Little DIY Project to add/increase resistance on your AL rollers

Thought I’d share a little DIY project I just completed to add/increase resistance on aluminum rollers. I came across this simple idea when I researching ways to increase resistance for my FTP Test earlier this week as I was afraid of spinning out. I found 2 ways; first was to fold or roll an old towel under the roller(s) to which I did as it was the simplest & easiest to do & worked fine. The 2nd method required a few more parts but is a better longer term solution. It’s also my understanding a few manufacturers used to make something similar and sell as an accessory however have since discontinued them.

I got the idea from this YouTube video -

All I had to purchased was 1 piece of angle bar and 2 x 1.8" long Rare Earth Channel Magnets. I’m in Toronto Canada, cost me $30 for the magnets & $10 for the angle bar, already had the clamps.

Just installed them on my rollers and did a quick test. I have Shimano Ultegra 8000 group set with 50/34 11sp. In big chainring and 19 tooth (5th cog) down from largest in rear WITHOUT magnets at 75rpm I was pushing on average 90w, then added the magnets same gearing and cadence I 'm now pushing around 193w - that huge! And most likely exponential as you move up through the gears and the rollers spin faster.

Here’s a few pics of my set up

The magnets

Hope this helps, any questions just ask it’s a very simple & slick little mod.


1 Like

That’s pretty neat, unfortunately I have the Tacx plastic rollers. I do wonder how it works with aluminum rollers, makes sense that it works with steel rollers.

Majority of rollers that aren’t plastic are aluminum, I don’t think they ever made steel rollers due to weight and it’s inherent rust properties around sweat & moisture it just wouldn’t make sense. It works with the aluminum rollers as there is some steel part inside. Here’s a brief explanation, as the aluminum passes by the magnet, an eddy current is induced in the aluminum. - there’s no resistance and you don’t feel it until the rollers start spinning. blah, blah blah…look up Faraday’s Law (Lenz’s Law describes the direction of the induced current.)…resistance. Works great and is super simple.


This is good info, I would use my rollers more if I could get more resistance out of them, it might be time to find a set of alloy rollers and give this a try.