I have a 2006 Stumpjumper FSR Comp. I love the bike ‘cept for one thing: the Deore LX front Derailleur will not drop into the granny ring under a load (my 175lb load…) The mechanics at my LBS tell me it is tuned perfectly, but all they are doing is riding around the parking lot where of course it works fine. Nothing is worse than railing a nice turn into a steep climb, trying to drop the chain…please, puh-lease, ohhh Gawd Puh-leeeease drop, only to have it stick in the middle ring. Find a different mechanic or ditch it for XT or SRAM?
When you apply your awesome power, the bottom half of your chain is loose, but the top half gets super tight. Make sense?
Because your rear derailleur adjusts the bottom/loose half of your chain, shifting the rear under load is no big deal (not since about 1990). But since your front derailleur is trying to nudge the top/tight half of your chain, shifting the front under load is a huge deal. Especially if you’re 175 pounds of pedalling fury. The solution here is about 15% equipment/85% technique. OK, maybe 5/95.
Equipment – A higher end derailleur (XT, X.9, XTR) uses a stronger return spring than your LX. It’ll do a better job of coaxing your chain onto your small ring.
Technique – Learn to shift without chain tension.
Entering a corner:
1. Anticipate the gear you need for the corner exit.
2. Downshift and soft pedal into the right gear (BEFORE you enter the turn).
3. Brake if needed.
4. Rail the corner.
5. Hammer outta there (in the right gear)
1. Pedal, pedal, pedal.
2. Anticipate when you’ll need the small ring. Shift BEFORE you need it!
3. Give it a very hard pedal stroke.
4. Back off and make your shift. You shift at the “loose” moment.
5. Pedal, pedal, pedal.
If your mechanic is an experienced rider, he probably backs off automatically. Keep him and your money. Anticipate those downshifts!