I saw that a while ago, and saw that it was lacking any means of aligning the drive wheel with the wheel rim, as is obvious from that photo. That will be why they recommend changing the o-ring (drive wheel "tyre") every 2000 miles. Having the drive wheel crabbing on the rim would also ruin the end to end efficiency (leg watts to USB watts ratio).
A degree of thread resurrection here for which I hope that I will be forgiven.
I recently discovered that front fork drop-out widths came in an old and a wider new standard size, my old bikes are to the old standard which IIRC is 90mm so the new wider hubs basically aren’t meant to fit them. So, I’m thinking new hub Dynamo’s don’t fit old style drop-outs. The next route then is re-use of a (front wheel) SA dynohub but, seems to me, they aren’t available second hand in 36 hole sizes and getting hold of 32 hole rims to (perfectly) match my existing 36 hole rims doesn’t seem possible. In short a front hub dynamo is too logistically hard for me to match to my bike.
Moving to the rear hub limits you a SA three speed but they are available second hand in 28, 36 and 40 hole shells so I could build a wheel using the 36 hole rims that I have. However the SA Dynohub comes in a narrow drop-out width so a new axle would be needed and (if available) you’re limited to three gears. I’m not sure whether the standard AW and Dynohub share the same axles because the innards of the shell geared sections must be different - so another potential logistics problem there.
TLDR: For some older bikes hub Dynamo options appear to be constrained.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
you don't say which OLN you would be shooting for with an AG hub. FWIW the only internal parts that are different in the AG gear are the planet cage and the LH cone, and these parts rarely fail, so AW axle swaps, gear repairs etc are easy.
SA front dynohubs were made in 36h so if you want one of those it is just a question of looking a bit harder. Rims that are an exact match for obsolete ones in any drilling are not that easy to find but there is a pretty good choice of 32h rims.
Regarding narrower modern hub dynamos; the HB-NX** series of hub dynamos have a spacer on the LHS which is about 5mm thickness. This is easily removed to take the OLN down to ~95mm which is 'close enough' in most cases. However because the locknuts and cones are on a fatter section of the axle in some cases you may need to file the axle down to make it fit the forks, thus making the conversion non-reversible.
Most hub dynamos which are meant to accept a roller brake can be reduced in OLN quite easily too. In nutted axle form, the shouldered locknut which normally sits inside the roller brake has the track nut thread on it. It is simply a case of replacing this locknut with a thinner, more conventional one and the hub goes to about 95mm OLN. You can fine tune the OLN with thinner locknuts both sides.
Panasonic do a hub which is meant to accept a drum brake; again it can be built to a narrower oln quite easily, for similar reasons
If you are willing to do a little machining a hub like an SP one can be modified by reducing the width of the hub (spacer and axle) on the LHS.
So there are more options than you might expect....?
Thank you Brucey, certainly some useful information for me there.
For my particular needs and logistics my inclination is towards a front rather than rear hub and towards the original SA product. I’m in no rush (its a case of some long term perfectionist desire rather than actual and current need) so I can wait to see what turns up, but having a variety of options is good. If a front hub doesn’t turn up before winter then I’ll likely fit a bottle (gets the lights in place, working and proven) and replace the bottle when a suitable hub - and time to build the replacement wheel - appears. It’s some long way in the future but I’m wondering about a switch now, something to go in line with any later hub Dynamo will save me from the potential trouble or restriction of needing a switch in the headlight.
Thanks again, all useful pointers.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
mercalia wrote:maybe it should have been attached some where on top?
As it says up there ^, the other standard-ish location was under the front of an above-the-wheel front rack, running on the top of the front tyre just in front of the mudguard. The disadvantage there is that it flicks water up off the tyre, to blow back into your face (and you need the rack).
Did anyone make a homemade? satisfactory mudguard for the maus-like front roller on rack?
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were not uncommon. It obviously helped, but I don't think it was a perfect solution.
IIRC bottle dynamos varied in the amount of noise they made depending on how they were mounted; the more solid the mounting the quieter they were. I remember seeing one mounted on a rack and it must have howled like a banshee when it was going.
Previously I had only ever fitted bottles on the back , and I don't remember them being so being anywhere near as bad as a front roller (maus style) sanyo dynopower for splattering road gunge even allowing for out of sight out of mind...
My brompton's front maus style sanyo roller is actually quite quiet compared to my other bikes retired nordlicht* bottle (replaced by a hub gen which my brompton wont take with out losing my nice front hub brake...)
*but dynamo whirr noise has never bothered me fortunately for me.
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Given that front bottle dyno mounting seems quite common on the continent, I presume front mounted standard bottle dynamos (eg axa 8201) are not prone to splattering unacceptable amounts of road crud everywhere and upwards unlike the front sanyo rollers?
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