Bokkie

Just exploring something here. When I serviced my wife's bike, I was able to set the height of the front mech cage relative to the big chainring. I think the Zinn book says something like 1-2mm above the teeth. On my bike however, there is no way I can see to adjust the height of the cage as it is a rigid construction that fits onto the bb. I can't see any screws on the cage that let me adjust the height.

So, what do they do with chainrings of a different size? For example, my chainrings are 22-32-44. If I fitted a different set of ratios then would the cage height no longer be compatible with the new set? Or do you have to replace the front mech at the same time with a version that matches the new chainrings? I know some front mechs of the same model have different tube diameters, but I've not heard of one that has a different cage height.

I'm not replacing my chainrings, but I'd like to know more about this if you can help.

Edit: I forgot to mention that the cage height above my outer chainring looks to be something like 6-8mm thereabouts, and I'd like to correct that but can't see how.

Retro Grouch 

You have an E-bracket front derailleur. They aren't height adjustable or cage angle adjustable for that matter. I suspect that the idea behind them is that it makes it faster to pre-assemble the bikes at the factory.

Bokkie

Retro, are you suggesting then that my $3000 bike was intentionally compromised by fitting a POS for a front mech?

What are my options for getting a front mech that allows height and parallel adjustment? I'd like to fit something that has quality, and you've got me kind of worried that Shimano are turning out sh1te products just to make it easy for the factory! SRAM apparently don't make front mechs anymore (?) so I'm locked into Shimano and I believe the latest XT/XTR front mechs might not be compatible. I spoke to the chief wrench at the lbs yesterday and he mentioned something like that but I might be misquoting what he told me.

Michel Gagnon

Good question. Derailleur braze-ons seem to be found at both extremities of the spectrum. On low-end bikes, this is sometimes done for faster assembly, whereas on high-end bikes, it is "more pretty".

There are a few drawbacks, however.

1. As you have discovered, you can't adjust the derailleur height.
If you change the rings for something really larger (ex. 50-40-30) and are screwed, you could file off a bit of the derailleur cage, but there are obvious limitations and you can't come back.
If you change the rings significantly, there is another issue, especially with STI: derailleur-cage curvature.

2. Some claim that the seattube is weaker and may break prematurely. I can't remember if it is Rivendell, Heron or Waterford that claims that on their website.


When I compare my old and newer bikes, I would suggest that derailleur clearance isn't as critical as it used to be, and it's quite likely that it would not work better with 1-2 mm clearance than with 6-8 mm clearance.

sydney

It's not necessarily a POS. The braze on on your frame might get in the way of mounting a traditional FD,and your frame design or seattube may dictate the E type.

Bokkie

I think it's imposed by the frame design. I'd post a pic but my wife has nicked the camera from me this week? I managed to straighten the cage and it looks better though the chain does scuff against it still.

Coming back to one my questions: what front mech should I replace it with? Exactly the same? Get the latest and greatest that fits?