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OT - Adjusting Spoked Wheels

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  • OT - Adjusting Spoked Wheels

    The back wheel on my bicycle is out of whack. I have a spoke wrench and I am trying to figure out the best method to get it true. My first thought is to loosen all the spokes and then true it up with four pairs of spokes and then tighten the rest. Maybe off base, but if so then how to do it correctly?

  • #2
    Same as a four jaw chuck.

    John S
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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    • #3
      ALMOST like a 4-jaw. Unlike a 4-jaw, the spokes pull both laterally (parallel to the axle) as well as radially (perpendicular to the axle, or axis, like a 4-jaw). So, when you tighten or loosen a spoke, you get pulling in both of those directions.

      I usually set up the wheel in an upside-down bicycle, then use the mag-base indicator on the rim. First, I snug down all of the spokes to about the same tension. Then, use the indicator to get it close radially. Check the lateral runout, and go back through the spokes to bring this closer to zero. Back and forth between lateral and radial adjustment, and pretty soon you'll have a nice, true wheel (provided that the rim wasn't too tweaked on its own). Finally, check to see that all spokes are pretty similar in tension and pretty tight. Ride the bike around the block a few times, make sure things stayed true. A fairly interesting procedure.
      If ignorance is bliss, why aren't there more happy people?

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      • #4
        http://mgaguru.com/mgtech/wheels/wl109.htm

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        • #5
          Definitely an 'interesting' procedure. I respoked a motorcycle wheel for a friend once. I found it helpful to make a length gauge from a strip of wood, actually two, since the hub had different diameters on either side, and the wheel had to be offset the right amount. For a bicycle wheel, without taking it apart, the thing to do first is check the distance from rim to hub as you spin it. If it's close that way, don't loosen the spokes, but start by finding where the rim leans to one side. Loosen two or three spokes from the close side, and tighten two or three from the other side. The rim should lead towards the tightened spokes. If the spokes were all loosened to begin with, the rim will be going off center radially, compounding your truing problem. If the rim is off center anyway, then you'll have to try adjusting all the spokes to an equal length before truing. A stick is a lot easier to handle than a tape measure, so cut one to a suitable length, preferably before you loosen all the spokes. Make sure you have the rim centered axially, so the brakes work as they should, and the tire doesn't rub. I agree if the rim is bent, it should be straightened first if that's possible.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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          • #6
            Rear wheels are "dished" , that is to say that the side with the gears (assuming it has gears) will be almost flat, and the other side angled more.The side with the gears actually has shorter spokes than the other side. Front wheel spokes are all the same length. This makes the rim end up centered on the hub, and therefore centered in the frame. You true for both hop (radial) and wobble, (lateral). If you look at the spokes, every other one pulls the same direction, so if you want to move the rim one way, you might loosen the spokes pulling toward the convex side (High) and tighten the ones pulling toward the concave side.The loosening and tightening might be in the quarter turn range to begin with. There is also probably a point you can pick as being the apex of the wobble, where you have to shift the rim most, until you blend back into an area that is ok. It is a bit of an art, but can be reasoned out. A truing stand is a help, but not necessary, as you can use the frame and an indicator as mentioned above or just a ruler for comparison. There was a bike shop that had a bowl of spoke wrenches with a "FREE-TAKE ONE" sign. They got more wheel repair work that way ....

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            • #7
              http://www.parktool.com/tools/TS_3.shtml

              http://www.parktool.com/tools/WAG_4.shtml

              http://www.parktool.com/repair_help/howfix_truing.shtml

              [This message has been edited by Sprocket (edited 09-05-2004).]

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              • #8
                also: www.sheldonbrown.com
                and look for article on wheelbuilding.
                If the wheel is 'recent' vintage (5-15yrs)
                it will be alloy and relatively strong hence not easily warped a lot except with severe spoke imbalance. All spokes on one side will need to be about the same tension (same twang when plucked) and the R side will be more highly tensioned than the L unless you have one of those rims with offcenter spoke holes. One important thing: after the tension builds up to a certain amount turning the nipple no longer advances the nipple screw down the spoke thread, rather the spoke twists and winds up. You have to take the wheel down off the bike and with the rim vertical on the floor,bounce your weight with stiff arms up and down a few times on the rim, rotate a hands breadth and repeat til 180 degrees have been done. The spokes will ping as they untorque, when the pings stop, go back and recheck every thing. Do this repeatedly til wheel is true and there are no pings. Once you get to the pinging spoke stage of tension it will be unlikely you will need more than one more complete turn of the nipple. There are 2-3 different sized nipples, make sure yours is correct as once the tension mounts you can round over those brass nipples easily. Steve

                [This message has been edited by sch (edited 09-05-2004).]
                Steve

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                • #9
                  Geez, you guys brought back BAD memories of respoking a set of Model T wheels. Wood Spokes! Learned a lot. Not something I'd want to do often.

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                  • #10
                    Thanks to all for the suggestions. Sprocket - It was very helpful to know that the wheel was dished. It is now much better than it was. It was much harder for me than a four jaw chuck though.

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