This thread has made me start looking for a bottle dynamo but as far as I can tell there is only one choice in the USA which is B&M dymotec which is imported by Peter White. Are there any other options in the US?

Exactly. The dynamo puts out enough power. It's the light that doesn't use the power to provide adequate light. As I said above, I have a modern headlight running on a 35-year-old sidewall dynamo.

Yes, AXA Quattro dynos are available at velofred and AXA HR Traction dynos are available at Cantitoeroad. I just picked up the Quattro and cantilever boss mounting bracket. Makes for a clean look, but adjusting the gap without bending the mount seems impossible.

You can order that from Harris Cyclery, I believe. But just about any older unit will work too. My experience has been that the Union ones have more drag but light up more quickly. They pretty much all work (unless they are broken).

Has anyone added padding to the knob? This would result in spinning the dynamo more slowly but also reduce drag. Given what Jim says about the Union unit, this could be a plus. What materials would you use?

"Back when" rubber dynamo wheel caps were common, they were supposed to reduce tire sidewall wear but I ran one to reduce noise as well.
A teammate took to using Clement red gutta to secure his gen-cap in place for the high speed midnight runs he was infamous for on the night shift commute.
Guy went thru lots of bulbs but was hella-strong.

-Bandera

OK, but how do I find or make one?

Might be a few hiding out in the the old bike shops. Dutch Bike Bits has them in stock... I wonder if a rubber foot for a chair leg might work.

The ones I used to buy in the States were the Velox brand. Maybe wrap the drive wheel in rubber tape?

Aaron

Search?

https://www.ebay.com/itm/Cover-for-Ge...item35cd32dca6

Old Schwinn shops should have them in a bin.

-Bandera

Thanks. I bought it.

These rubber grommets work well as dynamo wheel covers. They reduce the noise, tire wear and drag. Not sure how long a life they have in service. Measure the dia. of the drive wheel and use the one that fits yours.

https://www.homedepot.com/s/rubber%2520gromet?NCNI-5

Ooh, how clever!

I also considered a rubber roller and took wahoonc's of a rubber foot. I picked up a pack of 4, 5/8" rubber tips for $2.79. The drive roller on my dynamo is 19.7mm diameter, so the 7/8" rubber feet would have been too large. Anyway, the rubber tips were too long, so I cut it short with a razor knife. I intended to use the closed end but it was really difficult to install, so I used the other piece, it is basically a rubber ring. With a little spit as a lubricant, it slid on without too much trouble. In a test run around the neighborhood, it worked flawlessly. I'm not sure how it'll work during a longer ride, but I can keep you posted.

Are those furniture feet?

Your dynamo looks to be lopsided. Make sure that a line through its rotational axis goes through the bike wheel's axle!

I'm not sure exactly what the feet are made for, table legs? Good eye, must've pushed the dyno down when installing the ring. Thanks.

The LightSpin was said to have been the cream of the crop for electrical efficiency, although perhaps somewhat delicate mechanically.

It's far from sunset for bottles&beams. Here's an interesting modern system with LED headlamp from GoldenCat in China:

Hard to go wrong with the Dymotec. Depending on what you want out of life, ebay and Amazon have brand new Asian bottle dynamos by the bucket.

Can you connect them to any of the old generators, either bottle generators or dynohubs?

A few years ago a bike shop tried to tell me that the old dynohubs didn't put out enough power (I questione d this, but had plenty of other lights including 10-15w halogen lights, so I didn't spend more time or money on this.)

I think the old dynohubs have more magnetic poles than the bottle generators - does this make a difference?

I have bottle generators (original lights, I think both original) on a 1960 Gazelle and 1964 Rudge, it would be nice to make them more useful at night.

Thanks for your experience, or any other help.

When I called Peter White, I asked if the overvoltage protection circuits on the B&M lights made them compatible with any dynamo and he said yes.


EDIT: Should be compatible with any 6V dynamo. Sorry if I caused any confusion.

Old bottles easily put out enough power. Remember, LEDs don't need much! And as for over-voltage protection, we've run our Cibie on the tandem and I've run the Union at speeds near 30mph. No problem with the lights.

For vintage, I have a Union dynamo/headlamp block unit on my '53 Rudge Sports. Still works good, though needs frequent adjusting. This was gifted to me by a friend in NY.



For modern, on my '84 Raleigh Crested Butte I have an AXA HR bottle unit gifted to me by a friend in the UK (a pattern?), coupled with B+M LED headlamp and taillamp. This set-up works really well.

Basic output of dynos in general: MOST bottle dynos are 6 volt 3 watt, there are some 12 volt out there but they are the exception. The old Sturmey-Archer GH-6 dyno puts out 6 volts 1.8 watts (give or take) the ones incorporated into the gear hubs ie; FG or AG put out a bit less. Modern dyno hubs put our either 6 volt 3 watt or 6 volt 2.4 watt. The 2.4 watt is for the EU market to meet some specific requirement. I have at least one of each of these models. Modern LED lights will work well with ALL of the dynos I have. I have not tried them with the 12 volt one, on that one I expect you would need to be careful that you did not over drive the LED and burn something up.

My most successful LED system is the one on my 1971 Raleigh Twenty. I used a 1970's AG hub, it would barely drive a 2.5 watt halogen head light. I converted to the B&M LED (Lumotec Cyo) it would drive that and a 4 LED tail light at a brisk walking pace. I have since swapped the head light out for the newer B&M Classic

Aaron

Sounds like your teammate needed a voltage limiter.

He was definitely a Live Wire.

-Bandera

Peter White explains that modern lights have voltage limiters in them. Still, I wouldn't use a generator that is rated to put out 12V.

So I gather (and dimly remember) that the bottle dynamos always put out 3W and the dynohubs had lower output and lower drag. Now they have higher output, so the big disadvantage with bottle dynamos is that they present more drag than hubs. Still, the higher drag is sometimes justified by the greater convenience.

I now have three bottle dynamos to play with: a Union, made in Germany, marked Schwinn-approved; a Miller, made in Great Britain (and gorgeous), and one marked "Bike Parts." Here are the last two which I got cheap on ebay. I got the Schwinn one off an old bike. The Miller and the Bike Parts generators appear to be intended to mount on the drive-side chainstay, since they're supposed to be forward of the mounting point. Not sure why the tail light is mounted as it is. It is also branded Miller, but it's made in Germany.