A rule of thumb for chain tension?- Mtbr.com
Results 1 to 6 of 6
  1. #1
    mtbr member
    Reputation: jj1075's Avatar
    Join Date
    Oct 2006
    Posts
    27

    A rule of thumb for chain tension?

    I've been riding a 29'er single speed for a couple of weeks now and I love it. I may end up hanging the full suspension bike in the garage for quite some time. The only negative however, is fixing a rear flat-it takes a bit more time and farting around with chain line and tension after getting the tube and tire back on the rim. I was wondering if there was a rule of thumb as far as chain tension goes? After one flat, I had it a bit too tight (I think), as spinning the cranks with the rear wheel off the ground felt a bit rough. I assumed a bit tight was better than too loose when applying torque on a steep climb. The next time, I went a bit looser and spinning the cranks with the wheel off the ground again felt really smooth. I did worry about the chain hopping off the rear cog or the rig up front while applying full power on a climb but it has yet to happen. Right now, when I lift on the chain at the center point between the rear cog and front ring, I get about a half inch. Is that too much? Should I tighten it up a bit and suffer a bit of roughness in the drivetrain or should I leave it be?

    Thanks in advance,

    jj1075

  2. #2
    Yo!
    Yo! is offline
    mtbr member
    Reputation: Yo!'s Avatar
    Join Date
    Dec 2008
    Posts
    348
    A 1/2" sounds right....making tension too tight is really hard on bb's and hub bearings.

    Whenever I work with getting the right tension, I pick up the back end and drop it to see how much play the chain has; if it's excessive, I'll tighten it up a hair. It can take a bit of time to find the sweet spot where the chain is tight enough to stay put when you're jostling the bike around, yet not so tight that it registers resistance in the cranks. If I'm using a new chain or bb, I'll set it up a little on the tight side to compensate for stretch and set-in.

  3. #3
    smell the saddle...
    Reputation: stumonky's Avatar
    Join Date
    Mar 2004
    Posts
    612
    Quote Originally Posted by Yo!
    A 1/2" sounds right....making tension too tight is really hard on bb's and hub bearings.
    What Yo said. I like mine not too tight or loose. There is a secret spot, you just have to find it. I have never spun a chain off on either of my SS bikes. I run ENO freewheels with horizontal drop-outs with Surly or BMX tensioners on the frame.

  4. #4
    mtbr member
    Reputation: jj1075's Avatar
    Join Date
    Oct 2006
    Posts
    27
    Thanks, fellas. I rode it this morning and had no problems. I felt no resistance in the drivetrain and I feel better about the bb and hub bearings. So far, I think I have the sweet spot nailed. I'll watch for chain stretch and set and check tension before and after each ride.

    jj1075

  5. #5
    .......
    Reputation:
    Join Date
    Apr 2007
    Posts
    3,707
    Spin the crank backwards and see if you get any binding. That's what I go by. I get about 3/4" play in the middle, but this all depends on your chain stay length.

  6. #6
    trail rat
    Reputation: slocaus's Avatar
    Join Date
    Jul 2005
    Posts
    7,818
    Work at getting your chain line perfect, that is most important. If it is perfect, you do not need to worry about the chain dropping if it is slightly loose; I believe slightly loose is better than too tight, which is hard on bearing (as stated above), and robs energy. Way too loose and it can drop, but no binding is key, and slightly loose in places if fine - if you chainline is good.
    "The physician heals, Nature makes well" - real fortune cookie

    CCCMB trail work for trail access - SLO, CA

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
  •