Chains Help! Chain hits fender & tire

Discussion in 'Transmission / Drivetrain' started by jroyse, Dec 28, 2011.

  1. jroyse

    jroyse Member

    I'm installing a Skyhawk engine on an old style Schwinn bike.The drive chain is into the fender and just touching the tire. I have cut away nearly half of the fender and even welded spacers onto the coaster brake arm so I can move the sprocket out board !/4 inch. Not enough. I have seen many other bikes on Craiglist on the same type bike. Tried to email them but nobody answers. This is a fat tired full fender Schwinn. Can anybody help?
    Jim
     

    Attached Files:


  2. olow

    olow Member

    :idea::detective:from what i see the big gear [COGG]is on backwards in denture towards spokes is the way it should be:poop::tt1::jester::dunce:
     
  3. wan37

    wan37 Member

    I agree turn it around.:idea:
     
  4. jroyse

    jroyse Member

    The in-dent is toward the spokes. It just looks different in the picture. That is the teeth on the sprocket are facing away from the spokes. I can't imagine I'm the only nut who ever ran into this problem. Also can't believe others have went to the extent of welding up spacers to get things to work. Me, I'll cut, weld hack anything to make things work. But I don't know where to turn on this one.
     
  5. wan37

    wan37 Member

    Okay how do u got the rag joint rings you can play around on way to install them like both on the inside or 1 out and 1 in...I got faith you will figure it out plus turn the sprocket around and try it. I had trouble with my sky hawk so the installation manual is not always right.Try installing different way you will get.I had to turn the sprocket chrome shiny side out on mine. Hope this helps..
     
    Last edited: Dec 28, 2011
  6. jroyse

    jroyse Member

    I have tried flipping the sprocket ... then put it back, then welded spacer blocks onto the coaster brake arm to space it out so I could space the sprocket out. IT STILL RUBS. I have also cut away the fender...still rubs. I was thinking of an offset motor mount to move the engine to the left but the clutch housing won't allow movement that way.
    Come on guys bail me out! I know others have built these. What am I missing?
     
  7. wan37

    wan37 Member

    I was thinking to get another rag joint and put it like this:sprocket then 2 rag joints through spokes rag joint and then metal brackets.I'm not sure tho.You can search it on google and YouTube that might help too.
     
  8. wan37

    wan37 Member

  9. Cavi Mike

    Cavi Mike Member

    With a tire that narrow you shouldn't have a problem. I'm thinking the rear triangle(seat-stays and chain-stays) are bent.
     
  10. jroyse

    jroyse Member

    chain rubbing on tire

    After numerous attempts to move the chain outboard including welding spacers to the coaster brake arm so it to can move out and then adding spacers to the sprocket the chain still rubs. Plan B: move the engine out using custom built mounts. This just has to work. What else is there?
     
  11. Cavi Mike

    Cavi Mike Member

    Bending the rear triangle. Bend it to the left.
     
  12. Big Red

    Big Red Active Member

    jroyse, The best way I've found is to add more spacing to bring out the sprocket.(another rubber spacer or 1/2 width of one.) Just enough to clear the rear tire. I've even used car tire sidewall to make my spacers. You would have to enlarge the sprocket center or extend the coaster brake arm attachment. Spookytooth has a brake arm extender but is out of stock and has been for a while. SO, make your own. Get two brake arm attachments/bearing race, Figure out how long it needs to extend, grind or cut to length, and weld the two peices together. Leave the axle in it when you do so the threads will still line up on the two peices.
    I've got a build on hold waiting for Spookytooth to get it together but I'm almost ready to build my own brake arm extender for my Jesse James build. Bending the brake arm weakens it and it can snap under pressure. If you have to bend it, bend as little as possible. I've snapped two brake arms on the JJ build and am not going to do it that way again. It's real scary losing your brakes at 30mph coming up to an intersection.
    Shiney Side Up,
    Big Red.
    P.S. If you have to "bend the triangle" as suggested, then your frame may be bent. Your next move then would be a new frame.
     
    Last edited: Dec 30, 2011
  13. Cavi Mike

    Cavi Mike Member

    Why would you buy a new frame because its bent? How do you think frames are made in the first place? Do you think they are just "born" in that shape? They're bent into their current shape. If it happens to get bent a little bit, so what? Just bend it back.
     
  14. jroyse

    jroyse Member

    getting chain clearance

    I know what you mean about the brake arm. I welded some square spacers on the inside of the arm which will move it outboard. Had to cuz I moved the drive sprocket out. Still needed more clearance. Soooo now I'm fabricating some offset motor mounts to move the motor to the left about a 1/2 inch. What a pain. This better be worth it or there's gonna be a bike for sale.
    Thanks to all for the tips and help. If I ever get it to work I'll try to post some pictures.
    Jim
     
  15. Big Red

    Big Red Active Member

    Frame

    I guess you could do that. But unless you have a frame jig it's never gonna be perfect. Also, I guess a "slightly" bent frame would be OK for you to ride.
    Sure, A frame can be straightend with time, effort and a jig. And a blowtorch and a caliper and a tape measure and a ect, ect, ect. Once a frame is bent, unless it's a $1,000 frame, It's going on the scrap pile.
    Big Red.
     
  16. olow

    olow Member

    whats up u sound like a complete idiotocally depreesive human person do u want help or not just flip the dam cogg over and build the BIKE:poop::D:jester::(:D:bowdown::idea:
     
  17. Cavi Mike

    Cavi Mike Member

    Bikes aren't formed using heat, roll cages aren't formed using heat, CARS aren't formed using heat. If you had a $1,000 frame, why would that all of a sudden be safer? Quit sharing your wealth of ignorance, no one cares "what you would do" because that's just you being misinformed.
     
  18. Big Red

    Big Red Active Member

    Frames

    Perhaps you misunderstood me. If you have a frame you REALLY like, then yeah, go ahead and straighten it out. But you know as well as I do that when you bend metal and bend it back it weakens it. To strenghten the molecules of the metal again it needs to be heated and dipped, Some say cold water some say oil, To realign the molecules of the metal. All I was really saying is that if you just have an everyday, cheaper Mountain bike frame, Like MOST people do, Then it's easier to just switch frames. Most of these things are made in china using cheap metal to begin with. You don't want to take cheap metal, bend it, then bend it back again and trust it to hold up at 30mph.
    All that being said, If it's a very (very) small bend then it might be OK. I've had cheaper tweaked frames come apart on me and it's not a lot of fun. I build bikes for other people (a lot) and I can't take that kind of chance with other peoples lives. Most frames are a dime a dozen, So why not just use another one. Now if you have a frame you're REALLY in love with go ahead and try it. On a personal build no one gets hurt but you. I would just never chance it on one of my customer builds.
    Shiney Side Up,
    Big Red.
     
  19. bob haynes

    bob haynes Member

    chain hits fender and tire

    Did you ever get your problem solved? I had a similar problem. I solved it with offset motor mounts. Also had to take pedal sprocket apart and bend left pedal about 1/2" outwards. Muffler did not fit so chopped off mount, bent to fit and welded back together. So since your willing and able to cut,chop,weld,etc. stare at it long enough and you will figure it out. happy riding
     
  20. motorpsycho

    motorpsycho Active Member

    geeze, it shouldn't be this difficult.
    no spacers needed on the brake arm, just bend it to clear the sprocket.
    you shoudl not have to add spacers to the sprocket because if you do, your chain alignment will be way off.
    moving the engine over to compensate won't work either...Look at you engine mounts, how do you intend to move the engine over?
    you shouldn't have to go through all of this, but you may have to do some modifying to get it right.
    in theory and with my experience, when you install the engine cvorrectly and the sprocket correctly you shoudl be in the ballpark as far as chain alignment / tire clearance.
    from this point, MINOR tweaking can be done to get the clearance you need.
    something tells me that your frame is bent...and I don't care if it is brand new.
    Bike frames are crapped out by the thousands these days and the precision just isn't there like it used to be in the old days. anything can happen in transport too....maybe it got bent when the shipping guy threw out of the truck to the wal mart employee? who knows.
    so the chain is rubbing your fender...so what? cut the fender to clear the chain. get the chain alignment right, make sure there's clearance between the tire and the chain and then cut the fender to fit.
    it's not that difficult to figure out, unless you are battling against a bent frame.
    spacers and all that stuff won't fix the problem...you need to really look at your frame and take some measurements. if it's bent, bend it back...no big deal.
     
    Last edited: Jan 21, 2012
Loading...