to rag or not to rag

Discussion in 'General Questions' started by johnsteve, Sep 14, 2015.

  1. johnsteve

    johnsteve Member

    So i have been thinking about building a new bike and I am not sure whether or not to use the rag mount to the sprocket. I have heard that they are usually hard to true and problems with the chain falling off.

    Anybody ever have these problems in the past? Should I just go ahead and buy another hub or sprocket attachment? If so what should I use?

    Thanks in advance
     

  2. butterbean

    butterbean Well-Known Member

    The rag joints are "OK". Not really that hard to true unless the sprocket is warped to begin with, which does happen from time to time. The main issue is that it does put more pressure on the spokes. You can go with a sprocket adapter, they usually work pretty well. As long as you buy the right one to fit your hub and tighten it down properly, it will work fine. The other option is to go with a moped hub, the sprocket bolts directly to the hub so no rag joint or adapter is necessary. You will have to lace and true the wheel yourself, and also most likely will need to spread your dropouts. But they come with a drum brake and are also threaded for a freewheel.
     
  3. crassius

    crassius Well-Known Member

    I always use the rag joint - takes a bit of practice tho.

    I have never used an adapter since most only fit coaster brake wheels & I refuse to build on something that unsafe.
     
  4. To me, the main advantage of the hub adapter is to transfer torque to the HUB, instead of the SPOKES.

    If your using a low horsepower engine, with heavy duty 12 gauge spokes it shouldn't really matter.

    Now if your using a department store rim with the rag-joint, youll be o.k. for a few hundred miles, then look out!
     
  5. butre

    butre Well-Known Member

    few hundred meters maybe
     
  6. HeadSmess

    HeadSmess Well-Known Member

    dont you want the torque transmitted to the RIM? :confused:

    like, iunno...but isnt the tyre attached to the rim and thats the bit that gets you moving?

    and so...any load driven into the hub...still has to go through the spokes to the rim?

    iunno though....:detective:

    pffft, rag joints work, they maynt look high class, they may take some fiddling to get on nice and straight, but they work...and dont require relacing or buying a special wheel or anything like that...just pop em on...


    stuck em on flimsy 27inch racer wheels with no troubles... until the frame snapped!
     
  7. butre

    butre Well-Known Member

    the big advantage with hub adapters is that it makes the wheel easier to true. the way I ride that's a huge advantage
     
  8. johnsteve

    johnsteve Member

    so it just takes practice to get it right on a twelve gauge spoked wheel. Makes sense. It was a major PITA to get it right for me the first time and trying to figure out why my chain kept falling off. I am thinking was it the sprocket or was it the tensioner. It also did not help that i tightened it uneven to begin with. Thanks for everyones comments.

    They help,,,,,,,,really.
     
  9. KCvale

    KCvale Motorized Bicycle Vendor

    Actually the rag joint system is better than a clam shell to me.

    It puts a slight buffer between the engine and drive wheel.
    Not much, like .2mm 'give' but something for those hard clutch drops and 9 bolts holding it.

    If a clam shell gives it's 3 or 4 bolts spin on the hub and take out spokes.

    The thing is, they are just not that hard to install.

    1. Put your sprocket on a flat surface and makes sure it's true.
    You can never true a warped sprocket and I have probably 15 new ones that were warped right out of the box in my sprocket pile.

    2. Get the sprocket bolted in kind of loose, flip your bike over and put the wheel on (or put in a fork in a vice like we do), so you can spin it.

    3. There are 2 things to look at...
    Side to side wobble, look at it edgewise for this.
    And up-down no-center issues, look at the sprocket face for this.

    Side to side will throw chain, up and down will cause the chain to get loose, then tight, then loose again.

    Adjust your 9 bolts in a star pattern and look as you go.
    It also helps to see how much bolt end sticks out on the inside after the nuts are on, keep them close as you go.

    Finally, if you get it true horizontal wobble wise but have an issue with vertical up and down, you can put a piece of junk chain in the sprocket and tap it down into place vertically on that.

    4. Which way to cup the sprocket.
    This depends entirely on where your engine output sprocket is.
    The back sprocket has to be in line with it.
    415 chain don't bend around fat tires with a sprocket cupped wrong and a tensioner not centered in the true chain line .
    That goes for any mount system.

    I have ~60 builds with rag sprocket drive and just don't have problems.

    Just a side note, they are not rags, those rings are punched out of used tire sidewalls.
    That means they are not all the same and they have a slight curve to them.
    Done properly and tight they give enough for the spokes and come together to grip as one piece.
     
  10. butre

    butre Well-Known Member

    a properly installed clamshell that's been machined to spec will not slip one bit.
     
  11. wheelbender6

    wheelbender6 Well-Known Member

    I started with the rag joint and later switched to a sprocket that bolted to the disk brake hub. The disk mount sprocket was much smoother, but far more more difficult to mount and adjust. Pick your poison.
     
  12. butterbean

    butterbean Well-Known Member

    Not sure why you need to adjust a sprocket that bolts flush to the hub? No truing necessary, so what is there to adjust if the sprocket isn't warped and all the holes are centered. I can understand it being a little harder to mount, though.
     
  13. butterbean

    butterbean Well-Known Member

    I went with a moped hub in the rear, the sprocket bolts directly to the hub, no rag joint or adapter is necessary. Say what you want about rags or adapters, this setup beats them all.
     
  14. wheelbender6

    wheelbender6 Well-Known Member

    "Not sure why you need to adjust a sprocket that bolts flush to the hub?"
    I mounted the sprocket and hub on the back of a cruiser bike made in the 1970s.
    I probably would have needed no adjustments if I mounted it on a mountain bike. Spreading the dropouts didn't help.
    My chain stay interfered with the sprocket.
    -I trimmed the hub by 1/8" to create some room for the sprocket.
    -There was still some interference after the trim job. I lengthened the chain and moved the chain tensioner rearward to create more clearance. (See pic)
    [​IMG]
     
  15. johnsteve

    johnsteve Member

    whats that blue thing comming from the rear of the hub area? How did you mount the seat and where did you get the spring for it? The seat set up looks very comfortable and I might like to try it.
     
  16. wheelbender6

    wheelbender6 Well-Known Member

    The blue thing is your basic clip-on flashing taillight. I bolted the ell shaped bracket to the axle. The bracket that held held my seat to the seat post had worn out. The seat would not stay level, no matter how much I tightened it. I slid the seat as far aft as possible. A second seat clamp, like my original one, connected the coil over shock to the rear of my seat. (My shock was salvaged from pocket rocket. You can get similar shocks on EBay for around 15 bucks). I cut a small notch in the bottom of the coil over shock, so that it fit over the cross brace in my frame. Then I secured the shock to the cross brace in the frame with zip ties. You can do most anything with a hack saw, file and zip ties.
     
  17. HeadSmess

    HeadSmess Well-Known Member

    gunna chuck in something no-one has mentioned.

    "cush-drives"

    this fancy rubber shock absorber stuck in the rear sprocket of just about every motorbike to take up the "jerks" in a chain drive.

    notice that most cheap pitbikes dont have them...and suffer shredded spokes, shredded sprocket bolts, shredded teeth, etc... ive even stripped out the splines in a clutch at one point...

    probably not really a big issue on sub horsepower setups(havent ever shredded teeth off on a motorised bike!) but still nice to actually have some "slop" in there...
     
  18. KCvale

    KCvale Motorized Bicycle Vendor

    Rag joints are a cush drive.
     
  19. HeadSmess

    HeadSmess Well-Known Member

    :D exactly! :D

    simple yet effective. no real need to over complicate things.
     
  20. butre

    butre Well-Known Member

    a good cush drive out of a moped hub is nice, a ghetto cush drive made out of tire sidewall with spokes sandwiched between them isn't for me