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  1. #1
    Senior Member stevegor's Avatar
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    Another R20 mod question

    I'm using a BMX fork with Vbrake bosses for my next project, problem is the steerer is just too short for the R20's head tube, so do I...

    1: Cut the head tube down to fit, which means I need a longer headstem, (no problem there), or....

    2: Put a 22.2mm insert into the BMX steerer, then add approx 2.5 inch length of threaded steerer over the insert then drill holes and spot/tack weld it all together. This is quite a safe process and it would keep the R20's front angle original.

    Opinions please,

  2. #2
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    I had such a tough time with the fork on my r20. i thought about cutting the head tube as well, but i saw a few pics of that mod and imho it destroys the look of the bike. if you can stretch the bmx steerer and its good and straight (welding has a tendency of moving things around even on the best of set ups)i would go that route. on my 20 i wanted to use the qr and have the max height adjustment so i pressed the steerer from an rst sprite out and had the longest threadless steerer available threaded on a lathe. (a few pics are in another post). this gave me around 6+ inches of adjustment in height. on my next 20 i plan to try a disc version so ill probably modify a bmx fork the same way and then some. ill use a soma hi rider quill stem so my height will be fixed but i found it not to be as big a deal as originally thought. by no means will i even consider cutting the head tube. its like cutting the tailfins off a classic car.

  3. #3
    Senior Member
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    are you sure 22.2mm fits in there. BMX quill stems are usually 21.1mm.
    You can get some MTB stems in 21.1mm but I havent seen any road stems that size. BMX stems are short reach, so the bars are a bit close.
    I geuss you could ream it out. You can get adjustable reamers that size

    I would cut the Headstock. Maybe below the cross bar. This would give a more sporty head angle. But might lead to pedal strike, on the ground.

    I have heard of a tube lengthening process. Where the 2 tubes are put together and clamped down onto a bit of angle iron. this holds them straight. Not tried it though.

  4. #4
    Senior Member stevegor's Avatar
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    The BMX fork's steerer is definitely 1" and I've tried a 22.2 road quill stem which fits OK.

    No problem with pedal strike as I'll be using 145mm cranks.

    I would like to keep the head tube original if possible, so lengthening the steerer might be the way to go. However, with the BMX fork I can't "sweat out" its steerer then add a longer one, it's too big a job and I'd probably botch it, so I might use the angle iron idea and see what happens.
    Last edited by stevegor; 06-17-09 at 07:37 AM. Reason: add

  5. #5
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    Oh yeah I meant that the 2 tubes are clamped down into the angle iron. Then the tubes are welded together. The angle iron holds it straight.
    Think it was on Atomic Zombie that I heard about it.
    Maybe cover the threads on the steerer tube with oil to stop it getting damaged by weld splatter.
    Might be a plan to use an inner sleeve. Cut the top part of a steerer tube so you can get your stem into it a good amount. Then cut your forks steerer tube to length to make it the proper total length. Got to watch that the steerer tube get a thinner internal diameter near the bottom

  6. #6
    Senior Member stevegor's Avatar
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    Quote Originally Posted by ogeluv View Post
    I had such a tough time with the fork on my r20. i thought about cutting the head tube as well, but i saw a few pics of that mod and imho it destroys the look of the bike. if you can stretch the bmx steerer and its good and straight (welding has a tendency of moving things around even on the best of set ups)i would go that route. on my 20 i wanted to use the qr and have the max height adjustment so i pressed the steerer from an rst sprite out and had the longest threadless steerer available threaded on a lathe. (a few pics are in another post). this gave me around 6+ inches of adjustment in height. on my next 20 i plan to try a disc version so ill probably modify a bmx fork the same way and then some. ill use a soma hi rider quill stem so my height will be fixed but i found it not to be as big a deal as originally thought. by no means will i even consider cutting the head tube.
    its like cutting the tailfins off a classic car.
    Or de-seaming a mini Cooper S?

  7. #7
    my nice bike is at home kraftwerk's Avatar
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    Don't cut the frame!
    But let us know what product combination or custom fittings you decide on...

  8. #8
    my nice bike is at home kraftwerk's Avatar
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    Some people cut the rain gutters off 70's and 80's Porsche's and I always think that it is such a shame!

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