rear sprocket mount got to be a better way

Discussion in 'Frame Mounted Engines' started by azagthoth, Sep 1, 2008.

  1. azagthoth

    azagthoth New Member

    i know this may be a slightly redundant question, but after spending hours trying to center and true the sprocket to the wheel even with a torque wrench), i finally got it close enough. i don't think that with those crappy rubber rings that it is even possible to get it completely true. so i got as close as it would get, then realized i did not have enough tire clearance. many posts and instructions said to put the tooth side in towards the wheel, so i did. so i decided to flip the dished sprocket but when i was taking the bolts off 2 of them sheared just by my wrench! yikes. good thing it wasnt doing 35 or i'd be road pizza. are they made of tinfoil?

    anyway this bolt on spoke seems like a bad idea, but i've seen some alternatives like livefastmotors clamshell hub adapter has anyone used this? , or kings disc hub rig which requires a disc break hub, both will cost me almost as much as the whole bike itself. are there any alternatives that won't have me spending my rent and waiting forever? any help is greatly appreciated.
     

  2. I like to look at the way motorcycles have it and hope that one day someone will see a market of strong bicycle wheels made that way with fixed or freewheel sprockets you can interchange without worrying about alignment. You can get it laced up and it's been done but you have to build it. Right now the cheapest way to go your holding it.
     
  3. QuadManiac

    QuadManiac Member

    I've started looking at newer hubs made for disk brakes... they're starting to get common on even cheaper bikes. I figure that they're designed to handle the disk and the associated loads of stopping the bike, why not a sprocket instead? Match up to a sprocket that fits, align the motor to line up the sprockets and voila! Of course, i may not be telling you anything you haven't already thought of.
     
    Last edited: Sep 1, 2008
  4. s_beaudry

    s_beaudry Member

    I went with the teeth in approach on my Scwinn Searcher, put the wheel back on and it did not line up.... took it back off and flipped it over and in the process stripped two of the bolt heads!

    I got away easy as the sprocket centered itself perfectly on the hub, but I am on your side, there must be a better way of setting this up more easily!
     
  5. HoughMade

    HoughMade Guest

    There are, indeed, better ways of doing this, but believe it or not, this can work quite well.

    The first thing is to make sure the sprocket is flat and straight before mounting it. My 56 tooth was perfect, but my 48 tooth was tweaked. After I discovered that, I staightened it with a vice, a straight-edge and a pry bar.

    Also, when I installed my first sprocket, I snapped several of the bolts- that is, the bolts that came with the kit. I bought 9 new, good quality bolts and have not had an issue. I numbered the bolts holes with a Sharpie so I could keep track of which ones I was tightening and I could tighten bolts across the circle back and forth: 1 then 6, 2 then 7, 3, then 8, 4 then 9, 1 then 5, etc. I tightened in several steps snug, then snugger, then with the torque wrench 5 ft/lbs, 7 ft/lbs, etc. When it was getting close to tight, I ran a straight edge on the sprocket, the measured the distance from the straight edge to the rim at several locations, the tightened more where it was further away. Like I said, worked well.

    Also, make sure the bolts are centered between the spokes so a bolt does not rest against the spoke and put presuure on the spoke when power is applied.

    Finally, centering the sprocket has never been an issue for me because on the coaster hubs I have used, the sprocket hole fits tight, but close around the hub and centers it perfectly. As an aside, I think it is a grave mistake to counsel people to grind out the center hole instead removing the arm and dust cover and ensuring the hole is actually too small before modifying it.
     
  6. Skyliner70cc

    Skyliner70cc Active Member

    There is a better way. Clamshell hub adaptor from livefast motors is much better option than using two neoprene donuts mounted between spokes.
     
  7. psuggmog

    psuggmog Guest

  8. Ghost0

    Ghost0 Guest

    You could also use a shifter kit and eliminate the left wheel sprocket all together.
     
  9. Tinker1980

    Tinker1980 Guest

    I fought with my sprocket for a while before finding and fixing the problem. I thought maybe the sprocket was warped - but my bedroom window and my smallest feeler gauge said it was straight. Much straighter than the 1/4" dawdle I was getting. I checked the wheel and spokes, they too were straight. I tried the torque wrench - no joy. I tried only tightening the bolts on the side farthest from the wheel... and I tightened it up to the point of breaking the bolts and there was no change in straightness! The ones on the "Low" side were only finger tight.

    I started to look for odder solutions. Turns out, the rag/rubber pieces were the problem. They were not uniform in thickness. I bought 2 more bolts at lowes. (The local Lowes fails. They have no metric bolts. I have 2 1/4"-20 bolts and 7 M6 bolts.) I cut up an old pair of jeans. I tightened the sprocket, marked the low spots, and stuffed denim in between the sprocket and the rag. It is very nearly perfect now, dawdle is less than 1/32"

    -Mark
     
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