gear skip
03-18-11 | 11:39 AM
#1
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 19
Likes: 0
gear skip
Hello, When trying to shift from the highest to 2nd highest gear on my bike, the chain automatically skips one gear to the third highest(1st - 3rd). I've tried thightning the cord on the rear derailleur with no results. I've also tried the barrel adjustor on the derailleur, also with no results. I shift with thumb switch. Any suggestions would be appreciated. Thanks.
03-18-11 | 06:12 PM
#2
Senior Member
Joined: Feb 2008
Posts: 2,149
Likes: 76
From: Arlington, VA USA
Two possibilities come to mind.
1. When chain is is jumping a cog when shifting from smallest ring, it usually means cable is too tight, not too loose, so tightening the cable either by disconnecting and pulling out slack or with barrel adjuster exacerbates problem. Shift one click then, while turning crank, turn barrel adjuster slowly to loosen cable until chain settles back the second cog. Alternatively, with chain on the smallest cog, stand behind bike an check to see where derailleur cage is relative to cog. If not directly underneath the smallest cog (if cable is too tight the pulleys will be off a bit to the inboard side), loosen cable a bit with adjuster until the pulleys line up with the cog. Then click once to get chain on second cog and again ensure pulleys line up directly underneath 2nd cog via small turns of the barrel adjuster. No need to repat with rest of cogs, checking alignment with smalles two cogs should be sufficient to dial in shifting.
2. If too much cable tension is not the problem, it could be shifting technique. With trigger shifters, its pretty easy to over-shift when shifting from small cog to larger cog in the rear. Try being a bit gentler when pushing the trigger shifter to ensure you are getting just one click of the shifter with each shift.
1. When chain is is jumping a cog when shifting from smallest ring, it usually means cable is too tight, not too loose, so tightening the cable either by disconnecting and pulling out slack or with barrel adjuster exacerbates problem. Shift one click then, while turning crank, turn barrel adjuster slowly to loosen cable until chain settles back the second cog. Alternatively, with chain on the smallest cog, stand behind bike an check to see where derailleur cage is relative to cog. If not directly underneath the smallest cog (if cable is too tight the pulleys will be off a bit to the inboard side), loosen cable a bit with adjuster until the pulleys line up with the cog. Then click once to get chain on second cog and again ensure pulleys line up directly underneath 2nd cog via small turns of the barrel adjuster. No need to repat with rest of cogs, checking alignment with smalles two cogs should be sufficient to dial in shifting.
2. If too much cable tension is not the problem, it could be shifting technique. With trigger shifters, its pretty easy to over-shift when shifting from small cog to larger cog in the rear. Try being a bit gentler when pushing the trigger shifter to ensure you are getting just one click of the shifter with each shift.
03-18-11 | 07:48 PM
#3
Senior Member
Joined: Feb 2004
Posts: 30,225
Likes: 649
From: St Peters, Missouri
Bikes: Catrike 559 I own some others but they don't get ridden very much.
How many rear cogs do you have? The more rear cogs the pickier derailleurs are about having perfect derailleur hanger alignment. On a 7-speed I can eyeball alignment adequately. On a 9 or 10-speed I have to use an alignment gauge.
03-18-11 | 09:22 PM
#4
cab horn
Joined: Jun 2004
Posts: 28,353
Likes: 31
From: Toronto
Bikes: 1987 Bianchi Campione
****.
03-18-11 | 09:28 PM
#5
Senior Member
Joined: Jul 2005
Posts: 4,987
Likes: 709
From: Boulder County, CO
Bikes: '80 Masi Gran Criterium, '12 Trek Madone, early '60s Frejus track
I concur. If you can't tweak the cable tension so you can consistently single-step up and down the gears, it usually means something is bent. Usually it's the derailleur hanger, sometimes it's the derailleur. Another possibility is a worn out jockey wheel on the derailleur--either it wobbles from side to side on its bushing or the chain can't get properly seated on it.
03-22-11 | 02:59 AM
#6
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 19
Likes: 0
reply
Two possibilities come to mind.
1. When chain is is jumping a cog when shifting from smallest ring, it usually means cable is too tight, not too loose, so tightening the cable either by disconnecting and pulling out slack or with barrel adjuster exacerbates problem. Shift one click then, while turning crank, turn barrel adjuster slowly to loosen cable until chain settles back the second cog. Alternatively, with chain on the smallest cog, stand behind bike an check to see where derailleur cage is relative to cog. If not directly underneath the smallest cog (if cable is too tight the pulleys will be off a bit to the inboard side), loosen cable a bit with adjuster until the pulleys line up with the cog. Then click once to get chain on second cog and again ensure pulleys line up directly underneath 2nd cog via small turns of the barrel adjuster. No need to repat with rest of cogs, checking alignment with smalles two cogs should be sufficient to dial in shifting.
2. If too much cable tension is not the problem, it could be shifting technique. With trigger shifters, its pretty easy to over-shift when shifting from small cog to larger cog in the rear. Try being a bit gentler when pushing the trigger shifter to ensure you are getting just one click of the shifter with each shift.
1. When chain is is jumping a cog when shifting from smallest ring, it usually means cable is too tight, not too loose, so tightening the cable either by disconnecting and pulling out slack or with barrel adjuster exacerbates problem. Shift one click then, while turning crank, turn barrel adjuster slowly to loosen cable until chain settles back the second cog. Alternatively, with chain on the smallest cog, stand behind bike an check to see where derailleur cage is relative to cog. If not directly underneath the smallest cog (if cable is too tight the pulleys will be off a bit to the inboard side), loosen cable a bit with adjuster until the pulleys line up with the cog. Then click once to get chain on second cog and again ensure pulleys line up directly underneath 2nd cog via small turns of the barrel adjuster. No need to repat with rest of cogs, checking alignment with smalles two cogs should be sufficient to dial in shifting.
2. If too much cable tension is not the problem, it could be shifting technique. With trigger shifters, its pretty easy to over-shift when shifting from small cog to larger cog in the rear. Try being a bit gentler when pushing the trigger shifter to ensure you are getting just one click of the shifter with each shift.
Thanks, that did it.
Thread
Thread Starter
Forum
Replies
Last Post
Mitocatria
General Cycling Discussion
11
06-25-18 01:58 PM
loimpact
Bicycle Mechanics
8
11-28-14 11:00 PM
