Jim's Sprocket Adaptors "Great Value"

Discussion in 'Motorized Bicycle General Discussion' started by Retmachinist, Apr 25, 2009.

  1. marioaz

    marioaz New Member

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    New Point Beach. Both Front and Rear Hubs stamped "MODUS". Rear hub is round at 1.187. Seat tube at engine mount is 1.260. Front tube at mount is 1.520 across, and 1.460 front to back. Hmmmm.
     
    #21 marioaz, May 2, 2009
    Last edited: May 2, 2009
  2. 2door

    2door Moderator
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    Jim,
    Sorry to be the messenger of bad news. My rear hub, the QUANDRO measures 1.25 at the center and 1.375 at the spoke flange. As I said earlier it is a very slight ellipse but I knew it was not an illusion. Now what?
    Tom
     
  3. Creative Engineering

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    Apparently they use whatever wheels are available at the time.

    I bought my Jag in January. The hub is cylindrical @ 1.185". MB Monkey bought one a few weeks ago. I'll have to ask him what type of hub he has.

    I went to a lot of trouble to make this kit. I sure hope I don't come to find out this bike is all over the place dimensionally.

    Depending on how much trouble this ends up being, I may have to do a kit for Felt bikes or the worksman, or some other manufacturer with a stable product. I can live with annual changes...monthly is too much to deal with.

    Jim
     
  4. Retmachinist

    Retmachinist New Member

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    Tom, Jim's adaptor will probably work fine on that wheel. That is the way the wheel was on my silver bike and the adaptor worked because it is located back about 5/8 of an inch to the inside of the spoke flange. The way he has it built you have quite a bit of adjustment side to side. That is why it works so well for lineing up the sprocket.

    John
     

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  5. 2door

    2door Moderator
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    John,
    I was thinking the same thing. The amount of taper is slight. For no more torque that we're producing with these little engines I think the contact surface would suffice. If a guy was really worried about it, a few minutes on a lathe or another method of spinning the adapter, and an abrasive tool, sand cloth etc, could make it fit just fine. Even wrapping the center of the hub with some shim stock would work if the adapter was bored to fit the outer diameter. Jim? Comments? I don't think the issue is serious enough to abandon the universal kit concept just yet.
    Tom
     
  6. Creative Engineering

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    Most anything is possible:

    John, did your hub have a short section that was cylindrical? If Tom has the same hub that I'm thinking of...it is curved over the entire length. I talked to MB Monkey last night, and his is cylindrical.

    I didn't want to advertise that with some modification my adapter could be made to work. If it doesn't then I have to refund a part that will go into the scrap bin @ 35 cents per pound.

    The CAD graphics below show the potential pitfalls of an improper installation.

    Graphic #1

    The installed adapter has a bolt circle of 2.956" for small flange wheels, (I have another one for wheels with a larger flange, such as the OCC). The sprocket has a bolt circle of 2.956". The bolt holes in the sprocket are only a few thousandths larger than the bolts. If the adapter is not installed as intended, (graphic #2), the sprocket will not bolt up. This was the very reason I had to make sprockets for the adapters. The Chinese bolt circles vary. The bolt circles are not concentric to the teeth either.

    Graphic #3

    The adapter is made to work, by boring the through hole to the same dimension as the wheel hub. By mounting the adapter to a cylindrical hub, the adapter and sprocket assembly can slide along the hub for a perfect chain alignment, and then final tightened. If installed on a hub that has been machined to an elliptical, or parabolic, shape the adapter will not make full contact, (graphic #4). Obviously the ability to slide the adapter for chain alignment will be lost also.

    There are two ways to make it work, somewhat, for this type of hub.

    First method:

    1) Digitize the hub so that the curve can be plotted and input into the computer. 2) Machine the adapter in the mill, leaving the bore small. 3) Fixture the hub in the CNC lathe, and create in inverse geometry inside the hub. The ability to adjust the adapter will be lost so it will be necessary to take the measurements for sprocket alignment and make the mount accordingly.

    Second method:

    1) Digitize the hub so that the curve can be plotted and input into the computer. 2) Machine the adapter in the mill making the bore .030" larger than the smallest diameter of the hub.

    2) Using the digitized geometry from the hub, create tangent lines and determine the angle. Create chamfers in a manual lathe, after making a fixture, according to this angle. With this method, you would have to cut and test fit several times in order to sneak up on it, and get the correct bolt circle.

    Certainly I can't stop anyone from trying to make it work, but I don't want it back when it doesn't. :D

    Jim
     

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  7. Retmachinist

    Retmachinist New Member

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    Jim, Mine was cylindrical for a couple inches in the center, then tapered towards the ends at the spoke flange. I didn't realize some of the hubs actually had a slight taper the whole lenght. I hope I didn't confuse anyone. (Tom?)
    Wow, I can't believe how many different changes and parts they put on these bikes. I guess that is what we get when everything comes from China.

    John
     
  8. 2door

    2door Moderator
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    Jim,
    I was out riding today and came across a kid on a Jaguar. I asked if I could take a look at his bike while he was looking at mine...Cylindrical Hub...his didn't have the 'Thee Mile Island hub like mine. I asked where and when he bought it and he said he got it for Christmas and his parents bought it at the same Target where I bought mine. This sort of confirms that Schwinn, or Pacific Cycles, the Chinese arm of Schwinn uses whatever they have. It could be a matter of them buying from different suppliers and using whatever is available (cheaper) at the moment. While I was looking at the kid's Jag I also noticed his had different pedals and crank arms from mine. My cranks look like chromed forged steel, his were cast Aluminum. Go figure.
    Tom
     
  9. radrob

    radrob New Member

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    Ordered a sprocket kit the other day. cant wait to get it !!
    rob
     
  10. datz510

    datz510 New Member

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    I also ordered a hub adapter and sprockets from Jim the other day. I have to give him credit.. I had to change my sprocket tooth counts after the order was placed and he was able to modify the order no problem.

    Can't wait to get my set. Its gonna look great on my bike!
     
  11. Creative Engineering

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    They will start shipping this week. I have to be carefull, as each one is different. Believe it or not, out of 15 orders...not one hub is the same!

    You guys are going to love this part!

    Jim
     
  12. Creative Engineering

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    I have had a few irate emails over the sprocket adapters & Sprockets.

    I know...I know, If I can't provide instant shipping based on a custom product I should not be in business. I personnaly think a firing squad is too good for me! laff

    There is a solution to your impatience...SIMPLY ASK FOR A REFUND!!! I don't have a problem refunding your money...It costs me less than talking to you on the phone for 30 minutes about my inadequate business model.

    I'm making parts as fast as I can...I can't be bothered with your concerns and advice about how I should model my business the "Walmart way".


    Jim
     
    #32 Creative Engineering, May 4, 2009
    Last edited: May 4, 2009
  13. Creative Engineering

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    John,

    Yes...they are all over the place dimensionally. I meant to get back to you about the engine off-set on the OCC. The OCC here at the shop was up in the rafter storage area, I couldn't get to it. I don't think you'll have a problem...America was made on a lathe & a Mill.

    Jim
     
  14. NunyaBidness

    NunyaBidness Active Member

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    If I were in your shoes Jim, I wouldn't spend that much time on the phone with someone who doesn't understand and just wants to complain. Their money would simply be refunded and any future orders from that person would be rejected.
    But I have very little patience for some people and their attitudes.
     
  15. 2door

    2door Moderator
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    Okay, fine...I'll just buy all my custom machined and fabricated parts from Walmart from now on...
    Tom
     
  16. lennyharp

    lennyharp New Member

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    Who in their right mind would want to argue with you. A Machinist willing to do semi custom work for a production price. I love the stuff I have gotten from you and would like to slow down whoever is messing with you.
     
  17. Retmachinist

    Retmachinist New Member

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    That's O.K. Jim I did a little measuring and I think I have the offset right. If I don't I can always make another one. You know what they say. Your not much of a machinist if you can't fix your [email protected]*# ups.
    Oh I was out riding today with the guy I sold my Jaguar to and I checked out the rear hub. It was cylindrical all the way. I had bought it last fall.
    Oh, and don't worry about who ever is sending you the irate e-mails. You have got the best parts for the most reasonable prices I know of.

    John
     
  18. toker_ace

    toker_ace Member

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    Jim I'm am fix'in to order one from you, and I will need it ready the next day! "SO HURRY UP" LOL!!
    .bf.
     
  19. myke

    myke New Member

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    since I am not useing the stock hub from my jaguar, it was easy to measure and photograph.

    It measures at 32.3 mm everywhere I measure it, (1.27 inches) Just thought I would add mine into the pot. This one has MODUS stamped on it.

    [​IMG]

    It's a weird world we live in ;)

    myke
     

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    #39 myke, May 5, 2009
    Last edited: May 5, 2009
  20. Down_South

    Down_South New Member

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    I took a machining class at community college. Anyone who has a CNC machine can make some excellent stuff with a low to no margin of error. I haven't received the adapter yet, but I have full confidence that Jim knows what he's doing, especially after seeing the CAD drawings and some first hand experience machining for myself. Just give Jim some time he'll come through. It will take some time to make custom parts. Just remember that any fool can complain, it takes a real man to do something about it. I figure that if my measurement was off by one or two thousandths of an inch well, I can use some tape or sand paper to make up the difference. Hang in there Jim, Don't listen to the uneducated goof-tards. A culture of Instant Gratification leads to lazy unintuitive couch potatoes and reality TV.
     
    #40 Down_South, May 8, 2009
    Last edited: May 8, 2009

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