Cycling UK Forum

mattsccm wrote: ↑28 Jun 2023, 6:28am My Exposure branded one eventually had a bearing go. As this one wan't in the UK via the official importers, (I assume it was via Exposure) they wouldn't handle the standard repair whereby they sent it back to Taiwan. All the purchaser does here is pay them You can do it independently but you have to post it and either insure it at its value or say it has no value.
Check with your supplier.
I mended mine myself but then killed it doing something else.

How did the failure present itself?

My Exposure branded one eventually had a bearing go. As this one wan't in the UK via the official importers, (I assume it was via Exposure) they wouldn't handle the standard repair whereby they sent it back to Taiwan. All the purchaser does here is pay them You can do it independently but you have to post it and either insure it at its value or say it has no value.
Check with your supplier.
I mended mine myself but then killed it doing something else.

Out of interest what is the nature of failure on the SP hubs. Is it catastrophic or is it more a case of bearings start to get noisy and can keep going for a few hundred miles more?

I have SON, Shimano and SP hubs, so no brand loyalty. The SP ones do have a reputation for not being as long lasting, plenty of reports and the distributer stepped in offering a reconditioning service, that isn't to say every one is doomed to fail, it'd be hard not to notice the disproportional number of failures. I choose SP for my folder which doesn't get the same mileage as my other bikes and it was half the price of the cheapest alternative. I bought the SON in 2001 when there wasn't such a good choice, it went off for a service at around 70,000 miles, polished silver and came back looking and feeling like new, which you'd expect from a service which cost the same as a new Shimano. It's the old style model that can be serviced in the wheel, unlike the current versions, so that's an advantage gone.
If it was for a high mileage bike, I think I'd choose one of the better Shimano models. The flange offset isn't huge, not like a rear cassette, I read elsewhere of someone mitigating this with an asymmetric rim, but it isn't something I have experience of.
As others have already said, the failure mode is likely to be gradual, being user serviceable is a plus, but it wouldn't be a priority for me.

I’ve done about 9,000 miles on an Exposure branded SP-PD8, and, as the bike was second hand, who knows how many miles it did before that. So far, no problems.

iandusud wrote: ↑27 Jun 2023, 1:08pm Thanks for all the feedback. I take the point about the flange spacing. However I've looked up the Kasai specs and it is identical at 50mm. I don't think that the narrow(ish) spacing worries me that much as long as it is even. What I don't like is significantly unequal spoke tension on the two sides of a wheel.

This concerned me when I built my tandem wheel with a Shimano centreloc dynohub. In practice it has performed faultlessly despite the unequal spoke tensions due to the assymetric location of the flanges.

iandusud wrote: ↑27 Jun 2023, 1:08pm Thanks for all the feedback. I take the point about the flange spacing. However I've looked up the Kasai specs and it is identical at 50mm. I don't think that the narrow(ish) spacing worries me that much as long as it is even. What I don't like is significantly unequal spoke tension on the two sides of a wheel.

I think that makes sense. Does anyone here know what sort of spoke would make the strongest 36h wheel in these circumstances? Does it matter, or is it worrying about nothing?

Thanks for all the feedback. I take the point about the flange spacing. However I've looked up the Kasai specs and it is identical at 50mm. I don't think that the narrow(ish) spacing worries me that much as long as it is even. What I don't like is significantly unequal spoke tension on the two sides of a wheel.

Mick F wrote: ↑27 Jun 2023, 12:06pm Very happy with mine too ................ or maybe not ................

There seems to be a chuff-chuff noise from it recently. I've yet to investigate, but I suppose it could be something else up-front. Mudguard or tyre perhaps or even a brake block catching. Can't seem to hear anything untoward when I spin the wheel.

I'd be suspecting the tyre rubbing on something with that sort of noise. Have you got a loose spoke maybe?

Very happy with mine too ................ or maybe not ................

There seems to be a chuff-chuff noise from it recently. I've yet to investigate, but I suppose it could be something else up-front. Mudguard or tyre perhaps or even a brake block catching. Can't seem to hear anything untoward when I spin the wheel.

I've had 2 disc SP PD8 (I think) hubs fail on me. Bearings both times.
Never again.
The last wheel I built was with a SON delux hub which are legendary for their reliability and after service. £159 from sjs.
https://www.sjscycles.co.uk/dynamos/32- ... ub-silver/

I can't remember offhand if it's an SP-8 or SP-9 I have but I'm very happy with it.

The Kasai is purported to be field serviceable (hence the FS model name), but that is far from the truth.
In reality, they are built just like Shimano hubs but with cartridge instead of cup and cone bearings. That means that you can easily extract the internal assembly from one side, and you can easily replace the opposite side bearing, which is standard measure in the Kasai and you could source anywhere. But you cannot replace the other bearing, and will have to replace the whole internal assembly at a cost of more than half a new hub, and most likely, not easy to find and get quickly.
Maybe you can attempt to replace the internal assembly bearing, no idea if it is feasible, having to pull out a press-fit bearing with thin wires going through the axle.

If I were in the market for a dynamo hub right now, I'd be looking first at the Kasai hubs because of the facility for dismantling without un-building the entire wheel. I'd be asking whether there are any reasons not to choose Kasai.

All these cartridge-bearing hubs are as reliable and durable as the bearings themselves are, as nothing else is likely to cause issues. The bearings are sourced from big bearing manufacturers and quality varies a lot from the very cheapest for 1 or 2 quid all the way to top range SKF for 30. We discussed SP bearings a few years ago and Brucey was nor sure, but he seemed to remember that they were "decent Japanese bearings", in his own words. But SP could change suppliers as often as they like, and we would never know. I have a fairly new SP hub and I also dislike that it is too narrow between the flanges, and that I have not found a way to remove the outer caps/dust seals to get to the bearings and add lube regularly.
Being rather new, I haven't tried too hard, has anyone here done it?

I like the idea of the Kasai hubs, you can remove the whole internal assembly from the side without having to rebuild the wheel, as is the case of SP, SON etc. That makes bearing replacement easier, but, crucially, easy access to the bearings to clean and lubricate will undoubtedly prolong their life.