Bicycle Mechanics - How come every time I rebuild a wheel the spokes are too long?

So I've been through this once before. Picked up a free bike that had a bent wheel. Disassembled the wheel and got the (steel) rim bent back pretty straight and then rebuilt the wheel using the old spokes. Somehow the spokes were too long and I had to file off the excess. Got it pretty true and sold it.
Now I have another flipper bike with the same problem. I went through the same process (which may be my problem :notamused:). Disassembled, straightened rim, rebuilt with old spokes, spokes protruding a good 1/8"-1/4" through the nipple. What am I doing wrong?

1. You reduced the crossing when you re-laced.
2. The original wasn't tensioned properly - you did so and went a little overboard.

=8-)

So I've been through this once before. Picked up a free bike that had a bent wheel. Disassembled the wheel and got the (steel) rim bent back pretty straight and then rebuilt the wheel using the old spokes. Somehow the spokes were too long and I had to file off the excess. Got it pretty true and sold it.
Now I have another flipper bike with the same problem. I went through the same process (which may be my problem :notamused:). Disassembled, straightened rim, rebuilt with old spokes, spokes protruding a good 1/8"-1/4" through the nipple. What am I doing wrong?

1) There's no good reason to completely de-lace a wheel unless you're replacing the rim with one that has a different ERD or some one expects you to warranty the wheel when you have no idea whether the old spokes were properly stress relieved and may be close to failure.

2) Front or rear wheel? Multi-speed rear wheels with symmetric flanges have longer spokes on the non-drive side. On the 9/10 speed wheel I'm about to build the non-drive side spokes are 2mm longer than the drive side which is close to 1/8" off if you got the two spoke lengths swapped.

rear wheels often have 2 different size spokes- the left non drivetrain side is longer than the right drivetrain side.

I got a completely disassembled bike a while back, built up the rear wheel as 3-cross, and spokes were too long, relaced it as 4-cross, and they were perfect, so that will sure enough do it.

1. You reduced the crossing when you re-laced.
2. The original wasn't tensioned properly - you did so and went a little overboard.

=8-)

+1 on the reduced cross. many old 36 spoke wheels are built 4x (full tangent), odds are you rebuilt 3x out of habit. If you run the the specs through a spoke length calculator I'll bet the difference is exactly what you saw.

-1 on the higher tension, there's no way a rim would tolerate the tension difference 1/8" or 7 full turns of the nipples would add, even compared to a very loose wheel.

It's a rear wheel. I didn't remove the spokes from the hub, and thought I was careful to re-lace the same way. I guess I could try a 4-cross pattern and see how it turns out. Thanks for the help so far.

+1 on the reduced cross. many old 36 spoke wheels are built 4x (full tangent), odds are you rebuilt 3x out of habit. If you run the the specs through a spoke length calculator I'll bet the difference is exactly what you saw.

-1 on the higher tension, there's no way a rim would tolerate the tension difference 1/8" or 7 full turns of the nipples would add, even compared to a very loose wheel.


Actually with a cheap steel rim you can - it's just that the eyelets will take on a "tornado funnel" shape from getting pulled inward...eventually they'll crack pretty soon under use - assuming they didn't already before use.


=8-)

Maybe the spokes are so cheap they stretched. :D

Your diagnosis was spot on. It needed a 4 cross lacing. Thanks for your help everyone, it felt so good for a wheel build to turn out right for once.