SON S20R

[simon_brooke]

Has anyone yet tried a SON S20R in a 700c or 26" wheel?

The manufacturer's website is a bit contradictory - the PDF description says:

only approved for wheels up to 20",
but in these times of energy-saving LED lights it actually makes sense
to use it in 26" and 700C wheels, because it has particularly low losses

For a given speed a 700c wheel is going to rotate more slowly than a 20" wheel so presumably somewhat less power is generated, but are there any other potential problems?

 

[adrianlondon]

I have a SON20 fitted to a Mavic A719 rim (700c, 36 spoke) and it's fantastic. I got it as it's meant to have slightly less drag than the SON28 and the only reason they make two is that German regulations for dynamos mean that the lights must be full brightness by 7kmh or something (hence the "approved" text in the PDF).

I run a front LED light (and back LED wired into the front), but unless you're going to cycle quite slowly, it'll power the standard halogen bulb too.

 

[simon_brooke]

I have a SON20 fitted to a Mavic A719 rim (700c, 36 spoke) and it's fantastic. I got it as it's meant to have slightly less drag than the SON28 and the only reason they make two is that German regulations for dynamos mean that the lights must be full brightness by 7kmh or something (hence the "approved" text in the PDF).

I run a front LED light (and back LED wired into the front), but unless you're going to cycle quite slowly, it'll power the standard halogen bulb too.

Thanks, that's what I'd guessed.

I plan on using an LED for reliability reasons, anyway, so power output is not a big deal.

 

[andym]

It does look interesting. How much are they, roughly?

 

[willem]

I have a SON 28 and my wife an SON 20, both in 26 inch wheels and with a Schmidt Edelux headlight. In theory, the output of the SON 20 should be less, but in reality this is not visible with a led light (with halogens the difference was quite visible, however), since these have such a high output already at low speeds. There is one real difference, and I can feel it with the light on: less drag. I think the SON 28 only makes sense now if you ride really low speeds (perhaps), and if you want to comply with a now obsolete part of German legislation.
And yes, they are expensive, but you get value for money, given the superb quality. The SON 20R is quite a lot lighter than the SON 20, but the flanges are a bit closer, so it is not for ultra heavy use.
Willem

 

[simon_brooke]

It does look interesting. How much are they, roughly?

Frighteningly expensive. About £160 for the hub, about £130 for the matching LED headlight, plus the cost of lacing it into a wheel. Or, to put it differently, more than twice as much as the Shimano equivalent. I just have a weakness for really, really nice technology. You can get a B&M LED headlight to go with a SON hub for half the price of the genuine Schmidt part, but that's still frighteningly expensive.

I think I'm going to give myself one for my birthday

 

[andym]

Thanks. I was afraid it would be a question of 'if you have to ask you can't afford it'. I don't think I do enough night riding to justify it.

 

[adrianlondon]

I got my touring bike and the lights in Germany, although the strong Euro (or weak Pound depending on your point of view) has made this less of a bargain.

My LBS (Bikefix, Lambs Conduit St) did the wheel build and supplied the SON20.

 

[GrahamG]

I'd love the matching red son20 and edelux headlamp. I have zero justification for it but, oooh.....

 

[simon_brooke]

I'd love the matching red son20 and edelux headlamp. I have zero justification for it but, oooh.....

My thoughts exactly.

 

[arallsopp]

Another constraint is with disk brakes. I think, but may be mistaken, that the 20R does not allow lacing into a disk equipped wheel. I have SONs on both my bents, (one a 24" front, and one at 20") and both needed the "heavy" version.

"Heavy" is less than a set of batteries though.