Anyone ever have this fork problem [cutting a fork steertube]

Discussion in 'Bicycle Repair' started by redpiper777, Nov 8, 2008.

  1. redpiper777

    redpiper777 Member

    Hi all. Working on my first bike and just looking to head in the right direction here...The pic is just a frame with the forks resting in it...Its a 50's Hiawatha frame with new springer forks...As you can see the tube is quite long...I dont know if the threaded fork tube should be cut down ( scared of trashing the threads) or if I should put in some type of fancy spacer to hide the threaded tube...Any ideas would be very cool...

    Thanks
     

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  2. xPosTech

    xPosTech Member

    That would have to be some kind of spacer. Make your forks look like they were made for the bike.

    Custom fitting a new fork is common procedure. If you still have the original fork, measure the steerer portion. I'm gonna assume you're working with a threaded headset. Transfer that measurement of the steerer tube to the new fork.

    I don't know what the normal thread exposure is on a Hiawatha if you don't have the old fork. You will have to find out.

    To cut the tube, first make up a cut guide. Run an old headset nut down below the area you are going to cut. Then run two headset nuts just below the cut line and lock them together. One (two if you have them) more just above the cut line with just enough clearance for your hacksaw (or sawsall) blade.

    Carefully cut the tube. Use a vise to hold the fork (not too tight that you dimple the tubes) while cutting. Use a flat file to square off the cut and a round file inside the end of the tube to remove any burrs. Unlock the two nuts and remove them. With a file very lightly chamfer the end - just one or two threads worth. You still have one more nut that will dress the threads if the first two didn't do it. Remove this last nut and you're finished. (Except for reassembling and installing the fork.)

    Two things can wreck your fork. Trying to hold it with your foot while cutting and cutting off too much of the tube. Dismantle the fork so you can get the tube in the vise. Make sure you're cutting in the right place.

    Take your time and you will have a factory looking cut.

    Good luck. [​IMG]

    Ted
     
  3. redpiper777

    redpiper777 Member

    Thanks

    Hey Thanks for all the info...Way more than i expected and just enough to get the job done...Yes I still have the old fork...Ive been out of the bike loop for a while...I just turned 41 and I think the last time I tore a bike apart and rebuilt it was in my old BMX days in the early 80's...Thanks again for all the help, your idea is exactly what I was looking for...
     
  4. I had to shorten a fork once. I cut a section out of it and turned a smaller diameter pipe so it would fit snugly in the cut pieces and put some holes in the side of the fork tube pieces and welded the vee-ground ends togather and filled the holes with weld.
    You really don't want to shorten the threaded area and lose the slot for the keyed washer that goes under the nut. Keith Williams
     
  5. xPosTech

    xPosTech Member

    Thanks Keith I had forgotten to mention the slot. It's easy enough to lengthen or add it to the cut down portion. The placement radially is not that critical since it's purpose is to keep the headset nut from backing off from steering forces. I would put it in the same (180°?) place though.

    Ted
     
    Last edited by a moderator: Dec 18, 2015
  6. buck

    buck Member

    I just installed suspension forks on a friends bike this summer that the tube was too long. I removed the bottom bearing race from the forks and made a 1-3/4" aluminum spacer ( on my metal lathe ) to slide onto the forks, then pushed the bearing race on top of the spacer. The added spacer gave the bike a little extra rake in the front. Next we had to put a longer kick stand. It worked out great, and you wouldn't know that it wasn't made that way.
     
    Last edited: Nov 10, 2008
  7. xPosTech

    xPosTech Member

    Yeah you could do it that way.

    Take a look at the OP's pic in the 1st post. Mentally bring the frame up to the top of the steerer. Do you see what would happen to the spring bracket when moved to the top of the steerer tube?

    You would know it wasn't made that way.

    He may need a spacer anyway, though. For a true universal fit the manufacturer would need to thread a lot of that tube, rather than the 1 1/2" to 2" or so of an MTB fork. I think most of the repops are threaded about 4". For true universal fitting, they need to be about 12" long threaded 6" or even 7", with the slot cut all the way down.

    Also there may be other issues at work here. Take a look at this guy's problem. And some more springer problems.

    Here's a short (very) video of installing a springer. This is from a lowrider/cruiser site, where they, uh, "take liberties" with the classic Schwinn springer design. I would rather see the spring at a slightly nose down attitude than any other. But that's me.

    Not as easy as you first thought is it, redpiper?

    Again, good luck whatever you decide to do. It's now sleepy time 'stead of happy time.

    Ted
     
  8. Esteban

    Esteban Active Member

    Very well written & great instructions. Some people use a " Dremel " tool for some of the tasks as well.
     
  9. xPosTech

    xPosTech Member

    Redpiper I just had a nightmare. I dreamed you followed my instructions, cut your steerer, fitted it to the bike and it was too short! :shock:

    I didn't tell you to add the thickness of the fork crown ring to your measurement when transferring it to the new fork. Don't forget to add that thickness. It might even be best to measure the whole stack on the steerer for the measurement.

    Please post back and let me know. I won't be able to sleep. :(

    Ted
     
  10. redpiper777

    redpiper777 Member

    Nope didnt do a thing yet..I actually was ready to start and got freaked out..At the last second I just felt like something was wrong...I figured I would wait until I got the new head set before I did anything...I also never gave any thought about what to do with the keyed washer that was on the old fork. I'm not sure what I'm going to with that but I'll figure it out...Im sure not looking forward to trying to cut a notch in the threads. Thanks for the warning anyway.
     
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