You no longer need to hang your bike in the garage when winter comes. You can use your bike for your daily exercise regimen year-round by turning your conventional bike into an inside bike trainer. This is a fun do-it-yourself project that allows you to hop on your bicycle regardless of the weather.
Measure the length of your bicycle. Mark that length plus about 1 ft. allowance on the plywood. That will serve as the length of the base.
To determine the base width, measure the diameter of your bike's wheel. Use that measurement and give about a 5-inch allowance. Draw the measurement on the plywood panel to complete the rectangular base layout of your inside bicycle.
Using 2-by-4s, construct a pair of triangular-shaped braces with legs that are meant to be fitted at the bottom bracket of the bike or the bracket that supports the bike's rear and front wheel assembly. Drilling the wooden wheel braces at 2- to 3-inch gaps will enable the setup to accommodate different sizes of wheels. The dimensions of these brackets will depend on the diameter of the wheels plus tires. The rear bracket setup needs to be securely attached to the base to prevent imposing load to the front fork.
Using a 1 1/2-inch by 10-inch pipe nipple, make a bike kickstand and two floor flanges 1 1/2 inches in size, then make a bottom-bracket clamp. This will better secure the front and rear wheel braces on the wooden base
Mount the bottom-bracket clamp; position it on the rear tire of the bicycle. Allow about a half-inch tire deflection.
To keep the bike level and in a comfortable riding position, mount the bike forward. Make sure the rear tire clears the plywood base by about a half-inch. A conventional bike trainer has horizontal frame supports that work in conjunction with the vertical triangular supports to control deflection. These supports not only keep the bike securely upright when ridden but also optimizes the load that the inside bike bracket and brace support setup can take.
Position another bicycle wheel hub between the supports where the opposed hub that keeps the rear wheel upright is. Make sure that at least one of the hubs has quick-release mechanisms. The quick-release mechanisms may involve a piston with a socket that is fitted around the hub.
Use a spring biased cam with an attached lever to urge the socket on the piston towards the hub.
Make the rear tire rest on a frictional engagement by attaching it to a tensionable roller. This roller should work with a tensioning mechanism; have it attached to a push-pull cable brake setup to add resistance to the rear wheel rotation. Tensioning must be brake actuated.
Use the structure you created in supporting the rear wheel to create supports for the front wheel.
Test the setup. Make all the necessary adjustments to strengthen the structure. Make sure that the setup is supported by two parallel rollers that allow the rear wheel to rotate.