How To: Spreading Your Frame for Clearance

Discussion in 'Mounting Techniques for Bicycle Motors' started by bairdco, Feb 18, 2011.

  1. bairdco

    bairdco a guy who makes cool bikes

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    this was taken from : Sheldon Brown: Bicycle Frame/Hub Spacing

    Spreading the Frame
    There are a number of ways to do spread a frame. Probably the easiest way is to use a lever. A piece of 2 x 3 or 2 x 4 lumber, roughly 5-6 feet long works well for this:
    1.Remove the wheels, fenders and any seat-tube mounted bottle cage.
    2.Lay the bicycle on its side with the handlebars turned to face upward.
    3.Insert the lumber through the rear triangle, so that it goes underneath the upper rear fork end, and above the seat tube. The lumber should extend out past the rear end of the frame.
    4.Place the far end of the lumber onto a chair, crate or other raised structure, so that only the head-tube/fork area of the bike is in contact with the floor.
    5.Press down gently on the lumber where it crosses on top of the seat tube.
    6.Measure the spacing to see if it has changed.
    7.If the spacing hasn't changed, try again, pressing a little bit harder. Repeat until you get a result, applying a bit more force each time, until the spacing has increased by about half the total amount you are seeking.
    8.Turn the bike over, and repeat for the other side.
    In the illustrations below, the stays will be bent to the left (up in the photos) by pressing down on the end of the 2 x 4.
    The other end of the 2 x 4 is on top of a stool. The longer the 2 x 4, the less force is needed.

    The 2 x 4 is under the left fork end,
    widening the spacing by pulling the left side upward The 2 x 4 is under the right fork end,
    narrowing the spacing by pulling the right side upward
    The bike does not actually need to be stripped down this far, most parts can remain in place.
     

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  2. The_Aleman

    The_Aleman New Member

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    Great write-up bairdco! IMHO, everyone with pedals should have Sheldon Brown's site bookmarked! He was/is an inspiration to me, dating way back to my pedalhead days. May he RIP.

    Framespreading alternate method:

    I had to spread my frame on "OCD" when I went to install my X-RD3'd wheel in the rear dropouts. GAH, needed another .375"! I didn't use the great man's method for mine because the frame was not a day back from the powdercoating shop. :eek:

    Instead I created my own framespreading tool like any other industrious MaBer might be apt to do. Here's the parts I used:

    (2x) .250" bar stock, 2.5" x 6" (2" should also work)
    (2x) 0.5" coarse-threaded rod, 6" (12" if no coupler)
    (2x) 0.5" nuts and fender washers
    (1x) 0.5" coupler for threaded rod (you can skip this if using 12" rod)
    An old non-knobby tire and 4 zipties (can sub lots of ductape for either/or)

    How to build the framespreader with above parts:

    1) Drill a 0.5" hole in the center of each plate. Take the old tire and cut a couple pieces that will cover one side of each plate, and don't forget the hole. Secure tire to one side of each plate using zipties or ductape. The tire is so you won't scratch frame when spreading it.

    2) Take the threaded rods and thread them into the coupler. Thread the nuts onto the rod all the way to the coupler. Add washers. Slide plates onto the rod.

    Done! My notoriously junky cam has no batteries, so I supplied a crude MSPaint drawing. I'll update this post at another date with a proper pic. To use this tool, you simply tighten one of the nuts until you achieve the proper spreadage. Hope this helps!
     

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  3. camlifter

    camlifter New Member

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    i just use a bottle jack, theres some spring back when spreading a frame so go in small steps untill you get it where you want it.
    to spread the front part of the chain stays use a threaded rod or an old axle to keep the axle area from spreading and spread the area behind the seat tube with a port-a-power for fitting wide tires.
     
  4. killercanuck

    killercanuck New Member

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    That's cool bairdco, not just for hub clearance but for shifting the whole hub position.

    Aleman's technique is good just for hub spacing, but ain't much out there cheaper than a 2x4 :p

    That's a cool idea camlifter, throw a hub in there while you're cranking on it so both sides move the same.

    Great post!
     
  5. chainmaker

    chainmaker New Member

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    Just might have to refer to this for My Panther and sturmey.
    Cheers
     
  6. Desert Rat

    Desert Rat New Member

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    I hate to disagree with you but I used something like Aleman's technique
    had to spread rear forks almost 3 inches for the HD axle, do that with a 2x4 and NOT break it.


    and remember that advice you give can trash someone else's frame, not yours!!!
     
  7. killercanuck

    killercanuck New Member

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    FYI - I've used biards technique with a hub in place like Cam mentioned to straighten a frame once, and another time to give me upper chain clearance.

    I didn't just stomp on it, let it flex and give it the time to bend. Depends on the frame you're using too I guess, eh? ie. cruiser/mtb, alum/steel...
     
    #7 killercanuck, Oct 31, 2012
    Last edited: Oct 31, 2012
  8. brad2274

    brad2274 New Member

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    never thought of using a 2x4, i usually just use a spare tire car jack(the real tiny wind up ones) for bending forks, frames, and cranks.
     
  9. locell

    locell New Member

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    I did the same thing pretty much to get space for a rear brake. Pic attached
     

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  10. Desert Rat

    Desert Rat New Member

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    question on spreading, I mounted a HD axle and had to spread my frame open like 3 inches.
    what I would like to know from the experts, can you put a torch to rear
    forks (for lack of better word) to release the stress without doing damage
    to bike? I believe I can since the steel is not hardened a good heating and slow
    cooling should release stress without doing damage
    What are your thoughts?
     
  11. bairdco

    bairdco a guy who makes cool bikes

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    the two top "forks" are called "seatstays," and the bottom two tubes are called "chainstays."

    a torch wouldn't hurt (besides melting the paint, if it has it,) but it's probably not necessary.

    there's not too much lateral stress going on while riding. most frames break at the welds near the bottom bracket or the seat tube.

    obviously, if you bend the crap out of your frame it could weaken it, but as long as you don't crease or buckle the tubing, it should be ok.
     
  12. Desert Rat

    Desert Rat New Member

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    thanks for the advice, even though I'm a machinist I haven't worked on bikes
    for about 40 years, the problem I'm having is that every time I take the rear
    wheel off the frame springs back which makes it impossible for me
    to change rear tire on the road without spreaders.
     
  13. chainmaker

    chainmaker New Member

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    You need to over spread them so when springback happens it is at the width you need
     
  14. Desert Rat

    Desert Rat New Member

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    Did that almost to the point of kinking frame and they still popped back to original measurement after 200 miles on the road, and just in case you are
    wondering I have the huffy panama jack frame
     
  15. 2door

    2door Moderator
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    3 inches? Why would ever need to spread the frame 3 inches? That seems excessive unless you're trying to use a motorcycle rear hub. You're asking a lot of your frame. I'd keep my eye on it if I were you.

    Tom
     
  16. Desert Rat

    Desert Rat New Member

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    This is the axle I'm using, and by time you mount it you do have to spread your frame quite a bit.
    http://www.bicycle-engines.com/Freewheel-Sprocket-and-HD-Axle-Kit-w-Brake.html
    when I bought it I didn't think I would have to spread the frame that much but there you go, oh and I'm mounting a 79cc and ezm to it
     
  17. The_Aleman

    The_Aleman New Member

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    Like most bikes that originally came with coaster brakes, mine had 110MM spacing.
    Most the non-coaster rears are 135MM, so that 50MM is about a 2" difference overall.

    I used my tool to get most the spread, but I actually have just enough left to make
    installing/removing my rear wheel a 2-person job unless I use the spreader tool :D

    As I use a quality tube, Slime, and a tire liner, flats aren't something I have to worry about, thankfully.
    My bike carries it's own footpump :D
     
  18. 2door

    2door Moderator
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    Here's a little tool I made quickly from an old aluminum turn buckle. I didn't make it very pretty, just functional because I needed it 'now'. It was made to fit the seat stays on a Nirve Switchblade. I can spread the frame just enough to make removing or installing the rear wheel easier. I have chain adjusters that fit between the frame and the cone nuts and they take up some space that makes getting the axle into the dropouts difficult.

    It's the same principle as Aleman's but doesn't use the dropouts.
    Tom
     

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  19. BarelyAWake

    BarelyAWake New Member

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    Not as fancy, but effective;

    [​IMG]
     
  20. 5-7HEAVEN

    5-7HEAVEN Active Member

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    Your advice is timeless, bairdco.dance1

    Here's my problem.

    Dropout width is 130mm, so I can get a multi-speed hub in there w/no probs.

    I need more tire clearance for my motorcycle tire. I'm estimating less than -1/16" on one chainstay to +1/16" on the other side's seat stay.

    Do I have to cut off the fender bracket/cross brace on the seat stay?

    Do I have to cut off the bike stand bracket on the chain stay?

    To my thinking, that's the only way the stays will spread where the tire will be. I can secure the stays with C-clamps. That way, the welds on the seat tube don't get stressed during the spreading process.

    Thanks for help. I'll prolly use a Toyota jack or all-thread and washers.
     

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