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Shimano 105 (rd-1056)
#1
So I basically know very little about bicycle repair (not technical by nature either), but I found an old racebike just missing wheels, a steer and pedals.

I managed to get everything together and in working order, but somehow i can't get the shifting from my back wheel right. I did the thing with the limits (H and L screws), and I tried turning the adjusting barrel, but the shifting of the highest (smallest cogs right?) four out of eight gears doesn't work properply (up nor down). It's like I shift perfectly for the first four, then only shift half a cog, so I have to shift twice, and from that moment on I'm in trouble. At that point, when I put pressure on the pedals (so only when I'm actually riding) it starts flipping back and fro...

I found that the derailleur said it's a Shimano 105 rd-1056, and the shifter on the steer says Shimano Sora.

Help would be greatly appreciated...
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#2
(04-28-2013, 11:54 AM)Belgian Wrote:  So I basically know very little about bicycle repair (not technical by nature either), but I found an old racebike just missing wheels, a steer and pedals.

I managed to get everything together and in working order, but somehow i can't get the shifting from my back wheel right. I did the thing with the limits (H and L screws), and I tried turning the adjusting barrel, but the shifting of the highest (smallest cogs right?) four out of eight gears doesn't work properply (up nor down). It's like I shift perfectly for the first four, then only shift half a cog, so I have to shift twice, and from that moment on I'm in trouble. At that point, when I put pressure on the pedals (so only when I'm actually riding) it starts flipping back and fro...

I found that the derailleur said it's a Shimano 105 rd-1056, and the shifter on the steer says Shimano Sora.

Help would be greatly appreciated...

Sounds like the rear mech isn't straight, if you look at the mech standing at the back of the bike does it look straight? Some pictures would help resolve the issue
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#3
I'll take some pictures when it's light again tomorrow. If it is that, then I'm guessing I can't fix that myself?
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#4
Pictures added, hope they clear it up!
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#5
It is (at least for me) impossible to judge the dérailleur and hanger alignment by eye only. There is a tool for that. The bike being an old one, you definitely should check that! There is some trick with using the front wheel to do that, afaik you removed the dérailleur and threaded in the front wheel and then tried to see if the wheels would end up being parallel.
However, from your description it could also be something else. Since it is the smallest sprockets you are having problems with you might want to check the cables and housing. A frayed cable or slightly sticky cable can cause just enough friction that the dérailleur spring cannot overcome it when close to fully extended - or maybe the spring is not springy any more, I saw that on some of my bikes (but they were older than that at this point).
Definitely check the alignment and also the cables. Since it was an older bike, did you replace the cables and also the brake pads? Especially the latter is a good idea. I like KoolStop.
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#6
Thanks, I'll check the cables and housing and if I don't find anything, I think I'm gonna leave it to a Pro. Hope it works out.
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#7
(05-02-2013, 08:08 PM)Belgian Wrote:  Thanks, I'll check the cables and housing and if I don't find anything, I think I'm gonna leave it to a Pro. Hope it works out.

So it wasn't the cables or the housing, what the bicycle shop said was that the chain was simply worn out, and that I'd have to not only buy a new chain but also new cassettes.

Bummer
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#8
This simply does not fit the description of the problem. A worn chain usually leads to skipping under load, but not to the dérailleur not moving to the correct gear, at least I have not experienced that...
Still, on an old bike chain and sprockets can be worn. You will need a chain tool and a cassette tool, they are something every cyclist should have and be able to use. If you shop around for chain and cassette on the interwebs the tools basically pay for themselves.
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#9
(05-08-2013, 07:15 PM)Joe_W Wrote:  This simply does not fit the description of the problem. A worn chain usually leads to skipping under load, but not to the dérailleur not moving to the correct gear, at least I have not experienced that...
Still, on an old bike chain and sprockets can be worn. You will need a chain tool and a cassette tool, they are something every cyclist should have and be able to use. If you shop around for chain and cassette on the interwebs the tools basically pay for themselves.

The skipping under load thing happens as well, so i think they're indeed worn.
It's just a bit sour since the bike cost me less than the new chain and sprockets will.
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#10
(05-08-2013, 08:21 PM)Belgian Wrote:  The skipping under load thing happens as well, so i think they're indeed worn.
It's just a bit sour since the bike cost me less than the new chain and sprockets will.

You might ask them to check the "deraileur hanger alignment" when they replace the chain. It's a quick check and if it was bent it would explain the shifting issues. Everything looks straight in the pictures, but a see a gash on the rear der. in just the spot you'd expect if it had had a minor crash.

If you got that bike for less than the cost of a chain and cassette, you probably got a very good deal on the bike (or they're way overcharging you for the new parts Smile )
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#11
(05-08-2013, 10:24 PM)DaveM Wrote:  You might ask them to check the "deraileur hanger alignment" when they replace the chain. It's a quick check and if it was bent it would explain the shifting issues. Everything looks straight in the pictures, but a see a gash on the rear der. in just the spot you'd expect if it had had a minor crash.

If you got that bike for less than the cost of a chain and cassette, you probably got a very good deal on the bike (or they're way overcharging you for the new parts Smile )

Bought it for a little under 50€ (total), which is about what a chain and cassette would cost (if I install them myself).

Started tinkering with repairs because old bikes, and 'broken' bikes are quite easy and cheap to come by. People throw away entire bikes because one of the wheels is bent double, or because the chain and cassettes are rusty.

There is usually very little wrong with most of the bikes (which is why my limited scope of bike-repair skills usually suffices).
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#12
Well, if that works out ok you got a nice bike for under 100€. I would totally get that offer... but she-who-must-be-obeyed is right in telling me that we do not have space to sore more bikes Wink
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