HELP! Chain Skipping- Mtbr.com
Results 1 to 15 of 15
  1. #1
    indigosky
    Guest

    HELP! Chain Skipping

    Ok, I'm a SS Newb, so I need some help. I converted my old Raleigh aluminum to a SS using a 16t dx cog, a surly imitation singulator (pyramid), and a new sram 8 spd chain. It's skipping under pressure. Climbing hills, it feels like my knees are going to skip forward into my stem.

    The cassette lockring is tight, the chainline is spot on. The only other variable is the 32t chainring is old. Will this cause the skipping?

    Anyway, here is a pic of the Lucky Charms bike. Blue fork, purple grips, green tire, it's magically delicious. (Image is pre singulator & cog)

    Thanks.
    Attached Images Attached Images

  2. #2
    paintbucket
    Reputation: wooglin's Avatar
    Join Date
    Jan 2004
    Posts
    2,825
    Sounds like a chain wrap issue. Is the singulator set in push up mode (pushes the chain up towards the stay) to let more of the chain wrap around the cog?
    When the going gets weird its bedtime.

  3. #3
    indigosky
    Guest

    The imatation singulator...

    The imatation singulator only pushes down. Cheap. You get what you pay for I know. Before I got the DX cog & new chain, I took apart the original cassette (from when it was multispeed) and used that 16t ramped cog, with the original chain, the original chainring, and, the new singluator with no problems. I had to send that cassette back to SRAm for warrentee (some of the other cogs had broken teeth), so that was only a temporary solution.

  4. #4
    paintbucket
    Reputation: wooglin's Avatar
    Join Date
    Jan 2004
    Posts
    2,825
    Quote Originally Posted by indigosky
    Before I got the DX cog & new chain, I took apart the original cassette (from when it was multispeed) and used that 16t ramped cog, with the original chain, the original chainring, and, the new singluator with no problems.
    Double check your chainline then, and maybe tweak it. Sounds like the chain is riding up on the cog (or maybe the chainring but I doubt it), but not enough to throw the chain. The chunk you feel may be the chain dropping back down to where it should be.

    How's the tension on the chain? I don't know how that singulator works, but if its not spring loaded then having the chainring slightly off center (and they often are) will result in a loose chain at some point in the crank rotation. That could also be contributing to the problem.
    When the going gets weird its bedtime.

  5. #5
    KgB
    KgB is offline
    SNGLSPD
    Reputation: KgB's Avatar
    Join Date
    Jan 2004
    Posts
    1,034

    new chain and old cog and chainring

    will do it everytime.
    I've been inside too long.

  6. #6
    mtbr member
    Reputation: ernesto_from_Wisconsin's Avatar
    Join Date
    Jan 2004
    Posts
    4,004

    I 2nd that...

    Quote Originally Posted by KgB
    will do it everytime.
    I 2nd that...

  7. #7
    indigosky
    Guest

    it's a new DX cog, new chain...

    old chainring. Do you think the chainring alone could make it skip?

  8. #8
    Witty McWitterson
    Reputation: ~martini~'s Avatar
    Join Date
    Dec 2003
    Posts
    5,024
    Quote Originally Posted by indigosky
    old chainring. Do you think the chainring alone could make it skip?

    yep. Get a new chainring and you'll be golden!
    Just a regular guy.

  9. #9
    Retro Grouch
    Reputation: aka brad's Avatar
    Join Date
    Dec 2003
    Posts
    2,091

    Listen! I think not...my $.02

    Quote Originally Posted by ~martini~
    yep. Get a new chainring and you'll be golden!
    I'd go back to the chain wrap and DX cog. As far as I know chains don't tend to skip on chainrings (usually the problem is they won't let go). What happens is the chain rides up on the teeth of the cog and slips over under pressure. Having experienced the same scenario, a singleator in the push up mode solved my problem. Since you don't have the option of more chain wrap, I would first make sure your chain is as short as possible and then use a another cassette cog since a pervious ramped cog worked without the skipping. You can buy Shimano hyperglide cogs from <a href="http://sheldonbrown.com/harris/singlespeed.html#sprockets"> Harris Cyclery </a>. Also as you can see the BMX (DX) cogs have a different profile which may account for the skipping. You may want to take a file to your BMX cog and give it more area to bottom out. I've never tried it but for $5 @ cog its worth a try.

    1G1G, Brad
    Attached Images Attached Images

  10. #10
    One gear to rule them all
    Reputation: 32seventeen's Avatar
    Join Date
    Jan 2004
    Posts
    459

    I bet it is the Chainring....

    I have seen chains skip on worn rings many times. It is not as common as on cassettes, but it happens. Do you have the old chain? Measure 12 links and see what you get?


    Quote Originally Posted by ~martini~
    yep. Get a new chainring and you'll be golden!

  11. #11
    Witty McWitterson
    Reputation: ~martini~'s Avatar
    Join Date
    Dec 2003
    Posts
    5,024
    nah, I doubt its the DX cog. The depth of the teeth on it are too much, especailly if he's got good tension on the singleator. I've always run mine in the down position with out any issues. If he's got a new chain, and and new cog, with an old worn out 'sharked' chainring, of course its the culprit. But what do I know? I've only worked in the industry for 15 years. There's no way I'd suggest getting a HG cog to replace the DX either. That'd be silly. If anything, replace it with a 1st gen hyperglide with out the ramping, and he'd be ok. I know one can run a SS on a HG cog, it's simply not an ideal situation. Big, deep teeth are what you want. What 32-17 is refeering to is a new chain will measure 12", an old one longer, anything over 12" and I replace it. Some don't let things go to 12 and an eighth even.
    Just a regular guy.

  12. #12
    Retro Grouch
    Reputation: aka brad's Avatar
    Join Date
    Dec 2003
    Posts
    2,091

    Here's my reasoning...

    Quote Originally Posted by indigosky
    The imatation singulator only pushes down. Cheap. You get what you pay for I know. Before I got the DX cog & new chain, I took apart the original cassette (from when it was multispeed) and used that 16t ramped cog, with the original chain, the original chainring, and, the new singluator with no problems. I had to send that cassette back to SRAm for warrentee (some of the other cogs had broken teeth), so that was only a temporary solution.
    I too have had the old shark tooth chain rings, but since a a chain ring pulls the chain over itself and the chain pulls the cog from underneath, all the force is holding the chain on the chain ring not the cog. If you read indigosky (cool name by the way) statement above, it says he used an older chain/cog with the same chainring and there was no problem. He replaced the the chain/cog and now there is a problem. I have only used BMX cogs and the only time I had a skipping problem was when the singleator was in the push down mode. Just because the BMX cogs have those long pointy teeth does not mean they will stop skipping. As I said before the only skipping I ever had was on a BMX cog. Saying this I also realize I could be totally wrong. But it sounded good this morning.

    1G1G, Brad
    Last edited by aka brad; 03-16-2004 at 09:51 PM.

  13. #13
    paintbucket
    Reputation: wooglin's Avatar
    Join Date
    Jan 2004
    Posts
    2,825

    Oh my!

    Clearly we've got a solution here somewhere. Now its up to indigosky to implement it.

    Just how worn out does a chainring have to be to skip? I mean I'm cheap, but I guess even I don't let them go that long....
    When the going gets weird its bedtime.

  14. #14
    Retro Grouch
    Reputation: aka brad's Avatar
    Join Date
    Dec 2003
    Posts
    2,091

    Smile Variables are variable ..

    Quote Originally Posted by wooglin
    Clearly we've got a solution here somewhere. Now its up to indigosky to implement it.

    Just how worn out does a chainring have to be to skip? I mean I'm cheap, but I guess even I don't let them go that long....
    Again I am of the opinion that chainrings don't "skip". They may allow the chain to derail, but with a minimum of 16 tooth chain wrap (on a 32 tooth CR) and the nature of the chain being pulled over the chainring, I just don't think it happens; it seems the worn sharkfin teeth would hold the chain to the ring and not produce a skip.Using a tensioner the chain may actually fail to release properly from the chainring; this is a common cause of chain suck on a front derailleured bike. Indigosky said he had a imitation singleator (what ever that is), so the chain tension may be a factor. I agree with ~Martini~ that purposely using an HG cog over a BMX cog makes no sense, but you can't ignore that at some point it seemed to work better using a cassette (HG) cog. Hey stranger things have happened. I'm just guessing here and am certainly no expert.

    1G1G, Brad
    Last edited by aka brad; 03-16-2004 at 08:34 PM.

  15. #15
    indigosky
    Guest

    Ok, did some fiddleing around with it last night...

    basically the pyramid chain tensioner is crap. It's not providing enough and consistent tension of the chain around the cog. In addition the jockey wheel they provide seems to have way too much play.

    First I took out the o ring that went between the tensioner body and the mounting bolt. It was really making the action of the tensioner sluggish. Then I blue loctited (sp?) the bolt into the der. hanger, increasing the spring tension. I put a shim between the screw tab on the der. hanger and the spring. Also, blue loctited the bolt for the jockey wheel after I replaced it w/ on off of an old rear der. Worked great on my morning commute today. Thank god the snow is still in Southern Maine so far. They are supposed to get 6-8" by end of the day. Thanks again for everybody's advice!

Similar Threads

  1. $300+ for a freakin chain?!!!
    By Locoman in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 1
    Last Post: 03-08-2004, 03:25 PM
  2. Consequences of a too tight chain
    By Fett in forum Singlespeed
    Replies: 9
    Last Post: 03-01-2004, 03:47 PM
  3. 9spd chain on an ACS Claws freewheel... good idea?
    By jean-seb in forum Singlespeed
    Replies: 0
    Last Post: 03-01-2004, 07:40 AM
  4. Best way to keep a chain clean?
    By gottjr in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 7
    Last Post: 02-19-2004, 07:04 PM
  5. short vs med vs long derailleurs??
    By gettingsquirrely in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 3
    Last Post: 01-20-2004, 01:32 PM

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.