Replacing gears

[Graham1]

I am going to replace my compact double with a triple, I have the bits namely a triple chainset a triple front derailleur and a med cage rear derailleur plus new chain and cassette. My problem is I am not very technically minded so my wife works with someone who said he would fit the bits and set the gears up, he reckons that you need a jig for the rear derailleur I would have thought that it would just be a matter of removing the old one and bolting the new one in place,can anybody give me some info on this jig or if one is needed.Ta

 

[I am Spartacus]

To swap over from a double to triple...
a Jig for replacing the actual rear mech...? dunno what 'he' is going on about to be honest .
Obviously you should make life easier by sticking with same manufacturer.
However, you may need to heed..
perhaps you may/will require a god awful long cage rear for your triple and not a medium and
check your bottom bracket.. that may need to be a 'wider' fit
oh.. and yes your sti shifter may not be compatible with a 3 ring..

on last note, with a carefully thought about compact and cassette combination, you actually can get all the useable gears to get you up those hills (presuming this is reason to go triple, yuk) .. to save you all the hassle... but that does require a bit of thought

disclaimer:all advice guaranteed not to actually work

 

[PpPete]

perhaps you may/will require a god awful long cage rear for your triple and not a medium and
check your bottom bracket.. that may need to be a 'wider' fit
oh.. and yes your sti shifter may not be compatible with a 3 ring..

What Shimano call a Medium cage rear derailleur is fine for most triples. They don't make a "long cage". Only Short "SS" and Medium "GS" models.

Bottom bracket....typically a longer spindle is recommended for triples, but the difference is so small I'd try with the one you've got.

+ if your shifters are STI for a double that will need changing. Any other kind of shifter (downtube, bar end, thumbies) should cope just fine.

And as Spartacus says, make sure you know exactly what ratios you want and where before you change..... There's many people that find the typical Shimano 52-42-30 or 52-39-30 does not provide the gearing they want/need. I'm one of them, I've already built up a "custom" cassette to try & get around it, but now I'm thinking of changing the chainrings too.

 

[ianrauk]

Have changed a rear derailleur no problem without a jig. As long as the frame & gear hanger are not out of alignment the new derailleur will bolt straight on.

 

[Graham1]

Thanks people
The bottom bracket is fine according to the shimano website as are the shifters.

 

[PpPete]

In that case....you can do the job yourself. Really nothing difficult at all. I wouldn't give it to someone who thinks you need a jig to change a derailleur, however if he is into bikes you might be able to borrow a crank extractor (if sq.taper or octalink) or the splined thingy (if it's HT2). But even if you can't they are not expensive - or many LBS will help if it's just a small job like removing cranks and you go in middle of working week when they are quiet.
Everything else is allen keys, screwdriver, small spanner - which you should have anyway, in a multitool in your saddlebag(?) if nowhere else.