SP dynamo hubs - narrow flange spacing

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zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 29 May 2019, 2:24am

Well my home built SP dyno wheel (36 spoke 26 inch Ryde Zac 19 rim) survived my week long french camping tour (46lb total load) without going out of true.. After a brief off road excursion my rear LX/Sputnik rim DID need retrueing slightly..admittedly its the rear where all the weight is though...

More to the point the SP hub charged my phone really well..typically taking it from 50% charge to 100% in about 3 hours cycling (Samsung Galxy S5 Phone, Busch und Muller Luxos headlight/USB adaptor)

My only real concern about the hub is the way I can't see or service the "sealed" bearings in it. I have only done around 4250 miles on so far though so maybe I will wait until the10,000 mile mark before worrying about this - its running fine ATM.

I would be keen to hear from other SP owners how long their hubs have lasted.

bgnukem
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Re: SP dynamo hubs - narrow flange spacing

Postby bgnukem » 29 May 2019, 12:43pm

I've got one too. Don't think the bearings are user-serviceable (can see no way to access) but I gather the distributors (Ison?) offer a refurbishment service for bearing replacement if you send the hub back to them.

zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 29 May 2019, 1:51pm

bgnukem wrote:I've got one too. Don't think the bearings are user-serviceable (can see no way to access) but I gather the distributors (Ison?) offer a refurbishment service for bearing replacement if you send the hub back to them.


I will have to look at that option bgnukem. I do about 3000 muddy commuting miles a year and have aleady taken a Shimano dyno hub out of service (as a precaution - nothing visibly wrong with it) as it approached the 10,000 mile mark. Given I build my own wheels maybe I should unlace the SP hub and send it back for new bearings every 10,000 miles...rather than risk having it suddenly fail on a European tour? Or maybe I should just "demote" the wheel to commuting only use after 10,000 miles and make sure I go touring on a newer, low mileage, dynohub.

(or perhaps I need a NEW dedicated tourer ;-) )

I would be keen to know how SP hubs finally fail..i.e whether there is any audible or visible signs of distress before they pack in...anyone???

bgnukem
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Re: SP dynamo hubs - narrow flange spacing

Postby bgnukem » 29 May 2019, 6:13pm

Here's the thread which referred (in 2017) to a refurbishment service:

https://forum.cyclinguk.org/viewtopic.php?t=112106

I guess the bearings will start to feel rough, but can be hard to tell when the dynamo cogging effect (electromagnetic resistance) is very marked when rotating the axle by hand.

I'd suggest spinning the wheel in a bike stand in a quiet place and listening carefully for any grinding noises from rust or contaminants in the bearings . I find I can often hear bits of grit and dirt in a freehub body that way. Also maybe check for lateral play by trying to tilt the wheel sideways when the bike is on the ground. Best is to grab the rim immediately adjacent to the forks and push it sideways in both directions and feel for anything more than a tiny amount of play (ensure QR skewer is tight of course!).

zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 29 May 2019, 9:39pm

bgnukem wrote:Here's the thread which referred (in 2017) to a refurbishment service:

https://forum.cyclinguk.org/viewtopic.php?t=112106

I guess the bearings will start to feel rough, but can be hard to tell when the dynamo cogging effect (electromagnetic resistance) is very marked when rotating the axle by hand.

I'd suggest spinning the wheel in a bike stand in a quiet place and listening carefully for any grinding noises from rust or contaminants in the bearings . I find I can often hear bits of grit and dirt in a freehub body that way. Also maybe check for lateral play by trying to tilt the wheel sideways when the bike is on the ground. Best is to grab the rim immediately adjacent to the forks and push it sideways in both directions and feel for anything more than a tiny amount of play (ensure QR skewer is tight of course!).


£25 for a refurb hub sounds like a good deal bgnukem ... many thanks for posting this.

Brucey
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Re: SP dynamo hubs - narrow flange spacing

Postby Brucey » 29 May 2019, 10:10pm

regarding failures in hub dynamos these fall into three categories;

a) electrical failure; e.g. wiring goes open circuit
b) foreign objects inside generator itself (eg rust particles)
c) bearing failure

regarding b) most types of generator can occasionally end up with condensation inside and this causes corrosion that eventually makes the generator very draggy. In many designs the bearings are not sealed on the inside well enough to stop rust within the generator from interfering with the bearings. Corrosion is often implicated in a) as well.

IME cartridge bearings can fail gradually (i.e. so that they gradually become slightly loose over a long period of time) or can fail rather more rapidly and without great warning. If the bearings start to corrode they can fail quite quickly. The cartridge bearings used in most such hubs are standard deep groove (Conrad style) bearings. Common variations in design include grease fill, clip (material/design) and seal design; not all 2RS bearings are created equal by any means. Because of the way they are assembled these bearings are about half-full of steel balls which are separated by a clip. The clip isn't much loaded when the bearing is working normally but there is load on clip under most fault conditions. If the bearing fails quickly the clip can break up and this very rapidly results in complete failure.

The early signs of bearing failure (if there are any) are more difficult to detect in a hub generator because the 'feel' of the bearings is disguised by the feel of the generator itself, which is rather notchy anyway. There may be little or no audible noise from the bearings until shortly before they fail altogether.

Image

the above is a failed Conrad style bearing in an industrial application but it manifests some features which are not uncommon in other bearing failures; the clip has broken up and the balls tend to accumulate unevenly so that the bearing can't support loads in all directions any more. The balls rub the clip, rub one another, and even run over parts of the clip which causes immense destructive stresses in the bearing. If you start to hear noises from the bearings and the bearing turns abnormally then the chances are that you have a b) or c) type failure on your hands.

In SP generators you can spray a little SFG in the gap and this may keep the seal lips wetted for longer, helping to keep the crud out of the bearings, but if the inside of the generator is corroding then this may be gradually destroying the bearings from the inside out. The air trapped within the generator expands and contracts with temperature changes and this can drag water through the bearings; SON generators have a clever scheme for avoiding this eventuality but it still doesn't make the generator 100% proof against condensation and corrosion inside. The £25 SP refurb is good value but it is a shame that you have to dismantle and rebuild the wheel.

FWIW I run shimano generators and if they see a lot of (commuting) weather then I have to dismantle them once every year or two and deal with rust inside the generator and whatever collateral damage there is to the bearings. For this reason I probably wouldn't expect to both commute and tour on the same hub generator. Under more benign conditions I'd expect not to have to do maintenance of any kind for several years.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 30 May 2019, 12:32pm

Brucey wrote:regarding failures in hub dynamos these fall into three categories;

a) electrical failure; e.g. wiring goes open circuit
b) foreign objects inside generator itself (eg rust particles)
c) bearing failure

regarding b) most types of generator can occasionally end up with condensation inside and this causes corrosion that eventually makes the generator very draggy. In many designs the bearings are not sealed on the inside well enough to stop rust within the generator from interfering with the bearings. Corrosion is often implicated in a) as well.

IME cartridge bearings can fail gradually (i.e. so that they gradually become slightly loose over a long period of time) or can fail rather more rapidly and without great warning. If the bearings start to corrode they can fail quite quickly. The cartridge bearings used in most such hubs are standard deep groove (Conrad style) bearings. Common variations in design include grease fill, clip (material/design) and seal design; not all 2RS bearings are created equal by any means. Because of the way they are assembled these bearings are about half-full of steel balls which are separated by a clip. The clip isn't much loaded when the bearing is working normally but there is load on clip under most fault conditions. If the bearing fails quickly the clip can break up and this very rapidly results in complete failure.

The early signs of bearing failure (if there are any) are more difficult to detect in a hub generator because the 'feel' of the bearings is disguised by the feel of the generator itself, which is rather notchy anyway. There may be little or no audible noise from the bearings until shortly before they fail altogether.

Image

the above is a failed Conrad style bearing in an industrial application but it manifests some features which are not uncommon in other bearing failures; the clip has broken up and the balls tend to accumulate unevenly so that the bearing can't support loads in all directions any more. The balls rub the clip, rub one another, and even run over parts of the clip which causes immense destructive stresses in the bearing. If you start to hear noises from the bearings and the bearing turns abnormally then the chances are that you have a b) or c) type failure on your hands.

In SP generators you can spray a little SFG in the gap and this may keep the seal lips wetted for longer, helping to keep the crud out of the bearings, but if the inside of the generator is corroding then this may be gradually destroying the bearings from the inside out. The air trapped within the generator expands and contracts with temperature changes and this can drag water through the bearings; SON generators have a clever scheme for avoiding this eventuality but it still doesn't make the generator 100% proof against condensation and corrosion inside. The £25 SP refurb is good value but it is a shame that you have to dismantle and rebuild the wheel.

FWIW I run shimano generators and if they see a lot of (commuting) weather then I have to dismantle them once every year or two and deal with rust inside the generator and whatever collateral damage there is to the bearings. For this reason I probably wouldn't expect to both commute and tour on the same hub generator. Under more benign conditions I'd expect not to have to do maintenance of any kind for several years.

cheers

Thanks Brucey - some useful info for me to reflect on there...

amediasatex
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Re: SP dynamo hubs - narrow flange spacing

Postby amediasatex » 30 May 2019, 12:45pm

zenitb wrote:I would be keen to hear from other SP owners how long their hubs have lasted.


My SP is on my wet weather Audax bike and has done a little over 3500 miles so far, it's had numerous horrible horrible drenchings including two of the wettest 200's I've ever done where it's spent the whole day being rained on and ridden through a lot of road water, it's frequently put away wet and ignored, it's one half* of my most abused wheelset in that regard and no sign of any issues yet...but it's early days really.

* the rear hub is a Chris King and is over 20 years old, spent the first 10 years of it's life on an MTB, and I've only re-greased the bearings twice in its lifetime (last was ~ 4 years ago), I have no idea how many miles it's done but it's become my benchmark for low maintenance in cartridge bearing hubs as it is still in literally perfect running order.

zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 1 Jun 2019, 11:10pm

amediasatex wrote:
zenitb wrote:I would be keen to hear from other SP owners how long their hubs have lasted.


My SP is on my wet weather Audax bike and has done a little over 3500 miles so far, it's had numerous horrible horrible drenchings including two of the wettest 200's I've ever done where it's spent the whole day being rained on and ridden through a lot of road water, it's frequently put away wet and ignored, it's one half* of my most abused wheelset in that regard and no sign of any issues yet...but it's early days really.

* the rear hub is a Chris King and is over 20 years old, spent the first 10 years of it's life on an MTB, and I've only re-greased the bearings twice in its lifetime (last was ~ 4 years ago), I have no idea how many miles it's done but it's become my benchmark for low maintenance in cartridge bearing hubs as it is still in literally perfect running order.

Thanks for posting that amedias .. although your hub has done less miles than mine it sounds like its had a much rougher life - and I am keen to know how things end up with it ... I will post back if mine gives up the ghost at any point...but its looking good now... Going back to the OP's original point neither of us have had any issues with the narrow hub affecting the wheel build either so that all looks good ATM as well .....

Brucey
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Re: SP dynamo hubs - narrow flange spacing

Postby Brucey » 1 Jun 2019, 11:23pm

FWIW I happened to visit a fellow forum member a few days ago (who hasn't chipped in on this thread) and I found him merrily rebuilding a front wheel with a new SP hub. The old hub (after a few year's use) had suffered a gradual bearing failure, so was still turning smoothly enough, but with ever-increasing free play in it.

IME this isn't at all uncommon; most of my chums who have had these hubs and have also 'put the miles in' have had similar experiences.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

pwa
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Re: SP dynamo hubs - narrow flange spacing

Postby pwa » 2 Jun 2019, 8:00am

My own calculation in buying a wheel with an SP hub was that the hub was fairly cheap and if it only lasted a few years it wouldn't be an absolute disaster. The narrow flange thing was a concern until I thought about it and realised that the rear wheel should be a greater worry with its asymmetric spoke tension, and that was never something that bothered me.

FWIW if the SP hub gives up the ghost in a couple of years I will probably try to get it fixed and rebuild the wheel, but I'm not in love with the drag of generators and may take the opportunity to go back to a normal free running front hub and use my top class battery lights when lighting is required.

I really can see the advantage of a generator on a bike that is primarily for commuting, but my tourer is not doing that role much at the moment. Mostly I am using it for recreational rides in daylight and the constant, if slight, drag is not welcome. It is pointless. I'd never tour at night, so even on a tour I would prefer a battery system that could double up as a torch in the tent.

Brucey
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Re: SP dynamo hubs - narrow flange spacing

Postby Brucey » 2 Jun 2019, 8:20am

IMHO the drag of a good hub generator is more in the mind than in actuality. To create a similar amount of drag as a good hub generator with the lights off, just let ~5psi out of your front tyre. You might get similar variations in drag by using different thicknesses of grease in the hub seals, or different types of chain lube.

If you think you can tell the difference between 'lights on' and 'lights off', bear in mind that the difference between 'hub generator' and 'no hub generator' is a small fraction of that.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 3 Jun 2019, 9:01pm

Brucey wrote:FWIW .... The old hub (after a few year's use) had suffered a gradual bearing failure, so was still turning smoothly enough, but with ever-increasing free play in it.

IME this isn't at all uncommon; most of my chums who have had these hubs and have also 'put the miles in' have had similar experiences.

cheers

useful info.. to me that is the "good" way to fail - graceful degradation with plenty of warning. What none of us want is the thing suddenly self-destructing out of the blue... :-) I wont complain if that is how my SP hub fails in the end...

http://zenit-b.blogspot.com/2017/02/shu ... build.html

geocycle
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Re: SP dynamo hubs - narrow flange spacing

Postby geocycle » 4 Jun 2019, 1:51pm

When I bought my SP hub from Spa I was advised they would probably last around 5000 miles before the bearings needed replacing and I would have to disassemble the wheel to get them replaced. In contrast the SON would be 10,000 miles ++. It's done about 1000 so far without problem. I decided that for the use I was buying the wheel, the SP would be adequate whereas the extra cost of the SON is justified on the high mileage bike. If the bearings do wear in the SP it will be around the time the rim will also need changing so I probably would deal with both at the same time.

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NUKe
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Re: SP dynamo hubs - narrow flange spacing

Postby NUKe » 4 Jun 2019, 2:47pm

geocycle wrote:When I bought my SP hub from Spa I was advised they would probably last around 5000 miles before the bearings needed replacing .

I have an SP on small (406) wheel has done 15k with no noticeable play.
NUKe
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