Bicycle Mechanics - Chainstay angle, dual pull, top vs bottom swing?

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abreichenbach
09-27-08, 05:43 PM
I was wondering if anyone is familiar with Shimano's XT front derailleurs...I am getting a Surly LHT complete, but I want to switch out the front derailleur and crankset so I can get some lower gears. The bike is stocked with a long-cage XT rear derailleur, which I will keep, and I want to get a Shimano m442 crankset (44/32/22) and XT front derailluer.

The XT front derailleur has some options:
1) top swing vs bottom swing (I think I want bottom swing, currently I have a Tiagra FD and its a bottom swing)
2) chainstay angle- either 63-66 or 66-69 (the current Tiagra FD is 63-66).
3) only choice for pull type is "dual pull", but given the choice I believe I want bottom pull? I've read that the dual-pull is bulky, but this is what Shimano is pushing right now?

Thanks for your help!

joejack951
09-27-08, 05:54 PM
What will you be using to shift the XT front derailler? STI's won't do it.

If bottom pull is what you have now, then get the bottom pull and match your chainstay angle.
abreichenbach
09-27-08, 05:59 PM
I have bar end shifters, so hopefully that will work.
Thanks for your advice on the other stuff!

joejack951
09-27-08, 06:42 PM
Bar ends in friction mode should work fine.
maddmaxx
09-27-08, 07:18 PM
Will you have room between the tire and the seat tube for the MTB deraulleur? Unlike road (Tiagra) derailleurs, the cable mechanism for the down pull, operates in that space. Road derailleurs operate otboard of the tire and do not go into this space. Most road frames have the wheel too close to the seat tube for a mountain derailleur to work. If you are working on a hybrid or some road frames, (touring style sometimes has more space) then there may be enough room.

As far as bulky goes, the dual pull will have an extra pull arm for the cable going up (not what you are going to do). It will all be outboard of the derailleur mechanism and will not affect you.