Ye Olde Dynamo Hubs (especially Sturmey Archer) and LED lights

[KneesUp]

I've got a new job that I can commute to - so that means I need a 'new' bike to get there, I thought. n+1 etc. I can't be commuting on my drop bar bikes - I want my head up in traffic. And I can't commute on my rigid MTB and slicks because I've not ridden it for ages and the brake cables have seized ... Irrecoverable.

Anyway, the outcome is that I've bought a 45 year-old (1980, folks. How is that 45 years ago?) gentleman's city bike because it has guards already fitted, it has a chain guard, it has an upright riding position, it even has it's original grips with little red reflectors on the end - and it has a Sturmey Archer 3 speed dyne-hub on the back, as well as a wired up and functioning 1980-style lighting system. Oh, and it was for sale quite near me for less than £65. Given that I was going to have to spend £30 or so on mudguards anyway, that has to be a bargain.

Obviously the lighting system is rubbish though - it's incandescent bulbs, naturally - so even at full chat it's not exactly bright, and the lights go off as soon as you stop.

I would like to upgrade the lights but keep the classic looks if I can - my thoughts are to buy a cheap modern dynamo light and try and wrestle it's innards into the ones I have, or to replace the bulbs with a LED ones.

My rudimentary research suggests the bulb replacement option might be hard to source, and may need extra gubbins to keep it from strobing / blowing. But equally I can't seem to find a definite answer to how powerful the hub is, but I think it might be 2w 6V. Is that enough to run modern lights, even?

Thanks for any advice!

 

[mjr]

But equally I can't seem to find a definite answer to how powerful the hub is, but I think it might be 2w 6V. Is that enough to run modern lights, even?

Yes. There are now modern 6V 1.5W hubs from SP and Shimano, so any lights designed for those should work. For example:
https://www.sjscycles.co.uk/lighting/0-busch-muller-lumotec-iq-onefive-headlight-for-hub-dynamos/

 

[si_c]

Yep as @mjr notes pretty much any dynamo lights should work with your new dynamo - the output standards haven't changed as power needs for lighting have always been generally pretty low.

I'd be looking for a replacement front and rear light which will mount on your new bike, you can probably use much of the existing wiring in place, just splice and reconnect. From an aesthetic perspective, you can probably find something which matches the looks of the current ones (photos might help ) but I wouldn't try to replace the innards you'll not find a direct replacement for an incandescent bulb.

 

[mjr]

Yep as @mjr notes pretty much any dynamo lights should work with your new dynamo - the output standards haven't changed as power needs for lighting have always been generally pretty low.

That wasn't my note. I'm not sure how much power lights sold for the typical 3W dynamos actually need to light up in practice. The ones sold for 1.5W systems should work on 2W though.

As for replacement bulbs and regulators, nicelite and reflectalite used to sell them but I didn't find much in stock any more and I think it wouldn't be cheaper or easier than new 1.5W lights, which IMO don't look bad.

 

[KneesUp]

Thanks both - I’m still not totally sure what the out put is, but replacement being easier is noted!

This is the bike as shown on eBay - I’ve not taken my own pictures yet.

An ideal middle-aged-commute kind of bike.

 

[Chris S]

Thanks both - I’m still not totally sure what the out put is,

The original Dynohub's power output was 1.8 watts at 6 volts, while that of most other bicycle generators is 2.4 or 3.0 watts.
https://www.sheldonbrown.com/dynohubs.html

 

[MichaelW2]

You can get retro chrome LED front lamps ftom B&M, but it will cost more than the bike.

 

[Chris S]

You can get retro chrome LED front lamps ftom B&M, but it will cost more than the bike.

But will they run on alternating current?

 

[Dogtrousers]

You can get retro chrome LED front lamps ftom B&M, but it will cost more than the bike.

I suppose there are two ways to look at it: "The lamp costs more than the bike! How ridiculous!" but there's also: "The bike was so cheap I've got some cash to blow on a lamp!"

Personally I'd just just buy some cheap basic modern LED lamps that are transferrable between bikes and ignore the dynamo, because I know the faff would infuriate and probably defeat me. But I can see the appeal of bringing the rather nice looking original back to life.

Anyway, keep us posted - it's always interesting to see other people faffing around with stuff

 

[KneesUp]

The idea for this bike is that I can just get on and ride it without much thought - and ideally without much maintenance. Hence the hub gears and dynamo lighting. Battery lights are easier to steal, plus I’d have to remember to charge them. I know I’d forget to bring them or charge them or both!

I‘m not convinced by the chromed rims in terms of braking but I may get my lbs to rebuild the front wheel around a spare SA 70mm drum hub I have lying around if they’re horrendous. As @Dogtrousers says, cheap bike = justification for spending some money on upgrades. And a brake that works in the rain would definitely be an upgrade.

The Busch and Muller 1.5w (onefive) range of lights looks ideal. thanks @mjr However all rear lights seem to be 0.6w giving a total of 2.1w. Do any of you knowledgeable people know what would happen with that connected to my 1.8w dynohub? Will it be not quite fully bright, or not quite functional?

Thanks again.

 

[Chris S]

Do you just want lights so other traffic can see you? If so you can just fit conventional LEDs to your existing lights. They will strobe at lower speeds with alternating current but most cyclists have flashing lights these days. At higher speeds they will flash so fast that they will appear to be on permanently.

 

[KneesUp]

Bit of an update on this - the tyres on it are crumbly, and the valve on the back wheel was at all kinds of a funky angle, so I had to get the back wheel off to sort the valve and weigh up how bad the tyres are (bad ...)

Annoyingly one of the bolts for the small brass connectors for the dynamo spins freely (ie the nut and bold both rotate and it doesn't undo) so although I managed to disconnect it my prising the spade terminal from underneath it, I can't now reconnect it.

So it's on hold pending further investigation for now.

Thanks for all the lighting advice so far.