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-   -   For the love of English 3 speeds... (https://www.bikeforums.net/showthread.php?t=623699)

sloar 01-21-15 08:36 AM

I have a bike I'm building now with much higher priority than this one. But, I did want to get it out on the road. So I just did a quick cleanup, plan on cleaning the wheels, new tires and new cables. Rides pretty decent how it sits now.

BEFORE:



http://i1134.photobucket.com/albums/...ps563ee962.jpg



AFTER:


http://i1134.photobucket.com/albums/...ps6eb98392.jpg

arex 01-21-15 09:46 AM

Wow...that cleaned up nice!

Salubrious 01-21-15 10:40 AM


Originally Posted by sloar (Post 17487409)
I have a bike I'm building now with much higher priority than this one. But, I did want to get it out on the road. So I just did a quick cleanup, plan on cleaning the wheels, new tires and new cables. Rides pretty decent how it sits now.

http://i1134.photobucket.com/albums/...ps6eb98392.jpg

A classic problem- change out the stem and then you can't set up the headlight correctly. Nitto makes a 'dirt drop' stem that solves this problem but its a bit pricy. Was the original stem not usable?

sloar 01-21-15 10:46 AM

I still have it, I wanted a little more reach. Think I'm going to work on the bracket, cut and extend it.

noglider 01-21-15 10:58 AM

Really nice, @sloar. How does it ride? And why are your handlebars tipped up? I see some bikes like that, and it looks uncomfortable. I guess it's not?

Salubrious 01-21-15 11:09 AM

^^ I tilt my bars back- way way more comfortable!

sloar 01-21-15 11:09 AM

Rides pretty nice, I haven't got seat height and bars adjusted yet. I still have to work in fit. Shifts nice, and feels pretty solid.

markk900 01-21-15 11:19 AM

She's a beauty! Similar to my 49 but I haven't got the full chaincase. Mine was painted Royal Blue but the paint has come off in huge quantities (it appears to be very fragile), exposing the smooth, glossy black primer used in the day. I am tempted to carefully strip off the colour coat and apply new decals!

BTW - I think your rims will come up amaingly with the application of vinegar, tin foil and elbow grease. Other than the braking surfaces on mine, the rust almost completely came away with that treatment. I'd be interested if your rims are marked Sturmey Archer or Raleigh, and if they have a satin chrome centre section by the spoke holes.

@noglider: Tom - I can only speak for mine, but it rides very nicely. Mostly due to mass I think. The duplex fork is cool but I do not sense it is anything more than a mareting ploy as the bike doesn't ride that differently than my wife's 56 Standard.

sloar 01-21-15 11:44 AM

I did a small section of rim, and it did shine up pretty nice. I really hate cleaning wheels!

Velocivixen 01-21-15 12:15 PM

@sloar - your bike is gorgeous! Wow. I didn't think about the light bracket situation with a longer stem. Also, did you try your lights again with just one bulb? What bulb did you use?


Im interested in doing an "upgrade" of my SA light. Have read some, but seems complicated. Current bulb is not smooth - has tiny triangles or texture on it, and I was afraid to remove it because wasn't sure how, so left it.

nlerner 01-21-15 08:10 PM


Originally Posted by Velocivixen (Post 17488074)
Im interested in doing an "upgrade" of my SA light. Have read some, but seems complicated. Current bulb is not smooth - has tiny triangles or texture on it, and I was afraid to remove it because wasn't sure how, so left it.

Easiest upgrade is to install a new LED bulb for the current one:

(about a third of the page down) Gentleman Cyclist Merchandise

It'll still flash at low speeds, so just ride faster!

arex 01-21-15 08:14 PM


Originally Posted by nlerner (Post 17489382)
Easiest upgrade is to install a new LED bulb for the current one:

(about a third of the page down) Gentleman Cyclist Merchandise

It'll still flash at low speeds, so just ride faster!

Would wiring in a bridge rectifier help mitigate the flashing?

noglider 01-21-15 08:18 PM


Originally Posted by arex (Post 17489394)
Would wiring in a bridge rectifier help mitigate the flashing?

No, I suspect it would make it worse. It would remove the negative voltage from the left side and the positive voltage from the right side (using the terms left and right arbitrarily) so flashing would be half as frequent. And you'd be pumping half the power through your bulb.

You're thinking of a capacitor, perhaps.

arex 01-21-15 08:33 PM


Originally Posted by noglider (Post 17489405)
No, I suspect it would make it worse. It would remove the negative voltage from the left side and the positive voltage from the right side (using the terms left and right arbitrarily) so flashing would be half as frequent. And you'd be pumping half the power through your bulb.

You're thinking of a capacitor, perhaps.

I thought a bridge rectifier was made for converting AC to DC (albeit not quite perfectly)...basically converting the sine wave to, gah, what's it called...the voltage would be converted to all-positive, but with dropping-to-zero pulsing, rather than dropping way down into the negative for half the cycle. It would dim, but it wouldn't be shut off entirely for half the cycle...this is assuming the use of an LED rather than a bulb.

I know what I'm trying to say, but I'm having trouble describing it. You'd probably use a capacitor to smooth it out, but a bridge could be used as-is. It'd be a huge improvement (but imperfect) over the existing situation.

arex 01-21-15 08:38 PM

http://www.electronics-tutorials.ws/diode/diode23.gif

noglider 01-21-15 08:39 PM

Yeah I just read the Wikipedia page on bridge diodes (Diode bridge - Wikipedia, the free encyclopedia) and I see I'm in over my head. Ask the electronics expert in the electronics sub forum.

nlerner 01-21-15 08:40 PM

A capacitor would give you a stand light. A bridge rectifier will minimize flash. From Sheldon Brown:


A "rectifier" is a device for converting AC (Alternating Current) into DC (Direct Current). The simplest kind of rectifier is a "diode", sort of a one-way valve for electricity. If you hook up a diode in series (as part of the circuit wire) with an AC source, it will only pass current half the time, when the AC is in its compatible direction. What comes through is pulsating DC. The problem with using a simple diode is that you are throwing away half of the electricity.

There is a simple circuit using four diodes, called a "bridge rectifier" that gets around this. It effectively flips the polarity around every half-cycle (an oversimplification, I know) and turns the AC into DC with negligible loss. You could solder four diodes together in the proper configuration, as I did, but these days you can just buy a ready-made "full-wave bridge rectifier". [Considering that the Dynohub operates at low voltages, the loss is significant when using silicon diodes -- 1.4 volts. If you use germanium diodes, it is only 0.4 volts. Fancier circuitry can get the loss much lower yet, but this is only a do-it-yourself project for a serious electronics hacker. -- John Allen.]
But all of that is far more work than simply plugging in a new LED bulb!

arex 01-21-15 08:55 PM

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Got my frame back from the powdercoater tonight. He did a wonderful job, masking off the fork dimples and steering tube perfectly.

The color was the closest to the original Raleigh green as we could find. It looks like a muddy grey in normal room light, but shows a brilliant metallic green under bright light (an LED flashlight in this case) or out in the sun. Beautiful work for $110.

arex 01-21-15 08:57 PM


Originally Posted by nlerner (Post 17489452)
A capacitor would give you a stand light. A bridge rectifier will minimize flash. From Sheldon Brown:

But all of that is far more work than simply plugging in a new LED bulb!

Not really, half-hour of soldering, tops. What's a stand light?

JohnDThompson 01-21-15 08:59 PM


Originally Posted by arex (Post 17489497)
What's a stand light?

It allows the light to continue even when stopped, when the generator is no longer supplying power.

Salubrious 01-21-15 09:47 PM


Originally Posted by arex (Post 17489394)
Would wiring in a bridge rectifier help mitigate the flashing?

Yes, by itself would double the frequency.



Originally Posted by arex (Post 17489450)

The above circuit will cause the LED to light up with a more constant light. It does not make a lot of light at any rate, but its better than nothing! Since the pulsing in the LED off state is normally not used, the result of using this circuit will be that the load will be a bit higher, so it will be harder to pedal. But not by much, I suspect.

Velocivixen 01-21-15 10:25 PM

I have no idea what you are all talking about, therefore I am impressed. So would my dynohub power new, modern lights? Like if I removed the current ones & put some Busch & Muller Dynamo lights on? Could I just hook them up and off I go?
@arex - I like your bike! Was it a two phase paint job? Like with one color underneath and a sparkle/shimmer over the top?

desconhecido 01-21-15 10:25 PM


Originally Posted by noglider (Post 17489451)
Yeah I just read the Wikipedia page on bridge diodes (Diode bridge - Wikipedia, the free encyclopedia) and I see I'm in over my head. Ask the electronics expert in the electronics sub forum.

This is really pretty easy stuff and you can figure it out if you want to. There's nothing wrong with not wanting to, though. We all have the ability to do a whole lot of things that we don't have the time, motivation, or inclination to do. Life's too short, other interests occupy our time.

Anyway, the D part of LED is "diode" and diodes only work with electricity in one direction. Sort of like a switch in that a diode will pass current in one direction and block it in the other. AC, alternating current, is what the dyno hubs produce -- it goes in both directions. For normal light bulbs, that's fine. For a diode light bulb, however, you lose light half the time because the diode function of the LED blocks the current flow. That's the flicker.

So, a full wave bridge rectifier with smoothing capacitor, as described in Arex's diagram, will double the total light output by making the current appear to the LED in one direction. The smoothing capacitor will make the current flow almost constant, though the most noticeable feature will be the "rectification," that is, the conversion of AC to pulsating DC.

Almost five years ago in these forums this question came up and somebody made a reference to this site:Bicycle Electronics, Power LEDs, Dynamos and Batteries, Driver Circuits

I don't know whether the site owner is a participant here or not, but there's lots of good stuff there including: this background stuff
and this:
Dynamo LED Light Systems for Bicycles (electronic circuits) which shows a basic bridge circuit with proper part numbers and everything.

desconhecido 01-21-15 10:50 PM


Originally Posted by Velocivixen (Post 17489690)
I have no idea what you are all talking about, therefore I am impressed. So would my dynohub power new, modern lights? Like if I removed the current ones & put some Busch & Muller Dynamo lights on? Could I just hook them up and off I go?


Probably. The SA dynohubs only produced about half the power of other generator light systems and, therefore, required special bulbs, so I understand. LEDs produce more light with less power than regular old incandescent light bulbs and should give better results than you get with the original. So, if your hub is working properly and has a good output, I would expect that it would power an LED system just fine. But, that depends on at least one assumption and I don't know if it is justified. I don't know the electrical characteristics of the B&M light system -- what other electronics, if any, they have inside hidden from view to accommodate different generators, guard against over voltage, etc.

In the garage we have a wheel from a Raleigh Sprite which has a dynohub. Tomorrow, I'll get it down from the rafters and see if I can get it to produce light with the B&M headlight that we recently got for the 79 Sports. When we got the Sprite a bunch of years ago I checked that the dynohub was producing voltage, but didn't test to see what sort of power output it produced. I didn't want to spend a lot of time or money messing with it because there is not a real great need around here for a steel-rimmed and heavy 27" wheel with a dynohub -- nobody around here rides a bike with 27" wheels after dark. Also, didn't want to build the hub into a new wheel without verifying it's serviceability. In the end, buying a Shimano hub seemed the way to go as far as getting dyno-lighting on the Sports, which does get ridden after dark.

But, I've always been curious about the dynohub, so we shall see what we shall see.

desconhecido 01-21-15 11:01 PM


Originally Posted by Salubrious (Post 17489613)
The above circuit will cause the LED to light up with a more constant light. It does not make a lot of light at any rate, but its better than nothing! Since the pulsing in the LED off state is normally not used, the result of using this circuit will be that the load will be a bit higher, so it will be harder to pedal. But not by much, I suspect.

With a rectifier, the total light energy output will double, but it is true that that light energy has to come from somewhere and there's only one place for it to come. The first rule of everything: there is no such thing as a free lunch. If you were using a 3 watt dyno at full power, you would go from 1.5 watts to 3. I don't know how easy that would be to notice. Maybe I'll find out tomorrow.


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