Front Derailleur Shifting Problem

JoeAAA

I recently bought a Specialized Sirrus Expert. It's a great road bike, but I am having a problem shifting from the large chainring down to the middle chainring. It just hangs up and doesn't want to push the chain over. There is no problem going the other way. It is a Shimano Deore 31.8 bottom pull. I seem to remember a previous post saying that you had to shift all the way down to the smallest chainring and then back up to the middle one. Is this true??? The bike is only two months old and the bike shop where I bought it says it is adjusted correctly. But even when I am riding on level ground it still doesn't want to shift. I can pedal a couple of revolutions and the bike stays in the largest chainring more than half the time. The bike store said to take pressure off of the pedals to let it shift (doesn't help). My friend says to hold the shift lever longer (didn't help). Forget about trying to shift when going uphill. The derailleur appears to be positioned so the chain is in the middle, not leaning to one side or the other. My previous Trek mountain bike didn't have this problem. Shift levers are Shimano R-440 8-speed rapid fire, chainring is a Specialized 52/42/30. The rear derailleur is a Shimano Tiagra. Is there a better front derailleur that I can upgrade to? Do they make a Shimano Tiagra front derailleur and would it work better? The bike is a 24-speed bike. This is driving me nuts!

rek

It sounds as though the derailleur cable tension might be going off (maybe due to the new cable 'stretching', something all new cables do as the drive train wears in.) Either that, or the chain is getting dirty and it's affecting the cleanliness of shifts.

The suggestions your bike store and your friend mention are both relevant to making shifting easier; but it sounds as though something's not quite right adjustment-wise.

If you want to give the adjusting a go yourself, here is a good step-by-step guide:

http://www.parktool.com/repair_help...erailleur.shtml

When adjusting the front derailleur, it's sometimes not always possible to adjust it so that it doesn't rub the chain in any possible gear; sometimes accomodating for chain rub in extreme gears (e.g. large chainring/large rear cog) can compromise the shifting performance in other, more 'normal' gears.

Deore is part of a mountain bike groupset; Tiagra is a road bike part. Each occupy about the same level in their respective groupset hierarchy (the spot between recreational and race-spec gear.) Shimano mountain and road groups are largely interchangable, so mixing one with the other isn't a problem. Unless the derailleur itself is bent or otherwise damaged, I doubt replacing it will help.

__________________
Peter
Cannondale Synapse Carbon Scalpel Cyclocross Ultra

Spider1977

Wow! That parktool.com repair site is fantastic.

Although, for me, with two left thumbs, I just look but dare not touch.