stringmaster

I am trying to replace the front down tube friction shifter on my Basso Loto 1990s road bike with a Microshift sb-r473 shifter brake unit (7x3). The bike was originally double front. Crankset is a Campag Racing T 52 39 30 triple, FD is a Shimano 105 RD5604 triple, chain is old but not worn. It shifted perfectly with the down tube shifter.
The shifter has 4 positions. Shifting to position 2 pushes the chain against the middle chain ring but does not shift. Shifting to position 3 does the shift but trim is bad such that there is cage rub when on any of the three inner rear cogs. Also, cannot shift from big to middle chain ring- goes from big to small.
I have tried many variations of derailleur height, angle, limit screw settings, cable tension. Cage is close to the chain rings and cannot be raised any higher on the braze on mount. Cables and housing are new. Parts are lubed. Chain line is OK, though might be a little crank out.
Any suggestions?
Thanks
Jim
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bargainguy

Friction shifters have one superpower indexed shifters don't have - the ability to trim.

When you installed the brifter, you lost the ability to trim. So now you have four set positions and that's it. You can adjust cable tension and derailleur limits, but I don't think you'll ever get the brifter & triple crank to work nicely when you're limited to four set positions.

Although it looks weird, a lot of folks run a friction shifter front with a brifter for the rear. This allows you the trim the front but still retain the brifter for the rear.

If you had your heart set on a brifter front, might be able to use a different crank (double) that would work with your four positions. I don't see that happening with a triple.

john m flores 

Agree. Some brifters allow a limited amount of trimming with additional clicks in between the shifting positions, but in limited experience I've never been satisfied with it. My preference for triples is friction with infinite trim ability.

This isn't quite a brifter but it's close: https://www.gevenalle.com/product/audax/

Road Fan

It sounds to me like what I have seen in front ders when the cage is too far ABOVE the chainring teeth and is not forcing the chain into adequate engagement with the teeth of the next larger chainring. This is better when the bottom of the front derailleur cage is 2 to 3 mm above the large chainring teeth. Less than 2 might block the cage, and more than 3 or 4 might not give enough push. Another aspect of alignment is that the derailleur needs to be rotated so the right edge of the cage is parallel with the outer face of the ring, and it just clears (maybe ½ millimeter, or maybe ⅓ of a sixteenth of an inch if that's an easier way to visualize what I'm saying). This "just clears" point needs you to set the limit screw so it goes that far but not farther, throwing off the chain (PITA!). But if the cage is not shoving the chain into alignment with the big chainring, it might be that it is not moving out far enough, or due to flexing it is not transferring all the motion to the chain.

So I feel confident an approach like this will get you onto the big ring, and levering the cage the other way far enough should get it back onto the middle ring. But the indexed shifter needs to also click the cage to the right place to take you from ring 1 (big ring) to ring 2 and from ring 2 to ring 3. Here the other limit screw needs to let the cage go far enough to push the chain to the little ring 3, but not so far that the chain flies off to the inside (also a BIGGER pita!).

Accurate shifting to and from the middle ring really depends on shifter having internal clicks of the correct size. This is where Campy shines. You can pretty much count on a Campy triple front mech, indexed front controller (like their left-hand Ergopowers designed for triples), and the triple chainset being designed to work together. I think that mix and match across brands does not work very well. I know that mix and match across Campy product lines works pretty well triple to triple, double to double and compact to compact, but a double front mech might not shift a compact as well.

So after adjusting carefully, you still might have the problem that the front derailleur, chainset, and indexed controller might not be able to work together. The designs across brands are not standardized and might not be compatible, though they look as though they might be!

SW84

There are two different Microshifters that I've dealt with. One has three positions for a 3 speed FD, while the other has 2 intermediate positions between 1 and 2, & 2 and 3. Here are pics of both. Sorry for the poor quality. Cheap phone.

joejack951

Slightly old thread and maybe you got somewhere, but you are creating numerous problems for yourself with the mix of components you are using.

1. The 5603 crankset is a 50/39/30 and the FD-5603 is tuned to that specific set of chainrings. Because of the shape of the cage, you are likely being forced to compromise on the ideal cage height in order to clear the large chainring of your crank. I've BTDT and you're unlikely to ever get good shifts even with everything else optimized.
2. Which chain are you using? The FD-5603 is a 10-speed derailleur and has a far more narrow cage than even a 9-speed derailleur. If you are using a 7/8 speed chain, you are going to be fighting chain rub issues forever.
3. Your Microshift sb-r473 shifter brake unit is designed to work with a 7-speed Shimano front derailleur, not 10-speed. I have no idea of the exact cable pulls but I can almost guarantee Shimano futzed around with them at some point between 7 and 10 speed groups.

In your shoes, I'd grab the compatible Microshift front derailleur, or a Shimano 7-speed triple unit and start from there. I've set up many triple cranksets with brifters and was able to get every single one to shift through every gear without chain rub, save for a few instances of brifters missing trim positions for some rings (Ultegra 6503 series namely) and thus having to live with chain rub in one or two extreme cross-chaining gears.

Fredo76

Try backing off the lower limit screw, then tightening the cable some more.