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Front der.(9 posts)

Front der.mackgoo
Nov 21, 2001 9:25 PM
I'm interested in building up a bike. The frame I'm looking at runs the front der. cable across the top tube and down. Does any one know of any way I could use a conventional "bottom pull" type der in this aplication?
pulleybn
Nov 22, 2001 9:50 AM
you can get a pulley that mounts near bb. the cable runs down then back up to derailleur. these sometimes get gunked up though
pulleymackgoo
Nov 22, 2001 12:46 PM
Thanks I did run across something like that last night surfing. It was in the UK. Do you know of any sources in the States?
pulleyThe Walrus
Nov 22, 2001 6:12 PM
This topic came up a while back; I solved the problem of running a 105 triple front derailleur on a Bianchi Axis by mounting the pulley from a Travel Agent V-brake adapter on an E-clamp from QBP (look in the front derailleur pages of the catalog). Works very smoothly, and I don't see how mud could be much of a problem with it.
pulleymackgoo
Nov 22, 2001 6:45 PM
Thanks. Could you point me in the right direction for these parts?
pulleyThe Walrus
Nov 24, 2001 2:43 PM
Your LBS should have the Quality Bike Parts catalogue; the Travel Agent is in the V-brake area, and the E-clamp is with the front derailleurs. I'm guessing the parts will wind up being about $30, which sounds kind of steep, but it makes for a very clean setup. Be sure to measure the seat tube before ordering, since the E-clamp is available in a number of sizes. When you get the parts, just take the pulley, machine screw and bushings off the Travel Agent and put 'em on the boss on the E-clamp. I found the setup works best if you rotate the clamp on the seat tube about 15 degrees toward the left-hand (non-drive) side of the frame; this most closely duplicates the cable run you'd have if the cable were routed under the bottom bracket.
pulleytriangleforge
Nov 27, 2001 12:14 PM
Does your frame have a threaded hole (it'll look just like a water bottle cage boss) on the back of the seat tube below the front derailleur? Lots of mountain bikes (most? all?) with top-mounted cables have a boss specifically for a pulley there. If so, I've got probably a dozen pulleys kicking around in my parts drawer, and only one mountain bike that uses them. Drop me a note w/ an address at bradleyd@his.com and I'll pop one in the mail to you.

Cheers!
pulleyThe Walrus
Dec 4, 2001 10:52 AM
O.K., my curiosity was piqued and I started looking at all the MTB frames I came across in the last week--Jamis, Bianchi, Dean, Univega, Airborne, KHS, Litespeed--and I didn't see a single one with this boss on the seat tube. I gotta know--what make and vintage frames were you thinking of?
pulleytayo
Dec 4, 2001 2:39 PM
Fat Chance up to at least 95/96 and older Bontragers, say around 93-94, have the pulleys on the seat tube. Look for any older mtb with top tube cable routing that preceded the full suspension boom (when top pull derailleurs started becoming more common).

My newer Racelite has top tube routing but no seat tube pulley. XTR top pull derailleurs are a good choice for non-micro drive mtb or road cranks (IME) on a top routed 'crosser.