ok_commuter

This has happened twice now - a month ago, and yesterday - in basically the same spot on a group ride:

Hammering in the big ring on a slight decline. Decline turns to flat, then to slight incline, and the pace is really hard. I need more gears, so I need to get off the big ring. I shift the back ring a couple gears higher to prepare, then shift the front from big to little.

Chain drop. Hand up. I'm that guy, again.

I can't make this happen on the stand, and it never happens when I'm riding alone, probably because I never get pushed that hard alone.

I think I just need a simple adjustment, like an FD limit screw. But lots of people on the ride were recommending a chain guard thingy, saying they use them, acting like they were common, sometimes necessary. (I don't even know what type of gadget they were describing.)

What say you?

MONGO!

Probably a limit screw adjustment, but in any case, you should soft pedal when you shift.

kimconyc

Deda Dog Fang


Are you shifting while under load?

You could try shifting 2 gears higher on the big ring temporarily (I know, counter-intuitive) and then drop to the lower ring...

Vinci

Are you shifting the chainring under load? I used to get that on occasion on my Miyata, but only when I would shift to the small ring under load. If I was just spinning lightly during the downshift, there was never a problem.

Edit: Beat me to it.

ok_commuter

I *did* shift 2 gears higher before dropping, trying to prevent this very occurrence.

I probably am shifting under more load than I think. Things are happening pretty fast, and this move I'm trying to make is of course a desperate attempt to hang on to the group while the pace is really winding up... but I'm generally pretty good about soft pedaling especially when shifting the front.

Maybe I need to go up more than 2 - maybe try to get back to the middle of the cassette - before the shift? Though I have to admit, the name "dog fang" is rather appealing...

kimconyc

Just get the Dog Fang.

It's only a few bucks; plus it can be a conversation piece to change from the dull subject of Ti bottle cage bolts to anti-chain drop techniques when you guys stop for coffee.

Bianchigirll 

give the limit screw a little tweak. also as this only happens when you are 'hammering' check to be sure you BB is tight and adjusted properly and your crank is not loose.

you are riding a super stiff carbon or aluminum bike yes? I do not think fles would be the problem here anyway but just checking

khatfull

I had this problem with my new CAAD9. Turns out the LBS did a horsesh*t job of setting up the FD. My suggestion, go to Shimano's site, download the tech docs for your FD, and set it up again. I can now shift to and from anywhere with zero drop. Period.