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Author Topic: How to true a wheel  (Read 1284 times)

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Offline wowbagger

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How to true a wheel
« on: May 13, 2016, 08:20:35 am »
    I figured it was about time for me to write a "How To" on how I true spoked wheels after having completely disassembled and relaced them. Most methods I've seen are fairly imprecise and lend to the myth that wheel truing is some form of black magic. So here we go:

Tools You'll Need:

Optional But Highly Recommended "Tools"
  • Beer
  • Netflix or your preferred movie watching method
        - Note: Moosehead and Constantine may be switched for preferred beer and movie
       

Final Prep Work:
  • Mount the wheel on the stand making sure that the cones are firmly seated in the bearings. Then tighten the set screw on each cone. Ideally, the wheel should be on the stand in the same
        direction that it would be on the bike. So with the stand in front of you, the speedo drive side of the hub should be on your right. (or brake drum side if this was the rear wheel).
  • Clamp the vice grips to the axle shaft as close to the end of the shaft as possible without hitting the stand. This will ensure that only the wheel is
         moving. So that any variations in the shaft will not be picked up by the dial indicator.
         
  • Find your spoke groups.
        - A spoke group should be a set of spokes with an equal number of inside and outside spokes. The inside spokes pull on one side of the rim while
          the outside spokes pull on the other.
        - In this case, I am truing wheels off of a CB500. These are 40 spoke wheels. A set of 4 spokes will give me two inside and two outside spokes. 40
          spokes divided by 4 will give me 10 spoke groups.
        - We want to mark every other group 1 through 5. I like to start the first group immediately after the valve stem hole for easy reference
           
           
        - Now, mark the other 5 sets A through E. You should now have a wheel with all 10 groups of 4 spokes marked in the following patter:
           1-A-2-B-3-C-4-D-5-E
  • Prep the spoke tension for truing.
         - For all spokes in the 1 through 5 groups, tighten the spokes finger tight and then tighten them one full turn more.
         - For all spokes in the A through E groups, tighten the spokes finger tight and then loosen them at least one full turn. All the spokes in the
            A through E groups should rattle slightly.
         - We do this because we are going to start truing the wheel only using groups 1 through 5. We will then true A through E after the wheel is mostly
            trued. Loosening A through E will make sure that they do not interfere with truing 1 through 5
  • Now attach your dial gauge to the stand and set it to start truing the outside edge first. Make sure to preload some tension on the dial gauge
         so that it has sufficient room for the needle to move in and out. I normally set the dial gauge with the needle in the middle. Starting with the
         outside edge first will help keep the metal "Thing-A-Aa-Hoozit" from getting hung up later
       

Actually Truing The Wheel: Horizontally
  • Grab a piece of paper and label 5 columns named "1" through "5"
  • Rotate the wheel until the dial gauge is pointing at the middle of the center two spokes in group "1" and then set then zero out the dial gauge.
        (See previous photo)
  • Write a 0 in the "1" column on your paper
  • Rotate the wheel slowly until the dial gauge is pointing at the middle of the center two spokes in group "2" (skipping over group "A") and write down the reading for group two on your paper in the 2 column
  • Continue this process for groups 3,4, and 5 making sure to skip over groups B,C,D and E
  • Now we need to find the median of the wheel measurements as it currently is. Looking at my sheet, I see that only group 5 was in the positive while 2 though 4 were in the negatives. I'm calling
         group 2 my median since it is the closest to the median I can get.
         Note: The arrows on the first row are a visual reminder for me for which way the wheel is too far out of true. A left arrow indicates that section of wheel is too far left of the center line while a right
         arrow means too far right.
         
  • Now, set the dial gauge to the center of group 2 and zero out the gauge. Start a new row on your paper with a "0" in column 2
  • Remeasure groups 3,4,5 and 1 and note the measurements in the new row
  • Now were finally ready to start truing the wheel. For my wheel, I can see that groups 3 and 4 are too far left and groups 5 and 1 are too far right.
  • Starting with group 3, I tightened the two spokes on the right hand side of the rim 1/4 of a turn using the 6mm wrench. Then loosen the 2 spokes on the left hand side of the rim 1/4 of a turn.
         This now pulled that section of the rim to the right slightly. I then did the same for group 4 as it was also measuring in the negative.
  • For group 1, I tightened the two left hand spokes and loosened the two right hand spokes 1/4 turn. This moves that section of rim to the left.
  • It is best to only do 1/4 turns while truing so that you do not over tighten or loosen a section and throw the wheel further out. Also, as we are essentially treating each spoke group as a single
         spoke (with a single measurement), it is imperative that all 4 spokes in that group get tightened or loosened. If you tighten one side but do not loosen the other you will not get an accurate
         measurement.
  • I then took new measurements after making the adjustments and noted that my median had shifted again (row 4). I set my new median to group 5 and took new measurements (row 5). I then
         adjusted the spoke sets in the same manner as I explained above.
  • My median shifted yet again to group 3. I zeroed it out on group 3 and took measurements again (row 6).
  • I was finally able to maintain a steady median group with group 3. I tightened/loosened the other groups, remeasured (row 7), and repeated until I got all of the measurements as close to 0 as
         possible.
  • The guy that taught me this process always said to true the wheel within 20 thousandths of an inch. Within  .02" he claimed you could not feel the difference in normal street riding. So, I of
         course cut that in half and shoot for within .01" or 10 thousandths. My dial gauge has a couple of handy black markers that I set to +0.005 and -0.005 as a visual guide. Once I reached
         measurements within that range I called the wheel horizontally trued.
    NOTE: It is important to note that you may see groups A through E fall outside of that .01" range. At this point that is fine. We are still ignoring that those groups exist.

Actually Truing The Wheel: Vertically
  • It's time to move the dial gauge to measure the vertical runout of the wheel. This is where the metal "Thing-A-Aa-Hoozit" comes into play.
  • Unfortunately, I have no idea where I found that metal bit. It was lying around my shop from something. The important features, if you want to make one is that the center hole be large enough
         for the tip of the dial gauge to sit in without going all the way through. Also, the width of the metal piece should be narrower than the inside shoulders of your rim (where it dips down to the
         nipple heads). The toothpicks should get cut down so that they can ride on top of the rim shoulders without falling off or coming into contact with the lip of the rim.
  • Why the "Thing-A-Aa-Hoozit", you might ask. I use this because the inside of these old rims are often very pitted and uneven. The "Thing-A-Aa-Hoozit" give me a 4 point float the smooth out all
         of the variations in the rim and give me a more accurate reading. It also lets me measure from directly over the spoke heads rather than off to the side. Also, I get to name something
         "Thing-A-Aa-Hoozit"
  • Again, preload the gauge to about the middle. Position the "Thing-A-Aa-Hoozit" in the rim and set the tip of the gauge into the center hole.
       
  • Slowly rotate the wheel a full turn to make sure that your toothpicks are not going to fetch up on the rim and that your dial gauge does not move. Note the measurement on the gauge at the
         point you start. Rotate the wheel one full turn and verify that the reading is the same as before. This will ensure that the "Thing-A-Aa-Hoozit" is not throwing off the readings of the gauge
  • Start new columns labelled 1 through 5 on your paper.
  • Now set the gauge to point to the center of group 1, zero out the gauge and mark a zero in the "1" column on your paper
  • Measure groups 2,3,4, and 5 from the center point (making sure to skip groups A through E) and record the measurements
  • As with the truing process for the horizontal steps, find the median, set the gauge to that group, zero out the gauge again and remeasure.
  • I crossed out my first measurements because the dial indicator moved. I remeasured and then found my median (row 2) and then measured again (row 3)
       
  • For groups 1 and 2 the rim was too far from the hub (negative measurement). So, I tightened all 4 spokes 1/4 turn each in each group
  • For groups 3 and 4 the rim was too close the the hub (positive measurement). So, I tightened all 4 spokes 1/4 turn each in each group
  • After remeasuring, my median stayed put. So, I measured all groups again and adjusted again (row 4)
  • A few more rounds of that and I was dead on except for group 4. I had loosened these spokes to the point where they were barely finger tight. I made sure that the A through E groups were all
         still rattle-loose and not interfering. I have to assume that there is a bit of a flat spot in this old rim. Thankfully, I'm still within 0.01". So, I'll move on. I suspect that I'll be able to pull a bit of that
         flat spot out as I finish truing the wheel.

Rinse and Repeat
  • At this point, you have a wheel that is (or was) horizontally true at 5 points and vertically true at the same 5 points. You need to now switch back to the horizontal measurements and run through that whole process again. Most likely, vertically truing the wheel threw out the horizontal measurements.
  • Once the wheel is yet again horizontally true, you need to (you guessed it) double check for vertical trueness again. Follow the above steps to get groups 1 through 5 back into true.
  • Now....check for horizontal true again...and then vertical....and then horizontal...and then....well you get the idea
  • When the when measures true both horizontally without making any adjustments and then vertically without making any adjustments, you'll have a partially trued wheel.
  • Now we are ready to stop pretending that this is only a 20 spoke wheel. Go around the wheel and set all 4 spokes in groups A through E to finget tight. Now got back around and tighten the spokes in ONLY groups A through E one full turn. Do not touch any of the spokes in groups 1 through 5 or you will undo all of your hard work.
  • Start a new table on your paper with columns labelled "A-2-B-3-C-4-D-5-E-1".
  • Set your dial indicator to the center of group A for a horizontal measurement and zero it out. Now take measurements for all 10 groups.
  • As before, find your median, zero out the gauge on your median again and then remeasure all 10 groups
  • Follow the same procedure for the horizontal truing but make sure to measure and adjust all 10 spoke groups
  • Keep measuring and adjusting until all measurements are within 0.01". Then switch to measure vertically
  • Again, follow the vertical procedure, adjusting all 10 groups. Once all measurements are within 0.01", switch back to horizontal
  • Repeat the alternating adjustments until you can measure but horizontal and vertical without making adjustments and the runouts stay within 0.01"
  • CONGRATULATIONS! You have a trued wheel.......but there's on more steps

Torquing a Trued Wheel:
  • The last step is to torque each spoke so that the wheel will stay true without any of the spokes loosening and twisting the wheel.
  • Grab your trusty spoke torque wrench with a 6mm head on it
  • Put a piece of tape on the first spoke immediately after the valve stem hole. This will be your visual indicator to let you know you've tightened each spoke.
  • Tighten that first spoke that you just marked with tape ONLY 1/4 turn.
  • Now, count 3 spokes. The 3rd spoke should now be on the opposite side of the rim as the 1st one you tightened. Tighten that 3rd spoke 1/4 turn.
         
  • Now, count 3 more and tighten 1/4 turn making sure that each spoke you tighten is on the opposite side of the rim from the last one you tightened.
  • You will notice that it will take more than one rotation of the wheel before you get back to the spoke you started with. The wheel should now still be true and 1/4 turn closer to being torqued.
        Feel free to whip out your trusty dial gauge to verify but that's not necessary
  • Go around again tightening every 3rd spoke 1/4 turn starting with the 1st spoke you marked.
  • When you reach the first spoke that is torqued (you'll hear/feel the CLICK), mark it with something different than the marker for your 1st spoke
  • Continue around, tightening every 3rd spoke 1/4 turn and marking each spoke that is torqued. Do not skip spokes that are marked as torqued so that you do not throw off your pattern.
        Also, tightening other spokes may have thrown the torque off on the marked spokes.
  • Continue around and around, 1/4 turn on every 3rd spoke until all 40 spokes are marked as torqued.
  • Go around one last time and verify that all spokes are properly torqued
  • Check horizontal and vertical runout one last time with the dial gauge
  • If you are the unfortunate sound that has gotten the wheel out of true, go back to the truing steps and return the wheel. Then retorque the wheel all over again
  • You should now have a completely trued and torqued wheel! Sit back, have a beer (if you have any left) and finish your movie (or your 5th movie depending on how long this look)

Now........go back to the top and do the other wheel  ;D ;D ;D ;D ;D ;D[/list]

Offline Brian750

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Re: How to true a wheel
« Reply #1 on: July 07, 2018, 11:44:18 pm »
Thanks wowbagger this was very helpful!

 

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