Cycling UK Forum

mercalia wrote:

Brucey wrote:
I still wince when I see a quality frame with a standard 50p dynamo bracket nailed onto it. I know exactly what will be underneath; a ruined frame.

cheers

I agree with that. I wouldnt use one of those kid bolt on brackets any more. But then my kid bike was nothing special & once bolted on who cared if the paint was scratched under neath. what you dont see you dont worry about. I had lights!

Well a lot of cyclists do. Personally I'd never use a bolt on because in my experience sooner or later they always work loose.

This may seem a daft question, but if as I understand you can run a Nordlicht B/D on the rim as well as the tyre, is there any reason why you cant run any other B/D the same way,( on the rim) with a rubber roller of course. It would be a way of using tyres without a dynamo strip, and also saving the wear on the sidewalls. I expect there is a reason why not but I just wondered. Thanks.

There is at least one "rim dynamo" designed to be run on the rim.

In general though you get less grip between the rim and the dynamo wheel than the tyre.

some one posted here that he did. Cant see that it is a good idea. The rims get wet when it rains? You know how rim brakes squeal in the wet and dont work? Or if they do get a layer of slippery alloy deposit. So the dynamo would I suppose. I think the only reliable solution is to use the wire roller on the BM/B&M 6 bottle on the tyre. Now thats a bomb proof answer

ukdodger wrote:Well a lot of cyclists do. Personally I'd never use a bolt on because in my experience sooner or later they always work loose.

Not once they've rusted up good and solid. I had a fair job getting mine off to replace it with the much more solid alloy B&M one recommended by two contributors on page 1 (as well as by me).

On a winter hack bike, preserving the frame in pristine condition is not necessarily the aim.

(Edited to clarify what I was talking about after Vorpal merged the threads.)

Two similar topics merged. Sorry if it means that a couple of posts no longer follow logically fromt he previous one or two!

Brucey wrote:If you are going to mount a dynamo on the fork, I'd suggest to use a front mounted one on a secure bracket of some kind (braze-on or maybe one of those that mounts to a canti boss, if you have strong cantibosses). Mount it using nyloc nuts and washers that will make for a secure mounting.

I'd agree with that much. Mounting to a clamp wrapped around either front fork or rear stay does not sound secure. Use a braze-on or boss mount if you can (I've always used boss mounts). Even so, I feel there's much more chance of the wheel rotation kicking a loose dynamo out of the wheel than jamming on it - it seems improbable that a mount would be loose enough to slide around, yet strong enough for the dynamo spring to push against it hard enough to jam the wheel.

I'd also comment that I've run an Axa HR on Schwalbe dynamo-stripped tyres in rain without slipping, or much in the way of tyre or roller wear. The B+M Dymotec 6 did slip a bit in the rain when its roller got worn and I think roller wear was mainly due to it drifting slightly misaligned on the dynoshoe (which was fiddlier to set up than the Axa mount).

I think you would notice before you started out a ride that the bottle was loose. I cant see it loosening from tight just like that?

Ah I did google AXA dyno bracket and came across this --

http://www.reallyusefulbikes.co.uk/_shop/bicycle-brackets/

mjr wrote: .... Even so, I feel there's much more chance of the wheel rotation kicking a loose dynamo out of the wheel than jamming on it - it seems improbable that a mount would be loose enough to slide around, yet strong enough for the dynamo spring to push against it hard enough to jam the wheel....

dynamos have all kinds of sticky-out bits on them that will snag in the spokes quite happily; it isn't the spring force that causes the jam, it is just a lump of metal getting snarled in the spokes. A rear-mounted (i.e. to the rear of the stay ) dynamo will go into the spokes as quick as lightning and cause to a total jam. Dynamos with a horizontal pivot will often push away from the tyre, and then go in the spokes. Obviously if the thing works loose and slides down the stay it will cause a jam for sure, and this can happen at any time....

BTW if I had to have a BD the AXA HR would be my choice; the larger wheel makes all the difference. I have one fitted on a town bike at present. I still can't stick it for more than three miles at a stretch though.

cheers