Spokes keep on breaking

Discussion in 'General Questions' started by remichi, Aug 23, 2012.

  1. remichi

    remichi New Member

    Just had a look at my rear wheel and turns out 6 spokes are broken on the engine sprocket side!

    First time I installed the sprocket I broke 2 spokes by tightening too much. Got spokes replaced and next tightened it much much less, but still it seems that the spokes can't bear the stress.

    It's a 28 1 1/2 inch 40 spoke wheel as used in India and China on the old style roadster bicycles. The engine sprocket has 5 holes.

    I'm flying to the Netherlands from Kenya next week so I'm thinking of all the supplies I should bring back to Kenya.

    What is the thickest spoke available for 28 1 1/2 inch wheels? Is there another way of mounting the sprocket?

    At the moment I have:

    Bolt - rubber - sprocket - rubber - wheel - rubber - 2 metal half circles - washer - nut

    Somehow the pressure on the spokes is way too much, also see on the bolts that the thread is disappearing, meaning the spokes rub against the bolt.

    Supplies are scarce in Kenya as well as in the Netherlands, so hopefully someone has a kind of DIY solution.


  2. motorpsycho

    motorpsycho Active Member

    wow...only 5 bolt holes in the rear sprocket?
    most sprockets have 9 holes.
    what kit did you buy?
    is it an aftermarlet sprocket?
    you may want to invest in a sprocket adapter because it mounts the sprocket right to the hub and not to the spokes.
  3. remichi

    remichi New Member

    Well I'm back in Kenya after a short stay in Holland. Motored bike was doing fine until today when the wheel gave way because too many spokes had broken again.

    Now it turns out 12 spokes on the left side had snapped. Too much force on the spokes. The Kenyan bumpy roads also really aren't helping, but they're one thing I cannot change.

    So my next solution is to make my own hub adapter somehow. Seeing that it is a 40 spoke wheel with a sprocket of 5 holes. Has anyone made their own hub adapter and what are some tips? Mind you, half of the tools I'd like to have here are not available to me.
  4. Samdallas214

    Samdallas214 Member

    Free Wheel Heavy Duty Axle Kit They cost around $50.00 $80.00 depending where you get them
    A cut and past from from BB web page ( if you would like more info on there web site PM me I will PM you the web address.)

    With the Heavy Duty Axle Kit, you are guaranteed a sprocket that will always stay true. And because of the direct hub mount, less pressure is placed on the spokes. Normal sprocket mounting connects the drive sprocket to 1 side of the wheel by grabbing 18 spokes and sandwiching them with 2 rubber grommets. By mounting to the hub, the HD Wheel applies equal drive force to both sides of the wheel putting force on all 36 spokes evenly
  5. Ludwig II

    Ludwig II Member

  6. BigBlue

    BigBlue Active Member

    His bike has 40 spoke rims and 5 hole sprocket. The 9 hole sprockets and adapters won't work on his rims. His bike is a Flying Pigeon that is based on a design 75 years ago. The original sprockets for the HT engines were 5 hole sprockets for the Flying Pigeon bikes in China.

    AKA: BigBlue
  7. remichi

    remichi New Member

    I finally decided to weld all the existing holes in the sprocket and start with 10 brand new holes. Had to drill all 30 holes (sprocket and back plates) by hand though...very tiring.

    All seems to fit well though and already took it for a spin of about 25 km.

    See the pictures of the finished bike at: www.bit.ly/kenyanbicycles

    Even stumbled across an old MG A today near the school I volunteer at. If any of you are interested in the work my wife and I do visit the website of the school at: www.facebook.com/WaithakaTTC [ Feel free to like the school page.... ;-) ]
  8. wally

    wally Member

    Thats not right, Bolt - sprocket - rubber - spokes - rubber - 2half washer - nut working from outside to inside.
  9. BchCruizer

    BchCruizer Banned

    I have heard from a few people that the chain kits with the sprockets against the spokes have been known to break the spokes. Even cause serious injury when you tire folds on ya. I like friction personally..if your gonna be traveling around the world with your motorized bike i would look in to some reliable friction drive kits..theres alot less maintenance and tinkering required..Check out the bumblebeebolton design also stratton seems to be another reliable friction drive kit..with friction drive kits make sure the engine they are using runs at atleast 7,000rpms. gives you more top end speed..good luck and hope you get your bike reliable..theres alot of helpful people on here..im sure they will lead you in the right direction if you stay chain drive..
  10. Ludwig II

    Ludwig II Member

    I have a question. What local machining and welding facilities do you have? The simple solution, and we know simple isn't always easy or cheap, seems to be to strip the hub down and weld a sprocket carrier to it. The carrier can have holes in it to allow spoke fitting. Most places that have a 5kw generator, if not mains electricity can sustain some sort of welding and a small lathe. Is this worth considering?
  11. tom-fishing

    tom-fishing Member

    I've been reading this thread and the question that comes to mind is what are your spokes made of? I know my china made wildfire whizzer spokes are mostly made of brass with a thin center of steel. Is it possible that the quality just isn't good enough?

    P.S. Got to vent: I wish people would stop using these threads to brag up their choices. Remichi didn't post asking for advice about which kit to purchase, he came asking for help with a problem not a sales pitch. Vent over, thank you!