billd76

Morning all, been getting in a lot of miles these past few weeks. Did 23 yesterday in extreme heat. Anyway, after completing a hill climb yesterday in low gear (small front sprocket), after cresting the hill, I shifted rear gear set to midpoint, attempted to go to the middle sprocket on the front and the chain misguided. Had to stop and put back on. I understand that this could happen when under load on a hill, but I was on the down hill side and simply shifting up for speed. The gear set has done this a couple of times under the same circumstances. Shifting to any other sprocket works fine. Am I doing something wrong? I can't figure this one out. I have checked all the in and out settings on the front derailleur and everything is fine. Measured chain for wear, and its ok. Any advice would be greatly appreciated I'm running Shimano Tiagara. Bike is an 07 trek 1000
TIA

corrado33

What do you mean "misguided?"

Did the chain fall off to the inside, outside? Get stuck between the chainrings? (sprockets up front.)

TimothyH

There is no in and out settings on the front derailleur. There are limit adjustments on the front derailleur - the L limit screw prevent the chain from falling off the inside of the small ring while the H limit screw prevents the chain from falling off the outside of the big ring. These have nothing to do with shifting from the small to the middle ring on a triple.

As @corrado33 stated, the OP needs to clarify exactly what happened.

andr0id

It seems that *some* triples are fussy about the position of the chain on the rear cog with regards to how much they will cooperate doing the particular shift you want to do.

The rather generic Shimano triple on my tandem was like this. I replaced it with an FSA tandem set and it seems a lot more reliable. Of course that could be because I took a lot more care setting it all up.

billd76

Yes I know L limit and H limit. Inside = L, outside = H. They are set perfectly. I also understand that they really have nothing to do with the middle on a triple, Alas why I posted, I am at a loss for what is causing it. There has to be a reason other than it just being a triple fickle issue. Then again maybe not.

billd76

Thanks, sooner or later I figure it out. May end up going with a set up similar to yours. See a lot of riders with that set up.


I shifted to transfer from the small sprocket to the middle, the front derailleur was acting like it was trying to shift up, I bumped the shift lever again, then it misguided. This has a happened a couple of times and always after cresting a hill, under no load on the gears. If I remember correctly, the chain ended up between the small and middle sprocket. There are times when the shift is flawless. So maybe its not anything to really worry about.

corrado33

If the chain is going between the chainrings, you either have a chain that's too thin (10 speed chain on an 8 speed?), a bent chainring, or a chainring installed incorrectly (backwards or missing spacers.) A properly sized chain should not be able to fit between the chainrings.

I know the speeds of a chain don't usually matter for the front chainrings, but in this case they may. I've run into it before.

billd76

Great info thanks!!!!