Vagen

Hello,

Not looking to have a conversation on the merits/demerits of the configuration/ask. I have a Shimano road 10-speed setup and I am wondering if anyone knows of a double front derailleur which has a published capacity higher than 16 tooth.

I prefer not to modify pull ratio, but I am open to it. Shimano FD-5700 and MicroShift designs max out at 16 teeth.

Thanks!
Kevin

non-fixie 

I have no personal experience with those particular derailleurs (I tend to use older stuff), but I wouldn't worry too much about that limit. The worst that can happen is some rubbing in the small-small combinations, which I presume you're not likely to use very often.

FWIW, I have built a few bikes with "alpine gearing for flatlanders" and just mounted what front derailleur I had available and looked nice. Rear derailleur capacity is much more critical, IME.

djb

what chainring combos are you thinking of , on what crankset?
what kind of shifters?

Vagen

​​​​​​Good question.

My current setup is a 28-622 rear tire (that's the largest my aluminum rear triangle will accommodate).

Rear derailleur: Deore RD-M592-SGS
cassette: SunRace 11-40
Front derailleur: Ultegra FD-6600
Crankset: Shimano Hollowtech2 50/34
Shifters: Ultegra ST-6600

I'd love to eventually move up to 105 ST-5700 because I'd like to hide those cables for a potential handlebar bag. I've heard the hidden cables are a little less smooth, but I prefer the ability to easily swap bags from my Roubaix to my Enduro. The GRX 2x10 hydros are awesome, however I would need a Shimano compatible rear hydro rim brake,
Which is a pretty exotic part even if it does exist, so not really an option. Also I believe has the wrong pull ratio

Unfortunately here I'm stuck at around 22 gear inches and can't really go smaller unless I go subcompact. My issue with a smaller crank is that I do a century in the fall with older guys who are perpetually killing me in the pace lines. I'd really like to keep 1 bike for touring and for road riding, and I can easily build another rear wheel with less than 36 Alpine 3s and a tighter cluster. While I will never need more than a 50/11, I can't easily get my gear inches lower.

Tourist in MSN

A couple days ago on a different thread I posted a photo where a friend of mine used V brake noodles to re-route his cables from the shifter to clear his handlebar bag, I posted that at:
https://www.bikeforums.net/21724660-post72.html

I also had another pertinent photo and text at that other thread, thus did not just post that photo here.

Most of my bikes have friction front shifters, thus I never have to worry about proper indexing of the middle ring on my triple cranksets.

Regarding front derailleurs, I can't comment on anything to do with pull ratios, but I have never found a front derailleur that could only take 16 tooth difference. Right now my rando bike has a 22 tooth change on the triple crank, I have used a Campy front derailleur for a double, later changed to a Campy derailleur for a triple. I have two touring bikes with 22 tooth differences on triples, one is a Campy derailleur for a double and one is a vintage Suntour front derailleur for a double crank.

But, I run 11/32 cassettes, your bigger cassette range could run chain angles a bit wider.

That said, have you looked at your derailleur that you now have and checked to see if there is more clearance that is unused? I would not be surprised if you could use a wider range on your existing derailer.

At one time I used a triple crank for touring, 52/42/24, that had a difference from smallest to biggest of 28 teeth. It never occured to me that my Suntour front derailleur for a double might have had a clearance problem, I just installed it and expected it to work. It handled that just fine. Photo below, I took the photo because of the mud, not the equipment.



If you change your chainrings for a wider range, will your rear derailleur cage be able to take up all the slack in the chain.

The configuration in the photo above, 11/32 cassette with 52/42/24 chainrings, when I was on the 24T chainring I could not use the 11 or 12T sprockets because the cage could not take up the slack. But, those gears were so highly cross chained that I did not want to use those gears anyway. I mention this because some people like to use all gears, including the cross chained ones.

If you go with a chainring bigger than 50, don't forget to check to see if your chain is too short. Several years ago I was on a group century ride, some guy had shifted into the big and big and his chain was too short for that, jammed up his drive train, but fortunately nothing broke.

djb

Personally for a once in fall thing I'd put more emphasis on a smaller crankset, and change out to larger one and tighter cassette for the century,but that's the compromise of trying to make one bike do all. One of my bikes is set up more for fast riding and while I can change cassette to larger, I found I really never do it, but take a different bike now.

whatever you do, if you go more than 16t difference, put on a chain catcher, they work great. Really helps stopping chain drop.
good luck

Tourist in MSN

Better photo below of the same drive train that I posted above, you can see the front derailleur and the 52/42/24 crankset better. That crankset stock had a 30T granny gear, the 24T is an aftermarket chainring that I installed.



The photos above are old, about 6 years ago I changed the outer ring to 46T instead of 52T since I rarely used my highest two gears, now I use the big ring more often. That is a touring bike, I only use it for touring, thus that bike is only used with a load on it. I use other bikes for every day riding.

djb

My sti bike, 9 spd tiagra, works well with the triple tiagra fd and the 24t jump from 50 to 26, but this is all triple stuff,and 10 years old too.....

Tourist in MSN

Thanks, I forgot to mention the chain catcher. You can see it (the black little knobby thing) in the cleaner bike photo I posted above. The chain reliably lands on the 24T chainring.

Yeah, trying to do it all on one bike is difficult if you do not have a triple crank. But a triple to get the ultra wide gearing would mean a different shifter in his case.

robow

If you leave your Ultegra 6600 shifters for a newer Shimano offering with hidden sub bar tape shifter cables, be aware the pull ratios are changed and your drivetrain/braking may need further tinkering.