Join Date: May 2004
Location: Wilmington, DE
Bikes: 1984 Trek 660, 2003 Specialized Hardrock, 2004 LOOK KG386i (RIP), 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1, 2014 Islabikes CNOC 14 (son's)
Mentioned: 2 Post(s)
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The cage width is smaller on the 10 speed versus the 9 speed derailler. You may get a lot of chain rub because of that. Since you are using a 9 speed chain, you might as well use a 9 speed derailler which are much cheaper. You have two options for 9 speed deraillers. The best would be to head to Ebay and find a 6503 (Ultegra) or 5503 (105) front derailler. Either of those will work perfectly with your chosen chainrings.
If you don't want to use Ebay, you can get Tiagra 4503 9 speed triple front deraillers from many different sources. However, I haven't used one and can't comment on how well it will clear the 42 tooth middle ring. It's designed for a 50/39/30 crankset just like the 5603 FD so worst case it will work but you'll have more than optimal clearance for the big ring like my setup. If you do go with this derailler, I'd like to hear about how it worked out.
 This will work perfectly if you can wait for it to return to stock. The price is right too.
Last edited by joejack951; 05-31-09 at 05:27 PM.