Bicycle Mechanics - Missed gears...?
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I ride a 93 DeRosa outfitted with a Dura Ace gruppo from that same year. This past spring I not only had one but two tuneups completed on the bike of which one was an overhaul. I still however while on the small ring up front miss or should I say skip gears while downshifting. I'll change gears, hear the click then all of a sudden bang my gears are doing a dance and then they settle into place.:(
Some folks on the forum through other threads have mentioned that wear and tear of either the chain or rear cogs can cause misshifting. How do you diagnose this? Also how can you tell when your cables are worn? Any help would be appreciated. :D
08-14-01, 09:50 PM
Measure your chain, if it has more than 1,500 miles it's probably worn/stretched.
To measure chain- take a tape or rule measuring from center of one link pin to the center of another pin 12 inches away while putting tension on the chain, if the mark isn't center of pin to center of pin and is center of one pin to the edge of the other pin or worse the chain is worn anshould be replaced, to simplify the procedure use a "chain gauge" Park makes a very good one.
Cogs- Look at your cogs (edge on) if the teeth on the cogs you are using most are thicker than the ones you use less, then the thick cogs are probably worn, also if you look at the cogs from the side and some are getting a "shark fin" profile they're probably worn. It'a judgment call, the gauges for cog wear aren't as available or accurate/easy to use as the chain gauge.
If your cogs/rings are very worn a new chain will grind or skip. So either use the old stuff until everything quits shifting/working right and replace the drive train or replace the chain and the indiviual cogs now, some makers only allow replacement of the entire cassette, guees who- S*******.
Ride with little wear
Whomever did the tune up really didn't do a good job as they should have checked this and ridden the bike.
Best to purchase a new chain and cassette. That simple. These parts wear out quite fast and replacing one instead of the two will cause this problem.
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