new derailleur, gears slipping

[KateK]

I've got an old 1980s Raleigh Wisp which had a Sachs Huret derailleur which I do about 130 miles a week on. Last week I had a new shimano 6 speed block and chain put on, I've had this combination several times and it works fine. My LBS guy said that the old derailleur was knackered, he showed me: there is a lot of play in the joints. He said he was worried that it was getting to the point where it would foul the spokes. He had a second hand shimano tourney derailleur that he put on for nothing. The problem is that the gearing is now temperamental: taking to long to change gear or dropping out of gear when I'm negotiating traffic junctions. It's not easy to get back in either, and I'm used to friction gears so it's not just ineptitude. He took a look at it and the chain seems to stay between gears. I kept the old derailleur but putting it back on is really not an option. The current setup is not sustainable as even with really careful use it drops out in the most difficult places - and with the current weather it is very difficult to fine tune by ear.
Has anyone any suggestions?

 

[RecordAceFromNew]

Has anyone any suggestions?

While other reasons are possible, everything you described most likely point to a cabling issue. Did he change the gear cable housing? If so there is a possibility that the housing is not fitting snugly within ferrules, causing the housing to become compressible/springy and therefore can't hold a shift. The other possibility is that the friction shifter is slipping - it can usually be tightened manually at the shifter by a screw or knob. One thing you could try is to give an exposed bit of the gear inner cable a good yank - it will expose any shifter slip, and may help seating poorly fitted housing in the ferrules.

A slightly curious phenomenon you described is "taking to long to change gear" while you are using "friction gears" - perhaps you can confirm that your system was/is not indexed (i.e. shift with clicks), or perhaps it took too long only because you had to hunt around. The latter could be due to a) the Tourney rear mech likely require a different amount of cable pull to traverse the rear sprockets compared to an old Huret, or b) the cable housing is compressible (when it shouldn't). I am saying it is curious because one thing about friction shift is the shift should be quick, even if it can't hold the shift stable for some reason.

 

[Hacienda71]

If you have friction shifters then it sounds more like they need tightening, rather than the mech or possibly a sticking cable. Not sure how the mech would cause your symptoms though.

 

[KateK]

A slightly curious phenomenon you described is "taking to long to change gear" while you are using "friction gears" - perhaps you can confirm that your system was/is not indexed (i.e. shift with clicks), or perhaps it took too long only because you had to hunt around. The latter could be due to a) the Tourney rear mech likely require a different amount of cable pull to traverse the rear sprockets compared to an old Huret, or b) the cable housing is compressible (when it shouldn't). I am saying it is curious because one thing about friction shift is the shift should be quick, even if it can't hold the shift stable for some reason.

No it is definitely friction gearing, with levers on the stem post. "taking too long" means when I change gear there is a godawful rattling and my feet spin pointlessly round and round. I then try adjusting the lever until I can get the chain to catch by which time I'm almost at a standstill. The Tourney derailleur is designed to be used with indexed gears though: could this be a problem?
I tried the wingnut on the lever but it seemed fully tightened (couldn't tighten it any more). I agree it sounds like a loose shifter. I'll have another look tomorrow, but my LBS guy is pretty good at doing cable stuff:- he put in a new cable for the new derailleur because it needed to be longer, so it can't be rusty.

 

[Hacienda71]

The rear mech has nothing that prevents it working with a friction shifter. Sti type/indexed shifters simply regulate the amount of cable pulled. In theory precise as long as they are set up well, but no ability to trim the rear mech like friction.

 

[KateK]

ok, thanks, I'll have a look at the cable tomorrow

 

[mrandmrspoves]

Also worth checking that the cable is attached to the deralleur correctly. It is easy to clamp it in the wrong position and this could easily explain the problems you describe.

 

[RecordAceFromNew]

"taking too long" means when I change gear there is a godawful rattling and my feet spin pointlessly round and round. I then try adjusting the lever until I can get the chain to catch by which time I'm almost at a standstill. The Tourney derailleur is designed to be used with indexed gears though: could this be a problem?
I tried the wingnut on the lever but it seemed fully tightened (couldn't tighten it any more). I agree it sounds like a loose shifter. I'll have another look tomorrow, but my LBS guy is pretty good at doing cable stuff:- he put in a new cable for the new derailleur because it needed to be longer, so it can't be rusty.

It is hard to diagnose a problem remotely with any degree of precision, but your feet spin pointlessly round and round when you shift gear raises an entirely different red flag - an inaccurate or slipping rear shift would not allow your feet to spin pointlessly - such a phenomenon indicates a freewheel with loose cogs or faulty internal ratchet/pawl that fails to engage and therefore slips. You see since there is never enough room for a chain to fall between cogs at any rear block, you should always be in gear, albeit probably at a wrong gear, and the resistance should always be significant and should never let your feet spin pointlessly.

The Tourney being designed for indexed shifting has nothing to do with your problem, nor is the way the cable attached to it likely be the cause because that primarily affects indexing precision.

 

[young Ed]

could be new cable has stretched and now settled in (normal over the first 100 or so miles) and it just needs adjusting
i recently fitted s new front mech gear cable and after about 100 miles i couldn't change into 3'rd chanring it had stretched that much
Cheers Ed

 

[young Ed]

It is hard to diagnose a problem remotely with any degree of precision, but your feet spin pointlessly round and round when you shift gear raises an entirely different red flag - an inaccurate or slipping rear shift would not allow your feet to spin pointlessly - such a phenomenon indicates a freewheel with loose cogs or faulty internal ratchet/pawl that fails to engage and therefore slips. You see since there is never enough room for a chain to fall between cogs at any rear block, you should always be in gear, albeit probably at a wrong gear, and the resistance should always be significant and should never let your feet spin pointlessly.

The Tourney being designed for indexed shifting has nothing to do with your problem, nor is the way the cable attached to it likely be the cause because that primarily affects indexing precision.

he could be going super fast and his legs and keeping up so the free wheel kicks in?! sorry will get my coat now
Cheers Ed

 

[KateK]

Well, had a look at shifter and I tightened it as far as was practical : I still have to be able to change gear! Went out for ride and it was just as bad. The chain seems to get caught between gears. When I was cleaning it you can see it hopping on the gear. This is not the chain, I've had two chains on this bike in quick succession because my LBS didn't have a shimano chain in so gave me another temporarily. Could it be the spring on the derailleur? The chain seems quite loose when I'm cleaning and I'm sure my LBS would have got the right chain length.

 

[RecordAceFromNew]

Well, had a look at shifter and I tightened it as far as was practical : I still have to be able to change gear! Went out for ride and it was just as bad. The chain seems to get caught between gears. When I was cleaning it you can see it hopping on the gear. This is not the chain, I've had two chains on this bike in quick succession because my LBS didn't have a shimano chain in so gave me another temporarily. Could it be the spring on the derailleur? The chain seems quite loose when I'm cleaning and I'm sure my LBS would have got the right chain length.

The chain is not too loose if it is not droopy and close to doubling up at the rear mech when you are on the smallest cog at the back. It is also unlikely the issue if slipping can occur in lower gears (i.e. when the chain is on the larger rear sprockets).

For 6 speed chains between 7.1mm to 7.8mm wide are all fine.

Skipping/slipping can also happen if the rear derailleur or its hanger is bent (i.e. not in the same plane along the bike), and would be exacerbated by a chain having a stiff or bent link. It is probably worthwhile turning the bike upside down (keeping the handlebars off the floor with some cushions), spin the crank, and watch what happens as you shift through the gears.

 

[KateK]

Well, my LBS has found an old Sachs huret rear derailleur in better nick on an old kid's Raleigh and he's going to try that. I'll take the old one in so we can compare. He says he is at a loss as to why the TZ won't work. He wouldn't have put a damaged derailleur on, and I've done 100 odd miles on this chain so it would have softened up by now. If it works with the kid's kit it will give me time to source a newer replacement.

 

[KateK]

Thanks for your help anyway

 

[PatrickPending]

b-screw maybe. The one occasion I had a bike shop fit a chain, they didn't remove any links and it was too long. So don't discount that.
Oh you're better off with SRAM or KMC chains IMO - the 'missing link' joining system is far better than Shimano...