Derailleur Hanger Alignment ('12 Trek Madone 6.9 SSL)

Discuss light weight issues concerning road bikes & parts.
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baldkingpin
Posts: 232
Joined: Tue Mar 20, 2007 5:07 pm
Location: Palo Alto, CA

by baldkingpin

Been dialing in my new Madone ('12 6.9SSL) since I built it up a couple weeks ago. It's almost perfect but the rear shifting was just a little off. Nothing major, just some extra noise and the shifting wasn't as crisp/consistent as it should be. So, I checked and rechecked the cable tension, housing lengths (have gone up/down with bar height a bit), limit screw and "b" screw adjustments, wheel true, etc. and the setup is spot-on.

Hadn't checked the derailleur hanger alignment b/c the shifting was alright and I'd spaced on it, so checked the hanger bolts then threw the ol' alignment tool on there and found the hanger was waaay off. I've aligned hangers for years and broken a few (like all mechanics), and through trial and error have developed a decent sense for how much force you can/should apply. I'm especially careful with aluminum hangers on carbon frames as they can only be straightened a tiny amount before weakening and snapping. Anyhow, I figured the Madone hanger was a brittle aluminum number and tho' I didn't have a spare on hand, threw caution to the wind and for the hell of it did a very tiny (think 2-3 NM) torqueing with my tool - not enough to do much, if anything, to most hangers I've had. Surprisingly, the hanger came all the way into perfect true with this one small action. I checked it several times at 12-3-6-9 and it's perfect. The shifting seems flawless now, as well, at least on the stand (will ride it on the road tomorrow).

The hanger appears to be painted or clear-coated and, while I assume it's aluminum, I recall recent discussion about Trek experimenting with steel hangers on Madones for ease of alignment. Lots of flame-throwing on the boards about how that'd result in broken frames, defeats the purpose of a hanger, etc. However, I'm very curious to know what this hanger is made out of. Feels like steel. Maybe it's a softer aluminum compound that is designed to break but is soft enough to be adjustable? All I can say is it's way softer than the hard aluminum hangers I've had on my last 4 or 5 race bikes (e.g., Super6 hangers that'd snap if you looked too hard at them).

Cheers!

by Weenie


BdaGhisallo
Posts: 1795
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

Stick a magnet near it. If it's steel it'll stick. If it's aluminum it won't.

ECT
Posts: 31
Joined: Thu May 03, 2012 7:58 am
Location: North Carolina

by ECT

I'm pretty sure the hanger is aluminum, I have the same frame and I watched my mechanic adjust it easily. The steel hangers were only given to pro teams to give crisper shifting, I believe.

Barrie
Posts: 26
Joined: Fri Mar 23, 2012 8:56 am
Location: lancashire UK

by Barrie

Dont forget Titanium and stainless steel are non magnetic but a S/S hanger never !

Barrie

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ave
Posts: 1658
Joined: Sun Dec 28, 2008 10:15 pm
Location: Hungary

by ave

take it off, weight it, then measure the weight of water it displaces from a glass. Calculate density and voila. ;) A bit easier solution is to ask Trek. :)

Geoff
Posts: 5014
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Or, just take it off and feel it...

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baldkingpin
Posts: 232
Joined: Tue Mar 20, 2007 5:07 pm
Location: Palo Alto, CA

by baldkingpin

Duh, Magnet, great idea (prefer not to take hangers on/off once aligned as tiny bolts are easy to start rounding even when careful). Did it, no stick. So, aluminum as we all suspected. Still, darn thing is quite malleable, at least relative to most alu hangers. Anyone know if Trek designed this in as a compromise between normal alu and steel? Thanks, all.

clarkson
Posts: 188
Joined: Sat May 07, 2011 12:23 am

by clarkson

The Steel hangers were a team-only part Trek fabricated for the pros, who could care less about trashing frames. I don't believe any bikes were sold publicly with those bits.

by Weenie


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