Bottle dynamo, worth persevering?

[bikeworkshop]

As @Woz points out, you're lacking adequate grip between the tyre and roller to overcome the friction in the dynamo.
Little rubber caps, special grippy tyre sidewalls make a huge difference, as does the dynamo angle, height, bearing quality and condition, and spring tension.

But when it rains... your Friction is reduced... andin your case, the lights go out

Basically nobody makes bottle dynamos anymore, for many reasons.
The lower power requirement of led makes low speed lighting from a hub unit quite acceptable.

The Sanyo bb dynamo gets much better grip, but forms a shelf that collects all the cr4p off the road into a charming grey blob, than can even get transferred into your chain.

An old pre- index chain is a tough old beast, but modern chains don't like it much.

I've ridden around using acetylene lights, and I must say I much preferred it to using the bottle:

Lights up with a "pop"
(Preferably with a Swan Vestas match)
A soothing hiss, as opposed to the sound of your tyre sidewall being worn away.
A lovely smell of the days before traffic.
Curious interaction with caving equipment suppliers, and ownership of an extraordinary looking piece of victoriana.
A warm yellowy light...

Aaah bliss.

 

[jim haseltine]

Another thing about the Sanyo is that fitting is highly dependant on things such as the width between chain stays and the position of any stay bridge. I very much doubt that I'd be able to fit one on any of the bikes I currently own.

 

[mdvineng]

Some more photos of its positioning.

The Knurl on this has seen many better and brighter days!

 

[MatBH5]

I’ve had bottle dynamos come on bikes which had a plate designed to fit to a fixed bolt hole which then had a slot for adjustability. I’m sure you could make something up to offer that.

 

[Bats]

Basically nobody makes bottle dynamos anymore, for many reasons.

Not quite. AXA has a few different models between 13 and 40 euros, they're all over the Netherlands still in bike shops as well as B&Q equivalents like Gamma. The more expensive one like HR Traction is a world apart from the rubbish ones.

They don't show up on new bikes anymore, so the new bottle dynamos are mainly spares for the absolutely *massive* fleet of 80s, 90s, early 2000s Opas and Omas rolling around, but that's still a huge market. There just ridiculous amounts of such bikes still riding around and kept in presentable condition in the more well off areas, where people have a garage to keep them in.

(It's kind of interesting, actually, this huge pool of almost-new looking 40 year old bikes. They seem to (unsurprisingly) be owned by older people, and have a financial value barely more than the replacement dynamo. Whenever granddad dies or gets too old they're inevitably sold to a student for 50 euros or less and then rapidly ruined, but for now the supply still seems basically infinite)

 

[klunkrider]

Did a bit of playing about with the dynamo I have.

The locknut and wheel were turning as one on the threaded portion of the magnetic bit that protrudes through the brass bushings in the upper part of the body. I wonder if they tightened down a bit during the ride yesterday causing excess friction. I’ve freed them up and adjusted them better so it was spinning much more nicely in the hand.

Also, the wheel is quite worn down, I could file the teeth back into it a bit but I’ve fitted a bit of inner tube over it instead.

It still slips if I spin the wheel and then click the lever to ping it over onto the tyre but if I start off with it in against the tire it seems to grip a bit better.

Might get out on it tomorrow to give it a try.

 

[Canuk]

Did a bit of playing about with the dynamo I have.

The locknut and wheel were turning as one on the threaded portion of the magnetic bit that protrudes through the brass bushings in the upper part of the body. I wonder if they tightened down a bit during the ride yesterday causing excess friction. I’ve freed them up and adjusted them better so it was spinning much more nicely in the hand.

Also, the wheel is quite worn down, I could file the teeth back into it a bit but I’ve fitted a bit of inner tube over it instead.

It still slips if I spin the wheel and then click the lever to ping it over onto the tyre but if I start off with it in against the tire it seems to grip a bit better.

Might get out on it tomorrow to give it a try.

The Margil and Velox covers are made from quite a hard rubber and have a good strong contact on the tire. Ime they did not slip, even in very wet weather. Well worth the tenner of the purchase price.

 

[klunkrider]

Was watching a bettrr nick Lucy Baby 800 on ebay and got an offer for a few quid off it so have bought it.

I think it comes with it's own specific rubber cover.

 

[RobLoasby]

I seem to remember people using glued-on plastic bottle screw-tops or rubber bands wrapped around to try to improve contact back in the 60s/70s.