Tonight I'll be fitting my 1st front & rear mech

PostieJohn

A la the cable thread earlier in the week, which was really helpful and I got some good tips from, thanks.
I'll now be installing the front and rear campag Veloce mechs.

Although I've made adjustments before, I've never set them up from the very beginning.

Any help/tips/advise will be greatly appreciated, esp as youtube seems less helpful, this time.

I'm not even sure where the cogs and shifters should be first off.


Ta muchly.

neeb

Some random tips based on my experience (certainly not comprehensive).

- be very fussy about getting the position and angle of the front derailleur correct. The instructions tell you how to do this.

- try to stretch the inner cables before final attachment / derailleur adjustment, and have them taut, but not overly so, when doing up the fastening screws. Have the barrel adjusters screwed about 3/4s of the way in first (you are more likely to need to tighten the cables initially but you might possibly need to loosen them).

- make sure you thread the cables in the right places underneath the washers / fastening screws. The diagrams in the instructions can be a little confusing, but particularly with the rear, it is possible to thread the cable wrongly under the screw. This will appear to work fine initially but will cause all sorts of subtle shifting problems due to the slightly different angle of the wire. If in doubt, look at some close-up photos on the internet.

- try to use a torque wrench and don't be tempted to exceed the recommended torques for the cable fastening screws. Although the torques seem quite small, if you tighten them too much you will crush the cable and actually reduce friction, making the cable more likely to slip. This also goes for brake cables.

- set the limit screws correctly, then adjust the indexing with the barrel adjusters on the frame.

- be prepared to make the final fine adjustments to the indexing during the first ride. The shifting never seems to work quite the same under slight load as it does on the workstand.

giant_man

Let us know how you get on postiejohn, interesting thread ....

anto164

One thing i always fail to do is tighten the cable clamp on the mech tight enough.

Make sure that's tight otherwise the cable will slip through!!

neeb

anto164 wrote:

One thing i always fail to do is tighten the cable clamp on the mech tight enough.

Make sure that's tight otherwise the cable will slip through!!

You might actually be tightening it too much (see above). Once the cable is really squashed it slips a lot more easily, especially if you need to take it out and put it in again. Best to use a torque wrench and tighten to the specified torque, which only compresses the cable slightly without really squashing it.

Herbsman

The Park Tool repair help website is the answer to all of these questions. Follow the step by step instructions and you cannot fail.

Fenred

Herbsman wrote:

The Park Tool repair help website is the answer to all of these questions. Follow the step by step instructions and you cannot fail.

+1 Park tools is very good. Also youtube can help is you get stuck.
I always find front mech is a PITA until you've done it a few times and get to know what you are doing.

Take your time, be patient and crack open a couple of beers whilst fettling!

anto164

neeb wrote:

anto164 wrote:

One thing i always fail to do is tighten the cable clamp on the mech tight enough.

Make sure that's tight otherwise the cable will slip through!!

You might actually be tightening it too much (see above). Once the cable is really squashed it slips a lot more easily, especially if you need to take it out and put it in again. Best to use a torque wrench and tighten to the specified torque, which only compresses the cable slightly without really squashing it.

It's not.

When i tighten i tended to nip it up, then add a quarter turn. Cable never even squashed!

PostieJohn

OK chaps, we are down to specifics, now.
I've gone at it like a bully in a china shop, and realised that won't work.

I've now calmed down, I feel I'm pretty close for the front mech.

But the rear, is jumpy, has never shown any desire to go into the 3rd smallest cog, and I'm very close to tw@tting it with a hammer, to get it into the biggest cog.

I have been gentle, I have been barrel and screw adjusting but it still jumps over 3 and really won't go up top (in the small front) unless I push it up there.


HELP.

Fenred

Congrats on FD, thats the hard bit done!

Put the hammer down and relax, this is the hardest part of bike maintenance imo so take your time (hence why I recommended a couple beers! 8)

sounds to me like cable tension, dont go mad, just quarter turns on the barrell and keep shifting.

Is the RD shifting to all the other gears ok?

PostieJohn

The gears it wants to shift to, it's silky smooth.
Then a little 'lumpy' when nearing a 'bad' one.

Not to mention the flat refusal for the biggest cog.

Ben6899

Flat refusal for the 25 or whatever you have next to the spokes screams: "low limit adjustment error" to me. Check your limit screws and then check them once more.

Good luck and keep us posted.

Fenred

Ben6899 wrote:

Flat refusal for the 25 or whatever you have next to the spokes screams: "low limit adjustment error" to me. Check your limit screws and then check them once more.

Good luck and keep us posted.

Haha!

Indeed, get your limit screws set first, then concentrate on your indexing.

It's really tough first time out, when I built my first bike I couldnt sleep for thinking about it and was out in the shed at 4.30am trying to get the drivetrain running right.

Start again PJ, take your time and "feel" your way through it. Its difficult to describe on-line but you'll get there, refer back to Partk tools and check YT for practical demo's.

Limits first then indexing (cable adjustment) next...It'll happen, its not black magic.

Good luck, as above let us know how it goes/if you have probs.

PostieJohn

This is going to be quite hard to explain, so bear with me.

IT's as if I have too much 'room' around the small cog.
As I shift up to 10 it won't go and now struggles to 9.

But coming back down when I get into the smallest gear I can still click on a few more spaces.

As it's a new build with second hand parts (except the cables) is there something obvious I'm missing in the set up, as I have been in and out with limit screws to no avail.

Ben6899

Okay I think I may know what you need to do.

1. Unclamp the cable at the rear mech.
2. Zero the gear lever by pressing the thumb-shifter until there are no clicks.
3. Pull the cable inner through the outer to make sure it's bedded into the lever recess.
4. Start again.

Where 'Start again' = set limit screws, attach cable at rear mech, set tension as per Campagnolo instructions. It's important to follow the indexing guide and set up on the 9th sprocket as the rear mech pull is not linear.

Ben6899

Do you have the technical documents? They can be downloaded at the Campagnolo website.

PostieJohn

Reading instruction what kind of bloke do you take me for!!.

Thanks for the advise, all joking aside I do have the tech stuff open in the very next window.
Sometimes though I just need to be told.

Think of me as your Gran, and the rear derailleur as an i-phone, you'll be fairly close to what you're up against!.

g00se

On the rear mech, once the limit screws are set (max and min derailleur position), the changes up and down the sprockets should be similar in the same direction even when the indexing is not set right.

eg. If the indexing is out, then it'll be slow/skipping going up the gears, but too eager coming down (or vice-versa).

This is because the amount the cage is moving per click is the same, it's just that it's not centering on each sprocket. hence the need to use the adjustment barrel.

If it's behaving differently across the cassette, (fine at the top but under-shifting when getting to the top) then it looks like the index movement is too-small for the actual distance between the sprockets.

This could be as simple as a previous poster has said - in that the cable is attached on the wrong side of the bolt (putting the cable at an incorrect angle so a single cable pull doesn't move the mech enough). Double check what you have done and the manual/screenshots.

Alternatively, you could have mismatched levers/mech/cassette - eg, an 11-speed campag ergo shifter with 10 speed cassette.

g00se

Sorry - just saw the bit about having clicks left over when you get to the small cog. Ben is right, either you didn't start with the mech in the highest position, or you didn't take the cable slack up when attaching the cable.

mfin

Make sure the shifters in top gear.
Start with no cable to rear mech, mech will be in top gear.
Pedal the bike in a stand.
Adjust the high screw till top gear is running right, look behind at the top jockey wheel to see its in-line with the top cog on the cassette.
Then push the rear mech body with a finger or two all the way to bottom gear, and adjust the low gear screw as you need to get it running smoothly in lowest gear.
You should now have a mech that runs in top when you pedal, and you can push the mech by hand to bottom gear and it'll all run fine.
Then, pull the cable through taught with your hand and do the bolt up on the cable, just beforehand, wind the adjuster all the way clockwise, so youve got lots of anticlockwise movement to tighten the cable up and get the tension right and all the gears behave when you shift around them.

(If you cant get enough tension cos you run out of adjustment on the barrel adjuster, then wind it all the way back in cos you'll need to make sure the cables more taught than when you first clamped it, so go back to that step)

*If it still doesnt behave, have you got a long enough final bit of outer running to the mech, is the curve too tight, and are the cables lubed? If they're prelubed fine, if not, lube them... annd are all the ferrules all sat nice and is the cable run all nice and 'friction free'?

arlowood

Hi PostieJohn

mfin's description is spot-on but if you need a bit of visual prompting have a look at this YouTube vid. Clear and concise explanation of how to get your indexing set up after you have set the limit screws for the high and low cogs.

http://www.youtube.com/watch?v=SkzvfCaIbyQ

It's based around a Shimano Dura Ace set up but the principals are the same for Campag.

Hope this helps

PostieJohn

Thank you everyone, this should be a Sort Out Your Mech sticky.

I read all the last bits of advise following predominately mfin's, and it's all come together, pretty well.
I am now in the 'very minor tinker' zone, but will save that until after couple of spins out.

I have now completed the bike, which has become my alter ego it's a bit blingy for me.

If you want to have a look at what you have all helped to build, it's in the My Road Bike section, as - my bianchi winter 'hack'.

balthazar

@neeb- your advice was nicely composed, thoughtful, and I think generally right. However, I don't think you need a torque wrench to clamp a cable. You just clamp the damn cable. I think this is "torque wrench mania"..!

You claim that an "over-tightened" cable is in fact more loosely retained than a "properly" (less) tightened one. Please provide some evidence for this (or retract the claim). As counterpoint, I say a mashed cable may be unnecessary and annoying in future, but it isn't loosely retained.

neeb

balthazar wrote:

@neeb- your advice was nicely composed, thoughtful, and I think generally right. However, I don't think you need a torque wrench to clamp a cable. You just clamp the damn cable. I think this is "torque wrench mania"..!

You claim that an "over-tightened" cable is in fact more loosely retained than a "properly" (less) tightened one. Please provide some evidence for this (or retract the claim). As counterpoint, I say a mashed cable may be unnecessary and annoying in future, but it isn't loosely retained.

I can't provide conclusive evidence, but a bunch of different personal observations come together to convince me.

In the past I used to torque cables slightly tighter than recommended. If the instructions said 5Nm, I'd tighten them to 7Nm, either with a torque wrench or by feel with a standard allen key. I had one or two incidents of brake cables slipping, admittedly quite old ones that probably could have done with changing. I noticed that the washers that pressed the cables down often got a heavy imprint of the cable in them, and the cable was pretty much squashed flat.

I also notice that when the screw is torqued to the recommended torque it doesn't squash the cable, or at least only a little bit. The cable more or less retains its round profile.

I haven't had any incidents of cables slipping since I started always torquing to recommended torques with new cables.

I'm no engineer, but my assumption is that an unsquashed, rounder cable has more friction than a squashed one that is torqued higher, maybe due to broader profile and/or elastic forces that are not present when the cable is flattened?

If something like this wasn't the case, why would manufacturers (Campagnolo in my case) recommend 5Nm rather than a higher torque?

I also actually find it easier to use a torque wrench than to have to worry about possibly not tightening the bolt firmly enough or else stripping the thread.

balthazar

neeb wrote:

I'm no engineer, but my assumption is that an unsquashed, rounder cable has more friction than a squashed one that is torqued higher, maybe due to broader profile and/or elastic forces that are not present when the cable is flattened?

If something like this wasn't the case, why would manufacturers (Campagnolo in my case) recommend 5Nm rather than a higher torque?

I can think of two reasons for such a spec: it doesn't needlessly deform the cable, as you say; and the hardware itself may be liable to strip at higher values. I don't think you can assume that a tighter fixing somehow reduces the clamping force. I think you have an odd visualisation of the way a cable is compressed.

This tangent doesn't have much significance to the OP, but I just think it's interesting why people are so certain about things, to make claims with such conviction.

neeb

balthazar wrote:

This tangent doesn't have much significance to the OP, but I just think it's interesting why people are so certain about things, to make claims with such conviction.

When it comes down to it it's due to empirical observation. I may or may not have strange ideas/hypotheses about how cables are squashed, but at the end of the day my cables slip when torqued higher and they don't when they are torqued to spec.

I think I also read somewhere, somewhen that squashed cables didn't hold as well. Not 100% on that though.

balthazar

neeb wrote:

balthazar wrote:

but at the end of the day my cables slip when torqued higher and they don't when they are torqued to spec.

If so, fair enough.

west green

great thread, I will attempt to set my mechs up one day soon, however I always get the impression that everyone on this thread have natural fettling skills ie lots of home decoration, minor building DIY etc - therefore bike mechanics also comes naturally. Is it just me??? My level of DIY is painting, IKEA build ups and definitley a handy gardener - am hoping bike mechanics becomes 2nd nature, but the thought of messing up the shifters or mechs always makes me go for the easier and far more expensive LBC option.

Ben6899

west green wrote:

great thread, I will attempt to set my mechs up one day soon, however I always get the impression that everyone on this thread have natural fettling skills ie lots of home decoration, minor building DIY etc - therefore bike mechanics also comes naturally. Is it just me??? My level of DIY is painting, IKEA build ups and definitley a handy gardener - am hoping bike mechanics becomes 2nd nature, but the thought of messing up the shifters or mechs always makes me go for the easier and far more expensive LBC option.

You may be right that some people do have natural fettling skills, but it can all be learnt as well. You might not end up as competent as someone with the natural skills, but you'll be okay and certainly able to set up front and rear mechs.

One thing to remember is that you can't really damage anything. So go for it!

mz__jo

I will add one piece of advice for first time fettlers who have a problem with the mech changing up (to smaller cogs) less well than it changes down. Make sure that the cable is properly in the guide under the bottom bracket shell and, above all, make sure that your workshop stand, whatever type it is, is not snagging or compressing the cable. There are some, fairly simple stands that will do this and it can be a sxx if you don't think of it.

PostieJohn

west green wrote:

great thread, I will attempt to set my mechs up one day soon, however I always get the impression that everyone on this thread have natural fettling skills ie lots of home decoration, minor building DIY etc - therefore bike mechanics also comes naturally. Is it just me??? My level of DIY is painting, IKEA build ups and definitley a handy gardener - am hoping bike mechanics becomes 2nd nature, but the thought of messing up the shifters or mechs always makes me go for the easier and far more expensive LBC option.

So you read the thread without picking up on my input!

There's tonnes of great advise that when I put it all together I got the job done.

The only thing from me is to say IT'S NOT A QUICK JOB, TAKE YOUR TIME

When thinking 'right I'll quickly do that then' I made a bad job worse and stopped thinking.
You'll need this thread, time and patience.