2nd hand Sturmey front brake hub has arrived. Having had a look inside it's looks usable, but the bearings sound dry when turning axle by hand.....although no detectable play.
To use best to address the bearings. So:
1) Do the Sturmey 6000ZZ replacements have ' the right grease' ? If not can anyone point me the best alternative.
( I confess I don't really understand the seal types and the ones on the bearings in situ look like pictures of the Sturmey 6000ZZ....but different to others I've used elsewhere....and I presume I should be avoiding different seal types)
2) The bearings in place are 6000Z. Having just looked up the difference ZZ has 2 seals and Z only one. So if there is no detectable play in the bearings, could drilling a lube port and half filling with SFG be and option. I can't see how it could get to the brake drum...
unless the seal failed?
Last edited by hoogerbooger on 8 Sep 2024, 12:11pm, edited 1 time in total.
That looks like a metal shield not a seal. Shields don't rub so you may be able to squirt some grease through the gap using a syringe. Or if you access the other side you should find it open and easy to grease.
Z means a shield on one side only so the other side is open. ZZ means shields both sides.
Bearings with shields are generally cheaper than those with seals,
this link explains the difference https://www.bearingtips.com/difference- ... ing-seals/
I'm surprised they haven't used seals. perhaps someone replaced the bearings previously. or is there a secondary seal fitted.
Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X2, Raleigh 20 stowaway X2, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840, Giant Bowery, Apollo transition.
(The axle is the sort trapped between the two bearings. So taking them out will kill them. BUT if syringing SFG into the holes on the shields has a chance ? Seem like the 1st thing to try.
( not sure if the hub is an X-FD or an earlier one as no decals remaining...but bearings appear to be the same OD and ID )
The gap will between the ring with singapore on it and the bright ring on the axle. Its only a small gap so you would need to squeeze it in there.
or knock the axle out which should enable you to remove the bearing and the back side will be open enabling easy cleaning and regreasing.
Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X2, Raleigh 20 stowaway X2, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840, Giant Bowery, Apollo transition.
I can't see either likely to work. Knocking the bearing out requires knocking the axle which pushes against the inner journal only...so likely to damage the bearing.
To get grease in through a narrow gap would seem to require a pretty runny grease....which can run back out...... I guess though it's quite a contorted route for it then to run to the drum surface and pads.....but if the drum gets hot....it'll flow better?
My oldest front drum brake has now been used for 8 years, and I've not regressed the sealed bearings - and I don't intend to.
The bearings themselves, aren't that expensive, and when they start to break up I'll pull them out and replace them.
Personally, I'd give the hub a bit of a polish have it built into a wheel, and purchase some new bearings... i''d then use the wheel with the current bearings, but have it in the back of my mind that they would need to be exchanged at some point in the (near) future - perhaps even replacing the existing bearings with new ones if the bike was to be used on long tours rather than short local journeys (when a mechanical issue would be a problem, rather than simply an hours trudge home).
Although running dry is less then ideal, it's possible that without any contaminants on the races, they'll still go a season or two - it's also possible that my own bearings have or are running dry, but on the provision there's no play in the bearings, then I'm not going to do anything about it.
It's a mission, and you need to remove the bearing anyway, so you may as well replace it for the time, effort and cost (if you don't have the kit already) of regreasing. As for the grease type, it's not that critical. Bike wheel hubs aren't particularly demanding and almost any grease will do the job fine. Don't overthink it!
Small bearings can feel dry but actually the grease has settled into a niche but is still contacting the rolling elements and depositing a thin film of oil. Which is all that's needed. The non dry feeling is created when the grease is still being pushed out of the way by the balls.
If the bearing feels rumbly or the slightest bit notchy then it's genuinely dry.
SA hubs normally come with 6000 bearings fitted, each having two shields (naming conventions can vary). Despite the lack of seals, these bearings usually last quite well, which I attribute to the smallness of the airspace betwixt the bearings; nonetheless, I think that properly sealed bearing would be even better.
You can usually replace the outboard shields with seals in situ, regreasing if required. This poses no threat to the bearing. The proedure is simple; first carefully pry out the shields eg. using a small screwdriver. Don't worry too much about mangling these because they are not going back in. Add clean grease to the bearings, having cleaned them if necessary. Finally refit seals (taken from a 'donor' 6000-2RS bearing) in place of the shields. It turns out that not only do the use the same parts to make differently sealed bearings from the same manufacturer (which you might expect), but also these dimensions are very often common between manufacturers (which you might not). It is therefore likely that (say) a seal taken from a NSK bearing will fit a comparable SKF bearing.
If you wish to remove the bearings, do note that differential CTEs work in your favour here. So if you simply heat the hubshell by tipping a kettle of boiling water over it the bearings will come out more easily. Note also that in a built wheel the RH bearing housing sees some of the stress from the spokes, so the RH bearing ought to come out more easily than the left. Furthermore, there is no reason why one or both bearings cannot be converted to DFC or 3LFC specification prior to removal or prior to RS fitment. This alone will nearly halve the chances of causing bearing damage during removal, as well as conferring most of the usual FC bearing benefits.
If you find it difficult to source spare balls in the right size, you can use all bar one of the original balls in one bearing and then use all bar one of the balls from two spare bearings in the other.
Brucey wrote: ↑7 Sep 2024, 2:49pm
Furthermore, there is no reason why one or both bearings cannot be converted to DFC or 3LFC specification prior to removal or prior to RS fitment.
DFC - dandelion flower centricity?
3LGC - 3 lovely fox cubs?
...asked cycle tramp, chairman of PAA (people against acronyms)?
I'll probably go for replacing with Enduro 6000 LLB bearings......not expensive and supposed to contain an appropriate fill of appropriate-ish grease. If I've go it right, these should be better/ last longer than the original bearings.
Agree existing bearings may last a couple of years....but I'll change em anyway before I build into a wheel.
The intention is a low-ish maintenance utility bike a bit like Cycle Tramp's but as far as possible meeting the principles for a Sustainable Heritage Integrated Transport bike. So as you can probably work out I'm more likely to seal in the "patina" on the hub than polish it ( I'm not sure there is a point of polishing this type of bike anyway?)
I may for fun/ learning, try removing shields cleaning and regrease....replace with spare seals. If it rains enough.....and as I have enough dead 6000 bearings .....see if I can actual do a DFC bearing conversion.
Thank you all.
(right, now I must re- read the old post on floating trailing shoes)
Last edited by hoogerbooger on 9 Sep 2024, 2:21pm, edited 1 time in total.
hoogerbooger wrote: ↑8 Sep 2024, 12:08pm
Thank you for all comments.
Agree existing bearings may last a couple of years....but I'll change em anyway before I build into a wheel.
The intention is a low-ish maintenance utility bike a bit like Cycle Tramp's but as far as possible meeting the principals for a Sustainable Heritage Integrated Transport bike. So as you can probably work out I'm more likely to seal in the "patina" on the hub than polish it ( I'm not sure there is a point of polishing this type of bike anyway?)
Whilst I'd live to take the credit/blame.... it was all Brucey's idea (and 8 years on, still a good one).
