33 replies to this topic Post Order

[Merlin]

Hi all,

It's been MANY years since I've actively tinkered with this stuff, so go easy...

A week ago I discovered that the cage on my front derailleur had cracked right through on the back side. I took the bike up to the LBS and they fitted a new Deore mech', which is a seriously ugly piece of kit if you ask me, but anyways...

I got my rig Home and went for a test ride and whilst it shifted properly, through all of the usual combinations of gears, the chain was dragging on the bottom of the cage with the smallest chainring selected.

After some Internet consultation, I had a go at adjusting it but only made it worse.

This week I took the bike to my usual store, which I have a lot more faith in and again paid to have it set up. She's shifting like a champ, but the chain is still running on the bottom of the cage.



The costs are adding up, my frustration is building and I'm running out of ideas.

Why is the new derailleur doing this, please?

Thanks.

[Ryan]

Just loosen the bolt and move it lower down on the seat tube...  then adjust your cable again.

Make sure that it still clears the teeth on the big chain ring though.

[Thumper]

Ryan, on 17 August 2012 - 08:23 , said:

Just loosen the bolt and move it lower down on the seat tube...  then adjust your cable again.

Make sure that it still clears the teeth on the big chain ring though.

+1 to what he said!

[Wannabe]

As Ryan said, it is fitted to high. Looking at your photo, it is clear to see.

[SLiiick]

Do what Ryan said. There should only be 2 - 3mm between the big chain ring and the chain guide othetwise your chain can get through or stuck in that gap. Also make sure the guide is parallel with the chainrings.

When riding in the small chainring, stick to the largest five sprockets at the back.

Edited by slick, 17 August 2012 - 08:31 .

[Johan Bornman]

The clearance between the highest tooth on the large chainring and the lowest point on the derailer should be 1mm. In your case it is about 10mm.

Those bike shops are to blame. That orange sticker on there is the remnants of a transparent tab that Shimano fits to new derailers to help the mechanic find the sweet spot. It is transparent and marked at the 1mm mark so that it is easy to set up.

There are four adjustment positions that are important on a front derailer:

1) Low Limit
2) High Limit
3) Parallel with chainrings
4) Height above chainrings.

[4barlinkage]

Correct, deraileur too high.

Set it that either the inner plate just clears (2-3mm gap) the middle ring as you shift to the big ring. If it catches the big ring like this, then set it so that the outer plate clears the big ring by 2-3mm when you shift into the big ring.

[Woolf]

http://www.parktool....eur-adjustments

[Merlin]

Wow! Thanks for all of the replies.

I'm relieved to hear it's only a case of adjustment and not a wrong derailleur.

I'll have a go at setting it up again this weekend.

Hopefully I can get away without having to adjust the H and L screws.

[shaper]

Woolf, on 17 August 2012 - 08:35 , said:

http://www.parktool....eur-adjustments

+1 for the parktool link, I use it as a reference all the time as a reminder when servicing or changing parts.

As everyone says, your FD is too high

[SLiiick]

Johan Bornman, on 17 August 2012 - 08:33 , said:

The clearance between the highest tooth on the large chainring and the lowest point on the derailer should be 1mm. In your case it is about 10mm.

Those bike shops are to blame. That orange sticker on there is the remnants of a transparent tab that Shimano fits to new derailers to help the mechanic find the sweet spot. It is transparent and marked at the 1mm mark so that it is easy to set up.

There are four adjustment positions that are important on a front derailer:

1) Low Limit
2) High Limit
3) Parallel with chainrings
4) Height above chainrings.

I usually use the coin as a feeler gauge method which gives me around 2mm (depending on the coin). Is it better to be a mm closer than that?

[Mojoman]

Dont worry about it being ugly, mine has lasted for almost 3 years and thousands of K's with just about zero adjustment.

Suprised the bike shop did not realise its too high!

[LikeToRide]

Merlin, on 17 August 2012 - 08:19 , said:

Hi all,

It's been MANY years since I've actively tinkered with this stuff, so go easy...

A week ago I discovered that the cage on my front derailleur had cracked right through on the back side. I took the bike up to the LBS and they fitted a new Deore mech', which is a seriously ugly piece of kit if you ask me, but anyways...

I got my rig Home and went for a test ride and whilst it shifted properly, through all of the usual combinations of gears, the chain was dragging on the bottom of the cage with the smallest chainring selected.

After some Internet consultation, I had a go at adjusting it but only made it worse.

This week I took the bike to my usual store, which I have a lot more faith in and again paid to have it set up. She's shifting like a champ, but the chain is still running on the bottom of the cage.



The costs are adding up, my frustration is building and I'm running out of ideas.

Why is the new derailleur doing this, please?

Thanks.

Take it back to your LBS, and get them to fix it free of charge, with a klap behind the mech's head.

[JA-Q001]

What gets to me is that he paid his LBS twice and they (people that do this for a living) cannot figure out that it is set too high!

[Merlin]

My rig is such a mish-mash of parts these days it doesn't bug me too much, Mojoman.

I'm just glad if something lasts with my riding...

If time and transportation permis tomorrow, perhaps I should take it back to the second shop and ask them to have another go at it. It's the first time they've ever let me down.

[Ryan]

Mojoman, on 17 August 2012 - 08:54 , said:

Suprised the bike shop did not realise its too high!

Are you really?