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I have a mountain bike that's now about 18 months old. At the 12 month mark I took it for its first annual service. Since then there's been a problem with the front wheel coming out of alignment.

I've had the wheel re-trued a couple of times since the service now, it seems to need doing about once every 2 months. Obviously this regular attention is not a normal requirement for a wheel.

What is the normal period of time that you'd expect to pass between wheel alignment/spoke adjustment work? I'm riding the bike probably 20 miles a week on average on the road, with occasional weekend trips off-road. The wheel's gone out of true at least once without an off-road trip since the previous truing.

  • What brand and model wheel and spokes? – paparazzo Jan 13 '15 at 14:00
  • This is the bike: giant-bicycles.com/en-gb/bikes/model/2013.giant.xtc.composite.2/…. It's got a Giant S-XC2 wheelset with DT Swiss Competition Spokes – Matthew Jan 13 '15 at 14:02
  • A good habit to take is lightly tapping the spokes with a screwdriver or some other small tool and listen to the music. A deeper sound will reveal a lose spoke. All spokes sounding the same is a good sign. – Carel Jan 13 '15 at 15:35
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    On my commuter, my wheels have been essentially true for several thousands of miles. But i don't take it off road. – Batman Jan 13 '15 at 15:38
  • 2 months sound awfully short for quality spokes. Maybe the re-truing person is under-tensioning them (unintentionally)? – Vorac Jan 13 '15 at 15:57
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A well built wheel should go years without needed truing. If you are truing the wheel every 2 months something is wrong with the build.

There's no way to know via the internet, but my guess is that it's one of two things.

  1. The rim is bent slightly and requires significantly uneven tension in the spokes to get the rim true.

  2. There isn't enough tension in the wheel overall to keep the wheel true.

The way to diagnose this is to get a spoke tensiometer and measure the tension in the spokes, since the wheel is slightly offset to compensate for the braking disk, one side will have slightly higher tension than the other, but the spokes on any given side should be roughly equal. The rim should have a maximum spoke tension rating and the closer you can get the wheel to that the stronger and more stable the build will be. Most rims are rated to at least 100kg of tension.

A good wheelbuilder will have the spoke tension meter in his toolkit. They are relatively expensive and require some practice to get accurate readings.

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    One can abuse a wheel sufficiently to cause significant out-of-true, even if the wheel is perfectly built to begin with. But if this happens a lot it suggests that the wheel is too lightly build for the conditions it's being subjected to. – Daniel R Hicks Jan 13 '15 at 16:56
  • I'd go with defective rim. If it's been retrued that many times, it seems like it would have been done properly at least once (although that's something of a crapshoot as well). – Deleted User Jan 13 '15 at 17:29
  • They may have also forgot spoke prep, combined with insufficient tension, would allow spokes to loosen off. – Rider_X Jan 13 '15 at 17:54
  • @Rider_X, some people pot grease on the nipples. Tension is what keeps the wheel together, not some glue. – Vorac Jan 14 '15 at 9:10
  • @Vorac if you have a high-quality rim that can withstand high spoke tension. Even then under high vibration and load spoke nipples can back off. Spoke prep exist reason. – Rider_X Jan 15 '15 at 2:43
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You should wash and inspect the rim for cracks. I had a rear wheel that would not stay true, the problem was small cracks around the nipple holes in the rim. The nipples were slowly cracking through over a period of weeks. only a few were doing this so the tension was held by neighboring spokes. thus the only symptom was going out of true. pluck the spokes to listen for a loose one. front wheels are lightly loaded, I have a front wheel with 7000 miles on it in 3 years and have only trued it once at around 2k miles.

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Machine-built wheels are known to need re-truing after the first several rides, but not after that. This is because machines don't do stress-relief of the wheel.

On a mountain bike of medium quality, I would expect spoke re-truing to be needed at most once per year.

As far I know, tension of the spokes is the only thing, that is responsible to keep the wheel together. Some people put 'spokeprep' on nipples when building, but others advise for plain grease!

Consequently, the first thing I would expect is that the wheel spokes are under-tightened. There is a simple way to check this. Go to a bike shop and squeeze together parallel spokes of some high-quality bikes. You will notice that front wheel spokes have a certain tension, and rear-wheel spokes have different tension on the two sides of the wheel. Compare roughly the feel of those spokes to the ones on your bike. Thus you will know if yours are loose.

Sources of all the claim in this answer:
http://miketechinfo.com/new-tech-wheels-tires.htm
http://sheldonbrown.com/wheelbuild.html

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