my rear hub has recently shat itself(loosens when i brake and then slips when accelerating). lbs reckons it needs replacing, any suggestions??
anyway, i have a $100 gift voucher for a bike shop that i won a few weeks back, anyone got any recommendations for a decent, strong hub i can replace the knackered one with? i’m happy to spend the $100 as it was free. i’ve got all white rims so if anyone knows somewhere i can get good white hubs from that’d be great. i’d settle for black though i suppose
alternatively, if anyone has any ideas on how i can fix the slipping issue that’d be much appreciated!!
there’s been a few posts about this same problem, have a bit of a search.
assuming the lockring is tightened properly - first thing to check! - it’s probably caused by the lockring not quite clamping the sprocket against the hub, ie: leaving room for it to spin back and forth slightly. this is caused by the sprocket being ‘thinner’ than the space allocated for it on the hub, if that makes sense. some cheap no-name sprockets are thin like that.
if you’ve been riding it like that for a while, then yeah the hub threads might be damaged, and you’ll need a new hub. but check first, before you go rebuilding the wheel. see the local shop, you don’t need to spend $100 for one hub. the labour for rebuilding the wheel might actually cost more than the hub.
if this only just happened, and the threads look ok, then you might just need a cog that is ‘thicker’. again try the local shop and see what they’ve got.
i’ve had the bike shop check it out and they managed to get it to slip with the wheel out of the frame using one of those tools with the chainlinks on it (i forget what they’re called). they thought it was maybe something to do with the fixed cog so they tried a brand new surly cog and same thing happened.
they seem pretty confident it’s the hub. i was tempted to use a green hub i have (some of you may remember all the drama i had getting the correct wheels) but, like you said, the cost of taking it all apart and rebuilding it isn’t worth it.
i’ve only been riding it fixed for a month or two but the problems all started when i spent a bit of cash replacing the cranks, bb, pedals and chainring. not wanting to spend too much sorting this out but the voucher will definitely come in handy, provided they can get a decent hub in for me.
My initial incling would be the same as etomato - your cog and lockring aren’t tightening against each other properly. I don’t understand how the hub threads could be damaged enough that the cog and locking can slip - yet they are good enough that the cog and lockring can be screwed on - seems like a contradiction to me.
Tighten cog hard with a chainwhip, then put on a BB spacer, then tighten your lockring hard. Lastly, don’t trust everything your bike shop says.
ah ok, all good advice, i’ll see what i can do this afternoon/evening in regards to pics. got pretty limited tools at home.
i’ll see if a spacer or thicker cog will do the trick. the bike shop have been pretty good to me since i bought the bike but i understand they’re a shop looking to make money at the end of the day
the hub itself is a white ‘origin8’ high flange track hub. they’re in the centre of a set of weinmann deep v’s. i’ve got a mate with a set and he’s not had any problems with his. he rides brakefree and puts his bike through it’s paces pretty regularly.
boyracer, what thickness is the cog you have now? or is it irrelevant in that it will be hub specific?
I’m not saying they aren’t trying to be good to you/are trying to rip you off, just that maybe they don’t know what the problem is. Still, they might be right - but I’d prefer to try a cheap simple solution, before an expensive one.
It is somewhat hub specific. I’d try a cheap/free bottom bracket spacer before buying cogs to be sure that is the problem.
It is somewhat hub specific. I’d try a cheap/free bottom bracket spacer before buying cogs to be sure that is the problem.
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yeah, what he said. limited tools = limited choice of cogs too i bet. buy/make a chain whip and c spanner then shop around. LBS should have a caliper to measure your current cog.
cogs in my gearbox range 5.40mm to over 8.00mm.
etomato touched on it earlier in regards to cheap, thin cogs, but is there ever a chance of a similar effect happening from a cog being over-tightened. I mean, if you were to over-tighten a fixed cog on a cheap, soft hub, could the cog start to chew into the side of the hub and wind itself further onto the hub than it’s supposed to? If it were to do this far enough, then there’s a possibility of the lockring only being able to tighten up against the side of the fixed thread, not the cog itself.
I haven’t had any experience with broken fixed hubs, and I know the Origin8 hubs are just rebranded Formula hubs, which are mostly pretty reliable, so is this a possibility or am I thinking about this the wrong way?
went into the shop yesterday and had a chat with them about the possibility of a thicker cog/spacer and they are pretty adamant it won’t fix it. the thread itself is fine and there’s no gap between cog and lockring, that was the first thing they checked when it first started doing it. they were pretty sure i’d have trouble getting a spacer and lockring on anyway, as there doesn’t appear to be a whole lot of room available on the thread.
i’m not too sure what goes on inside the hub itself, could it simply be a dud and the internals are all fucked up? :?
if it’s a conventional track-type hub the only internals are bearings and an axle, unlikely that that’s causing the sort of ‘slippage’. you describe.
oh, and the tool that looks like a stick with some chain hanging off it is called a “chain whip”.
If the shop johnnies can make the sprocket slip with a chain whip while the lockring is “tight”, It could still be a sprocket that’s too narrow. It doesn’t have to be much to make a difference - the difference need not be enough to be easily visible to the naked eye. You say they tried a surly sprocket - is the surly definitely wider than the one you had on originally? It would probably need a vernier measurement to be sure one way or the other.
where are you located, and which shop are you taking it to?
located in north carlton and been taking it to ray’s on sydney road where i bought it from. the guy i’ve been dealing with is a great guy and very near to completing his own fixie so i’m pretty sure he knows what he’s talking about. would like to get into abbotsford more often but i’m never in richmond. might be worth heading over on my day off and getting a second opinion.
i’m sure if i hassled rays enough they’d be willing to try out a wider cog. i’ll put some more pressure on em…
any shops in north carlton/brunswick area you’d recommend chatting to? i’ve been into velohub(i think that’s the name of it?) on nicholson street but yet to get any work done by them.
I’m sure he’s a nice bloke and all but your interests might be better served by taking it to someone who is somewhere well beyond their first fixed gear bicycle. Go to one of Blakey’s recommendeds.
my favourite way of tightening a cog is putting the cog on at the bottom of a hill, and then hammering up the hill, tightening the lockring at the top.
sounding off on the other suggestions, especially try a spacer, i had a problem early on similar to yours, and it turned out to be a quarter turn on a lockring solving the problem (ie lockring wasnt butting up to the cog properly - a spacer might solve this issue for you)
seeing as i got so much help on this topic i thought i’d update everyone on the outcome…not that there’s much of one!!!
i took it to pony (i think her name is Sasha?) and had a chat to her about it. she was confident that it just needed to be tightened. she also felt there was no way i could get a spacer onto the thread and didn’t think there was any gap to worry about.
i realised i hadn’t actually tried it out after rays tightened it but didn’t think there was much point as they were quite sure it was fucked.
so anyway, after sasha promised to tighten it for me if i had any problems i switched it back onto the fixed cog.
haven’t had a single problem in the week since i changed back (touch wood). i guess it must’ve just loosened itself and needed tightening. whole lot of fuss over nothing!!
thanks again everyone, i’ll know to check the lockring first next time!!
Awesome that you got it fixed up, Sasha’s great and always willing to help.
About rays bikes on sydney road, I remember going in a while back asking for a new cog. The guy looked and me wierdly like I was from outer space. After explaining what I wanted they all whispered to each other and then their mech out the back came out saying “errr ahhhh no way man thats not possible, we would never do that, its unsafe plus it would come off with back pedalling”.
Every time I ride past the shop I shoot it with my imaginary machine gun.
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