Dynamo hubs for rim brakes

[alexb]

Hi all,

I'm considering building a new wheel for the posh bike. I have an old, but good Shimano hub dynamo and was considering just buying another shimano dynamo, but it looks as though their range has been greatly reduced and if I'm not mistaken, the current top of the line model is the SHIMANO-DH-UR700-3D (https://bike.shimano.com/en-EU/product/component/deorext-t8000/DH-UR700-3D.html) which is for disc brakes, but will obviously be fine for rim brakes as well.

What are the equivalnets models from SP and SON?
SON seem to have a bewildering range of models now, but I'm guessing the SON 28 is their top-end model for rim brakes.
Similarly the SP SV-9 looks to be the equivalent model.

Has anyone got experience with using SP hubs and venture to compare SP with SON and Shimano?

Thanks.

[Brucey]

arguably the best generator  hub for rim brakes is the SON widebody (or the current 28 model, although this is slightly heavier).  Most other SON and all SP hubs have narrow spaced flanges and they build into significantly weaker wheels. The shimano hubs also have fairly narrow-spaced flanges but IIRC they are somewhere inbetween the SP and SON widebody spacing.

There is a bewildering selection of shimano hub generators but somewhat fewer actual differences in the electrical guts inside them.  The result is that there is very little difference between the performance of many shimano hub generators.

Depending on inclination/budget/ how much you use the dynamo you might like to consider using one of those tiny (velogical) 3W rim-driven generators.  A much stronger wheel is possible, there is no drag at all when the dynamo is not in use, and no problems with hub bearings etc either.

cheers

[Hot Flatus]

I have SON, Shimano and SP dynohubs. 

The worst?  SON. 

I had to send it back after it stopped working, and the connectors are like something from the 19th century.  The Shimano and the SP have been faultless.

[sg37409]

I've used Shimano and SON. I'd choose shimano over SON because of price  and the connectors. I've never noticed any performance difference.  Flange spacing might be of interest to me on the tandem but not a solo.
I have read elsewhere about quality concerns regarding SONs, but equally they seem to have many devotees.

[sojournermike]

I’ve used SP and also a couple of very very cheap Shimano in the trailer wheels.

The SP SV-9 is a tiny little jewel of a thing - notionally for 20 inch wheels, but was fine on 700c for me. The SV-8 is a bit bigger and rated for the bigger wheel. Both have, as Brucey pointed out, narrow flange spacing - c.50mm I think. I built the SV-9 up as a 24 spoke radially laced wheel and it was actually fine, against my expectations really - it is a front of course. I can’t remember what spokes I used, but do recall thinking about it beforehand. Certainly not Lasers/cx-ray possibly d-light (1.65mm).

Count me as 80kgs for this purpose:(

[Kim]

Personally, I'd buy a disc-compatible hub as future-proofing.  A Centerlock mount with a dust cover over it is almost indistinguishable^[1] from a non-disc hub.

While a 3W dynamo is a 3W dynamo electrically (there are some 1.5W models out there), the hubs designed for the faster rotation of smaller wheels will produce less power at low speed in a full-sized wheel.  Not a problem in practice with LED lighting, but I'd avoid them if you want to charge batteries, or anticipate a lot of walking-speed riding.

I have two SONs, two Shimano hubs and a SP.  The only one I'm not happy with is the Shimano Capreo (narrow fork spacing) hub on the Brompton, which seems a bit draggy.  It's a fairly low-end hub; the SP equivalent wasn't available at the time, and I couldn't justify the cost of a SON.

While initially sceptical, I prefer the Shimano/SP connectors, as they're more tolerant of accidental non-disconnection, and can be re-terminated at the roadside with minimal tools.


_{[1] I have a rear wheel with a hub that I only realised had a Centerlock mount when I came to service the bearings.}

[Brucey]

FWIW when I say 'stronger wheel' using a hub with wide-spaced flanges, this means 'stronger at any given weight, or with any given rim design'.   The lateral loadings on front wheels (in some folks use eg when sprinting out of the saddle ) are not inconsiderable, and collapse of front wheels when they are built poorly on narrow spaced generator hubs is not unknown.

[aside;  Recently  I saw a set of vintage tandem hubs meant for track use and they were specced 36h rear and 40h front, presumably because the lateral loading on the front wheel was expected to be worse than that on the rear.]

Anyway if you use a rim that is stiff enough then the wheel will be less likely to collapse (or suffer Euler type buckling, which is closely related to laterally induced wheel collapse) even when using a hub with narrow spaced flanges.  However in the risk/consequence game the consequences of a rear wheel collapse are slight, but a front wheel collapse by contrast is likely to be life-threatening.  Any disc brake wheel with a 100mm OLN hub likewise builds into a significantly weaker wheel than 'normal'.

I might well vary my choice of hub generator on a 'nice bike' depending on what rim will match the rear wheel.

FWIW if you have any electrical background whatsoever the spade terminals on a SON need hold no fear. Provided you have not made the wires so short that there isn't any spare length in them (a common rookie mistake) then in the event of problems a freshly bared wire can be trapped beneath the connector even when the connector has come off the end of the wire, so roadside repairs are usually no worse than with any other generator. SON also allows connector-free installation of the hub (with some models) if the fork ends are modified.

A final comment relates to warranty and repair issues.  SON comes with a super warranty (five years?) but outside of warranty the overhaul cost is about the same as the purchase price of a shimano or SP generator (which come with shorter warranties).   You can rebuild the bearings in a shimano generator (both sides, but the RHS is less easy) and/or buy another hub and rob the centre out of it as necessary. With SP hubs the UK distributors offer a ~£25 (plus P&P) exchange/refurb but you will need to cover the cost of the wheel rebuild. 

If you use/store any hub generator in the weather then the bearings can fail. SON has a clever breather system in it, which is intended to prevent the airspace inside the hub from contracting in the cold and sucking water into the hub wholesale, through the bearings.  The latter thing can and does afflict most other hub generators. However the SON system ain't perfect; too much grease on the skewer will block the breather and there is always moisture in the trapped air inside the hub which means that you can get condensation inside the hub; taking a warm bike out into the cold will cause condensation inside the hub and the contraction of the air when it cools is what causes water to be sucked in via the bearings too.

FWIW I have used shimano SON, SA and SP hubs and IMHO they each have their place;  I'm sure that their various qualities will appeal to different people.

cheers

[Hot Flatus]

The male connectors on the SON hub are vulnerable to damage, hence my comment.  I have a useless one in my shed which will attest to this.  I think we can all probably manage to wire up a spade connector, Brucey. 

But in the third decade of the 21st century, there are better solutions.

[sojournermike]

Brucey’s point about Tim stiffness is well made. I bu I’lllt my SV9 with Kinlin 31t rim, which is one of the stiffer alloy rims out there.

[Polar Bear]

When I ventured into dynamo hubs the clear and unchallenged leader of the pack was the Son.  As a result we have seen a significant number serve duty on the fleet.  I have bought new ones and used ones and each has continued to serve us well without fault.  I have never needed to get one serviced and have sold on a few of the used ones that I have acquired and not received any complaints.

HF makes a good point about the spade terminals which are both fiddly and vulnerable imo.  I have always fitted the wheel with the spades pointing up the inside of the fork leg and with a loop of excess cable as per a diagram I remember seeing in the early days of Son ownership.  I have removed the front wheel half adozen times in nearly two decades without removing the connectors first and have been fortunate in that the result has either been a wheel dangling in the forks below the dropouts suspended by the cable or indeed for the connectors to rip off the terminals but no damage done.  I see that you can but a better system now for connecting and disconnecting to add to your Son but it also adds quite an extra premium.

I have cycling friends with SP and Shimano variants who seem to be very happy with their choices though I would always opt for a Son.

[Paul H]

But in the third decade of the 21st century, there are better solutions.

There are, like this SON one, which I find easier to disconnect and reconnect than the plastic blocks on the SP and Shimano.


https://www.peterwhitecycles.com/sch-wiring.php

I have SON (Older model) a SP- PD8 and Shimano LX.  They all work well enough that I can't tell any difference in performance, though they're different wheel sizes so not a direct comparison.
The SON is over twenty years old, it went back to Germany via SJS for a service after sixteen (Which may have just become more complicated) though the cost of that was more than a new Shimano and not far off the SP. If you like shiny, some SON models are polished rather than anodised,  half an hour with the silvo and mine looks new, they're also available in a range of colours if you want something different and do lights to match.  Yes I am that shallow,  I'd buy the one I liked the look of.

[Brucey]

  I think we can all probably manage to wire up a spade connector, Brucey. 

yeah, badly...?    In case you missed it, my point was that you can usually make running repairs (e.g. in the event of wire breakage) to SON wiring with comparable ease to rewiring a shimano/SP style plug. One of the common mistakes folk make with spade connectors is that they don't ease the fit of the connector (where necessary) which means that instead of the spade connector pulling off the hub, it damages the hub instead. Other common problems are lack of strain relief, lack of weatherproofing, not allowing slack in the cable length, allowing solder to run up the wire so as to embrittle the connection, etc etc etc. Wiring up spade connectors is one of those jobs which looks easy but the only thing truly easy about it is making the connection unreliable and risking damage to the hub itself.

FWIW I have seen a SON hub  (not mine) go open circuit after the connectors took a knock. I have also seen an (almost new) SP hub have its connectors torn to bits (which scrapped the hub) after a similar incident. I've also seen shimano ones work loose somehow (I suspect inept attempts at hub maintenance) and a sanyo one go open circuit because the hub parts corroded in the earth return part of the circuit.   So I don't think there is a hub generator with a perfect and robust connecter arrangement, not if you are determined to wreck it.

  AFAICT the only hub generator where you can buy parts to repair the connector on the hub itself is the SA one, but that probably isn't in the running, not for a posh bike.


Sturmey Archer HSE001

I note also that the SA plug is a simplified design which uses a one-piece moulding, where the Shimano plug is a two-piece assembly. So if 'simple is good', the SA one is arguably better.

cheers

[Cudzoziemiec]

I agree with Flatus on the SON plugs. They are rather crude and vulnerable to damage. Brucey says people wire them badly; I'm sure this is true, because people. The SP connector is much easier to wire without experience or skills. Also, once you've broken or lost the SON spade connector, they turn out to be a size not easily available at eg Maplins (back when Maplins was a thing).

The SON co-ax adaptor shown by Paul H looks much neater and stronger, but requires use of Edelux-style co-ax, which again is more fiddly than B&M-style wire.

However, the hub itself works perfectly. The SP I have failed as a hub when it rusted up internally after a series of very wet winter rides. Its replacement under warranty – SP have excellent warranty service – has so far been faultless. The newer shells are a slightly different shape, I don't know if they've also upgraded the seals.

[Hot Flatus]

  I think we can all probably manage to wire up a spade connector, Brucey. 

yeah, badly...?    In case you missed it, my point was that you can usually make running repairs (e.g. in the event of wire breakage) to SON wiring with comparable ease to rewiring a shimano/SP style plug. One of the common mistakes folk make with spade connectors is that they don't ease the fit of the connector (where necessary) which means that instead of the spade connector pulling off the hub, it damages the hub instead. Other common problems are lack of strain relief, lack of weatherproofing, not allowing slack in the cable length, allowing solder to run up the wire so as to embrittle the connection, etc etc etc. Wiring up spade connectors is one of those jobs which looks easy but the only thing truly easy about it is making the connection unreliable and risking damage to the hub itself.
cheers

You are kind of arguing against yourself here, Brucey, and you don't seem to realise it.

You don't need to do any of those things with the Shimano plug. other than allowing a bit of slack.

[Brucey]

FWIW I have seen more than one shimano hub that was declared 'broken' but in fact the connection to the hub was bad at the plug.  So that connection design also (like many things elec-trick-eral, including spade connectors) looks simpler than it really is, which I guess is what I was angling at in relation to other connectors too.   

In the case of the shimano connectors a combination of

a) the wires in the plug being a bit thin or slightly misplaced
b) even slight corrosion on the wires or the hub contacts and
c) slight deformation of the hub contacts

can result in an arrangement that looks perfectly normal but actually gives no contact at all, or an intermittent one.

On one bike I have, the headlamp wire came to me a bit short and a bit skinny for my liking. I spliced in an extra length of wire near the hub, and I used wire with about x3 cross sectional area in the copper, mainly because this gives a more consistent contact with the shimano plug design.

I've also run shimano plugs using just the inner part before now, because the outer part doesn't always want to come off when you need it to, harbours water, and hinders you from seeing if the wires are really in the  right place or not.

There is a common problem with folk's experience of bike parts which is 'the fallacy of perfection'. To the casual observer everything is 'perfect' until they see it go wrong for themselves:  Something can be a pretty hopeless design such that it only works 90% of the time (no matter what you do with it), yet this will still lead to nine out of ten people reporting a positive experience with it. Equally the design can be OK if installed and used in the way intended, yet a negative experience which is due to a true design failure is not easy to discriminate from one that is otherwise attributable, eg not reading the instructions or just assuming that something is 'very simple' (it rarely is, IME).

cheers

[alexb]

Thanks for all the comments and discussion. The fact that I can buy the current to of the line Shimano hub for less than £100 from Spa cycles seals the deal for me.

I've had no problems at all with my 14 year old Shimano hub and if it wasn't for the fact that the front wheel for totaled in a road accident is just build it into another rim, but sadly I'm not convinced that the hub hasn't taken too much of a hit.

I have an Alfine dynamo hub that's done 8 years of daily commuting in all weathers with not a hiccup ever, so I guess I'll stick with what I know.

[Brucey]

I've not used DH-UR700-3D but if shimano's reports are accurate, it might be the most efficient hub dynamo currently available.

[edit: it isn't.  Some clever chaps have done some relevant tests on this and other hub generators in which the generators are tested with real-world (i.e. reactive rather than purely resistive) loading in the form of real lights etc and they have found some major differences in drag vs power output. 

https://www.cyclingabout.com/dynamo-hub-power-drag-testing-schmidt-son-shutter-precision-shimano/

the results show that (of the hubs tested) the SON28 was the most efficient when connected to a typical load, (and in most cases  not just by a little bit either).

However if you are running a simpler, low power light (they used a 40lux Spanninga model to represent this type )  then it is closer to a purely resistive load (as per Stvzo tests) and there is less difference in efficiency between hubs.

However the shimano DH-UR700-3D does seem to have the highest output at low speeds which may mean it is the best choice for some users.]

cheers

[Zed43]

The male connectors on the SON hub are vulnerable to damage, hence my comment.  I have a useless one in my shed which will attest to this.  I think we can all probably manage to wire up a spade connector, Brucey. 

But in the third decade of the 21st century, there are better solutions.

If you ever go for a custom bike, have them make a fork for the SON SL, it is really neat.

[Cudzoziemiec]

That does look neat ^^ but it might be taken as a good example of making things overly complex and requiring special items. "This dynamo has 95% efficiency and connects via a neat 'lego block' which can be used on any bike. This other dynamo has 99.9% efficiency and connects via a wonderfully easy and totally invisible connector, which requires a custom made fork."

[Hot Flatus]

There is a lot of heavy lifting in this thread to justify SON's shit connectors.

 

[Brucey]

There is a lot of heavy lifting in this thread to justify SON's shit connectors.

 

if you have managed to break one then its only to be expected that you might condemn the SON connectors as 'shit' or somesuch, no matter how many others 'somehow manage' to avoid similar problems.  Its only human nature.  It isn't necessarily logical, but it is human nature.

My chum who broke his SP hub responded by buying a SON to replace it, even though it cost about x5 as much and would probably have broken too had the same thing happen to it. Not exactly logical either.

If you understand how you are meant to install any given component as well as how and why things break, you can choose according to what kind of unfortunate/daft happenstance you think is most likely to happen.

FWIW I've personally done more miles on shimano hub generators than any other type in recent years, but they are not 'perfect' either.

As the link I posted above shows, the disparity in drag between different hub generators varies according to the characteristics of the load, more than you would imagine.  However if you are after the lowest drag in a hub generator, the SON still has it in most circumstances, is very lightweight and it builds into the strongest wheels too, so would be my first choice for a 'posh bike'.

cheers

[Hot Flatus]

There is a lot of heavy lifting in this thread to justify SON's shit connectors.

 

if you have managed to break one then its only to be expected that you might condemn the SON connectors as 'shit' or somesuch, no matter how many others 'somehow manage' to avoid similar problems.  Its only human nature.  It isn't necessarily logical, but it is human nature.

Careful Brucey.

Sounds like you might be falling victim to a fallacy...

There is a common problem with folk's experience of bike parts which is 'the fallacy of perfection'. To the casual observer everything is 'perfect' until they see it go wrong for themselves:  Something can be a pretty hopeless design such that it only works 90% of the time (no matter what you do with it), yet this will still lead to nine out of ten people reporting a positive experience with it. Equally the design can be OK if installed and used in the way intended, yet a negative experience which is due to a true design failure is not easy to discriminate from one that is otherwise attributable, eg not reading the instructions or just assuming that something is 'very simple' (it rarely is, IME).

[Brucey]

since I have seen most sorts of hub generator fail in multiple different ways, I might be in danger of suffering a 'fallacy of imperfection'....





cheers

[Kim]

There is a lot of heavy lifting in this thread to justify SON's shit connectors.

It's a spade connector.  It's a proven technology, works fine in this application and if you're familiar with the nuances of spade connectors, their main source of annoyance is that they're an unusual size.  Something that matters not a jot once you've installed the wiring on your bike.

It's just that the lego-brick connectors are, well, better.   


(Assuming that both are used competently, of course.)

[Cudzoziemiec]

Their being an unusual size does matter if it's your first encounter with spade connectors and being generally a bit ham-fisted and unused to the ways of the wire, you damage the female spade. No problem, Maplins is just down the road. Those ones look right. Get them home and, oh, they're 0.1mm too small. Cos standards.