Sprocket and coaster brake dont play well together?

Discussion in 'Frame Mounted Engines' started by rylekyans, May 9, 2009.

  1. rylekyans

    rylekyans New Member

    If I have a coaster brake on my huffy cranbrook , will I most likely have to widen the center hole on my sprocket for it to fit? Can I take the brake off, put the sprocket on, then put the coaster brake back on? I eventually want to get rid of my coaster brake but I wanna tackle getting it up and running before I get down to the add ons.

    Thanks everyone for any and all help

  2. Most coaster brake hubs work will work with a sprocket having a 1.75" center hole.

    The hole can be easily enlarged by grinding, cutting with a hole saw etc...

  3. Johnny Blaze

    Johnny Blaze New Member

  4. 22Velocity

    22Velocity New Member

    Creative engineering ???

    Hey Blaze,
    Did you have to remove the dust cover ?
    I looked at the web sight for creative engineering & they ask for a "spoke flange" measurement , OK being new to this bike thing WTF do they mean by "spoke flange measurement" ??
    I know this seems like a dumb question to you veterans
    but give me a break here guys I'm a "newbie" ... LOL
    Also what is considered the hub, the part the sprocket goes over or what ?
    Ok, I've been outed ... "I'm a seriously dangerous man with a wrench in my hand & know diddly about bikes".... :dunce:
  5. Johnny Blaze

    Johnny Blaze New Member


    I went to his shop because I live near by. In my case I had a Huffy Cranbrook and he already had a sprocket design specifically for that bike. I'm not sure what he means for a spoke flange measurement, but the hub is just the cylinder in the center of the tire. I did not have to remove the dust cover or modify the brake in any way. I think the best ting to do would be to call him or email him to see if he already has a design for your specific bike. He is very knowable and friendly, and will be able to answer all your questions.
    Last edited by a moderator: Dec 15, 2015
  6. motorpsycho

    motorpsycho Active Member

    most coaster brake arms can be removed from the hub. Take the wheel off the bike and look at the brake arm. there will be a nut on the outside of the brake arm. take that nut off and the arm will slide off of the axle. the brake arm hole will have a flat spot in it, which is used to locate it to the axle. you will have to hold the other side of the axle tight to loosen the brake arm nut. screw one of your axle nuts onto the axle on the sprocket side and hold it with a wrench while you loosen the brake arm nut. do not hold the axle itself with vise grips or channel locks because you will damage the threads.
    take the brake arm off, put your new sprocket on (you may have to remove the dust cover because the sprocket hole may not be large enough to fit over the dust cover). after you get the sprocket on, then just slide the brake arm back onto the axle, and put the nut on tight. you will have to check the clearance between the sprocket bolt heads and the brake arm...the bolt heads might rub on the brake arm. you can slightly bend the brake arm for it to clear the bolts if you have to. make sure that the brake arm will still mount to the frame similarly as to how it came off. i am not familiar with the cranbrrok, so i am not sure if it has a mount welded to the frame for the brake arm or if it just uses a metal strap.
    it's not that difficult to do, but you must be able to understand how it will all come together and you must be prepared and able to make adjustments to make it all work.
  7. motorpsycho

    motorpsycho Active Member

    this is how accidents happen! people who don't know jack about bikes go putting a motor on one and then have a catasrophic failure at high speed because it was not put together right.
    If you don't have a clue as to how a bike works, goes togther and is maintaned, then why in the world would you put a motor on one to make it go 30 mph and risk having a back wheel lock up, or a chain come off the sprocket?
    if you don;t understand, get someone who does understand and have them show you how to do it, or have them do it for you. asking questions here is a great idea, but if you can't grasp the concept then why would you put yourself at risk?
    there is A LOT more to a bike then most people think and if you do not understand the mechanics of one you should get a couple of books from the library and read up on them. there is more to making a bike ride and work right than just jumping on it and peddling away. strapping a motor to one only increases the things that you need to attend to, and to make exactly right. a crash on a bike at 30 mph is no picnic, and when it happens, everyone else gets blamed except for the person who put the bike together with no knowledge of how to do it.