Front Wheel question: 28/14-15 2x or 32/14-17 3x

Peter Chisholm wrote:

I"m having a set of wheels built using Open Pro rims and DuraAce
7700 hubs. I have both a 28 and 32 hole front hub. I'm
185-190lb. Will a 32 hole front wheel, 3x, using DT revolution
(14-17) spokes be a strong enough wheel? Better to go 28H/2x with
DT Competition 14-15?

Why not 32 hole and 14/15, laced 3 cross? I know it will be about
50 grams heavier than the others, but stronger and that 50 grams
is only a small part of your 92,000 gram or so riding package.
Â*Seriously, why do people make wheels 'just strong enough? Those
teeny additional grams will make for a more reliable, worry free
front wheel.

when is the last time you had a 28 spoke wheel fatigue or buckle?
Â*my lardy ass seems unable to break my 24 spoke front, 28 spoke
rear Mavic cosmos unless i ride through a pothole in the dark.
Â*and more spokes wouldn't stop those rims getting bashed in that
situation. Likewise, my Shimano r540's have only 16 spokes front
and rear. No failures and no trueness problems so far.

We see under-built wheels that need truing all the time. More
spokes, thicker spokes, stronger wheel. My point is why try to save
a few insignificant grams and purposely design a wheel that is
weaker than another when the only 'penalty' is 50 grams??

I have a wheelset for building next Friday, for a big guy, laced
36/3 cross on a CXP-33 rim(good), but 32 2 cross for the front.
Reason to 'save a little weight'. Weight saved is the weight of ONE
224mm spoke. Also alloy nipples, again to save less than an ounce
of weight but significantly weaker wheel.......

We see many 16 spoke wheels for service as well. 16 spokes, big,
heavy rim but still not as reliable as a 32 spoke, decent rim,
wheel.

A different number of spokes, front and rear, is a holdover from the
days when it was believed that torque loads caused spoke failure in
rear wheels, so more or thicker spokes were believed to be
appropriate. Spoke failures arise from residual stress of lacing a
wheel (inbound and outbound spokes of a flange) and in some cases,
just higher tension on the right side of the rear wheel.

More important is that if one rides other than smooth flat city
streets, hard braking into downhill curves puts all weight on the
front wheel, while sitting up riding no-hands puts nearly all weight
on the rear wheel. That is to say, peak enduring loads are the same
front and rear, so as Peter says, don't scrimp a measly couple of
grams to make a less durable wheel because you might miss being world
champion from not doing that.

Jobst Brandt

wrote:
Peter Chisholm wrote:

I"m having a set of wheels built using Open Pro rims and DuraAce
7700 hubs. I have both a 28 and 32 hole front hub. I'm
185-190lb. Will a 32 hole front wheel, 3x, using DT revolution
(14-17) spokes be a strong enough wheel? Better to go 28H/2x with
DT Competition 14-15?

Why not 32 hole and 14/15, laced 3 cross? I know it will be about
50 grams heavier than the others, but stronger and that 50 grams
is only a small part of your 92,000 gram or so riding package.
Seriously, why do people make wheels 'just strong enough? Those
teeny additional grams will make for a more reliable, worry free
front wheel.

when is the last time you had a 28 spoke wheel fatigue or buckle?
my lardy ass seems unable to break my 24 spoke front, 28 spoke
rear Mavic cosmos unless i ride through a pothole in the dark.
and more spokes wouldn't stop those rims getting bashed in that
situation. Likewise, my Shimano r540's have only 16 spokes front
and rear. No failures and no trueness problems so far.

We see under-built wheels that need truing all the time. More
spokes, thicker spokes, stronger wheel. My point is why try to save
a few insignificant grams and purposely design a wheel that is
weaker than another when the only 'penalty' is 50 grams??

I have a wheelset for building next Friday, for a big guy, laced
36/3 cross on a CXP-33 rim(good), but 32 2 cross for the front.
Reason to 'save a little weight'. Weight saved is the weight of ONE
224mm spoke. Also alloy nipples, again to save less than an ounce
of weight but significantly weaker wheel.......

We see many 16 spoke wheels for service as well. 16 spokes, big,
heavy rim but still not as reliable as a 32 spoke, decent rim,
wheel.

A different number of spokes, front and rear, is a holdover from the
days when it was believed that torque loads caused spoke failure in
rear wheels, so more or thicker spokes were believed to be
appropriate. Spoke failures arise from residual stress of lacing a
wheel

no jobst, for the 50 billionth time, they don't. spokes fatigue
because, by definition, spoke elbows bend under load [since they are
offset from the load axis]. hence we see fatigue nucleate in portions
of the spoke where there is either zero or even compressive residual
stress. you'd not keep making this mistake if you'd have bothered to
observe actual failures or understood the nature of fatigue. or even
bothered to receive rather than just broadcast.



(inbound and outbound spokes of a flange) and in some cases,
just higher tension on the right side of the rear wheel.

More important is that if one rides other than smooth flat city
streets, hard braking into downhill curves puts all weight on the
front wheel, while sitting up riding no-hands puts nearly all weight
on the rear wheel. That is to say, peak enduring loads are the same
front and rear, so as Peter says, don't scrimp a measly couple of
grams to make a less durable wheel because you might miss being world
champion from not doing that.

that's irrelevant decoy waffle. the cure for spoke fatigue is to either
use straight pull spokes where all load is fully axial, or to use
fatigue resistant [vacuum degassed] steels in traditional spoke
manufacture. making sure they're fully bedded into the hub flange helps
of course to minimize the effect of their load bending.