28 spokes or 32?
bik...@excite.com
spokes for use on let say a Mavic Open Pro rim? I ride moderately fast,
but no racing or touring.
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Before you buy.
Carl Gonzalez
wheels with no problems. The problem with 32s and 28s I've seen is riders
barely able to get home after breaking a spoke. I think 36s give you
greater probability to "make it home" after a spoke croaks. Carry spare
spokes and a spanner to get you back.
<bik...@excite.com> wrote in message news:7u2n2c$77d$1...@nnrp1.deja.com...
Limey
The front is a 28 spoke, open 4 CD rim, laced to an Ultegra hub and the
rear is 32 spoke. I weigh 163lbs and rode them on club rides and in
triathlons and have no recollection of re-truing the front after the
first 500 miles. On the rear the head pulled off one of the nipples at
about 8K and I might have 'tweaked' the spokes a couple of times but
not often.
Hope this helps, Lewis.
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Wayne Lim
Dan Connelly
is moderately heavy for a cyclist. I'd prefer the extra
robustness.... less chance to break a spoke, less
concern if you do.
Does anyone know of any good experimental data showing the
effective drag difference of two wheels with similar design
but different spoke count? I expect it would be below
the threshold of measurement accuracy of a windtunnel.
Perhaps simple spindown tests on a truing stand have been done....
The difference in weight is clearly insignificant in anything
but a race, and even then so remote that it can only
be of theoretical importance (ie virtually impossible
to separate from experimental noise).
Dan
Wayne Lim wrote:
>
> How about 28 on the front and 32 on the back?
>
Jeffrey J. Potoff
>
> How about 28 on the front and 32 on the back?
>
I've been doing this for years on my road and MTBs without much
excitement. I did have a Sun MAE14 crack severely on the rear,
but that was most likely due to poor rim construction.
Jeff
>
> In article <7u2n2c$77d$1...@nnrp1.deja.com>,
> bik...@excite.com wrote:
> > For a rider weighing 170 pounds, what is the recommended number of
> > spokes for use on let say a Mavic Open Pro rim? I ride moderately
> fast,
> > but no racing or touring.
> >
Jeff
expect about 0.03 watts reduction in drag per spoke removed (40km/hr).
On a real ride you might calculate about 0.1 watt per spoke reduction at the
same rotational speed purely from spoke drag after taking into account the
different spoke velocities with respect to the apparent wind. However, other
factors such as rim distortion between spokes may increase energy
consumption there and may reduce the gain considerably (depending on rim).
The 0.03 watts is an average so expect very slightly less drag (est 5%) for
aero spokes and very slightly more drag (est 5%) for plain gauge spokes.
Jeff
PS true up aero spokes with a mechanical aid (eg paper clip) to get the best
results.
Dan Connelly <djco...@flash.net> wrote in message
news:380534D7...@flash.net...
> Why mess around? It seems the 32 will be stronger, and 170 lb
> is moderately heavy for a cyclist. I'd prefer the extra
> robustness.... less chance to break a spoke, less
> concern if you do.
>
> Does anyone know of any good experimental data showing the
> effective drag difference of two wheels with similar design
> but different spoke count? I expect it would be below
> the threshold of measurement accuracy of a windtunnel.
> Perhaps simple spindown tests on a truing stand have been done....
>
> The difference in weight is clearly insignificant in anything
> but a race, and even then so remote that it can only
> be of theoretical importance (ie virtually impossible
> to separate from experimental noise).
>
> Dan
>
> Wayne Lim wrote:
> >
> > How about 28 on the front and 32 on the back?
> >
Dan Connelly
Okay -- some quick numbers, then:
If the rider can climb at, say, 1500 meters / hr, w/o rolling resistance
or wind resistance, and bike+clothes+water+food+tools+rider = 88kg, then he is
capable of a peak power of
(1500 m/hr) / (3600 sec/hr) * (88kg * 9.8 N/kg) = 360 watts
The 4 spokes save 0.12 watts.
If rolling resistance coefficient = 0.005, and rider is riding
40km/h on the flats, then power lost to rolling resistance is :
0.005 * 88kg * 9.8 N/kg * 40 km/h / 3.6 ks/hr = 48 watts
This leaves 282 watts of aero power. If speed ~ aero power^(1/3),
then (neglecting speed dependence of rolling resistance power)
delta speed delta power 0.12 watts
----------- = ----------- = ----------- = 1.4 x 10^-4
speed 3 power 3 x 282 watts
Or, approximately 0.5 seconds over 40 km.
(this will be slightly increased due to speed dependence of rolling resistance
power ... 1.4 x 10^-4 x 48 watts = 0.006 watts yields an extra 0.02 seconds
as the first-order correction )
A bit hard to notice....
Dan
Jeff wrote:
>
> For a free spinning wheel in a training stand or truing stand you might
> expect about 0.03 watts reduction in drag per spoke removed (40km/hr).
Mary Sutherland
said about the dangers of less is better when it comes to spokes. Strictly
speaking there must be some kind of advantage to less spokes as far as aero
goes, but if you sproing a spoke out of 28 the resultant wheel deformation
might be more than a typical brake quick release can handle, and you may be
riding a real clunker all the way home. In short 28 works fine for a front
wheel but I think you have to let your conscience be your guide on this
one. Me, I weigh 160 and put 36 on both wheels. Cheers, charles
Jeff <smith....@hunterlink.net.au> wrote in article
<3805...@news.hunterlink.net.au>...
> For a free spinning wheel in a training stand or truing stand you might
> expect about 0.03 watts reduction in drag per spoke removed (40km/hr).
>
Bas Dunnebier
> For a rider weighing 170 pounds, what is the recommended number of
> spokes for use on let say a Mavic Open Pro rim? I ride moderately fast,
> but no racing or touring.
Why not settle for the "good-old-bomb-proof" 32 front and 36 rear? Works
always great, very strong and reliable. If built well, of course.
just my $0.02
Bas
John Carrier
wheels the injustice of up to 210# rider weight.
32H wheels most of the time, but I ran a 24H bladed spoke semi-aero rim for
a front TT wheel. 32H rarely (very rarely) needed attention. The 24 didn't
either, but its wobbly nature during out-of-the-saddle accelerations
convinced me that 28 spokes or less ought to be reserved for special event
wheels.
My 2 cents / John
n2...@my-deja.com
Seriously, I think the lightweight/aero thing is getting to be extreme.
I'd like to blame the bike manufacturers, but I think we are the real
culprits. We tend to value lightness more than durability.
I'm 6'3" and 200 pounds and ride only on 36-spoke wheels. But today I'm
hard pressed to find a high-end bike (or any bike) that meets my needs
in that regard. You would think bike makers would equip their larger
frames with beefier wheels and tires, but they don't. Car makers
wouldn't get away with putting sub-compact wheels/tires on a full-size
car. Yet with bikes, we accept and even demand exactly that.
Sure, at 170 pounds you'd probably be OK with 28F/32R. But considering
the risk vs. reward I don't think it's worth it.
Art Harris
In article <7u2n2c$77d$1...@nnrp1.deja.com>,
bik...@excite.com wrote:
> For a rider weighing 170 pounds, what is the recommended number of
> spokes for use on let say a Mavic Open Pro rim? I ride moderately
fast,
> but no racing or touring.
>
Jobst Brandt
> Seriously, I think the lightweight/aero thing is getting to be extreme.
> I'd like to blame the bike manufacturers, but I think we are the real
> culprits. We tend to value lightness more than durability.
> I'm 6'3" and 200 pounds and ride only on 36-spoke wheels. But today I'm
> hard pressed to find a high-end bike (or any bike) that meets my needs
> in that regard.
It's not that 28 spokes won't carry a 200# rider adequately but rather
that a spoke failure with fewer than 36 spokes on a 700c wheel,
regardless of what the rider weighs, is a show stopper. This was more
evident in the days when even well built wheels broke a spoke on
occasion. They guys with the low spoke count were out of it. It
doesn't matter what you weigh, if you want a reliable wheel stay with
36. You're not going to lower any world records by a few tenths of a
second soon. On the other hand if you are, you wouldn't be interested
in this thread.
Jobst Brandt <jbr...@hpl.hp.com>
Qui si parla Campagnolo
spokes for use on let say a Mavic Open Pro rim? >>
32 both ends, 3cross all around-
OR if you don't care about those 4 extra spokes(weighs a whopping 15 grams or
so)use 36 rear-
peter