Upgrade Trek 620 Drive Train to 9 sp
 

Recently acquired a well used 1985 Trek 620. I would like to upgrade to a modern 9 speed drive train with DT shifters. I am thinking Dura Ace 7700 DT shifters for index and friction options, a compact crank with interchangeable rings (Rene Herse from Compass bicycles 48/32)
and ultegra 6500 12-27.

Recommendations for new derailleurs with this setup?

Appreciate your input.

I guess the question is why do you want to do this. You'll need to spread the frame (not a big deal but it is a job) and you won't end up with better gearing than with a 3 by 7.

Edit: I think this is a useful discussion of the trade-offs between a compact and a triple: http://www.bikehugger.com/post/view/...-compact-crank.

Gearing, No. Interface, Yes (depending on personal preference, yadda...).

Let me explain why this would make sense for my situation.

I want to change to a compact primarily for my riding style. I ride in an area with relatively little climbing. I stay almost entirely in the 52 ring on my current bike. My "cruising" speed is 52/19 (72 gear inches).

i would never use the 30 ring on the trek 620 triple. A 48 ring with a 12/27 cassette falls right in the middle my "sweet" spot ("cruise" in 48x18 @ 70 gear inches) and I would not have to move to the lower 32 ring 90% of the time. Much less fuss. Would also get more "top" end with 48/12 (105 GI) than the 50/14 triple (94 GI). The Trek 620 will not be used for loaded touring - light stuff only.

Back to my original question. What currently available new off the shelf FD and RD would index with a 9sp Ultegra 6500 12/27 cassette using Dura Ace SL-7700 downtube shifters?

So- just to clarify- you're planning to stick with a double, not triple, crank? That is, 2 x 9, not 3 x 9, correct?

Question: the 620 is a touring frame; do you intend to use this bike to commute or tour?

According to Sheldon any 9s front and rear der will work just fine. I think what you're doing is fantastic. I just did it myself and love it.
So parts to look for would be: fd-5500, 6500, or 7700 and rd-5500, 6500, 7700. Stay away from the gs versions of those, they are the long cage for triple cranks.

Edit: just realized you asked for new off the shelf and I can't answer that question. But there's still plenty of good parts to get from ebay for the stuff I listed.

If you are planning on using new parts, you will have better choices by converting to a 2x10 drivetrain. I converted this Trek 400 to 2x10 using a mix or Ultegra 6600 and 105 5600 series. You could also use 10 speed Tiagra. Due to supply and demand you will pay less overall than trying to use a 2x9 drivetrain.

http://i289.photobucket.com/albums/l...ictures015.jpg

I had a spare drivetrain sitting around after I converted my CX bike from a double crankset to a triple. I ended up with an extra Ultegra 10 speed FD, RD, 11-25 cassette, a new 105 chain, along with a Sram 46 & 38t Cyclocross Crankset & BB. I also had a Mavic Open Pro W/ 36 spoke Dura Ace hub rear wheel.

I was able to upgrade the Trek 400D Elance to a modern 2x10 drivetrain. I found new Dura Ace 10 speed bar-end shifters at a good price. The drivetrain is quick shifting and the gear set with 46 & 38t chainrings and a 11-25 10 speed cassette has a tight range.

The bike was fun and sporty. I liked having the drivetrain performance of a modern bike while keeping the stealthy looks of a vintage bike.

If you're buying new, the 10 speed conversion recommended above makes sense as the cost difference is not that great. However, if you're going used, 9 speed stuff can be had really cheap, especially 105 level. Very good stuff, for a low price.
As for making the conversion, I've converted/upgraded two vintage road bikes and find those are the two I ride. It's your bike, convert it to help you ride more.