2

When I roll a new wheel (tyre mounted on wheel, wheel mounted on frame, frame on stand), it is dead-on true.

Still, out of curiosity, I go around the wheel squeezing and plucking the spokes. The tensions do not seem equal.

But that's inherently subjective. There might be a speck of grease at the points of spoke intersections, or, alternatively, a speck of dust. In either case it would affect the perceived tension or the musical note. I cannot go back to the store and protest a lower QA based on informal squeezing or plucking.

Now suppose that I had a tensiometer and it revealed, objectively, that the tension on some spokes is much more than on others (by some factor).

  1. Would it then be a good idea to return the wheel and shop for another?
  2. Would it be a good idea to ask LBS staff to adjust the tension when the wheel is already true?

(Note to self: check trueness and tension before adding rim strip and tyre. This way I can return the wheel as still brand new without the risk of hassle during a return transaction.)

This is a sequel question to:

Related:

Sam7919
  • 9,112
  • 4
  • 28
  • 92
  • 4
    How valuable is this wheel? The eu regulations alow a full 4mm of run out for a wheel. Many shockingly bad wheels last years of abuse with a normal rider, the structure has an enormous amount of redundant strength. – Noise Jun 26 '22 at 15:37
  • 1
    @JoeK You're saying a lot. 1/3- Whether a wheel as a consumer product is "fit for the particular purpose of (recreational) riding" (defining when the consumer can complain) is determined by the jurisdiction—and so I should check what my local authorities have to say on the matter. 2/3- EU guidelines are quite relaxed about wheel quality (4 mm is huge when the brake pad is 1.5-2.5 mm away from the rim). – Sam7919 Jun 26 '22 at 20:06
  • @JoeK 3/3- If I'm investing in a Dura-Ace wheel, I could potentially protest (as what, a racer who can expect higher quality?), but if I'm just buying a Sora wheel to use and abuse, then I should accept a different level of tolerances, and accept lesser trueness and strength. Am I reading all that right in what you wrote? – Sam7919 Jun 26 '22 at 20:07
  • 1
    I think you should get some quantitative tension meter data before attempting to return the wheel on the basis of "It doesn't feel right" – MaplePanda Jun 26 '22 at 22:43
  • 1
    Why not visit/call the shop, explain what you've observed, and ask their advice? – avid Jun 27 '22 at 19:00
  • @avid too simple – Swifty Jun 28 '22 at 16:49
  • @avid 1/4 So you're saying: "Why are you asking a question on a QA site?" Uh.. 1- Buyers must know something about what they're buying before going back to the store to harass the staff by complaining about a non-existing problem. SE is an excellent place for this learning. – Sam7919 Jul 05 '22 at 02:01
  • @avid 2/4 2- Consumers who face an unscrupulous seller may find that their (real) problem is swept under the rug; hence they need to know what they're talking about before going back to the store. – Sam7919 Jul 05 '22 at 02:01
  • @avid 3/4 3- It is not the job of the seller to spend 60 minutes to educate the buyer in what they're buying, especially when they're as busy as they are. It's reasonable to expect a 10-15 minute discussion for a wheel, but that would be hardly enough for the many facets of what is deceivingly a complex object. – Sam7919 Jul 05 '22 at 02:01
  • @avid 4/4 4- Greed and laziness. I can get deeper and more incisive information from the folks here by simply typing on a keyboard than by spending the time to ride to the LBS and wondering whether I'll get to talk to one of the two people who really know what they're talking about, rather than with one of the clueless "summer co-ops". – Sam7919 Jul 05 '22 at 02:02
  • @avid 5/4 I could go on. 5- For my time allotment at the LBS, and before I overstay my welcome, I'd rather be talking about other stuff, such as surveying the nice bikes they have and lining up my future presents to myself. – Sam7919 Jul 05 '22 at 02:02

4 Answers4

8

You may well be worrying about nothing.

A spoked bicycle wheel is a fantastically strong structure. Modern box-section rims and modern steel/stainless spokes are astonishingly reliable when compared to ones in common use 30 or 40 years ago.

A wheel built with a high spoke count on a stiff rim can remain true and round to the eye even if some spokes do not meet the same tension as others, provided that all the spokes are generally at a high tension.

Rims do not always arrive flat or round before they are built into a wheel, and this often shows up in spoke tension variation, especially with the stiffest rims, particularly at the rim joint.

It sounds like you have invested in a high end wheel with a light rim and low spoke count. With this type of wheel, each spoke is accountable for more adjustment variation in truth and roundness than on a higher spoke count wheel. The rim will be a stiffer shape too. To maintain a round, true wheel where brake pad clearance may be 1mm or less, inevitably some of the spokes will have a slightly different tension to others. Perhaps spending more time on the wheelbuild would eliminate this, and perhaps it wouldn't but it doesn't make the wheel less reliable unless the variation is beyond a recommended tension differential (park suggest a value as supplied with their tensiometer as do many rim manufacturers).

If you have a rear wheel where the drive side tensions are all very close values and none of the non-drive spokes are loose, that's good. If you have a front wheel where nearly all the spokes are of a tension value, it will be fine. If everything is nice and tight it will be reliable.

All wheels have a warranty and if you had to have the wheel trued repeatedly that is clearly a problem, a problem you will be covered for.

Very very few fully true wheels have a truly equal balance spoke tension. Undersanding what constitutes the difference between poor, good and excellent requires some experience with various different wheels and you should examine other wheels that are available to you before making that call.

Noise
  • 13,943
  • 1
  • 14
  • 46
  • 1
    2nd note to self :-) . If I buy a bare rim, buy it in person and take a piece of cardboard with a circle drawn of the requisite radius. If the rim doesn't align too closely to the circle, especially if it's a carbon rim, look for another. – Sam7919 Jun 27 '22 at 15:02
  • 1
    @Sam a carbon rim, due to its construction, is almost always very round out of the box. An aluminium rim has a joint, either welded or pinned, and whatever type it is, it always shows up in wheel roundness, even if by a tiny amount and even on the very best rims but that doesn't matter to the wheel. – Noise Jun 28 '22 at 07:50
  • @Sam if you are interested in the wheel as a structure and what makes a good or durable wheel, Jobst Brandt's book The Bicycle Wheel is very informative, even though it is now quite an old publication. It is one of the most important texts on the science of wheel building and explains how the structure works even down to the rôle of each spoke. – Noise Jun 28 '22 at 07:52
  • @Sam Check out this video to watch the manufacturing process: https://youtu.be/FDQj84MQZ3o Note that rims are not cast, but extruded instead. I don’t think a casting process would necessarily preclude the hollow box structure anyways. – MaplePanda Jun 29 '22 at 07:33
6

As mentioned by @JoeK, how much you spent, and what you told the shop the wheel will be used for will play a big factor in deciding if the wheel is fit for purpose. If you told them it was a to keep a round town beater going and the wheel cost $10, then you have a bargain. If you told them it was for an around the world cycle trip and you paid $10000, you likely have a valid complaint.

In any instance, you should go back to the bike shop and have a conversation with them around your expectations and what they provided you. You can go back to the shop for that conversation with just your informal squeezing and plucking. Going to the shop with folders of forensic evidence suitable to a supreme court case is not going to help you case if you have no idea what is considered acceptable.

Presuming it is not a $10000 wheel, the first question the shop will ask you is what is you preference, a round wheel, or even spoke tension.

mattnz
  • 50,413
  • 3
  • 78
  • 173
0

Subject the wheel to whatever loads it might at worst encounter during its use. If it's a rear wheel, climb many hills seated while carrying maximum weight panniers on your rear rack. If it's a disc brake front wheel, brake often so hard that your rear wheel rises to the ground, with as much cargo on the bike as you can put there. Whenever encountering a curb, ride over it as fast as you can without pinch-flatting your tubes.

I have found it doesn't take many hundred kilometers to reveal whether a wheel is going to fail in a catastrophic total and complete loss of tension in all spokes. It could be a poor pair of wheels are ok for some people, for example those who weigh no more than 70 kg. If the wheels last 1000 km, I can be reasonably confident they don't fail due to a complete and total loss of spoke tension. They might still fail due to spoke fatigue in 10 000 - 100 000 km, though, so even and high spoke tension still has some value.

If/when the wheel fails, then it's time to decide what to do (on most rims losing all spoke tension is not dangerous, you'll notice it). I have found that many (most?) bike shops don't know what makes a wheel durable. Their solution appears to be to put some thread glue into the spoke nipple threads and quickly put some (but not enough) tension on the spokes, unevenly. Well theoretically this might withstand the "does it last 1000 km?" test but on one pair of wheels where the bike shop glued the threads, I found the rear wheel is still creaking when I climb hills. Most likely due to uneven spoke tension.

However, a second approach could be to find a good bike mechanic with knowledge on wheelbuilding but most do a poor job and I don't know where to look for "mechanics with good wheelbuilding skills". It's almost easier to learn the skill yourself because that's about what you need to ask few questions about wheelbuilding from a bike mechanic to estimate whether you can trust their wheels. If you're not a software developer, you don't know how to hire software developers. If you're not a wheelbuilder, you don't know how to hire wheelbuilders.

A third approach might be to either build yourself a new pair of wheels or to tension the wheel yourself to an even and high spoke tension.

On my wheels that were thread-glued by a bike shop, I still haven't used them after I found they creak. They're my spare wheels. I replaced them by a pair of wheels that I built from the beginning, not finding the 28 spokes, lack of double eyelets and so-called "tubeless ready" rims where mounting a normal tire takes an hour and three tube punctures adequate (I use 36-spoke wheels).

If you find the wheels adequate, e.g. if they have double eyelets, triple-butted spokes, 36 spokes per wheel, if it's easy to mount tires and everything else is ok too apart from equal and high spoke tension, you might want to touch up the wheels yourself if they fail due to lack of spoke tension. The thread glue most bike shops would put there would just be a hindrance in the eventual necessity of touching up the wheels yourself.

Maybe some day I put the deficient 28-spoke wheels with thread glue into a truing stand and see what I can do for them.

juhist
  • 18,668
  • 3
  • 27
  • 49
  • Running a stress test with electronics purchases (and with computers in particular) is a good idea. Running a first-day-after-purchase stress test on bike wheels is also a good idea, but you'd have to make sure it fits within "use" rather than "abuse". – Sam7919 Jun 27 '22 at 18:47
  • I agree that learning wheelbuilding is ideal. Following your analogy with software development, someone can learn to code from small systems and move gradually to larger ones, but how does one take small steps when learning wheelbuilding? – Sam7919 Jun 27 '22 at 18:48
0

The OP passionately requested that I write a proper answer to this question, so I will indeed do that.

In a perfect world, yes, we would want a wheel that uses a rim which is perfectly straight on its own, and which has equal spoke tension among all DS spokes and NDS ones, but due to real-life factors, that rarely happens. However, as JoeK points out, bicycle wheels are so strong and durable that any deviance from this expectation of perfection is generally not a problem. Perhaps if you're Jobst Brandt riding the same wheel for 100Mm you might run into issues, but for mere mortals like you and I, I doubt it would be problematic.

Regarding my initial comment on the question, I wanted to stress the importance of having some observable data or observations to support your claim. Plucking the spokes indeed can be a reasonable method of checking tension (especially if you have a good musical ear and can differentiate varying pitches of the "twang" sound). However, it would be more convincing if you had the tension meter data from the start. Furthermore, consider the optics of your scenario. Especially with the pandemic supply situation and the start-of-summer rush season, bicycle shops may not be very motivated to address fairly mundane complaints (such as a true wheel with somewhat uneven spoke tension).

I think the general consensus is that even spoke tension is more important than wheel trueness, at least to a reasonable extent. Disc brakes don't care about rim waviness, and there's no real harm in riding a wheel which is a few millimeters out of true. Of course, if you have rim brakes, disregard this paragraph—of course you need your rims dead true then.

Also, in response to this part of your question:

(Note to self: check trueness and tension before adding rim strip and tyre. This way I can return the wheel as still brand new without the risk of hassle during a return transaction.)

As I discovered in this question, wheels actually change their spoke tension and trueness when the tire is installed and inflated. This makes sense due to both the bead tension and pneumatic pressure. I think the pertinent goal is that your wheel is true and evenly tensioned in the state it's going to be used in, and that is with tire and rim strip installed.

MaplePanda
  • 15,547
  • 2
  • 31
  • 77