Large Capacity Front Derailleur
 

I just got my tandem back from the shop and noticed that they overtightened the clamp on my front derailleur and cracked it. Thanks a bunch, guys! I had a Sachs Quartz on there which was large enough to handle 54-42-28 on my 8-speed drivetrain. These are nearly impossible to find anymore, and I'm going to ask the shop to pony up for a replacement. Any recommendation on what front derailer will handle that range of gears?

An Ultegra 6603 FD certainly shifts a 52-39-26 pretty well, and several other combinations. As long as the tooth difference between the middle and big rings is at least 12 teeth, then it's not too bothered what the inner ring is. If the big to middle difference is 10 or 11 teeth then a 105 or Tiagra will work better.

However, are you using an 8-speed chain? That is likely to rub on the narrower 10-speed FD cages. An Ultegra 6503 might therefore work better, as it was designed for a slightly wider 9-speed chain, but those are now hard to obtain.

Chris_W, thanks for that recommendation. Yes, I am using an 8-speed chain, which makes all of the 10-speed stuff a little too narrow. I'll see if the shop can dig up an Ultegra 6503.

In fact, I just checked, and the 6503 crank came with 52-42-30 rings, so the 6503 FD also won't work great. According to Sheldon Brown, running a chain designed for one more gear than you have in the back should work OK. Therefore, you could use a 9-speed chain on your 8-speed cogs and have a 10-speed 6603 front derailleur and hopefully it won't rub in too many gear combinations. Obviously, that is also not an ideal solution. You could also think about using a bar-end or down-tube shifter so that you can trim the front derailleur's position whenever needed, or a Campy ergo shifter for the left hand.

I haven't used it yet, but the IRD alpina looks promising.

I use an FD6503 with 54/44/28 with very good results (an N-stop jump stop provides extra security for the granny shift). I'm on 9-speed. The main problem with most newer shimano FDs is that they are designed for a 13/14 tooth middle to big ring difference (eg 53/39/30). But the FD6503 is designed for the more sensible 10 tooth gap (52/42/30). You're just adding a couple of teeth, but the gap is right. Getting harder to find, but they are out there.

I would say that triple FDs designed for 10-11 tooth differences are easy to find. All recent 105, Tiagra, and 6500 series Ultegra fit that requirement (i.e., models 4403, 4503, 5503, 5603, 5703, and 6503). Ones designed for 12-14 tooth differences are the less common, but include 6603, 6703, and 7803; it looks like we can also add 7703 to that list, which was made for a 9-speed chain, so that might be the best for the OP, although it will be very hard to find (it's from the 9-speed Dura Ace group which was discontinued 7 or 8 years ago now).