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Should all the rear wheel spokes have equal tension? Or should

the spokes from the side of the cassette be tighter, in order to skew to wheel in that direction, and the wheel to be centered in the frame

EDIT:

Ok, so this thing is called "dished" wheel. In the meanwhile I learned that often shorter spokes are placed on the side of the cassette.

If I do not own a spoke tension meter, how can I approach straightening a rear rim, or tightening up loose spokes? What is the difference in the procedure from a front wheel, where one uses the brake calipers to measure rim trueness, and pinching the spokes together indicates spoke tension, which has to be more or less equal around the wheel?

Aaron
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Vorac
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  • "It depends" is the only possible answer as the question currently stands. Do you have a single speed or internally geared hub or a regular derailleur system? What kind of bike are we talking? What kind of hub? – arne Mar 21 '14 at 10:31
  • @arne, MTB with a cassette of 8 gears. – Vorac Mar 21 '14 at 10:43
  • When I build a wheel I make 'em all the same tension. But I'm not an expert wheel builder (even if I sometimes still ride one back wheel I built in 1993). – andy256 Mar 21 '14 at 10:56
  • I bought a decent set of wheels a couple of years back. They were for a road bike not a mtb, but were still designed for a cassette so I'd assume the same principles apply. Came with a datasheet in which it gave recommended tensions etc. I can't remember exactly what the numbers were, but they were indeed asymmetric. – PeteH Mar 21 '14 at 12:30
  • I'm struggling to see how to answer this. @Nui's answer kinda answers the title but not the body, but that's because the question is asking for opinions, and amounts to "should wheels be dished". Even if just to make it clear that the question is "can a dished wheel have equal spoke tension" – Móż Mar 22 '14 at 09:19
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    Possible edits: "why are rear wheel dished" or "can a dished wheel be as strong as a non-dished one". Even "what are the advantages of a dished wheel" – Móż Mar 22 '14 at 09:23
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    @Mσᶎ, as is evident, I didn't even know the term. I would love to know the answers to the proposed by you question. However, I am even more interested in how to work with those, hence my edit. |IF you can sneak those in my question, or ask another and answer it, that'd be great! – Vorac Mar 24 '14 at 08:07
  • In regards to the lack of spoke tension meter, typically you need experience (i.e. you ruin a few wheels). Some people can do it by spoke pitch or squeezing or whatever, but if you're doing this in a workshop, you should really use a spoke tensiometer. In the on the road case, for most people, its the case that they just need to get to the next point. – Batman Mar 24 '14 at 08:14
  • @Vorac I'm not criticising you for not knowing the term, especially since it's not even in our terminology index :) – Móż Mar 24 '14 at 09:13
  • I will give it a day and see if @Nui comes back with an edit before I have a go. Quickly though, spoke pitch is one approach (ping the spoke, listen) – Móż Mar 24 '14 at 09:15
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    Note that you don't need a tension meter to "true" a wheel. To "true" a wheel you "simply" tighten the spokes that need to be tighter to pull the wheel straight (and maybe slightly loosen ones on the other side). Sometimes the rim is bent or sprung and this results in uneven tension when the wheel is "true", but, within limits, it's more important to have a "true" wheel than to have all the spokes equally tensioned. – Daniel R Hicks Mar 24 '14 at 11:59
  • And I forgot to mention that if you intend to do a complete job on "truing" the wheel, you either need a more expensive truing stand (one that accurately gauges the inset of the rim from the end of the hub) or a relatively cheap "dishing tool" that does the same thing a bit less efficiently. A properly "dished" wheel has the same measurement from the plane of the rim to the end of the hub on both sides. – Daniel R Hicks Mar 27 '14 at 14:59

2 Answers2

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If the wheel is symmetrical the spokes should all have the same tension. If dished (what you've called "skew" the bicycle world calls dished), the side closer to the centre of the hub will have more tension. All the spokes on the same side of the wheel should have the same tension.

Since you have derailleur gears the wheel will almost certainly be dished (it's possible to build a frame such that this isn't necessary, but that requires other compromises, so if it's a mass produced frame with derailleur gears it's got a dished rear wheel). With hub gears it is almost certainly symmetrical, and with a singlespeed it's probably symmetrical.

In general, the spokes should be as tight as the rim allows. Jobst Brandt in "The Bicycle Wheel" is quoted in this question as saying:

With tensioned wires as spokes, the wheel can support loads only to the point where its spokes become loose. At this point the wheel will collapse. Therefore, for greatest strength, spokes must be as tight as the rim permits. Structurally the rim supports spoke tension as an arch that is compressed by the inward force of the spokes. The load limit for most rims is far less than what the spokes could deliver if they were tightened to their breaking point.

That book is short and cheap (but densely written) and well worth buying if you're interested in wheelbuilding.

edit: You don't need a tensiometer, you can probably do it by ear. This question discusses truing by ear and links to a useful article. Like Daniel said in the comments, focus on getting the wheel true, stress relieve it, re-true it (repeat as needed), ride it for a day or two, then check it. The closer you can get the spoke tension to even the less the wheel will go out of true when you stress relieve it/ride it, so the faster that process will go.

But if the rim or spokes are damaged you won't be able to get the tension even, and the older the wheel is the less likely it is that you'll get it even. The advantage of a tensiometer is that it speeds the process up and is more reliable (doing it by ear is very sensitive to the exact length between the rim and the first cross of the spoke, and you can change that by pushing on the spoke)

Community
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Nuі
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Yes, drive-side spokes have higher tension. Matter of angles -- physics 101 stuff, related to the fact that drive-side spokes are "more vertical" than non-drive-side" spokes (because of the horizontal space taken by the cassette).

A.G.
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  • Welcome to Bicycles SE. We prefer answers on this site to be self-contained. Please consider summarizing the "physics 101 stuff" that you refer to. We also prefer that the relevant information from links be summarized in case the link dies. – jimchristie Mar 24 '14 at 00:13
  • The Fat Bike rims are also not typical rims. – Batman Mar 24 '14 at 00:17