Wheel building gone wrong - a "twang" and disaster
11-05-14, 01:09 PM
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Wheel building gone wrong - a "twang" and disaster
Ok, so I'm working on my first wheel build. I'm building up a very not performance set of 28 ½" westwood rim wheels for an old dutch city bike. Aluminum rims, 14g spokes, 36 h, 3 cross pattern.
I knocked out the front wheel on a sanyo dyno hub and felt pretty bad-ass. No real problems, very zen, felt like I was getting the hang of it on a basic level. I've been following Sheldon Brown's instructions, all good so far.
Then, the rear wheel. Lace up was no problem, but I kept chasing the dishing and truing back and forth, not really able to get it dialed in. I left and came back a few times and this morning was feeling pretty good about it. So then I went to do the stress relieving per Sheldon's instructions, and after working on maybe the 3rd set of spokes I heard a pretty good "TWANG".
At first I thought maybe I'd pulled a nut through the rim, but all looked well. I finished stress relieving and put it back on the stand and.... it was seriously messed up. WWAAAY out of true, the rim has a long torqued sway to it now, but no sharp bends.
Can I recover from this? What happened? I tried to start pulling it back and it isn't budging much, so no I've started backing everything off and starting again. The now pretty loose spokes don't seem to be making much of a difference, so it looked like I bent the rim. Is that a thing that happens?
Any input appreciated.
Thanks all, great forum.
I knocked out the front wheel on a sanyo dyno hub and felt pretty bad-ass. No real problems, very zen, felt like I was getting the hang of it on a basic level. I've been following Sheldon Brown's instructions, all good so far.
Then, the rear wheel. Lace up was no problem, but I kept chasing the dishing and truing back and forth, not really able to get it dialed in. I left and came back a few times and this morning was feeling pretty good about it. So then I went to do the stress relieving per Sheldon's instructions, and after working on maybe the 3rd set of spokes I heard a pretty good "TWANG".
At first I thought maybe I'd pulled a nut through the rim, but all looked well. I finished stress relieving and put it back on the stand and.... it was seriously messed up. WWAAAY out of true, the rim has a long torqued sway to it now, but no sharp bends.
Can I recover from this? What happened? I tried to start pulling it back and it isn't budging much, so no I've started backing everything off and starting again. The now pretty loose spokes don't seem to be making much of a difference, so it looked like I bent the rim. Is that a thing that happens?
Any input appreciated.
Thanks all, great forum.
11-05-14, 01:36 PM
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11-05-14, 01:49 PM
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Guessing the spoke tension got too high. Loosen and re-do it, assuming the rim is straight w/o spoke tension. I start stress relieving before getting to final tension or true.
11-05-14, 01:56 PM
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Sounds like too much tension "tacoed" the rim. If you're lucky, loosening all the spokes will allow the rim to revert to straight, and you can re-tension the wheel a little less zealously. If it stays "tacoed" you'll likely need to replace the rim.
11-05-14, 01:56 PM
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remember that stress relieving, IMO, if it is successful will relive some stress in a spoke or two, which would, most likely, cause the wheel to lose some of it's trueness.
11-05-14, 02:01 PM
#7
incazzare.
Are you stress relieving while you are working, or did you get it pretty tense and then stress relieve? You need to be doing the former.
I have followed these instructions for many builds now and had no major issues:
Wheels
But yes, loosen it all up and start over. Hopefully the rim is OK.
I have followed these instructions for many builds now and had no major issues:
Wheels
Optimising your spokes -
Method 1. Perform this once only, just after you have got a fair amount of tension in the wheels. Where the "heads in" spokes exit the hubs – take the plastic tipped hammer and tap the spoke bend a little flatter. This does not take much effort. You can also use your thumb to flatten this curve.
Method 2. Perform this after every "round" of truing or tensioning. Grasp parallel pairs of spokes on each side – one pair in each hand - while wearing leather gloves and squeeze them in the hands as hard as you can. Go all around the wheel once.
Method 3. Perform after every round. Take a plastic handled screwdriver or wooden dowel, place the handle or dowel just above the spoke crosses furthest from the hub and force the spoke cross down towards the hub with the handle. Don't go ape here, use judgment, control and passion.
Method 4. Perform once. Take the screwdriver handle and slightly twist the final spoke crosses around each other. Be gentle here. Place the screwdriver handle in the final cross and above it, press down slightly and twist the two spokes around each other. This is not really a "twist" but just a slight, very slight bending. The spokes will do this themselves if you don't do it but then they might lose a minute bit of tension too.
Method 5. Do this once after you have a fair amount of tension on the spokes. Take a thin punch and a hammer. Tap the head of each spoke to seat the head squarely in the hub flange. I said "tap"................not "pound the **** out of". We're just seating the head in the flange and aligning the head.
Method 6. Place wheel flat on floor with the rim part nearest to you touching the floor. A piece of cardboard or carpet will prevent the QR from scratches. With hands at 9 & 3 o'clock, press down gently but firmly and quickly. Rotate wheel 1/8th turn & repeat for one full turn of the wheel. Turn wheel over and repeat. The pings you hear are spokes unwinding. Check for true afterwards. Repeat this after each stage or "round".
Method 1. Perform this once only, just after you have got a fair amount of tension in the wheels. Where the "heads in" spokes exit the hubs – take the plastic tipped hammer and tap the spoke bend a little flatter. This does not take much effort. You can also use your thumb to flatten this curve.
Method 2. Perform this after every "round" of truing or tensioning. Grasp parallel pairs of spokes on each side – one pair in each hand - while wearing leather gloves and squeeze them in the hands as hard as you can. Go all around the wheel once.
Method 3. Perform after every round. Take a plastic handled screwdriver or wooden dowel, place the handle or dowel just above the spoke crosses furthest from the hub and force the spoke cross down towards the hub with the handle. Don't go ape here, use judgment, control and passion.
Method 4. Perform once. Take the screwdriver handle and slightly twist the final spoke crosses around each other. Be gentle here. Place the screwdriver handle in the final cross and above it, press down slightly and twist the two spokes around each other. This is not really a "twist" but just a slight, very slight bending. The spokes will do this themselves if you don't do it but then they might lose a minute bit of tension too.
Method 5. Do this once after you have a fair amount of tension on the spokes. Take a thin punch and a hammer. Tap the head of each spoke to seat the head squarely in the hub flange. I said "tap"................not "pound the **** out of". We're just seating the head in the flange and aligning the head.
Method 6. Place wheel flat on floor with the rim part nearest to you touching the floor. A piece of cardboard or carpet will prevent the QR from scratches. With hands at 9 & 3 o'clock, press down gently but firmly and quickly. Rotate wheel 1/8th turn & repeat for one full turn of the wheel. Turn wheel over and repeat. The pings you hear are spokes unwinding. Check for true afterwards. Repeat this after each stage or "round".
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Last edited by lostarchitect; 11-05-14 at 02:07 PM.
11-05-14, 02:03 PM
#8
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perhaps next time sort out increasing the dish by loosening the NDS rather than overdoing the DS tension..
11-05-14, 02:21 PM
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Ahh, I see. Yeah, I was doing the latter. I will loosen all and start over.
11-05-14, 02:22 PM
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11-05-14, 02:23 PM
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ok, starting over, wish me luck...
11-05-14, 02:24 PM
#12
incazzare.
I mean, obviously you don't have to stress relieve when they are loose, but as soon as they start getting tight I start stress relieving.
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11-05-14, 02:25 PM
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This is the only advice that's for this situation!
And this is most likely the cause too much tension "tacoed"
And this is most likely the cause too much tension "tacoed"
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11-05-14, 04:16 PM
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Maybe.
Assuming you didn't pull the eyelets or rim bed out you exceeded the rim's elastic limit when stress relieving.
Using the Jobst Brandt method of achieving ideal tension in moderate weight box-section rims with reasonable spoke counts you alternately add tension and stress relieve until the wheel goes out of true in waves at which point you back off half a turn and re-true. Wheels I built that way before getting a tension meter using 32 or 36 spokes and Mavic Reflex, Mavic Open Pro, or Mavic MA-40 rims measure 105-110kgf front and rear drive side which is what I'd shoot for with a tension meter based on popular wisdom.
That doesn't work for low spoke counts since individual spoke tension becomes high enough to cause fatigue failure in the rim bed. It doesn't work for deep rims since stiffness is proportional to the cube of depth and you're going to have problems before reaching such a rim's elastic limit.
The deformation in that case is very minor, and tension variation to keep it straight minimal. You may have gone way past the elastic limit so it's not fixible.
If the rim bed isn't visibly deformed around the spokes and you can make the wheel true with reasonable tension variation you're OK.
If not the rim is shot.
Assuming the rim isn't done I'd either use a tension meter (there's even a smartphone ap for that which calculates tension from tone) and set it right or back way off and sneak up incrementally.
What happened?
Using the Jobst Brandt method of achieving ideal tension in moderate weight box-section rims with reasonable spoke counts you alternately add tension and stress relieve until the wheel goes out of true in waves at which point you back off half a turn and re-true. Wheels I built that way before getting a tension meter using 32 or 36 spokes and Mavic Reflex, Mavic Open Pro, or Mavic MA-40 rims measure 105-110kgf front and rear drive side which is what I'd shoot for with a tension meter based on popular wisdom.
That doesn't work for low spoke counts since individual spoke tension becomes high enough to cause fatigue failure in the rim bed. It doesn't work for deep rims since stiffness is proportional to the cube of depth and you're going to have problems before reaching such a rim's elastic limit.
The deformation in that case is very minor, and tension variation to keep it straight minimal. You may have gone way past the elastic limit so it's not fixible.
If the rim bed isn't visibly deformed around the spokes and you can make the wheel true with reasonable tension variation you're OK.
If not the rim is shot.
Assuming the rim isn't done I'd either use a tension meter (there's even a smartphone ap for that which calculates tension from tone) and set it right or back way off and sneak up incrementally.
Last edited by Drew Eckhardt; 11-05-14 at 04:26 PM.
11-05-14, 05:05 PM
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Assuming you get the rim back to good shape you should not have to be "chasing the dishing and truing back and forth." Get the rim close to dish (toward the drive side), mostly tensioned and very true. Then tighten all the drive side spokes to get the dish and tension close to final.
If dish is still not quite right, loosen all the NDS spokes (1/4 or 1/8 turn) before you tighten the drive side, both by equal amounts if tension is OK, 1/8 turn more on the drive side if tension was still a bit low when you started. Retrue - remember, always tighten/loosen in pairs or you will change tension). Recheck dish, repeat once more if necessary.
If dish is still not quite right, loosen all the NDS spokes (1/4 or 1/8 turn) before you tighten the drive side, both by equal amounts if tension is OK, 1/8 turn more on the drive side if tension was still a bit low when you started. Retrue - remember, always tighten/loosen in pairs or you will change tension). Recheck dish, repeat once more if necessary.
11-05-14, 05:16 PM
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Maybe.
Assuming you didn't pull the eyelets or rim bed out you exceeded the rim's elastic limit when stress relieving.
Using the Jobst Brandt method of achieving ideal tension in moderate weight box-section rims with reasonable spoke counts you alternately add tension and stress relieve until the wheel goes out of true in waves at which point you back off half a turn and re-true. Wheels I built that way before getting a tension meter using 32 or 36 spokes and Mavic Reflex, Mavic Open Pro, or Mavic MA-40 rims measure 105-110kgf front and rear drive side which is what I'd shoot for with a tension meter based on popular wisdom.
That doesn't work for low spoke counts since individual spoke tension becomes high enough to cause fatigue failure in the rim bed. It doesn't work for deep rims since stiffness is proportional to the cube of depth and you're going to have problems before reaching such a rim's elastic limit.
The deformation in that case is very minor, and tension variation to keep it straight minimal. You may have gone way past the elastic limit so it's not fixible.
If the rim bed isn't visibly deformed around the spokes and you can make the wheel true with reasonable tension variation you're OK.
If not the rim is shot.
Assuming the rim isn't done I'd either use a tension meter (there's even a smartphone ap for that which calculates tension from tone) and set it right or back way off and sneak up incrementally.
Assuming you didn't pull the eyelets or rim bed out you exceeded the rim's elastic limit when stress relieving.
Using the Jobst Brandt method of achieving ideal tension in moderate weight box-section rims with reasonable spoke counts you alternately add tension and stress relieve until the wheel goes out of true in waves at which point you back off half a turn and re-true. Wheels I built that way before getting a tension meter using 32 or 36 spokes and Mavic Reflex, Mavic Open Pro, or Mavic MA-40 rims measure 105-110kgf front and rear drive side which is what I'd shoot for with a tension meter based on popular wisdom.
That doesn't work for low spoke counts since individual spoke tension becomes high enough to cause fatigue failure in the rim bed. It doesn't work for deep rims since stiffness is proportional to the cube of depth and you're going to have problems before reaching such a rim's elastic limit.
The deformation in that case is very minor, and tension variation to keep it straight minimal. You may have gone way past the elastic limit so it's not fixible.
If the rim bed isn't visibly deformed around the spokes and you can make the wheel true with reasonable tension variation you're OK.
If not the rim is shot.
Assuming the rim isn't done I'd either use a tension meter (there's even a smartphone ap for that which calculates tension from tone) and set it right or back way off and sneak up incrementally.
Thanks for the advice.
11-05-14, 05:17 PM
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Assuming you get the rim back to good shape you should not have to be "chasing the dishing and truing back and forth." Get the rim close to dish (toward the drive side), mostly tensioned and very true. Then tighten all the drive side spokes to get the dish and tension close to final.
If dish is still not quite right, loosen all the NDS spokes (1/4 or 1/8 turn) before you tighten the drive side, both by equal amounts if tension is OK, 1/8 turn more on the drive side if tension was still a bit low when you started. Retrue - remember, always tighten/loosen in pairs or you will change tension). Recheck dish, repeat once more if necessary.
If dish is still not quite right, loosen all the NDS spokes (1/4 or 1/8 turn) before you tighten the drive side, both by equal amounts if tension is OK, 1/8 turn more on the drive side if tension was still a bit low when you started. Retrue - remember, always tighten/loosen in pairs or you will change tension). Recheck dish, repeat once more if necessary.
11-05-14, 05:50 PM
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Dish on this wheel should be very small, so DS/NDS spokes shouldn't have too different tension.
11-05-14, 06:09 PM
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Know the feeling, it was years before I finally got my Park Tension Gauge as a Fathers Day gift from my boys - It's been fun checking all the wheels in the stable - For a wheel not too out of round I used to successfully use the pinging method of equalizing spoke tension - Remember there's a different sound for each side on the rear wheel...
https://www.bikexprt.com/bicycle/tension.htm
Or you could do this...
https://www.youtube.com/watch?v=HI8tDjDZK54
Last edited by zandoval; 11-05-14 at 06:18 PM.
11-17-14, 02:21 AM
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Having a 32 spokes laced rearwheel and don't know it's worth to rebuild or not. Tension is OK, it doesn't need trueing, but:
Leading and trailing spokes are not symmetric.
NDS: leading spokes = heads are out of the flange
DS: leading spokes = heads are inside of the flange
Should I rebuild wheel or not?
Leading and trailing spokes are not symmetric.
NDS: leading spokes = heads are out of the flange
DS: leading spokes = heads are inside of the flange
Should I rebuild wheel or not?
11-17-14, 06:49 AM
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Having a 32 spokes laced rearwheel and don't know it's worth to rebuild or not. Tension is OK, it doesn't need trueing, but:
Leading and trailing spokes are not symmetric.
NDS: leading spokes = heads are out of the flange
DS: leading spokes = heads are inside of the flange
Should I rebuild wheel or not?
Leading and trailing spokes are not symmetric.
NDS: leading spokes = heads are out of the flange
DS: leading spokes = heads are inside of the flange
Should I rebuild wheel or not?
11-17-14, 07:24 AM
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11-17-14, 08:07 AM
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