C
Call me Bob
Guest
On 15 May 2005 04:36:57 -0700, "emma" <[email protected]> wrote:
>Sorry Guys, I don't totally get this yet - if I'm going with friction
>shifters, can I just use whatever comes to hand?
For the derailleur, pretty much, yes. Of the components involved in
changing gear the derailleur is basically passive, it simply does what
it's told to do. If you are using friction shifters, then it's *you*
who controls the amount of cable adjustment delivered, so almost any
derailleur will work (as long as the cage has enough capacity for
high/low combos).
The difference with an indexed setup is that the shifter is designed
to deliver a set amount of cable pull per shift (each click), and this
amount corresponds to the cog spacing on the cluster of gears at the
rear (the cassette). The critical thing here is that the cassette and
the shifter are matched, so again the derailleur is essentially a
slave.
If you wanted to move to an indexed set up, it's not the derailleur
you'd need to worry about so much as the gear cluster and shifters.
>For instance ebay has
>a chap selling a shimano 105 triple, front and rear mech and BB - could
>be a potential bargain - can I get this to work with my 5 cog rear hub
>, assuming the front mech is bottom pull.
That bundle will potentially work, you'd need to confirm a couple of
things first.
Bottom bracket size: he doesn't give a shell width, and that would
need to match your frame. It's probably 68mm, which could well be what
you need, but that should be checked. You can measure the width very
easily, just put a steel rule across that part of your frame where the
BB lives; measure accurately from one face to the other. You'll need
to ask the seller to confirm the dimension of the BB he is offering.
The bottom bracket axle length is 118mm, which suits the triple
chainset and is therefore probably close enough to what you will need,
but matching older frames with BB lengths can be a bit hit and miss.
If it's a little out you might have chainline issues.
His front mech is band on with a diameter of 28.6mm, does that match
your seat tube? If it doesn't you could always keep your existing
front mech and ebay the new one.
>If not, what would I need to do - change the rear hub to cassette?
>Would the wheel need to be redished if I put more cogs on it - Looks
>like the frame is going to be resprayed so could get it cold set at the
>same time if need be...
Your current 5 speed hub is too narrow to use with a modern 8 or 9
speed cassette. If you want to increase the gears at the back you'll
need a new wheel with a wider hub, and consequently the frame will
need cold setting. You can make this jump now, or at some point in the
future. If you buy something like the bundle you've spotted on ebay
then it should (provisos above) work fine for the moment, then, when
you are ready, you could buy a new wheel and modern cassette. At that
time you could also consider buying indexed shifters which would bring
you up to a fully modern drivetrain.
Alternatively, I think you mentioned you already have everything you
need to get up and running except for a rear derailleur? You could
just buy a stand alone rear mech and go with that for the moment.
"Bob"
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Email address is spam trapped.
To reply directly remove the beverage.
>Sorry Guys, I don't totally get this yet - if I'm going with friction
>shifters, can I just use whatever comes to hand?
For the derailleur, pretty much, yes. Of the components involved in
changing gear the derailleur is basically passive, it simply does what
it's told to do. If you are using friction shifters, then it's *you*
who controls the amount of cable adjustment delivered, so almost any
derailleur will work (as long as the cage has enough capacity for
high/low combos).
The difference with an indexed setup is that the shifter is designed
to deliver a set amount of cable pull per shift (each click), and this
amount corresponds to the cog spacing on the cluster of gears at the
rear (the cassette). The critical thing here is that the cassette and
the shifter are matched, so again the derailleur is essentially a
slave.
If you wanted to move to an indexed set up, it's not the derailleur
you'd need to worry about so much as the gear cluster and shifters.
>For instance ebay has
>a chap selling a shimano 105 triple, front and rear mech and BB - could
>be a potential bargain - can I get this to work with my 5 cog rear hub
>, assuming the front mech is bottom pull.
That bundle will potentially work, you'd need to confirm a couple of
things first.
Bottom bracket size: he doesn't give a shell width, and that would
need to match your frame. It's probably 68mm, which could well be what
you need, but that should be checked. You can measure the width very
easily, just put a steel rule across that part of your frame where the
BB lives; measure accurately from one face to the other. You'll need
to ask the seller to confirm the dimension of the BB he is offering.
The bottom bracket axle length is 118mm, which suits the triple
chainset and is therefore probably close enough to what you will need,
but matching older frames with BB lengths can be a bit hit and miss.
If it's a little out you might have chainline issues.
His front mech is band on with a diameter of 28.6mm, does that match
your seat tube? If it doesn't you could always keep your existing
front mech and ebay the new one.
>If not, what would I need to do - change the rear hub to cassette?
>Would the wheel need to be redished if I put more cogs on it - Looks
>like the frame is going to be resprayed so could get it cold set at the
>same time if need be...
Your current 5 speed hub is too narrow to use with a modern 8 or 9
speed cassette. If you want to increase the gears at the back you'll
need a new wheel with a wider hub, and consequently the frame will
need cold setting. You can make this jump now, or at some point in the
future. If you buy something like the bundle you've spotted on ebay
then it should (provisos above) work fine for the moment, then, when
you are ready, you could buy a new wheel and modern cassette. At that
time you could also consider buying indexed shifters which would bring
you up to a fully modern drivetrain.
Alternatively, I think you mentioned you already have everything you
need to get up and running except for a rear derailleur? You could
just buy a stand alone rear mech and go with that for the moment.
"Bob"
--
Email address is spam trapped.
To reply directly remove the beverage.
