FD shifting question - larger gap than optimum
 

This is a mock up on my new Evo. FD-6800 is at the bottom of the FD tab, 46T chainring, gap straight on is 5.5mm. Will this be noticeable when shifting?

I'm still 1X-curious so this may be just musing. If I run a dbl I'd likely pick 44-33 and stick with the 11-28 cassette (11s). Bu the 44T would add 4 more mm to the gap, getting pretty big.

Looks a little big to me, but only one way to find out how it'll actually perform. If it's an issue, there are solutions out there,

https://www.ebay.com/itm/334591702631

That Bikingreen adapter may work, my Wickworks one lowers it too much!

How's the gap between the back of the cage and the chainstay? I'd definitely get an FD extender/dropper if you have the room

It maybe was not quite that wide, but I changed from a 50T to a 46T and did not lower the derailleur. The shifting while not bad, it was sometimes what I will call clunky going to the small ring, and a bit hesitant going to the big. Really had to have the limit screws precise the get the shift to the big ring with out it dropping to the outside. I knew if I was going to be keeping the 46 on the crank, I had room to lower the dr. No added solution, just give what you have a try, and it may be okay. If I had not had room to lower the dr, I probably would have left it and used it as it was. I live in flatland and do not shift chain rings a whole lot.

If there’s enough material on the tab, a carefully used rat tail file can be your friend… if you find, as I suspect, that shifting is sub-optimal.

Big gaps and oddball combinations are unlikely to work well. I recently tried a 44/28 matched pair for Shimano grx cranks from Specialties TA. Installed with a proper gap, shifting to the little ring was fine, but the shift up to the big ring threw the chain off the right side, if made from one of the 5 smallest sprockets. Many minor tweaks to the FD didn't help. I put my 46/30 Shimano chain rings back on and perfect shifting was restored.

Moving ahead with a 46-30 set of chainrings. My question now is are there FDs that have more drop from the tab mount to the cage than the 6800 series I have, or are they pretty much all the same?

SRAM Red and Force 10 speed braze on FDs have two different mounting holes for this exact reason. IIRC, later versions of theirs don't.

I never had trouble with mixing FDs between Shimano, Campy, and SRAM unless it was one of the FDs that had the long lever arm.

That's interesting, never saw that! Thanks

The Shimano CX-70 is also shaped more for a 46T rather than 50/53 big ring and is worth a try. It was made in many variations (braze-on, multiple band diamaters, bottom, and top pull). I've only used it on band-on frames though so can't speak to how it drops from the tab mount. However, I have used it with both Shimano and SRAM shifters no issue.

This reminded me that I have one and I thought it was band-on but lo and behold it's braze-on, just mounted on a clamp adapter. So I'll try that one.

Thanks!

I just installed the Hollowgram 46-30 chainrings and the 10s CX-70 FD on the Supersix. Even pulling the cable completely tight I can't get the R9100 shifter to pull the cage far out enough that it doesn't have chain rub in the four smaller cogs. I'm going to try to fool with this by adjusting the inner limit screw to push the cage out a bit and then re-tightening the cable, but I'd like to know if the 10s front shifters and the 2nd gen 11s front shifters like R8000 and R9100 have different cable pulls.
On my Anderson years ago I had the same FD shifting a 44-33 with the pre-series RS685 11s shifters and it worked, but perhaps the pull ratio on the later gen 11s was different. The Supersix also doesn't have cable tension adjusters which makes setting this up a bit more challenging!

[QUOTE=NHAero;3372722]Snip
I'm going to try to fool with this by adjusting the inner limit screw to push the cage out a bit and then re-tightening the cable/QUOTE]

This worked.