Wheel characteristics?

[martl]

Originally Posted by oldpotatoe

The tension of a 14g, non butted straight gauge spoke and a thin, oval spoke should be the same on a well built wheel...as measured on a spoke tension meter...both should be 'about' 100-110 kgf for a normal rim...fronts and drive side rears.

Same tension but a thinner spoke -> higher stress -> higher risk of failure; or other way around: Thinner spoke with same stress -> less tension -> softer wheel

[November Dave]

Originally Posted by martl

Same tension but a thinner spoke -> higher stress -> higher risk of failure; or other way around: Thinner spoke with same stress -> less tension -> softer wheel

Assuming equal spoke material, the wheel with the thicker spoke would be stiffer because of its thicker cross-sectional area. Once the spoke is in tension, adding more tension doesn't increase stiffness. So a Sapim Race spoke at 110kgf is no stiffer than a Sapim Race at 70kgf, or 5 kgf. I think that aligns with what you are saying but not sure.

Thinner spokes also have lower ultimate yield strengths (tension at which they break), but I've never seen or heard of a spoke breaking in tension except in a crash. This is why straight gauge spokes break more often than butted ones - straight gauge spokes, when they go slack, force all of that cyclic stress to the spoke end, where butted spokes absorb some of it by bending in the middle. But it's best to avoid spokes unloading at all, which is why we like hubs with good geometry and why we put as much tension as we do on the drive side of rear wheels and the disc side of front disc wheels - so that the lesser-tensioned side doesn't go slack. I usually build rim brake front wheels at 90kgf, where I'll think nothing of putting nearly 1.5x that mount on a drive side rear.

[November Dave]

Originally Posted by Mark McM

And as far as stiffness goes, it is possible to have too little stiffness, but not really possible to have too much. Or to put it another way, as long as the wheels have adequate stiffness, any additional stiffness makes no meaningful difference.

This whole post -

[jamesdak]

Trying to understand this thread is making my head hurt, LOL!

Fortunately the only think I really need to know if getting a new wheel built is to give OldPotatoe a hollar!

[GregL]

We are very fortunate to have highly experienced independent wheel builders, industry leaders/professionals, and engineers all contributing to this discussion. Thanks to everyone for the collaborative atmosphere!

Greg

[Mark McM]

Originally Posted by oldpotatoe

You tie and solder mostly to reduce the amount of movement of the spoke at the hub, mostly on non drive side rear, to try to eliminate broken spokes there.

The reason that low static tension spokes are more prone to breakage isn't because they move around in the hub. The reason low tension spokes break is because it is more difficult to adequately stress relieve a spoke at low static tension, and because spokes at low static tension don't bed into the flange hole as well as spokes at higher tension. Tying and soldering don't effect either of these. And like martl says, tying and soldering may affect the spokes' ability to independently stretch to absorb wheel loads.

[Mark McM]

Originally Posted by martl

Same tension but a thinner spoke -> higher stress -> higher risk of failure; or other way around: Thinner spoke with same stress -> less tension -> softer wheel

Like November Dave says, the thin middle section of a spoke might have a lower yield stress, but except when directly struck (say, getting a branch or a skewer caught in the spokes) spokes don't normally break in their middle sections. Instead, spokes more typically break at the ends (elbow, head or threads) where spokes are at the same thickness as straight spokes.

As far as tension affecting wheels stiffness, this was tested in Damon Rinard's Wheel Stiffness Test. The effect of tension on wheel stiffness was the first question he addressed in the test:

1. Does stiffness vary with spoke tension?

Some believe that a wheel built with tighter spokes is stiffer. It is not. Wheel stiffness does not vary significantly with spoke tension unless a spoke becomes totally slack.

I measured the deflection of Wheel #2 while gradually loosening the spokes in quarter turn increments. The wheel did not display any significant change in stiffness until the spokes were so loose some became totally slack

[cmg]

My take, lowest weight at the rim. Use lightest rim, lightest tire. Lightest inner tube. If the rim is shallow use higher spoke count. . Wider rims are stiffer. This will produce faster spin up but lighter rims may not hold speed, may require constant engagement. Flame on......

[Mark McM]

Originally Posted by cmg

My take, lowest weight at the rim. Use lightest rim, lightest tire. Lightest inner tube. If the rim is shallow use higher spoke count. . Wider rims are stiffer. This will produce faster spin up but lighter rims may not hold speed, may require constant engagement. Flame on......

The ability to hold speed is down to the total system inertia (wheels, bike, rider, etc.). A bike with light wheels and a full water bottle will "hold speed" just as well as a bike with heavy wheels and an empty water bottle.

[November Dave]

Originally Posted by Mark McM

The ability to hold speed is down to the total system inertia (wheels, bike, rider, etc.). A bike with light wheels and a full water bottle will "hold speed" just as well as a bike with heavy wheels and an empty water bottle.

Exactly, and add aerodynamics to that list. "Heavier wheels" are often deeper wheels, and deeper wheels are most often more aerodynamic wheels.

Next time you're in a smoking paceline and you get too close to the rider in front of you, just hold an outstretched palm outside of your hip and see what that does to your ability to hold speed!

[oldpotatoe]

Originally Posted by Mark McM

The reason that low static tension spokes are more prone to breakage isn't because they move around in the hub. The reason low tension spokes break is because it is more difficult to adequately stress relieve a spoke at low static tension, and because spokes at low static tension don't bed into the flange hole as well as spokes at higher tension. Tying and soldering don't effect either of these. And like martl says, tying and soldering may affect the spokes' ability to independently stretch to absorb wheel loads.

But that's why you stress relieve spokes, even non drive side rear. The vast majority of broken spokes I have seen are on non drive side rear and often on a rim that is wacked, making the tension lower at that point. T&S helps to reduce that at that point...

But, what do I know, I just build them. Even tho I was a pilot, I didn't know the Bernoulli's of why the airplane flew.
"Pull back on stick, airplane went up, pull further back, airplane went down"

[edgerat]

need some Potato wheels, this is clear.

[jamesdak]

Originally Posted by edgerat

need some Potato wheels, this is clear.

Rode a set of mine yesterday!

[oldpotatoe]

Originally Posted by edgerat

need some PotatoE wheels, this is clear.

Yes you do!! Give me a shout.

cp51errc@gmail.com