Chinertown
Chinese Carbon MTB => 29er => Topic started by: carbonazza on September 19, 2014, 08:45:17 AM
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Yesterday while putting oil on the chain, I noticed the rear wheel was not perfectly true anymore.
Over an area of 6 spokes and max 4mm out, and only minor scratches on the rim.
The front wheel is still perfect.
The last rides were rough and fast.
I contacted light-bicycle.com who built them, for advice.
And they told me that after a few rides, you need to re-true the wheelset.
While I knew I would have to learn this, I didn't expect to have to do this so often.
How often do you true your wheels?
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Didn't they mean "after the first few rides" ?
On my old bike, I didn't true the wheels in 2 yrs :) And I used the bike a lot.
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Me too. I bought a second hand bike, with its wheels on.
And after a year full of rides, I never thought it was necessary to do it.
It looks it's not the same now :)
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It's not uncommon for new wheels to need truing after the first few rides. I have a friend at the LBS who does it while I wait and only charges a few dollars. He also applies thread locker to the nipples to help keep the spokes and nipples from loosening while riding. I have been told by a couple of wheel builders that the usual process after building a wheel is to ride the wheels a few times, bring them back, true them up and apply thread locker.
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Thanks Carbon_Dude, I didn't know that.
I will try to find an LBS who does it.
And drop for now, to learn truing them myself.
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when you read the wheel building threads a common discussion/argument is what to put on the spokes when you build your wheels. I built my LB 35mm 650b wheels myself and not being a pro it was a learning experience. Some guys recommend spoke prep, loctite, grease, boiled linseed oil, anti seize or nothing. Recommended spoke tension is more of a range than a given. I built mine with DT Swiss revolutions which are so thin in the middle that windup is a bit of a concern and I used aluminum nipples front and brass rear. I opted to grease my spoke ends since if I needed to retension later on it would be easier with the revolutions and aluminum nipples. Then I tensioned to about 90-100 kgf on the drive side and front disc side, which is probably not enough. This equated to around 17/18 on my Park meter. I found that after a couple rides I had to retension a quarter turn and I may have to do that again. So maybe the combo of grease and lower tension is an issue but I just keep an eye on them. With a thicker spoke, brass mipples and spoke prep then maybe the wheel will stay tensioned forever.
In a perfect world and in the hands of very experienced builder you may get wheels that never need a true. I don't mind throwing them up on the stand and giving them a quick true. Routinely I will quickly pluck the spokes and listen to the pitch, like plucking a guitar string. A spoke that has lost some tension will have a lower note. Spokes on the drive side will of course have a higher pitch. A local bike builder says he always builds his wheels to spoke pitch. There is even an app for your phone that will tell you the tension by the pitch. https://itunes.apple.com/us/app/spoke-tension-gauge/id518870820?mt=8 I don't have that good an ear so I will stick to my tension meter.
I replaced some spokes and a hub for a friend of mine. The wheel had been built by a local lbs. Before I took it apart I measured the tension. 29 on my Park meter. 1/3 of the nipples and been rounded and distorted trying to get it that tight. I think that was maybe over the top.
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I finally bought a spoke wrench.
Put some zip ties on the frame, and trued the wheel mounted on the bike with the tire on.
The first spoke was a bit rock and roll(for a moment, the spoke blade became a spiral).
I then gripped the spokes with a plier to keep them straight, while screwing the nipples.
One thing that helps is snipe's pitch trick.
You can quickly spot the spoke that has a trouble, just by the sound it makes compared to the others of the same side.
In about 20 minutes, the wheel was true again.