Spoke choice for touring wheels

[James Fitch]

I'm about to build a new set of fully loaded touring wheels, 40 spoke. Is
there any reason to prefer butted vs straight gauge spokes for this
application?

-Jim



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[daveornee]

I'm about to build a new set of fully loaded touring wheels, 40 spoke. Is
there any reason to prefer butted vs straight gauge spokes for this
application?

-Jim



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"Double-buttedspokes are thicker at the ends than in the middle. The most popular diameters are 2.0/1.8/2.0 mm (also known as 14/15 gauge) and 1.8/1.6/1.8 (15/16 gauge).
Double-butted spokes do more than save weight. The thick ends make them as strong in the highly-stressed areas as straight-gauge spokes of the same thickness, but the thinner middle sections make the spokes effectively more elastic. This allows them to stretch (temporarily) more than thicker spokes.

As a result, when the wheel is subjected to sharp localized stresses, the most heavily stressed spokes can elongate enough to shift some of the stress to adjoining spokes. This is particularly desirable when the limiting factor is how much stress the rim can withstand without cracking around the spoke hole."
It is a small compromise in stiffness to attain more durability.

 

[Zog The Undeniable]

James Fitch wrote:
> I'm about to build a new set of fully loaded touring wheels, 40 spoke. Is
> there any reason to prefer butted vs straight gauge spokes for this
> application?

Generally, butted spokes are superior for all applications. P/g spokes
have one thing in their favour for touring, which is that when one
breaks, the wheel goes out of true by a smaller amount and you may be
able to ride the rest of the day without fixing it. I think it's better
to avoid breakage in the first place.

I looked into having different spokes on different sides of the rear
wheel, but in the end just used DT Competition all round, front and rear.

 

[A Muzi]

> James Fitch wrote:
>> I'm about to build a new set of fully loaded touring wheels, 40 spoke.
>> Is there any reason to prefer butted vs straight gauge spokes for this
>> application?

Zog The Undeniable wrote:
> Generally, butted spokes are superior for all applications. P/g spokes
> have one thing in their favour for touring, which is that when one
> breaks, the wheel goes out of true by a smaller amount and you may be
> able to ride the rest of the day without fixing it. I think it's better
> to avoid breakage in the first place.
>
> I looked into having different spokes on different sides of the rear
> wheel, but in the end just used DT Competition all round, front and rear.

I don't agree that with PG spokes "when one breaks, the wheel goes out
of true by a smaller amount", but I agree with your conclusion - use
butted stainless spokes!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Chalo]

A Muzi wrote:
>
> Zog The Undeniable wrote:
> >
> > Generally, butted spokes are superior for all applications. P/g spokes
> > have one thing in their favour for touring, which is that when one
> > breaks, the wheel goes out of true by a smaller amount and you may be
> > able to ride the rest of the day without fixing it.
>
> I don't agree that with PG spokes "when one breaks, the wheel goes out
> of true by a smaller amount", but I agree with your conclusion - use
> butted stainless spokes!

In my observation, the things that govern a single broken spoke's
ability to distort the wheel are
1) spoke count,
2) spoke tension,
3) bracing angle, and
4) rim lateral stiffness.

Chalo

 

[Qui si parla Campagnolo]

On Jan 29, 7:36 pm, "James Fitch" <jfitchatnapannetdotnet> wrote:
> I'm about to build a new set of fully loaded touring wheels, 40 spoke. Is
> there any reason to prefer butted vs straight gauge spokes for this
> application?
>
> -Jim
>
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Butted spokes, specifically 14/15/14(2mm/1.8mm/2mm) will build a
stronger, longer lasting wheel than straight gauge.

 

[Paul Kopit]

On Mon, 29 Jan 2007 18:36:26 -0800, "James Fitch"
<jfitchatnapannetdotnet> wrote:

>I'm about to build a new set of fully loaded touring wheels, 40 spoke. Is
>there any reason to prefer butted vs straight gauge spokes for this
>application?

Majority of r.b.t. folks will write there is a diffence. I've found
no difference in use on my tandems that carry loads in excess of 350
lbs. With 40 hole wheels, and heavy loads, you have more problems with
failing hubs and denting rims.

 

[Art Harris]

Paul Kopit wrote:
> >I'm about to build a new set of fully loaded touring wheels, 40 spoke. Is
> >there any reason to prefer butted vs straight gauge spokes for this
> >application?
>
> Majority of r.b.t. folks will write there is a diffence. I've found
> no difference in use on my tandems that carry loads in excess of 350
> lbs. With 40 hole wheels, and heavy loads, you have more problems with
> failing hubs and denting rims.

If tensioning a box section rim to near its limit, 40 spokes will
result in lower spoke tension than 36 spokes. That could cause the
left side spokes to go slack under load. Using butted spokes makes it
less likely for spokes to go slack.

I'd be inclined to use 36 spoke wheels and butted spokes.

Art Harris

 

[James Fitch]

"Art Harris" <[email protected]> wrote in message
news:[email protected]...
> James Fitch wrote:
>> >I'm about to build a new set of fully loaded touring wheels, 40 spoke.
>> >Is
>> >there any reason to prefer butted vs straight gauge spokes for this
>> >application?
>>
>> Paul Kopf wrote:
>> Majority of r.b.t. folks will write there is a diffence. I've found
>> no difference in use on my tandems that carry loads in excess of 350
>> lbs. With 40 hole wheels, and heavy loads, you have more problems with
>> failing hubs and denting rims.
>
> Art Harris wrote:
> If tensioning a box section rim to near its limit, 40 spokes will
> result in lower spoke tension than 36 spokes. That could cause the
> left side spokes to go slack under load. Using butted spokes makes it
> less likely for spokes to go slack.
>
> I'd be inclined to use 36 spoke wheels and butted spokes.
>
> Art Harris
>

Thanks to all who have replied.

Art, would it make any difference to you if you knew I was a pretty big guy
(6-2, 200 lbs), so the load on the bike would be in the vicinity of 250?

-Jim



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[daveornee]

"Art Harris" <[email protected]> wrote in message
news:[email protected]...
> James Fitch wrote:
>> >I'm about to build a new set of fully loaded touring wheels, 40 spoke.
>> >Is
>> >there any reason to prefer butted vs straight gauge spokes for this
>> >application?
>>
>> Paul Kopf wrote:
>> Majority of r.b.t. folks will write there is a diffence. I've found
>> no difference in use on my tandems that carry loads in excess of 350
>> lbs. With 40 hole wheels, and heavy loads, you have more problems with
>> failing hubs and denting rims.
>
> Art Harris wrote:
> If tensioning a box section rim to near its limit, 40 spokes will
> result in lower spoke tension than 36 spokes. That could cause the
> left side spokes to go slack under load. Using butted spokes makes it
> less likely for spokes to go slack.
>
> I'd be inclined to use 36 spoke wheels and butted spokes.
>
> Art Harris
>

Thanks to all who have replied.

Art, would it make any difference to you if you knew I was a pretty big guy
(6-2, 200 lbs), so the load on the bike would be in the vicinity of 250?

-Jim



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If you already have the 40 spoke hubs and rims I think you should go ahead.
40 gives you 4 more spokes to spread the load over than 36. 40 spoke wheels are stiffer... all other things being equal..... than 36 spoke wheels.
Touring load is dead weight, unlike a rider who can help remove some of the peak dynamic loads by using hip, knee, elbow, shoulder, etc. joints as shock absorbers.
Of course the quality of the other components you select and the qulaity of the wheel builds themselves also make a big difference.
We ride 48 spoke wheels on our 700C touring tandem and 40 spoke wheels on our 26" MTB tandem. I would not go with less on either and was forced into the 40 spoke choice on the 26" tandem because I could not find any 48 hole 26" rims at the time I built the wheels for that bicycle.
I know a tandem couple who is touring 36 spoke wheels on rugged roads. They are using substantial rims, but they are breaking them. I will be interested to learn their experiences when they move up to 40 spoke wheels and use 14/15 DB spokes.
What rims will you be using?
Co-Motion Americano touring bicycle has the option for 36, 40, or 48 spoke wheels. They are a quality tandem maker and have decided that serious touring bicycle could also benefit from a wider OLD to provide for better spoke suppoort angle balancing right-to-left resulting in better load sharing from right-to-left.

 

[[email protected]]

Art Harris writes:

>>> I'm about to build a new set of fully loaded touring wheels, 40
>>> spoke. Is there any reason to prefer butted vs straight gauge
>>> spokes for this application?

>> Majority of r.b.t. folks will write there is a difference. I've
>> found no difference in use on my tandems that carry loads in excess
>> of 350 lbs. With 40 hole wheels, and heavy loads, you have more
>> problems with failing hubs and denting rims.

> If tensioning a box section rim to near its limit, 40 spokes will
> result in lower spoke tension than 36 spokes. That could cause the
> left side spokes to go slack under load. Using butted spokes makes
> it less likely for spokes to go slack.

Not so, the ratio of left to right remains constant and with a greater
spoke complement, rim flex is reduced so the reduction of tension in
the load affected zone is likewise reduced (distributed over more
spokes).

> I'd be inclined to use 36 spoke wheels and butted spokes.

Extending that logic would indicate that 16 spokes were even better.

Jobst Brandt

 

[jim beam]

[email protected] wrote:
> Art Harris writes:
>
>>>> I'm about to build a new set of fully loaded touring wheels, 40
>>>> spoke. Is there any reason to prefer butted vs straight gauge
>>>> spokes for this application?
>
>>> Majority of r.b.t. folks will write there is a difference. I've
>>> found no difference in use on my tandems that carry loads in excess
>>> of 350 lbs. With 40 hole wheels, and heavy loads, you have more
>>> problems with failing hubs and denting rims.
>
>> If tensioning a box section rim to near its limit, 40 spokes will
>> result in lower spoke tension than 36 spokes. That could cause the
>> left side spokes to go slack under load. Using butted spokes makes
>> it less likely for spokes to go slack.
>
> Not so, the ratio of left to right remains constant and with a greater
> spoke complement, rim flex is reduced so the reduction of tension in
> the load affected zone is likewise reduced (distributed over more
> spokes).

eh? the ratio remains the same, but that's got nothing to do with
magnitude. and if the rim will only take a given compression before it
buckles, and that compression is a function of spoke count and tension,
then the more the spoke count, the lower the permissible tension, right?

>
>> I'd be inclined to use 36 spoke wheels and butted spokes.
>
> Extending that logic would indicate that 16 spokes were even better.

at #205, i ride 16 spoke shimano r540's no problem. and their
manufacturer spec spoke tension happens to be about the same as a
standard 32 spoke wheel.

 

[Chalo]

jim beam wrote:
>
> at #205, i ride 16 spoke shimano r540's no problem. and their
> manufacturer spec spoke tension happens to be about the same as a
> standard 32 spoke wheel.

Any 700c rim stiff enough to survive when built up with 16 spokes
would be much stronger with 32. The reverse is not the case-- many
rims that work well with 32 or more spokes would not work for an adult
rider if built with only 16 spokes.

Chalo

 

[jim beam]

Chalo wrote:
> jim beam wrote:
>> at #205, i ride 16 spoke shimano r540's no problem. and their
>> manufacturer spec spoke tension happens to be about the same as a
>> standard 32 spoke wheel.
>
> Any 700c rim stiff enough to survive when built up with 16 spokes
> would be much stronger with 32. The reverse is not the case-- many
> rims that work well with 32 or more spokes would not work for an adult
> rider if built with only 16 spokes.
>

my mavic cosmos rims appear to be the same as open pros - the front is
only 24 spokes and works well for me. rear is 28.

 

[Zog The Undeniable]

A Muzi wrote:

> I don't agree that with PG spokes "when one breaks, the wheel goes out
> of true by a smaller amount", but I agree with your conclusion - use
> butted stainless spokes!

They're less elastic, so the next spokes on the same side of the hub
don't stretch as far due to the sudden increase in load caused by the
missing spoke. This means the wheel may still be rideable without
opening up the brake or tweaking the adjacent spokes. As I said, it's
better to avoid this situation in the first place by using better spokes.

 

[James Fitch]

"daveornee" <[email protected]> wrote in
message news:[email protected]...
> What rims will you be using?

I haven't got to that, yet. I was discussing the project with my wheel
consultant (who has a very good local reputation) and he said that he
thought straight gauge spokes would be best. My inclination was that butted
spokes would be better. I asked the group to get more input. The group seems
very strongly to prefer butted.

-Jim



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[Art Harris]

[email protected] wrote:

> > If tensioning a box section rim to near its limit, 40 spokes will
> > result in lower spoke tension than 36 spokes. That could cause the
> > left side spokes to go slack under load. Using butted spokes makes
> > it less likely for spokes to go slack.
>
> Not so, the ratio of left to right remains constant and with a greater
> spoke complement, rim flex is reduced so the reduction of tension in
> the load affected zone is likewise reduced (distributed over more
> spokes).

Which part of my post is "not so?" Certainly, if a wheel is built for
maximum safe tension as described in your book, the tension in
individual spokes will have to decrease as spoke count increases. I
agree that the left / right ratio stays the same. I'm not sure why rim
flex would would be significantly different between 36 and 40 spoke
wheels.

>
> > I'd be inclined to use 36 spoke wheels and butted spokes.
>
> Extending that logic would indicate that 16 spokes were even better.
>
No, but I wouldn't want to go to the opposite extreme either. I ride
on 36 spoke wheels, and don't see a compelling reason to use more or
less spokes than that (except maybe that 32 spoke rims and hubs are
more readily available).

Art Harris

 

[James Fitch]

"daveornee" <[email protected]> wrote in
message news:[email protected]...
>>
>> James Fitch Wrote:
>> I'm about to build a new set of fully loaded touring wheels, 40 spoke.
>> Is there any reason to prefer butted vs straight gauge spokes for this
>> application?

> What rims will you be using?

Mavic A719, Shimano 105 hubs, and now, it seems, butted spokes. I must say I
was surprised at the one-sidedness of the opinion. I really expected to hear
at least some argument.

Thanks to all to contributed.

-Jim



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