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Old 05-23-12, 09:18 AM   #1
ryker
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Noisy rear wheel, new wheelbuild

I've built about a dozen wheels and all have gone well with no follow-up maintenance needed.

I built a new wheelset for my Surly Disc Trucker and am having a problem with noise from the rear wheel under low-medium pedaling torque. No noise when braking. It sounds like the creak heard when stress relieving a wheel except the wheel is true within 0.5mm, evenly tensioned and repeatedly stress relieved. I determined it was the rear wheel after going crazy replacing all the parts on the bike and finally silenced it by using a different rear wheel. I can 95% get the noise to go away by increasing the tension but I'm not comfortable with the final tension - 142kgf average - when I have built 10 quiet wheels with the same rims/spokes/nipples using only 110kgf. I suspect it is the spokes rubbing under load but that's just speculation (no idea which side or both).

Any ideas? Maybe I need to get aggressive bending the spokes for a better spoke path?

The wheel is 36h Shimano XT hub to Mavic Open Pro CD rim with DT Swiss 2.0/1.8/2.0mm spokes and 12mm brass nipples. All new parts. The wheel is laced 3x using Shimano's recommended pattern for rear disc hubs (DS pulling spokes heads in, NDS/disc pulling spokes heads out). I can post a picture of the wheel if it helps.


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Old 05-23-12, 10:36 AM   #2
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1. Drop of lightweight oil where each spoke crosses another will reduce noise where spokes "fret".

2. Consider re-lacing such that all pulling spokes have heads out. This will eliminate the machine style lacing you currently have that cause the rim to shift to one side a millimeter or so upon application of torque. Shimano's diagram is a recommendation...while the disc side (NDS) is the real concern and the one mostly to follow...the drive side is not written in stone. Going heads out on pulling spokes on the drive side will not do any harm.

As a matter of fact, when properly tensioned going all heads out OR all head in in general is not a deal killer either. The wheel will do just fine.

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Old 05-23-12, 10:41 AM   #3
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Originally Posted by ryker View Post
142kgf average
I wouldn't be comfortable with that, either. I think that's significantly too much tension for your Open Pro rims.
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Old 05-23-12, 11:17 AM   #4
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If this is a Shimano Disc rear hub, then it's a 135mm rear. Which results in a more symmetrical wheel than a typical 130mm rear. Target should be the 107-110 KGF range for the drive side.

=8-)

142 kgf is way too freaking much...

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4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
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Old 05-23-12, 11:26 AM   #5
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Yeah I agree that the tension is too much - pretty much motivated my post. The wheel has only been ridden up and down the block to test the theory that spoke tension silences the wheel but I'm not comfortable taking it on proper test ride let alone a cycle tour. I used the same 135mm Shimano disc hub on my mtb, laced in the Shimano-recommended manner and it's quiet without using crazy tension. So that confuses me. It's no problem to re-build the wheel with symmetrical lacing. I will probably go that route since I'm not riding it at 142kgf and have no better ideas.
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Old 05-23-12, 02:21 PM   #6
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i might question the calibration on my tensionometer or whatever it is called.
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Old 05-23-12, 10:53 PM   #7
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Quote:
Originally Posted by ryker View Post
I've built about a dozen wheels and all have gone well with no follow-up maintenance needed.

I built a new wheelset for my Surly Disc Trucker and am having a problem with noise from the rear wheel under low-medium pedaling torque. No noise when braking. It sounds like the creak heard when stress relieving a wheel except the wheel is true within 0.5mm, evenly tensioned and repeatedly stress relieved. I determined it was the rear wheel after going crazy replacing all the parts on the bike and finally silenced it by using a different rear wheel. I can 95% get the noise to go away by increasing the tension but I'm not comfortable with the final tension - 142kgf average - when I have built 10 quiet wheels with the same rims/spokes/nipples using only 110kgf. I suspect it is the spokes rubbing under load but that's just speculation (no idea which side or both).

Any ideas? Maybe I need to get aggressive bending the spokes for a better spoke path?

The wheel is 36h Shimano XT hub to Mavic Open Pro CD rim with DT Swiss 2.0/1.8/2.0mm spokes and 12mm brass nipples.
1. Your tension is way too high unless you've picked the wrong column in the Park conversion table.

2. Assuming you're reading the right column you're either not stress relieving correctly or not paying attention. Stress relieving is where you take the spokes past their yield point thus removing residual stress from the elbow forming operation that leads to premature failure requires overloading the spokes by squeezing them together (gloves help) or twisting them around themselves at the outer crossing using something softer (I like a brass drift, other people use old left cranks or plastic screwdriver handles). Eventually (not much past 110kgf) moderate weight box section rims will deform in waves indicating that you've exceeded their elastic limit when stress relieving. At that point it's prudent to back off tension half a turn, re-true, and be happy.

Putting the axle on the ground and pushing opposite sides of the wheel can relieve spoke wind-up but won't stress relieve.
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