Pedal Sprocket For Grubee HD axle

Discussion in 'Frame Mounted Engines' started by Mike S, Mar 16, 2008.

  1. Mike S

    Mike S Member

    I purchased the Grubee HD axle and drumbrake and brought it to a bike shop to install on my wheel. They informed me the rear smaller sprocket for the pedals needs to be a free wheel type and the threads have to fit the Grubee
    HD hub. The sprocket does not come with the kit. Does anyone know where I can purchase this special sprocket? This is a single speed bike, nothing fancy. Mike S

  2. highrider

    highrider Guest

    i take it your bike is a single speed and dont have gears, freewheels can be purchased from any bicycle shop.
  3. Mike S

    Mike S Member

    Yes I have a single speed bike. No, the bike says their freewheel sprockets have a different thread and I need a special one. They advised me to get it from a moped dealer.
  4. ocscully

    ocscully Member

    Any BMX single speed freewheel will fit that hub. If you have the GRUBEE hub that is threaded on both sides the pedal or right side of the hub is the one with the least/single set of threads. The other is for the motordriven sproket and its freewheel and the drum portion of the band/drum brake.

  5. Mike S

    Mike S Member

    Thanks for this advice. I will go to a BMX bike shop. Mike
  6. bnocon7

    bnocon7 New Member

    Mike S - Where did you purchase the "Grubee HD axle and Drumbrake"? I'm specifically looking for the HD Axle MODEL-1.

    Thanks ahead of time for the reply!!!
  7. klassard

    klassard Member

    I purchased one of these things from
    I went to three different bike shops today and they can't find a freewheel that fits this hub. Has anyone located the special-threaded freewheel for these things?
  8. Irish John

    Irish John Guest

    Why can't the suppliers of the HD axle & drumbrake also supply a correct single speed freewheel pedal sprocket to go with it? I'll tell you why - they don't give a toss about practical solutions and they get a diverse pleasure from creating really big problems for people who buy their poorly conceived products!
  9. biketec

    biketec Member

    :detective: Or maybe were not a bike shop and that's why don't we carry spokes or the bands?? there's many sizes, colors, brands etc.
  10. Irish John

    Irish John Guest

    That's why I said suppliers & not vendors. Should have said suppliers at source or manufacturers of the kits. I'm still right though about it being a disgrace not to supply the freewheel single sprocket if it is really a different thread to the 6, 7 & 8 speed freewheels clusters. The adapter for the 3 piece crank comes from France and costs Aus.$60. That's what I'm talking about - a general lack of grey matter in the upstairs department at manufacturing HQ!
  11. klassard

    klassard Member

    The HD Hub is not I.S.O. thread.

    I gave Jeremy at bicycle-engines a call today. I was told that he is their technical expert. He told me that it is normal for the freewheels to get stuck and that I should just chain them up and pedal them to force them on. Unfortunately, this solution damages the threads if they aren't correct.

    I've confirmed today that the threads are not I.S.O. threads. I took a freewheel from a Chinese electric scooter and tried it. It went on like butter. Unfortunately, it didn't have bike teeth. So I ordered one from this site -

    It came in the mail today. It also went on like butter.

    Here's the clincher:

    The Chinese electric scooter freewheels don't fit on any of my normal bike hubs, but they fit perfectly on the Grubee axle. My other normal freewheels from my regular bikes are completely interchangeable with any of my hubs EXCEPT the Grubee.

    The Grubee hub has some kind of non-standard thread that is shared by Chinese scooter hardware and not by bicycle freewheels.

    This means that either the 100s of people birddog that distributing says buys their hubs are forcing freewheels that don't fit and inadvertently ruining their threads or the hub I received was an anomoly that got shipped to by mistake and the majority of their hubs do in fact have ISO threads and I was just unlucky.
  12. Irish John

    Irish John Guest

    I think that it is fair to assume from the evidence that Grubee buy the hub from a factory supplying the scooter manufacturers and that if these hubs were ever meant for bicycles they would be threaded to accept the freewheels that are generic to the bicycle industry. I very much doubt that Grubee would have a clue about the required threads for a bicycle freewheel because if they did they would get them threaded for bicycle freewheels especially given that all freewheel threads for bicycles (including single speed freewheels) are all the same for screw on freewheels (as opposed to the cassette type). Doesn't inspire much confidence in them.. That's what I like about Staton, Dax etc., they actually know the basics about bicycles and are professionals. I take professional to mean someone who, not only does it well, but actually knows why they are doing it and who they are doing it for.
    When I hear stories like this it really makes me angry that they think they can fob anything on us and we'll just lump it.
  13. jimmie46

    jimmie46 New Member
  14. JohnGrahamIV

    JohnGrahamIV New Member

    so is there a way to get a shimano freewheel on an hd axle?
  15. biketec

    biketec Member

    Only if it's a non cassette single speed 35X1 CW thread.
  16. JohnGrahamIV

    JohnGrahamIV New Member

    I like my 7 speed. Somebody ought take make an HD axle for it.
  17. biketec

    biketec Member

    Yea it would be nice but it would be WAY to big to fit on a bike your lookin at about an extra 2-3 inches on top of the already too wide hub.
  18. JohnGrahamIV

    JohnGrahamIV New Member

    What about spreading the frame?