Rim dynamo

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A rim dynamo is a bicycle dynamo that is similar to the side runner dynamo . In contrast to this, the friction roller is not on the tire flank, but on the rim flank. For example, it allows dynamos to be used on mountain bikes with heavily profiled off-road tires or on racing bikes with very small tire cross-sections. Their distribution is low, as the market is more and more dominated by hub dynamos .

A rim flank as a contact surface for a friction wheel offers the advantage of being largely flat. This allows a smooth, even run. With large tire cross-sections compared to the rim, the dynamo must be swiveled very far or dismantled for a tire change / breakdown. Compared to the hub dynamo, the higher speeds allow a very compact design of the electric generator.

If the bike is equipped with rim brakes, the abrasion collects on the rim and the grooves wear out the soft dynamo wheel as a contact partner to the hard rim, which means an additional wear part.

When mounting the rear wheel, the adjustment of the dynamo depending on the chain tensioning system (especially wheels without gearshifts and with hub gears) must be checked and corrected if necessary with each chain tensioning process / wheel removal. Misalignment leads to increased wear of the friction wheel.

When converting side-rotor dynamos, the uneven running of the dynamos, which are often inexpensive only with two poles, favors slipping when the contact pressure is too low. This problem also exists on the tire, but a more robust power transmission (“toothing” tire / dynamo wheel) can often be established there. Modern multi-pole dynamos alleviate this problem.

Historical designs:

  • With the touring bikes of French designers (e.g. René Herse, Alex Singer, Camille Daudon) experiments with the topic of rim dynamo were apparently already in the early 1950s, but with different friction wheel attachments for conventional side-rotor dynamos from the French company Soubitez in the classic bottle shape.

Individual evidence

  1. http://www.pianosromantiques.com/projetRH.html .
  2. http://www.pianosromantiques.com/images/DSCN00302.JPG .


  • Michael Gressmann, Franz Beck, Rüdiger Bellersheim: specialist knowledge of bicycle technology. 1st edition, Verlag Europa-Lehrmittel, Haan-Gruiten, 2006, ISBN 3-8085-2291-7