How to set up a 21 speed from scratch

[Zippy]

I am rebuilding my bike from the frame and all the cables, sleeves, rear derraileur and nuts and bolts are to be replaced again.

Fortunately I have the cables and stuff that I took off so I know they are correct lengths and can replace any new ones using hte old lengths as a guide.

My question is how do I set up my rear derraileur and front chainring shifter from scratch as this is not just an adjustment exercise?

 

[MacB]

At the very least I'd read up on Sheldon Browns site and also find instructional videos at Park Tools and Bicycle Tutor. If you can afford it then I'd spend £30ish to pay a bike mechanic to supervise and train while you set it up.

 

[Zippy]

Thanks for the sites info which I have found useful.

Wrt the tech at my lbs, he should be paying me £30 after the pants service I got from him last time - which is why I'm DIYing!

 

[GrasB]

Exactly what is your problem with setting up? Sheldon B's & Park Tool's web sites should have enough information to work out how to set things up.

In all honesty though setting up from scratch is really just the same as fettling a current setup only the initial adjustments are bigger.

 

[MacB]

Thanks for the sites info which I have found useful.

Wrt the tech at my lbs, he should be paying me £30 after the pants service I got from him last time - which is why I'm DIYing!

Ah, fair comment I should have said 'decent' bike mechanic

GrasB, it's a daunting prospect if you've not done it before and could prove expensive, or even dangerous, if mistakes are made. Folks aren't posting in Know How, asking for help, coz they're too lazy. I can also vouch for the fact that all the internet reading, and video watching, you like, isn't the same as real life.

There's plenty of sections on here to mock/abuse/sneer at others, I think Know How should be immune from this.

 

[GrasB]

I wasn't mocking etc. I was wondering what his problem is... Setting up gears properly has a number of elements to it & rather than give a reasonably detailed description of how to do all of it, which the park & SB sites do, it's easier to give very specific hints & tips on how to do a certain part of the setup.

 

[PpPete]

Cassette on wheel?
Wheel on bike?
Chainset on?
Adjust chain length if necessary. Big rings front & back + 1 or 2 links max
Fit derailleurs. Should come with instructions or see sites mentioned above.
Thread cables. Pull "finger tight" when on small rings front & back. Secure at mech end.
Check cable length does not interfere with steering.
Adjust cables as normal.
Double check limit screws front & back.
Can't think of too many things that can go wrong....

done it dozens of times, simples, and then last time I did it - this happened:

Just take it steady, one step at a time, and don't forget to check the limit screws.

 

[MacB]

I wasn't mocking etc. I was wondering what his problem is... Setting up gears properly has a number of elements to it & rather than give a reasonably detailed description of how to do all of it, which the park & SB sites do, it's easier to give very specific hints & tips on how to do a certain part of the setup.

My bad then, it was just the way the opening line read:-

Exactly what is your problem.......

Must work on my reading and comprehension

 

[Zippy]

Cassette is on, chainrings ok, derraileur ok and front shifter was never moved so that is ok.

I suppose my main problem is cables - how much tension should be be under initially and how much by fine tuning - need to get sufficient cable tension to prevent the chain from falling off the hardest gear on the cassette, but how much of this is cable length and how much tuned in from the derraileur tensioners.

Same with front shifter - how much is cable tension and how much from the fine tuners there.

Is there a base tension I set up before messing with fine tuning?

I've tuned indexing before, but not a lot of experience with cable replacement.

 

[jimboalee]

If it's Shimano kit, all the tech blurb is on their website.

 

[GrasB]

At the rear derailleur wind the adjuster all the way in then back it out 1/4 of the adjustment, same for the shifter but give that about 1 turn of adjustment. Pull the cable through until it's fairly taught & clamp down. Dial in the indexing as you would normally at the rear derailleur. I prefer to pull the cable rather tight initially & then release some tension. Similar method for the front but you usually only have the shifter indexing adjustment to change the tension.

 

[jimboalee]

Even BEFORE threading the cable thru to the rear mech, SET THE LIMIT STOPS. Get the chain running on it and use your hand to push the mech to the ends of it's travel to check the chain doesn't fall off the end.

If you've set the stops OK to the manufacturer's instructions, it shouldn't.