Advertise on Bikeforums.net



User Tag List

Results 1 to 11 of 11
  1. #1
    Senior Member
    Join Date
    Dec 2009
    Location
    Palm Harbor, FL
    My Bikes
    2010 Specialized Sirrus Sport, 2005 Specialized Dolce
    Posts
    50
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    shop testing a chain skip problem

    Wife's bike has a chain that will skip or jump only on steep climbs. This only happens on one of our normal routes, and it's one that is a 20 minute drive away and then the hills start 4 miles into the ride. What I'm saying is that it won't be easy to do a quick road test. Is there any way to simulate this in my garage so that I can tell if I am doing any good?

  2. #2
    Senior Member
    Join Date
    Sep 2004
    Location
    boston, ma
    Posts
    2,841
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    chain, cassette, chainring condition? also check the freehub

  3. #3
    Packfodding 3 caloso's Avatar
    Join Date
    Jul 2002
    Location
    Sacramento, California, USA
    My Bikes
    Ridley Excalibur, Gazelle Champion Mondial, On-One Pompino, Specialized Rock Hopper
    Posts
    30,310
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by rojeho View Post
    Wife's bike has a chain that will skip or jump only on steep climbs. This only happens on one of our normal routes, and it's one that is a 20 minute drive away and then the hills start 4 miles into the ride. What I'm saying is that it won't be easy to do a quick road test. Is there any way to simulate this in my garage so that I can tell if I am doing any good?
    Do you have an indoor trainer? If so, can you crank it down and use the same gearing?
    Cyclists of the world, unite! You have nothing to lube but your chains!

  4. #4
    Biking Viking. goatalope's Avatar
    Join Date
    Nov 2007
    Location
    Camp Hill, PA
    My Bikes
    '01 Lemond Buenos Aires, '11 Specialized Stumpjumper FSR, 70s Austro Daimler Inter 10, 80s Motobecane Mirage 10 Fixed Gear
    Posts
    305
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Skipping is usually a result of a worn chain or cassette. There's a tool to measure chain stretch/wear. But cassette might be shot too.
    Tuesdays I work on my hair helmet.

  5. #5
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    22,556
    Mentioned
    69 Post(s)
    Tagged
    1 Thread(s)
    Try this, which requires 2 people. Shift the bike into the problem gear combination and put it in a corner of the room with the front wheel against the other wall. Have someone sit on it and load the pedals (try to ride through the wall) while you carefully observe the chain on both sprockets Front and rear. If there's enough wear to cause skipping under load you'll see the chain slide forward or back on the sprocket and climb outward on the teeth.

    If it does so significantly, either the chain is stretched, or the sprocket is worn. Start by measuring the chain, if it's OK (less than 1/2% stretch) it's the sprocket, but if the chain is stretched the sprocket may or may not be worn also. You won't know until you replace the chain.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  6. #6
    Constant tinkerer FastJake's Avatar
    Join Date
    May 2010
    Location
    Madison, Wisconsin
    Posts
    6,121
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    The first thing I'd do is measure the chain stretch. You only need an accurate ruler to do this. If the chain is significantly worn you should replace it.

    Can you remove the rear wheel and take a picture of the cassette and post it here? We could probably judge the condition of the sprockets with a good clean picture.
    Why "derailer" is the correct way to spell the gear-change mechanism: sheldonbrown.com/derailer.html

  7. #7
    Senior Member
    Join Date
    Dec 2009
    Location
    Palm Harbor, FL
    My Bikes
    2010 Specialized Sirrus Sport, 2005 Specialized Dolce
    Posts
    50
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks everyone. Bike is new to us, but a 2005. PO claimed it was only ridden a few times, and the condition seems to agree. My wife has ridden about 100 miles. I have not gone through the bike well enough yet. First I need to really clean the chain and relube it, and measure the stretch at the same time.

    I can borrow a trainer, and I like the wall idea.

    I'm on the road, but will take a picture this weekend

  8. #8
    Senior Member Old Hammer Boy's Avatar
    Join Date
    Aug 2005
    Location
    Utah
    My Bikes
    Trek, Cannondale Tandem, Surly LHT
    Posts
    1,082
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Probably not the problem, but confirm that the chain is the proper length and the B-adjustment is correct. Most probably worn components.

  9. #9
    Senior Member
    Join Date
    Feb 2005
    Location
    Oklahoma
    My Bikes
    Trek 5500, Colnago C-50
    Posts
    9,209
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Could be a simple cable adjustment. Does the chain act like it wants to change gears when it skips?

  10. #10
    Senior Member
    Join Date
    Dec 2009
    Location
    Palm Harbor, FL
    My Bikes
    2010 Specialized Sirrus Sport, 2005 Specialized Dolce
    Posts
    50
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I know that there are some gear combos (but don't remember which ones) where the chain jams when back pedaling. This issue improved by itself with about 20-30 miles of riding.

  11. #11
    Senior Member
    Join Date
    Dec 2009
    Location
    Palm Harbor, FL
    My Bikes
    2010 Specialized Sirrus Sport, 2005 Specialized Dolce
    Posts
    50
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Al1943 View Post
    Could be a simple cable adjustment. Does the chain act like it wants to change gears when it skips?
    on a mild hill the chain skipped but I don't think that it wanted to change gears. On a steep hill, the chain ended up off of the front gear

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •