sure there are is no warping in your lumber. If I were to remake the frame I would use hardwood myself.
The most important thing is to keep all the holes aligned. I'd also advise clamping the side boards together when drilling them and using a drill press if possible to keep the holes straight. I have notched out all the holes on the frame for the rollers and center support so I can change belts easily. You can use just holes if you prefer. I have shown a range of holes for adjustability which you are free to ignore. You should check the wheelbase(s) of any bicycle(s) you intend on using to make sure the holes are ideal. 668
The front roller should be set just slightly ahead of the front axle of your bicycle.
My frame came out with some slightly misaligned holes (lag bolt end holes in 2x4's) and slots. As a result my frame has some racking in it, but it wasn't the end of the world. If it doesn't come out perfect, it can still work.
Step 3: Rollers
The rollers are made from PVC pipe, skateboard wheels (and bearings), and a steel axle.
The roller shell is 2" schedule 40 PVC pipe. It is cut to fit inside the frame: the ones used here are 17-3/4" to fit inside the frame with an internal dimension of 18" (1/8" clear each side).
52mm skateboard wheels are epoxied into the PVC pipe ends, with enough inset to allow for a washer and shaft collar (see drawing). For 2" PVC pipe the outside diameter is 2.375" and the inner diameter is 2.067"+/-. The magic here is that the skateboard wheels are 52mm = 2.04" diameter which should just fit in the PVC pipe. Unfortunately I have found that with skateboard wheels 52mm is not always 52mm. Bones, Series 100, 52mm wheels had a snug press fit into the PVC (great fit), whereas DGK Street Formula wheels slipped right in with clearance (poor fit). I tried pinning the DGK wheels in place with two wood screws through the PVC and into the wheel from both sides without epoxy, but it wasn't a great solution (pinched section / poor fit) and the screws tried to work themselves out. I epoxied up a test roller with the DGK wheels and the epoxy did work, but it was very slightly eccentric. It was not hugely noticeable, but it was not as smooth as the roller with well-fitting Bones wheels. If you do end up with wheels that are slightly small, I would try wrapping them in thread (or tape) until they fit centered in the PVC. You can then glue the wheels with the thread in place holding them centered and use enough glue fill the voids. I only used a thin coat of epoxy on the well fitting wheels. Note: Take special care not to get any epoxy on the bearings. Once the rollers are glued up, the inner bearings will be in accessible. I kept a clean cloth and some alcohol on hand just in case. 668