Wednesday, December 16, 2020

Add resistance to aluminum bike roller




BIKE NERD POST! Do you have an old aluminum bike roller? Do you love the feel, but hate that you can't do any more than a tempo ride on it? Would you LOVE to be able to go from an easy zone 1 to "I'm gonna puke" watt output with a couple of gear changes!? I found a solution on the internetz!!!! FOR CHEAP!

Step 1) Buy yourself some Neodymium Bar Magnets for $10! The ones I found on the Amazon were a pack of 6, 33 LB Strength, 60mm x 10mm x 5 mm. I only needed 5 of them.

Step 2) Find yourself a scrap 1x2 (you know you have one) and cut it about 1-2mm longer than the length of the bars between your rollers (as shown in picture). Remember to start long!

Step 3) Loosen one of the bolts on the middle roller — also a good time to tighten everything else up too 😉. Bolt on outside is a 9/16 socket, bolt on inside is a 14mm wrench — you're welcome!

Step 4) Now, wedge the 1x2 between the bars, adjust, tighten the bolt, and test the fit. Make sure the wood scrap is tightly in place and the roller isn't loose. It may take a couple of cuts to get it perfect. Once everything fits well, take the 1x2 back out and it's time to mount the magnets!

Step 5) Before mounting, test each magnet on each other to see which side is the pull side ("pulls" to one another) and mark with a marker.

Step 6) Mount the magnets starting from the center. My magnets came with double sided tape, but you can use whatever. After the center is mounted, space the next two magnets from the center rest just outside the limits of pulling/pushing from adjacent magnet. You want the last magnet to be placed far enough from the end of 1x2 that the whole bar is over the aluminum roller and not the plastic end where the band lays.
UPDATE:  The doubled sided tape didn't work so hot when things got hot.  I added a layer duct tape around each magnet.  I met go back and use another type of adhesive if that doesn't hold.

Step 7) Wedge the 1x2 back between the roller bars and adjust the magnets about 2-3mm from the roller to start. The magnetic pull isn't strong enough to pull the magnet to the aluminum roller, nor is it even strong enough for the magnet to cling to it. Regardless, I can assure you it'll work. 😉

Step 8) Hop on the rollers with a bike and test out the resistance! What you just did was create an Eddy current! You can adjust the resistance by moving the 1x2 closer for harder, and farther for easier.

Step 9) Buy an Ant+ USB Stick ($20 on Amazon), download zwift, connect your gadgets, and enjoy the zwift 7-day trial. 😁

I was able to easily do VO2max intervals with my big ring and middle/lower cassette gears.

Enjoy the suffering!