serex711

Using a tiagra front derailleur for a trek 660 and am unable to retain tension to the outer chain ring.

any suggestions?

bargainguy

I don't think the derailleur is the issue. If the shift lever flops back when you apply tension, that's your problem. Missing parts? Not installed in correct order?

sloar 

First thing I would check is the shifter, make sure all the parts are there. Especially the tiny flat washer with the adjuster screw.

dddd

...and if the outermost anti-rotation washer is rotated into alignment with the flats on the boss.

79pmooney

I second looking at the shifter parts. I'd see if I can find an on-line diagram. (I found several for the SunTour Command shifters.) Also - does your rear derailleur shifter work well? If it does, take it apart carefully, keeping everything in order and nothing flipped upside down. Now - take the FD shifter apart. Clean everything. Lay out those parts as a mirror image to the RD shifter parts. Obtain any missing items.

Now, find the two plates that act as the friction plates. (One stays stationary, sitting on the column of the base. The other rotates with the lever.) Don't let any grease or oils see these! Careful lubricate the rest as you re-assemble the shifter. Tighten as needed to the friction you want.

I have noticed that at least some Shimano FDs have stronger springs than the old Suntours so having the shifter up to snuff is more important.

Hope this helps.

Classtime 

When you inspect the pieces in that front shifter, see if the thick black plastic convex compression friction thingy is buggered up. The two flats need to be pretty perfect so it won't rotate. I used a piece from a Campy shifter for a while. Then RT sent me a good bit and my Turbo was Superbe again.

RiddleOfSteel

Agreed with the others here. How tight is that D-ring? The older these friction levers get, the less they can work well due simply to time, use, and degradation. That build looks to be a snazzy one, and you'll have to let us know how it rides and steers (1985 Trek 460/560/660/670s had high trail geometry which I am curious to see how it does for you. My 1988 560 had a little less trail and I really liked it).

serex711

Figured it out, just needed to tighten the thumbscrew a little more!

serex711

So you were right about the D ring, was a little loose. It is very responsive and todays maiden voyage was exhilerating on am old '85! My compressor only pumps up to 80 so I need to get those tires to 120 so I can get a better feel on the Conti Gatorbacks!

What is trail geometry?

85 TREK 660 Celadone Milan 1 spray.bike color Shimano Tiagra gearset Conti Gatorback 700x23

serex711

Thank you, tightened the D ring and was good to go!

Classtime 

I'm pretty sure the trail on that trek with 23mm tires is ideal. AND don't bother going past 100 on your Gatorskins.