[History]
So, time comes to replace my DA chainrings and I'm too cheap to buy DA again..I've had problems in the past with FSA chainrings doing this but have read some other things about FSA finally fixing the problem so I go for the chainrings that are less than half the price.

[The Equipment]
Quarq Cinqo Crankset
10spd FSA Road S10 53/39 https://www.excelsports.com/new.asp?p...jor=1&minor=12
Ultegra 6700 FD
DA 7800 10SPD Chain

[The Problem]
Chain drops BETWEEN the chainrings while pedaling.

[I've Tried:]
I don't even know what to try aside from making the push or pull of the FD so extreme that the chain is likely to drop inside/outside of the small/big chainrings (respectively). The other option is to lap brand new chainrings, no thanks.


[Picture]
2010-05-22 09.31.17..jpg
You can see the teeth not catching the chain in the picture.



[Other Info]
Maybe I don't have the chainrings on correctly but I doubt it. The small one's text is visible from the NDS of the bike and the shoulders are facing the NDS (to allow the bolts to sit flush). Logo is facing out.

I've never had this problem with SRAM Red, Shimano DA, Ultegra, or 105 chainrings or adjusting the FD for these chainrings.

I wonder if these are 8-speed chainrings. They would have been spaced wider than 9 or 10-speed rings. When Shimano went from 8-speed to 9-speed, they offset the inner ring a bit toward the outer ring to narrow the gap and prevent just what you are experiencing.

BTW, your link to Excel Sports doesn't work.

Sorry, all 10spd stuff. Link is also fixed.

Yeah, it says 10-speed so I don't know what's wrong either. Are the rings oriented so the pins, ramps, etc. are in their proper relationship to the crank arms and to each other?

As far as I can tell, anything specifically I should go check? Pin out on the big is near the crank arm.

Most times, when you try to save money on critical/precise things, you get suckered (at least that's been my experience). I'll have bought the DA or Ultegra chainring instead of the FSA. Just saying.

Sorry, I don't have a solution for you.

No worries, these are FSA and they've been in business a while so I'll contribute it to my incompetence until I've absolutely exhausted options.

That's obviously the correct alignment for the big ring. Shimano orients their inner ring as you have yours with the engraving and tooth count facing the inside and that engraving is placed 180° from the drive side crank arm. FSA? Dunno.

Gonna go double check. Oriented them the same way I received the crank with FSA rings the first time (d'oh). Will go try (180° [& 360° if 180 doesn't work]).

Seems to work ok now. The inside text is at a right angle from the crank arm, was at 180. I lined up the label on the front of the small ring with the crank arm and now it at least auto corrects and doesn't drop unless I'm going less than ~50 RPM.

Thanks HillRider. I guess the moral of the story is just keep rotating it until it doesn't drop, or is, at least, acceptable. Race time! (I'm glad I didn't have to put back on the breaking down DA rings!)

I had the same problem with using some TA Specialites chainrings on a Truvativ Rouleur crankset. The crankset is not top quality, but is rated as 10-speed, the TA rings are decent stuff and should work with any crank. However, the 10-speed chain frequently went between the two rings. The only solution I could think of was to file less than 0.5mm of of the outside of the spider's mounting tabs to get the rings closer together. This has worked, but the filing was not easy, especially when doing the two tabs next to the crank arm without marring the arm. I have another similar crank that I haven't done anything with yet, so if anyone has any better ideas then I'd love to hear them.

If you go the same route there is something that machinists (and, I'm sure, others use) call lapping that would be a much more uniform adjustment than filing I just don't, and shouldn't need to, want to do this to brand new rings.

A sheet of sandpaper on something very flat is usually good enough..I use it on a piece of granite to lap a stone for straight razors.