DIY Chain Tugs $4

Discussion in 'Transmission / Drivetrain' started by Timbone, Dec 12, 2014.

  1. Timbone

    Timbone Active Member

    I keep riding my motorbike daily and I keep making improvements.

    My frame has horizontal dropouts (like those on a track bicycle) and I had the recurring problem of the right (pedal) side of the rear wheel scooting forward over time, leading to a loose pedal chain and all the frustrating effects that come with that (chain skip, chain drop, etc).

    What I needed were those chain tug things and I saw some online for almost $20, plus shipping. Funk Dat!

    I went to the hardware store and picked up a pair of threaded rod eyelets ($1.50) made of stainless steel. I ground down one side of the eyelet to thick washer width and bent the rod very slightly towards the ground side.

    My dropouts are 1/4" wide and run a full inch from top end to bottom end. I couldn't find any kind of stamped bracket to serve as the stop end. All I really need is a small rectangular box with a small hole in the center, something I could not find. But I did find a 3/16" hanger bolt set ($2.98) that was really two strong pieces of rectangular channel 3/16"wide and 2" long - and a center hole that was threaded. I ground out the threads in the center hole, and it works perfectly as a stop for the tug. That's not going anywhere!

    I am going to run this on the pedal side for a while as the motor drive side seems very happy where it is.

    If anyone needs photos I can provide them.


  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    Interesting coincidence. Just a couple of weeks ago I made myself an axle adjuster.

    I'll have to read your post and digest it a bit more to really picture what you've made. But I think we're talking about the same thing.

    Here's mine.
    Axle adjuster 01.jpg
    Axle adjuster 02.jpg
  3. Timbone

    Timbone Active Member

    Here is my chaintug. 20 miles of testing and this thing looks good. It's two pieces:a threaded rod eyelet big enough for the axle and a heavy duty toggle bolt made for wall hanging. very simple.

  4. bluegoatwoods

    bluegoatwoods Well-Known Member

    Yes! That is good.

    Simpler than mine, too. Less fabrication.

  5. Timbone

    Timbone Active Member

    Make sure the eyelets are stainless steel so you know they are strong. Grind them down a bit to make them something like a washer, but not too much. Then add a bit of bend towards the ground side. If you have horizontal dropouts there's no way these things can fall out- they have no where to go.

    Isn't this fun? :)

    I am currently thinking of fabbing up some kind of sprocket brake for the rear. Maybe a permanently attached rear light,too.

    And maybe a new, better quality engine as a Xmas present to myself.:)
  6. SunkyWorks

    SunkyWorks Member

    Nice work Timbone. You might could flatten the eyelet with a 2 pound hammer.

  7. KCvale

    KCvale Motorized Bicycle Vendor

    Interesting design there BlueGoat, are you a big fan of the Mouse Trap game?
    You could have taken the direct route to that rack mount bolt with just a single flat piece and used a longer bolt ;-}

    Another option for forward dropouts is just put another bolt and washer in the channel in front of the axle.

    Timbone has rear dropouts and that makes it easy as he demonstrated.
  8. bluegoatwoods

    bluegoatwoods Well-Known Member

    Oh, no! I hadn't even noticed that Timbones dropouts opened in the rear. Still, I wonder if it could be made to work on front facing dropouts........

    And, no, I'm not a big fan of Mouse Trap. But I am a big fan of hacker engineering. I think of myself as a 'hacker'. (In the mechanical sense, not the computer sense.) And if my creations sometimes (often) have a Rube Goldberg feel to them, well that just adds a bit of soul to them.

    Though I'll quickly mention that I have a lot of admiration for the precise and polished work that some guys do. And I've noticed that you're one of them. But there's just something about the 'caveman' approach that really speaks to me. That's my comfort zone.

    Now I am having a hard time picturing your suggestion that one piece of flat steel might bridge the gap between axle and cargo rack mount, yet still be adjustable.
    I'll study the photo and see if I can see what you saw.

    But if you'd elaborate, that'd be good too.
  9. KCvale

    KCvale Motorized Bicycle Vendor

    With another design yes, but it's the open area for the eyebolt that lets it work when open in back.
    You have a little bolt and washer holding your rack support to the back of the frame.
    That is the bolt you plumbed around.


    Now if that 1st piece of bracket was flat with a slot at the end the width of the that rack mount bolt, a longer bolt would hold the rack and your back wheel in place.
    I'd take a triangle file and make some vertical groves in the flat tug piece as well as the dropout just to add some horizontal friction as well.
    Just an idea.

    One other note is your frames dropout connection (above the axle), that looks like it's ready to pull right apart, maybe a tack weld or two would be wise.
  10. SunkyWorks

    SunkyWorks Member

    Looks like you can buy these for 2 cents (per 1000) plus shipping. I am surprised every MAB online store does not have them for $3.

    Good quality bike chain adjuster (link not working)

    Free shipping pocket bike chain adjuster 10mm chain tensioner set for mini Quad 33cc 49cc
    US $5.99 / Pair
    $3 for 10 pair

    Chain Adjuster Set for 2-stroke 47cc & 49cc Pocket Bike ($1.90)

    BMX bicycle steel chain tensioners tensioner for 3/8" axles (PAIR)
    $3.99 FREE Shipping
    Last edited: Dec 16, 2014
  11. KCvale

    KCvale Motorized Bicycle Vendor

    Yep. Those are dandy for open back horizontal dropouts, but the OP has open fronts.
  12. SunkyWorks

    SunkyWorks Member

    Attached Files:

    Last edited: Dec 17, 2014