I have a Specialized Sequoia Elite road bike. It came with 3 front gears.
Now, I want to switch and put an Easton crank with two gears. Will it work properly with the current 9 gear derailleur in the back? Will I have problems shifting gears and chain jumping out of gear?
Thanks
The back: yes. The front: no. You need to change the left hand shifter and maybe the front dérailleur (depending on the tooth count of the new chain rings).
To me it sounds as if the front dérailleur overshifts quite a bit. If you would very carefully shift only one click it should work, though. The rear dérailleur should be able to cope with the tooth difference on the crank set, the one you had before likely was bigger.
Which "two screws" were you trying to adjust?
I can't tell if you having trouble with the chain falling off on the triple crank or on the new Easton crank. One thing to check is the alignment (height and angle compared to the chainrings.) If these are off, it is difficult to get the front der adjusted right no matter how much you play with the limit screws. If you're using your old der on the new crank, it might perform better with a front der designed for double chainring cranks. They are a bit different than those designed for triple. But there's no rule that says you have to swap it out.
I think you can actually keep your old shifter. But you'll have to be aware that it will have an extra shift position that goes to nothing. The limits should keep the derailleur from moving, but you'll need to keep track of keeping the shifter out of the defunct position.
One question of course is "why" change the crank? What are you trying to achieve?
Joe, Dave, thanks again. I found that I reduced the weight by almost 1 lb while removing an unnecessary gear, which means simplifying the shifting. BTW, I followed the advice of adjusting the front der. and so far it seems to have worked while shifting only once on the left side.
thanks both