I have just got a bike with one of these Shimano granny gears considerably larger than the other gears. Its a roughy I want to use to go to the library and shopping etc
The deraillier is a cheap one but seems to be designed for these gears (it says so on the arm!). but it doesn't have a screw adjusting its distance from the gear teeth and the inner most cog touches the largest cog. (I don't mean the two screws which act to limit the derailleur travel from high to low gear I mean the one which restricts the ammount the small cogs can be pulled toward the sprockets by tension in the chain)
I suspect that the chain is too short - perhaps these larger gears and deraillers have been added but the original chain left on. Does this sound right to you?
I have a new chain to fit and will follow the Richards' advice on the length of the chain but I wonder if anyone has any other advice.
I have just got a bike with one of these Shimano granny gears considerably larger than the other gears. Its a roughy I want to use to go to the library and shopping etc
The deraillier is a cheap one but seems to be designed for these gears (it says so on the arm!). but it doesn't have a screw adjusting its distance from the gear teeth and the inner most cog touches the largest cog. (I don't mean the two screws which act to limit the derailleur travel from high to low gear I mean the one which restricts the ammount the small cogs can be pulled toward the sprockets by tension in the chain)
I suspect that the chain is too short - perhaps these larger gears and deraillers have been added but the original chain left on. Does this sound right to you?
I have a new chain to fit and will follow the Richards' advice on the length of the chain but I wonder if anyone has any other advice.
If the chain is long enough to allow large chainring and large cog at the rear then it's not too short.
The problem you describe will usually be made worse by lengthening the chain, as the pivot point for the derailleur cage is usually below the upper jockey wheel.
"Harry 'Snapper' Organ" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I have just got a bike with one of these Shimano granny gears considerably larger than the other gears. Its a roughy I want to use to go to the library and shopping etc
The deraillier is a cheap one but seems to be designed for these gears (it says so on the arm!). but it doesn't have a screw adjusting its distance from the gear teeth and the inner most cog touches the largest cog. (I don't mean the two screws which act to limit the derailleur travel from high to low gear I mean the one which restricts the ammount the small cogs can be pulled toward the sprockets by tension in the chain)
I suspect that the chain is too short - perhaps these larger gears and deraillers have been added but the original chain left on. Does this sound right to you?
I have a new chain to fit and will follow the Richards' advice on the length of the chain but I wonder if anyone has any other advice.
If the chain is long enough to allow large chainring and large cog at the rear then it's not too short.
The problem you describe will usually be made worse by lengthening the chain, as the pivot point for the derailleur cage is usually below the upper jockey wheel.
"Harry 'Snapper' Organ" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I have just got a bike with one of these Shimano granny gears considerably larger than the other gears. Its a roughy I want to use to go to the library and shopping etc
The deraillier is a cheap one but seems to be designed for these gears (it says so on the arm!). but it doesn't have a screw adjusting its distance from the gear teeth and the inner most cog touches the largest cog. (I don't mean the two screws which act to limit the derailleur travel from high to low gear I mean the one which restricts the ammount the small cogs can be pulled toward the sprockets by tension in the chain)
I suspect that the chain is too short - perhaps these larger gears and deraillers have been added but the original chain left on. Does this sound right to you?
I have a new chain to fit and will follow the Richards' advice on the length of the chain but I wonder if anyone has any other advice.
-- Bean
"I've got a bike You can ride it if you like It's got a basket A bell that rings And things to make it look good I'd give it to you if I could But I borrowed it" Pink Floyd
A good rule of thumb is that when the chain is on the big chain ring and largest sprocket (i.e. full stretch - please correct me if that's the wrong gear combo) the jockey wheels (pulleys) should be directly one on top of the other. If the tension pulley (bottom jockey wheel) is too far forward then the chain is too short. -- Bean Remove "yourfinger" before replying
On Fri, 12 Oct 2007 17:22:47 +1000, Bean Long <[email hidden]> wrote in aus.bicycle:
Quoted message said:
Harry 'Snapper' Organ said:
chain length suff <snipped>
A good rule of thumb is that when the chain is on the big chain ring and largest sprocket (i.e. full stretch - please correct me if that's the wrong gear combo) the jockey wheels (pulleys) should be directly one on top of the other. If the tension pulley (bottom jockey wheel) is too far forward then the chain is too short.
Yes that is the way I have always understood it to be done
On Fri, 12 Oct 2007 17:22:47 +1000, Bean Long <[email hidden]> wrote in aus.bicycle:
Quoted message said:
Harry 'Snapper' Organ said:
chain length suff <snipped>
A good rule of thumb is that when the chain is on the big chain ring and largest sprocket (i.e. full stretch - please correct me if that's the wrong gear combo) the jockey wheels (pulleys) should be directly one on top of the other. If the tension pulley (bottom jockey wheel) is too far forward then the chain is too short.
Yes that is the way I have always understood it to be done
