I just built some wheels. Front is Mavic 571 front hub, Mavic Open Pro rim, DT Swiss butted spokes, 28H.

Well, I was sprinting out of the saddle - okay, I was racing a bus over the Burnside Bridge - and my cleat came out of my clipless pedal. Lurched forward, shoe went into the front wheel, no spokes are broken but the magnet for the computer is gone so there was some contact. Lucky I didn't fall and go under the bus, I guess.

The wheel now has a lateral wobble, quite noticeable. No other apparent damage.

I will true it, but my question is, should the wheel have been de-trued by that incident? Does it suggest I built a weak wheel, should increase the tension, etc? Or is all this normal, my question stupid, and just crank down the pedal retention and move on?

1. First try to true the wheel back up...
2. Report to us the overall result...
3. Report to us the tension spoke to spoke...

Also, what was you average tension when you first built it in KGF?

=8-)

It's perfectly normal for a crashed or otherwise hyper-stressed wheel to go out of true. IMO if a wheel is subjected to excess stress and doesn't suffer, it was overbuilt, and heavier than necessary.

Most people think of spokes in terms of tensile strength, or the amount of load they can take before breaking. But for the types of stainless steels used for spokes there's the much lower (50-60% or tensile) yield strength. The yield strength is how much load the material can take before it exceeds it's elastic limit and deforms permanently.

Imagine a scale. If used within it's rated capacity the spring will return to the original length when the load is removed. But if you overload it the spring gets stretched out and the scale won't go back to zero and will now always read high, unless the zero point is reset to match the modified spring. It's the same when we "cold set" a steel frame, we stretch it beyond the yield point, and it returns to a new position.

So back to the spokes, your jammed foot overloaded the wheel, and now some spokes are longer than they used to be, and the wheel is out of line. The good news is that the spokes are probably as strong as before (or very close) so once you re-align the wheel it'll be as good as new.

If you bent it too far out of line, the rim will also have been cold set and if the rim is fairly stiff, you won't be able to have even tension and an aligned wheel at the same time, since there'll be variance in tension to overpower the bent rim and force it into line. The amount of variation needed depends on the strength of the rim and how much it was bent.

Errr, average was 20-21# on the Park TM1 scale, I don't know what that is in pounds (I'm not at home).

I will do as suggested. Hope I haven't mucked up a brand new rim.

Fingers crossed here...I'll be checking back in...

=8-)

Bike wheels are meant for radial loads. They don't do well with debris between the spokes. When I bought my first good bike a dog ran in front of me while I was going slow. I turned the handlebars too far and the wheel skidded sideways and was tacoed.
Next time I went that way I kicked the snot out of the mutt!

I think I lucked out. The wheel trued up easily. I checked tension on every spoke, is between 20# and 21# on the Park tool, so 110 to 122 kg? 1.7 mm middle section on the spokes. Well, there's a couple closer to 22#, but none below 20#.

Man - I need one of those...

I wonder if you have the wheel slightly overtensioned - and the minor impact revealed it?

Typically my 32 hole fronts are 95-100, I can see a 28 hole front ending up around 100-107 average?

Just wondering, that's all OP...

=8-)

Possibly - I don't have any sense of the desirable tension level, it just sort of ended up with most spokes being 20-21#, so I fiddled with the few that were lower (there were a couple in the 18-19# area after truing) and brought them up while staying true.

What determines the ideal tension? Does fewer spokes inherently mean higher tension?

A little bit each step down in spoke count, slight increase in spoke tension....problem is we are typically using the exact same rims with fewer holes without any modifications made to reinforce the centerline of the fewer holes left.

By the time you are down to 24 holes with most alloy rims, you are already pushing past 110 kgf - with most rims in their standard drillings not rated warranty wise for anything higher.

Paired hole arrangements on the rim side are the worst...

Star Circle in China actually makes rims with increased wall thickness at the holes only on low hole count rims - problem is they are heavy - and no one wants 'em.

Try to get your wheel average kgf a little under 110 kgf...

=8-)

FB, again with The Gospel.

Fewer spokes require higher tension. Mavic recommends 110kg on their rims. You should be able to use more. Did you stress relieve the wheel when you built it? If it were overtensioned when you squeezed the paired spokes the rim would have taken a curve.

More tension is generally a good thing, but too much is as bad or worse than too little. It's like taking aspirin. the normal dose of two may be right for most people, but heavier people or possibly for a more sever headache, 3 aspirin might be better, bit that isn't to say that the benefit is proportional to the dose, and you wouldn't go to 5 or 6 pills no matter how much you hurt.

Likewise with spoke tension, too little cause problems, and may lead to short lived wheels, but as tension increases, the static load on rims and hubs gets higher possibly leading to cracked flanges, or stress cracks at rim eyelets.

Front wheels are more lightly loaded than rear wheels, so there's no percentage to going to the max tension the rim manufacturer recommends. This is especially true for a radial spoke pattern and the unusual stresses it can impose on hubs. Just because the rim can take 110kgf is no reason to go to the max. I'd say that something closer to 90-100kgf will probably serve as well as the higher tension, while reducing the risk of a hub flange failure.

You'd have to severly overtension a wheel to cause is to take a curve after a stress relief cycle...

Typically what happens is that the rim come out of true in 3-4 spots...spots that you'd swear had been corrected only a few minutes earlier...

Inflating a tire an tube on the same overtensioned wheel however tends to reveal alot...

=8-)

I wonder if its possible to have a wheel that's true with tyre pressure, but overloaded and deformed without it...? Like, a wheel that's fine to use.