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  • Filling a bottom bracket with oil. Has anyone tried it ?
  • The subject of regreasing BBs comes up on here occasionally, along with the risk of damaging the seals by removing and refitting them, so I wondered about using oil instead.

    If you removed the inner seals from the bearings, you could put oil in the space between the crank axle and plastic tube which would keep them lubricated.
    No need to ever disturb the outer seals. If you want to change the oil, just pull the crank part way out and tip the oil in through the gap on the opposite side, or unscrew the LH cap.

    The crank it’s self is only a metal on metal light press fit in the bearings, so I don’t know how oil tight that would be. Maybe it would all run out over time, or maybe there would always be a reservoir lying in the bottom.

    I got to thinking about this because I’m about to replace a pair of Hope ceramic bearings.
    I don’t really want to experiment with £50 worth of bearings, so I wondered if anyone else has tried it.

    coatesy
    Free Member

    I’d imagine most of it would seep past the plastic top hats, may be worth trying(wouldn’t leave the bike on a nice floor though).

    wwaswas
    Full Member

    I don’t know how oil tight that would be

    not very would be my guess.

    old road wheels hubs (when I were a kid) used to have a hole in the middle of the shell with a cover and you put oil in to keep the bearings lubed. If you could get that sort of arrangement on the bb it would matter less if oil leaked out?

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    fasthaggis
    Full Member

    Graham
    I think it was Suntour in the 90s (xc Pro groupset maybe?)had grease points in the hubs and BB,where you just pumped through new grease after a wet muddy ride . You could replace the bearing surfaces in the BB as well.Still seems like a good idea .

    I remember those on old style hubs, it was a C shaped spring steel cover.
    That wouldn’t work on a BB without some sort of modification, because you’d only be tipping the oil in to the space between the BB shell and the plastic tube.

    Whenever I’ve stripped a BB, the space around the crank axle isn’t full of water, so if water’s thinner than oil and doesn’t get in, the oil shouldn’t get out.
    It might be different if the crank was submerged in water on the outside though, the way I’m talking about submerging it in oil on the inside.

    Thinking about this a bit more, I’m sure I’ve got an old Race Face BB around here somewhere.
    It came on a second hand bike and I replaced it with a Hope one before it’s inevitable sub 2 month failure, but kept it as an emergency spare.
    I’ll experiment with that. It’s no great loss if it doesn’t work.

    Marko
    Full Member

    I think it would work if you designed it from the ground up. Not on my bike, because I’ve done the old trick of drilling a small hole in the BB shell to let the water out.
    Hth
    Marko

    partyboy
    Free Member

    Why?

    Shimano HT2 BBs can be had for a tenner and last for ages.

    z1ppy
    Full Member

    I think you’d be better off trying fivespot’s grease port rather than dripping oil everywhere..

    toys19
    Free Member

    Unfortunatly the “seal” on these bearings is just a dust/debris seal, it wont keep water out, or oil in.A greaseport is an excellent idea.

    cookeaa
    Full Member

    it’s an interesting thought, I think implementing it with current HT2 BB designs might be tricky though.

    Effectively you want an Oil bath for the BB Bearings, I’m not sure the Seals on the Bearings would prevent oil seeping out past them and I’m not totally certain how you would load the BB assebly with oil, you’d need an injection point of some sort…

    a thin grease would make sense to me, and possibly an injection port/hole at the mid point of the inner sleeve oriented up top be accessable via the seat tube with a bloody long greese gun, or down for access via a hole in the bottomo of the BB Shell.

    you could do away with the inner sleeve, pop the inner seals off of the Bearings and again load up the whole Shell post Assembly with Grease via the seat tube, Wate ingress does happen depending on the frame and how often its ridden through fords/rivers and in pissing evil rain. the trouble with filling a BB shell with oil is that its quite likely to migrate down chain stays or out past the Bearing seals.

    But your looking at lugging about quite a bit of extra oil or Grease…

    clubber
    Free Member

    Graham, you are William Heath Robinson and I claim my £5

    cookeaa, if you remove the LH crank and bearing cup, leaving the plastic tube in place, then lay the bike down on it’s RH side, you can tip the oil down the gap between the BB axle and plastic tube.
    No need to fill the whole BB shell.
    Replace the LH bearing cup and crank, then stand the bike back upright.

    I just had a go with the Race Face BB and knocked the bearing out of the LH cup OK, removed the inner seal and refitted the bearing in the cup.
    I tried the RH bearing and there’s a raised rib around the inside of the cup so I couldn’t use a socket to punch the bearing out. I’ll take it to work and have a go there.

    One advantage with the Race Face BB is that it uses plastic shims between the bearing and crank. Hopefully these will seal better than the metal to metal of a Hope BB.

    Punching the bearing out with two sockets.

    I don’t think this bearing had much of a service life ahead of it.

    Nothing to lose if it doesn’t work.
    The bearings are almost scrap anyway and it won’t damage the frame or crankset, so why not give it a go ?

    Ecky-Thump
    Free Member

    Hmmm, you’ve got me thinking.
    I might just try something along the lines of…. remove innerboard seals from HTII bearings and fill the plastic tube with 90 wt gear oil to form a reservoir/open bath. Not sure if there is going to be sufficient space in the tube to be an effective reservoir though.

    [Edit] Damn… too slow again…. exactly same plan as MTQG [/Edit]

    clubber
    Free Member

    I agree with that – no harm in trying but I think that you’ll find as above that the bearing seals won’t hold the oil so it’ll slowly drain out – I guess that the key thing is how long it takes as taking the cup out every ride to refil with oil would be a drag.

    PJM1974
    Free Member

    I’ve tried doing this with a Truvativ BB. I didn’t notice any significant change in bearing life, it still died within a year.

    A better modification would be to slip a plastic cover over the axle to help prevent water ingress between the seals. I’ve seen this in the top tips section of MBR I think, a reader uses the plastic cover of a McDonald’s orange juice cup to accomplish this.

    woody2000
    Full Member

    At least experiment using green oil or olive oil or something so you’re not polluting the countryside everywhere you go. Or leaving little oil slicks on the road for unwary bikers!

    TBH, it’s nowt of a job to flick off the bearing seals and refill with teflon grease every now and then, and that does seem to improve longevity.

    🙂

    rootes1
    Full Member

    probably better to drill a small hole in the shell to let any water drain away…

    also you could put an O ring over the axle shaft – bit if a fiddle for HT2 but this would act as a flinger to stop water moving along the axle towards the bearings

    rob-jackson
    Free Member

    cynic_al did something with a grease port last year or so

    I stripped the Hope ceramic BB and thought I’d give it a go with the old bearings.
    I only just realised how little room there is between the axle and the plastic tube.

    I managed to dribble some light gear oil down there anyway.

    Another thing I only just found out is that Hope cups have got a little cut out, almost as if it’s meant for a grease gun.


    It can’t be, because the bearings are sealed both sides.
    It does mean though, that if you dismantle a Hope BB, remove the inner seals from the bearings, then refit the bearings, you could then regrease them by simply removing the cups. No need to disturb, and risk damaging, the outer seal.

    By the way, I’m using Truvativ cranks, so that’s the aluminium adapters you can see in the picture above, not the bearing it’s self. Another reason why I want to avoid removing and refitting the seals.

    wwaswas
    Full Member

    there’s an ecosystem developing on your bike 😯

    rob-jackson
    Free Member

    one hole for grease to go in – where does the old grease and muck come out?

    DezB
    Free Member

    I agree with Partyboy, the Shimano BBs last for ages…
    Thing is, I don’t store mud on my bike!

    wwaswas
    Full Member

    where does the old grease and muck come out

    the pressure from the grease gun blows the seals off the outside of the bearing, obviously 😉

    matt_outandabout
    Full Member

    You need to faff with some of this, not different engineering my man…

    Zulu-Eleven
    Free Member

    Bring back WTB Grease-Guard 😀

    michaelbowden
    Full Member

    also you could put an O ring over the axle shaft – bit if a fiddle for HT2 but this would act as a flinger to stop water moving along the axle towards the bearings

    I have done this and my Hope SS BB is 2 1/2 years old ans still as smooth as day 1

    michaelbowden
    Full Member

    Another thing I only just found out is that Hope cups have got a little cut out, almost as if it’s meant for a grease gun

    They’re so you can get a punch on the outer race to remove the bearing!

    wwaswas
    Full Member

    I was quite pleased to find that my Carbon 456 has a full length aluminium sleeve that the BB runs in – the only way water can get into the sleeve is via the BB threads so as long as they’re sealed then the whole of the inside of the BB assembly will stay dry.

    fasthaggis
    Full Member

    That fivespot’s grease port mod ,looks like a great idea .

    😆 @ Matt’s bucket

    binners
    Full Member

    Are you in fact Hora?

    Well, I’ve been for a test ride and I didn’t die.
    There’s no obvious signs of oil leaking out yet, so I’ll run it for a bit with the old bearings, then, if it’s still OK, I’ll fit the new bearings with the inner seals removed.

    cruzheckler, the grease would go in that little slot, then force the old grease out round the circumference.

    michaelbowden, it looks like a slot for punching a bearing out, but they are normally in opposite pairs. I think it would be more likely to jam the bearing at an angle than punch it out using it like that.
    Normally, you’d only remove a bearing from the cups if it was scrap, so there’d be no further damage done by punching it out by the inner race.

    there’s an ecosystem developing on your bike

    Let it develop.
    Titanium and carbon fibre is not just bling you know. It doesn’t go rusty. 😛

Viewing 34 posts - 1 through 34 (of 34 total)

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