« Here's how one person got improved bicycle parking | Main | Ex-cop who knocked over Critical Mass rider escapes jail »

July 14, 2010



Powering things by magnetic induction still induces drag on the wheel the magnets are attached to. On the plus side, there's no mechanical losses in the system, like on those old dynamos, so it's small enough that you don't notice it.

Basically, all of the power to run your lights gets sucked out of the wheel. Thus saith the Second Law of Thermodynamics. Luckily, modern LED lights don't require very much power to give decent illumination.


Hi David,
Of course you are correct: there is some drag effect, which is particularly noticeable if you mount the generator unit to close to the magnet (go slowly enough and have enough flex in your spokes and the magnet will actually stick to the generator). It is marginal compared to the dynamos of yore: engaging them was like pedalling uphill. And of course, since Reelights are always "on," you can't compare engaged and disengaged when you're on the road.

Jason Light

Why is it that I haven't found one up to this day. The concept is great. I'm tired with the battery operated bicycle lights. I want something like this. Hoping to find one.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Your comment could not be posted. Error type:
Your comment has been saved. Comments are moderated and will not appear until approved by the author. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.


Post a comment

Comments are moderated, and will not appear until the author has approved them.

Your Information

(Name and email address are required. Email address will not be displayed with the comment.)

Bill Bean

  • North America is eventually going to figure out that, for all the right reasons, we need more bicycles on our roads. Dust off your bicycle and go cycling. And if the gas-burning dinosaurs start to crowd you, it's your road and you paid for it. Take the lane for yourself.

September 2013

Sun Mon Tue Wed Thu Fri Sat
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30