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#1
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Old derailleur and chainrings, new chain and cassette
I recently had to replace my rear wheel, and switched from the old
6-cog freewheel to a freehub (Deore XT) plus an 8-speed cassette (Shimano HG50). The old chain was very worn - it had started to slip - so I replaced that too (Sram PC850). While doing the swap-out, I dug substantial quantities of black gunge (a solidly caked mixture of oil and mud, I think) from the rear derailleur. After I'd done this I noticed that the sprocket nearest the cassette was very wobbly - perhaps 5mm of side to side motion available at the edge of the sproket compared to the derailleur cage. This didn't seem likely to be very good but the old wheel was well and truly gone and I couldn't be bothered to reassemble everything while I asked some kind of expert, so I thought I'd carry on see how bad the effects were. In fact, it turns out that I have no difficulty shifting; I only had to adjust the endstops for the wider gearing range. After I got the hang of the new setup it seems quite adequate. I have non-indexed shifters and am very lazy, so I'm used to riding bikes with a poorer state of maintenance than perhaps most people here :-). Ie, I'm used to compensating for poor cables and shoddy old equipment, which I'm sure helps. Also, I haven't done anything about the front chainring set. It's still the old setup which came with the bike (some kind of Shimano). I don't experience any slippage and it shifts just fine. (Although posting reminds me that I need to adjust the inner endstop.) My main question is: have I done anything hideously wrong ? As I say I'm lazy but if I wonder I should swap out the derailleur and/or the chainring anyway to avoid having the chain wear excessively quickly. I used to lubricate the old chain with chainsaw oil as it was cheap, but experience with recent wet weather suggests it is quite quickly washed away (about one short journey in heavy rain seems to be enough to make it want re-oiling) which doesn't fit my lazy nature very well :-), so I've pretty much decided to go back to `three in one' or the equivalent. As advised by various sources I didn't add any oil when fitting the new parts. How soon should I think about oiling the chain ? I assume I shouldn't ever try to lubricate the new hub. (Of course, dismantling it periodically to repack with grease is out of the question.) The bike is a tourer (Raleigh Randonneur) which I use for commuting and other mainly urban trips, sometimes with substantial luggage and/or a trailer. -- Ian Jackson personal email: These opinions are my own. http://www.chiark.greenend.org.uk/~ijackson/ PGP2 key 1024R/0x23f5addb, fingerprint 5906F687 BD03ACAD 0D8E602E FCF37657 |
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#2
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Old derailleur and chainrings, new chain and cassette
On 2008-03-25, Ian Jackson wrote:
I recently had to replace my rear wheel, and switched from the old 6-cog freewheel to a freehub (Deore XT) plus an 8-speed cassette (Shimano HG50). The old chain was very worn - it had started to slip - so I replaced that too (Sram PC850). While doing the swap-out, I dug substantial quantities of black gunge (a solidly caked mixture of oil and mud, I think) from the rear derailleur. After I'd done this I noticed that the sprocket nearest the cassette was very wobbly - perhaps 5mm of side to side motion available at the edge of the sproket compared to the derailleur cage. Assuming you mean the little plastic sprocket (called a "jockey wheel") in the derailleur cage that's fairly normal and doesn't matter. Check the bolt through it isn't loose, but it usually isn't. They aren't on proper bearings (unless you have some vintage Campag stuff there) just bushings and especially the cheap stuff wobbles a bit. I suspect it actually works better that way-- things can be a little bit out of line without it mattering so much. [...] Also, I haven't done anything about the front chainring set. It's still the old setup which came with the bike (some kind of Shimano). I don't experience any slippage and it shifts just fine. (Although posting reminds me that I need to adjust the inner endstop.) My main question is: have I done anything hideously wrong ? It doesn't sound like it. You often don't need to change the front chainrings. As I say I'm lazy but if I wonder I should swap out the derailleur and/or the chainring anyway to avoid having the chain wear excessively quickly. See if it does. The derailleur wheels won't wear the chain (and actually the teeth on those can wear down to nothing with practically no ill-effects). The chainring probably could accelerate chain wear in theory. I used to lubricate the old chain with chainsaw oil as it was cheap, but experience with recent wet weather suggests it is quite quickly washed away (about one short journey in heavy rain seems to be enough to make it want re-oiling) which doesn't fit my lazy nature very well :-), so I've pretty much decided to go back to `three in one' or the equivalent. As advised by various sources I didn't add any oil when fitting the new parts. How soon should I think about oiling the chain ? When it's either starting to go a bit rusty or is covered in gunge. Which happens first depends on weather conditions and your generosity with the oil. Then clean it and oil it again. I assume I shouldn't ever try to lubricate the new hub. (Of course, dismantling it periodically to repack with grease is out of the question.) Correct, don't put any oil on the hub-- if it does anything it might interfere with the sealing and let the grease out or dreaded foreign bodies in. As for repacking I can't see much point. If it's a reasonable quality hub and you don't ride in severe rain or wash the bike with a hose the grease that's in there stays in there and all you achieve by repacking it is risking getting it dirty. Sometimes you can tell it's dried out because it starts to make a bit of noise. In that case repack, but it may be too late anyway. |
#3
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Old derailleur and chainrings, new chain and cassette
Ian Jackson writtificated
How soon should I think about oiling the chain ? It should be oiled *before* it starts to squeak, get stiff links etc. It should also be thoroughly cleaned before oiling or you'll drive tiny bits of grit inside the chain and *accelerate* wear (this is from experience). That said, peeps with posh groupsets need to be a bit anal about lube 'cos their cassettes and chainrings are often made of softer (but lighter) alloy rather than the steel of cheaper stuff. Oh, and they're stuff costs squillions more. |
#4
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Old derailleur and chainrings, new chain and cassette
Ian Jackson wrote:
I recently had to replace my rear wheel, and switched from the old 6-cog freewheel to a freehub (Deore XT) plus an 8-speed cassette (Shimano HG50). The old chain was very worn - it had started to slip - so I replaced that too (Sram PC850). While doing the swap-out, I dug substantial quantities of black gunge (a solidly caked mixture of oil and mud, I think) from the rear derailleur. After I'd done this I noticed that the sprocket nearest the cassette was very wobbly - perhaps 5mm of side to side motion available at the edge of the sproket compared to the derailleur cage. Lateral float on the upper jockey wheel is an intended design feature of all modern derailleurs. It helps indexed systems align properly. -- (Simon Brooke) http://www.jasmine.org.uk/~simon/ Q: Whats a webmaster? A: Like a spider, but nowhere near as intelligent. |
#5
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Old derailleur and chainrings, new chain and cassette
Ben C wrote:
On 2008-03-25, Ian Jackson wrote: I assume I shouldn't ever try to lubricate the new hub. Shouldn't be necessary if it really is new and a good brand. I have bought new-old-stock hubs though that just contained a small amount of dry grease. You may want to adjust the cones anyway as they can be too tight to start with. See http://sheldonbrown.com/cone-adjustment.html (Of course, dismantling it periodically to repack with grease is ....not... out of the question.) Correct, don't put any oil on the hub-- if it does anything it might interfere with the sealing and let the grease out or dreaded foreign bodies in. As for repacking I can't see much point. If it's a reasonable quality hub and you don't ride in severe rain or wash the bike with a hose the grease that's in there stays in there and all you achieve by repacking it is risking getting it dirty. Sometimes you can tell it's dried out because it starts to make a bit of noise. In that case repack, but it may be too late anyway. Don't leave it until it could be too late then - because too late could mean a lot of expense and inconvenience. Every so often it makes sense to clean and repack as a preventative measure. Use your own judgement as to how often - depending on model of hub and amount and type of use. ~PB |
#6
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Old derailleur and chainrings, new chain and cassette
In article ,
Pete Biggs wrote: You may want to adjust the cones anyway as they can be too tight to start with. See http://sheldonbrown.com/cone-adjustment.html The wheel rotates fine, so I think I don't need to do that. Ben C wrote: (Of course, dismantling it periodically to repack with grease is ...not... out of the question.) Well, you can speak for yourself. Personally I'm far too lazy for that. (Or if I'm allowed to put a nicer spin on it, I'm far too busy.) Sometimes you can tell it's dried out because it starts to make a bit of noise. In that case repack, but it may be too late anyway. Don't leave it until it could be too late then - because too late could mean a lot of expense and inconvenience. Every so often it makes sense to clean and repack as a preventative measure. Use your own judgement as to how often - depending on model of hub and amount and type of use. Are you suggesting that I should take it to the LBS to have it disassembled and repacked ? It's certainly not a job I'm going to do myself as I'll only do it a few times a decade - nowhere near enough to get at all good at it, and paying someone else to do it is a far better tradeoff. My own inclination, which you seem to refer to, would be to ignore it until there is some kind of symptom of a problem. -- Ian Jackson personal email: These opinions are my own. http://www.chiark.greenend.org.uk/~ijackson/ PGP2 key 1024R/0x23f5addb, fingerprint 5906F687 BD03ACAD 0D8E602E FCF37657 |
#7
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Old derailleur and chainrings, new chain and cassette
In article ,
Ben C wrote: Assuming you mean the little plastic sprocket (called a "jockey wheel") in the derailleur cage that's fairly normal and doesn't matter. Yes, that thing. Good. Check the bolt through it isn't loose, but it usually isn't. I didn't check it but it seemed very unlikely that anything in the vicinity was loose that shouldn't be :-). On 2008-03-25, Ian Jackson wrote: My main question is: have I done anything hideously wrong ? It doesn't sound like it. You often don't need to change the front chainrings. Oh, good. How soon should I think about oiling the chain ? When it's either starting to go a bit rusty or is covered in gunge. Which happens first depends on weather conditions and your generosity with the oil. Then clean it and oil it again. I've never cleaned a chain yet and I don't intend to start now :-). (Although I did clean my rear brake blocks with IPA when I changed the wheel and the resulting massive performance improvement can't have been entirely due to the new rim, so I'll probably clean my front blocks and rim too when I get a moment. Also, I have the most excellent brake squeal now.) IME the main thing which causes degradation is using it while not properly lubricated, by which I mean that it makes a different kind of noise. I've had quite adequate life out of chains just by oiling them when they start to sound like they need it. The problem with the chainsaw oil was that it tended to wash off. (Also, it's very thick at most temperatures and strands of it tend to get on the rim.) Since it's several new kinds of equipment now I'm not quite familiar with the normal kinds of transmission noise yet (the cassette seems to sound rather different to the way the freewheel used to), but I suppose I'll just wait to see if I can hear it when it starts to run out of lube. As for repacking I can't see much point. If it's a reasonable quality hub and you don't ride in severe rain or wash the bike with a hose the grease that's in there stays in there and all you achieve by repacking it is risking getting it dirty. I live in Cambridge where it rains quite rarely. I suppose I end up riding in heavy rain for less than an hour a year on average. -- Ian Jackson personal email: These opinions are my own. http://www.chiark.greenend.org.uk/~ijackson/ PGP2 key 1024R/0x23f5addb, fingerprint 5906F687 BD03ACAD 0D8E602E FCF37657 |
#8
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Old derailleur and chainrings, new chain and cassette
In article ,
Simon Brooke wrote: Lateral float on the upper jockey wheel is an intended design feature of all modern derailleurs. It helps indexed systems align properly. I see. Well, that's fine then :-). -- Ian Jackson personal email: These opinions are my own. http://www.chiark.greenend.org.uk/~ijackson/ PGP2 key 1024R/0x23f5addb, fingerprint 5906F687 BD03ACAD 0D8E602E FCF37657 |
#9
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Old derailleur and chainrings, new chain and cassette
Ian Jackson wrote:
In article , Pete Biggs wrote: You may want to adjust the cones anyway as they can be too tight to start with. See http://sheldonbrown.com/cone-adjustment.html The wheel rotates fine, so I think I don't need to do that. That's not a good enough test because a new wheel can rotate fine even when the cones are tighter than ideal. Bearings last much longer when the cones are no tighter than necessary. Fortunately there is an easy test with quick-release types. There should be some play in the bearings when the wheel is not fitted to the bike. Read the article for more on that. Note that none of this applies to cartridge bearings, only the traditional "cup and cone" type bearings - which Shimano still use for most of their models, for example. /snip Are you suggesting that I should take it to the LBS to have it disassembled and repacked ? It's certainly not a job I'm going to do myself as I'll only do it a few times a decade - nowhere near enough to get at all good at it, and paying someone else to do it is a far better tradeoff. You can get good at it in just one session with the help of Sheldon's instructions - but yes I would suggest taking it to a good LBS if you don't want to DIY. Of course a lot of cyclists can't or don't like to do these kind of jobs, and that's what bike shops are for. My own inclination, which you seem to refer to, would be to ignore it until there is some kind of symptom of a problem. By then the cups (hub bearing surfaces) could be ruined. It only takes a few dimples for them to be ruined, and you don't notice this damage happening. These can be so expensive or difficult to replace that it means a new hub - which can it turn mean a new wheel if it's not worth rebuilding the wheel. Wheels are expensive. ~PB |
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