Dear all, I have an old Schmidt dynohub designed for use in my 20" wheel touring bike. I'm using this bike less and less and I wanted to ask your advice about whether this hub would work in a larger wheel (700c). The power output will be less for a given speed I guess, but does this matter with modern LED lights now? I'm rubbish at building wheels so will have to take the hub to my local bike shop which will cost a few quid, any ideas if this will work?
Thanks for any advice!
dynohub designed for 20" wheels in a 28" wheel size?
- Mr. Viking
- Posts: 371
- Joined: 6 Jun 2012, 9:29pm
- Location: Liverpool
Re: dynohub designed for 20" wheels in a 28" wheel size?
The larger wheel will rotate at 70% the rate of the smaller wheel for any given speed. This means that the light will not reach full brightness until a slightly higher speed. In my experience with dynamos they reach full brightness slightly above walking pace so this shouldn't be an issue. I've only used bottle dynamos, but I can't see how a dynohub would be any different
Re: dynohub designed for 20" wheels in a 28" wheel size?
Schmidt 20R dynohub was originally specified for 20" wheels, but now is approved for 700c to the German industry standards .....they are more than good enough for LED lights.....http://www.spacycles.co.uk/products.php?plid=m2b0s133p1093
Bike fitting D.I.Y. .....http://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Tracks in the Dales etc...http://www.flickr.com/photos/52358536@N06/collections/
Re: dynohub designed for 20" wheels in a 28" wheel size?
It is a popular "trick" with faster riders. The dynamo is built to meet the German regulations that want adequate light output at just above walking pace. Fitting a 20" type hub will mean that you have a lower resistance at any given speed but if you are a faster cyclist you will easily be producing enough power for your lights.
Tourers on the other hand tend to be a bit slower and often want extra electricity production for charging their toys. So they wouldnt want to use the lower power hubs.
Tourers on the other hand tend to be a bit slower and often want extra electricity production for charging their toys. So they wouldnt want to use the lower power hubs.
Yma o Hyd
Re: dynohub designed for 20" wheels in a 28" wheel size?
That's great! Thank you for your replies. I'm going to use it just for a front LED light, with a back up flashing front light for visability.
Cheers
Cheers