|
|
FEATURES: ADJUSTING YOUR SHIFTING ON THE FLY
Richard Cunningham
January 8, 2010
|
|
|
|
 |
|
|
(Photo: Yuzuru Sunada)
Unless you ride in the company of a transmission fairy, there will come a time when your derailleurs fall out of adjustment mid-ride. If you are armed with a little knowledge, getting your shifting back to normal might be as easy as twisting an adjustment barrel. If not, the rest of your ride might slip from anxious to angry as you struggle to stay in the group while wrestling with miss-shifts and a chain that skips all over the cassette cogs. Of course, if you happened to be Alberto Contador, you would only have to raise your right hand and the team mechanic in your follow car would rush to make the adjustments while you hung onto the car door handle. The rest of us, however, should read these easy-to-follow tips.
BEFORE YOU GET STARTED
First, get your head around the fact that derailleurs have no clue where the chain needs to be. It’s the shift lever’s job to mete out or reel in the precise length of cable to cause the derailleurs to place the chain on the next sprocket. So, the primary cause of poor shifting is a slack cable—and the fix is to turn the cable adjustment barrel to take up (or in rare cases, release) just enough slack to re-center the derailleur over the sprocket.
ADJUST YOUR REAR DERAILLEUR ON THE FLY
1. You’ll need to shift to the smallest cog to begin this procedure, so it may be wise to drop into the small chainring at the same time in order to stay in contact with your riding group.
 Be careful when using the barrel adjusters as fingers can get sucked into the fork (Photo: Yuzuru Sunada)
2. Shift one click. If the cable is slack, the shift may not happen at all, or it will occur slowly. If this is the case, turn the downtube cable adjuster or in-line adjustment near the handlebar one click at a time (1/4 revolution) counter-clockwise, and then repeat the shift. Stop adjusting when the shift up and down between the two smallest cogs occurs equally in either direction. Shift across the cogset to verify that all gear options are in order, and then get on with it. If not, turn the adjustment barrel one click in the appropriate direction and retest until it does.
WHAT ABOUT THE DERAILLEUR STOP SCREWS?
1. The stop-limit screws on your derailleurs are one-time adjustments that prevent the derailleurs from over-shifting the chain to the extreme right or left side of their travel. Unless you crashed or mishandled your bike in a way that bent the rear derailleur hanger or the front cage, the possibility that your problems are rooted in the stop-limit adjustments is a remote one.
 A bent derailleur hanger often prevents shifts to the smallest cog...
2. Bent rear derailleur hangers are not uncommon, and they always bend inward, which causes the derailleur to over-shift the chain into the spokes. The best fix is to stop, grab the entire rear derailleur and use it to bend the flexible hanger back until the jockey cage swings on a vertical axis—then repeat the adjustment exercise in part one to retune your shifting. Re-adjust your limit screws when you get home—or have your bike mechanic handle the repair.
 ...and is almost always the cause when the chain over-shifts into the spokes
3. The bent-hanger on-the-fly fix is more coarse, but you’ll be able to get your shifting back to the point where you can stay in contact with the group—or at least, keep them in sight. First, shift to the smallest available cog—because the hanger is bent, you will not be able to access the smallest cog, because the stop-limit screw prevents this. Use the barrel adjuster (first, in a clockwise direction) to get the shifter to shift up and down from the smallest available cog as if it was the first one. Carefully shift across the cassette until you reach the largest and then return. Make adjustments as necessary one click a time to achieve the best possible shifting in both directions and then leave it be. Beware and don’t over-shift into the spokes. The bent hanger negates the protection of the inner limit screw, so the final downshift will always toss the chain into the spokes. Be mindful of this, and you should be able to make it back to the car without too much trouble.
FIX YOUR FRONT DERAILLEUR WOES
1. The front derailleur is far less susceptible to damage because it is sheltered by the crankset and tucked into the pocket created by the chainstays and bottom bracket. This means that any new chain rubbing or change in shifting performance must originate from a cable adjustment issue—which is good news.
 Tighten the shift cable when the chain rubs the outer cage plate
2. This most common front derailleur issue is noise. Use your ears to dial in your front changer by shifting to the gearing combination of chainring and cassette cog that causes the chain to rub. Turn the adjustment barrel two clicks in one direction or another until the grinding ceases. To check your work, shift to the big chainring and then run the rear derailleur across the entire cassette. Shift into the small ring and repeat. The chain may grind slightly in the extreme crossover gears, but it should not make noise in any other combination. Make one-click adjustments to find a happy medium between the two crossover combinations and leave it alone.
3. Not being able to get the shift to the big chainring is a common frustration for new bike owners and bikes with fresh cable replacements. Turn the cable adjustment barrel counter-clockwise until the front derailleur makes a crisp shift to the big chainring. Test the adjustment by shifting to the smallest cassette cog to ensure that the chain does not rub on the front derailleur’s outer cage plate and then adjust as needed—then recheck the shifting throughout the entire range like in step two.
Tip: Mid-ride adjustments are provisional. Completing a race or a group ride with a not-quite-optimal-but-functional transmission is much better than rolling back to the pits a half-hour late alone, but with a perfectly shifting bike. If you end up with a limited gear selection, make a game out of it. Not so long ago, pro racers were happy to compete with ten speeds. We should be able to survive with less than 20 in a pinch.
|
|
|
|
|
|
|
|
|
|
|
|