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Front derailleur - Converted frm internal BB to external


The Cheuh
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Hi

 

New to bike wrenching but I want to do it myself. Took ages to get internal BB out. Put Deore M590 crankset with external BB in and realised that my front derailleur is now too low and can't shift past biggest chainring. It is a crappy Alivio derailleur so I have an excuse to replace it. It has a chainstay plate (not sure what you call it) that is attached to the BB.

 

What I want to know, if I install a new derailleur like SLX or XT how can I make sure before I buy if it will work? IS there any specification that I need to look for aside from the size of the clamp?

 

I see SLX comes in a M660 and M661 and XT in M770 and M771 models. What is the difference between them?

 

Thanks

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If I understand you right, you're describing an e-type or BB mount derailer that's clamped on by the BB cup.

 

If that is the case, I can's see how another derailer higher up in the status chain will change the position of the der wrt the chainring. They have two screws in the mount plate that allows the derailer to be moved up and down for the 1mm adjustment, dont they?

 

The two model numbers you mention describe a high or low clamp derailer. These clamps fit around the seat tube. Carbon frames usually flare towards the BB and a low-clamp interferes with the flare, hence the high-clamp model for those frames. However, these are different from BB clamp/e-type models.

 

A photo tells a thousand words. Show us the problem

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Thanks for the info Johan.

 

Will try and take a pic, have already removed the derailleur.

 

Saw the info was not 100% clear. What I meant was that the derailleur is shifting to the side but it is too low as the derailleur cage hits the teeth of the biggest chainring when I try and shift it over.

 

Figured as I can't move the derailleur up I might as well change it.

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