The curse of snapping spokes

[Vernon Levy]

For the second weekend in a row I have managed to snap
spokes in the rear wheel of my road bike.

The first time, I could link the sanpping to hitting a pot
hole the dul ping as the spoke head snapped off at the hub
coincided with the impact.

Having had the spok replaced and the wheel trued, a spoke
snapped within 25 miles. Pot holes were studiously avoided
and there wer no significant jarring loads on the wheel
prior to the second spoke failure. Is this just bad luck or
should I consider having the wheel re-laced with heavier
gauge spokes? I am still a porky 20 stone the wheel has a
Shimano Sora hub and a Rigida rim if that is any help.

[Tony Raven]

vernon levy wrote:
> For the second weekend in a row I have managed to snap
> spokes in the rear wheel of my road bike.
>
> The first time, I could link the sanpping to hitting a pot
> hole the dul ping as the spoke head snapped off at the hub
> coincided with the impact.
>
> Having had the spok replaced and the wheel trued, a spoke
> snapped within 25 miles. Pot holes were studiously avoided
> and there wer no significant jarring loads on the wheel
> prior to the second spoke failure. Is this just bad luck
> or should I consider having the wheel re-laced with
> heavier gauge spokes? I am still a porky 20 stone the
> wheel has a Shimano Sora hub and a Rigida rim if that is
> any help.

Its a badly built wheel. You don't need heavier gauge
spokes, you just need the ones you have used properly. The
problem you have is the spoke tension is too low and the
spokes have not been stress relieved after the wheel was
tensioned. Ask around the local clubs for a good local
builder or else spend the money instead on The Bicycle Wheel
by Jobst Brant and a spoke key and do it properly yourself.

Tony

[GearóId Ó Laoi/]

Good advice Tony but 20 stone is a lot. I'm big and it's
like me touring carrying more than 5 stone of luggage, which
is 70 lb. I've never carried more than 35, and I was lighter
then. If a rebuild does not solve the problem, he might need
a really strong wheel.

[Just Zis Guy]

On Sun, 13 Jun 2004 22:24:03 +0100, "Gearóid Ó Laoi/Garry Lee"
<glee@iol.ie> wrote in message <caih79$7tc$1@kermit.esat.net>:

>Good advice Tony but 20 stone is a lot.

All the same, a hand tensioned wheel should be strong
enough. I know people who ride tandems with 36 spoke wheels,

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk (http://www.chapmancentral.co.uk/)

88% of helmet statistics are made up, 65% of them at Washington University

[Tony Raven]

Gearóid Ó Laoi/Garry Lee wrote:
> Good advice Tony but 20 stone is a lot. I'm big and it's
> like me touring carrying more than 5 stone of luggage,
> which is 70 lb. I've never carried more than 35, and I was
> lighter then. If a rebuild does not solve the problem, he
> might need a really strong wheel.

I'm four stone lighter and ride 36 spoke wheels on some
quite rocky off-road which gives them a pounding they will
never see on road plus I ride 40 spoke wheels on touring
tandems with luggage for two, two people and only two wheels
to carry all that weight with only 10% more spokes. A
standard 36 spoke wheel will do fine for 20 stone if
properly built.

Tony

[Vernon Levy]

> >Good advice Tony but 20 stone is a lot.

But I'm a light twenty stone :-)
>
> All the same, a hand tensioned wheel should be
> strong enough. I know people who ride tandems with
> 36 spoke wheels,
>
When I took the wheel in the first time, I asked about
heavier gauge spokes and the LBS reckoned that heavier gauge
spokes should not be necessary. The tension on the spokes
after repair was noticeably higher. I'll ask again when I
take the wheel in tomorrow.

None of my other bikes have had this problem. I've only done
250 miles on the road bike. Perhaps it's the highly strung
nature of such beasts. :-)

BTW

what is the going rate for a rebuild?

cheers

Vernon in Leeds

[Pete Biggs]

Tony Raven wrote:
> Its a badly built wheel. You don't need heavier gauge
> spokes, you just need the ones you have used properly. The
> problem you have is the spoke tension is too low and the
> spokes have not been stress relieved after the wheel was
> tensioned.

1. The wheel probably was built poorly, but still, some
spokes are better than others and it's sensible for
heavier riders to use better than average spokes.

2. Jobst Brandt claimed low tension does not increase
fatigue when I mentioned the subject on
rec.bicycles.tech. So probably lack of stress relieving
and/or inadequate spoke type/number is responsible for
Vernon's problems rather than low/uneven tension (which
is more relevant to general strength and ability to
stay true).

~PB

[Anonymous]

"Tony Raven" <junk@raven-family.com> wrote in message
news:2j41hkFsent9U2@uni-berlin.de...

> I'm four stone lighter and ride 36 spoke wheels on some
> quite rocky
off-road
> which gives them a pounding they will never see on road
> plus I ride 40
spoke
> wheels on touring tandems with luggage for two, two people
> and only two
wheels
> to carry all that weight with only 10% more spokes. A
> standard 36 spoke
wheel
> will do fine for 20 stone if properly built.

Wheel size makes a difference in all of this - Vernon is
talking about 700's, your mtb rims are 26" and have big fat
tyres to cushion the pounding.

But our tandem wheels (on + off road) are all 36 spoke/26",
and I agree with you really - Vernon just needs his wheels
building properly.

cheers, clive

[Pete Biggs]

vernon levy wrote:
> For the second weekend in a row I have managed to snap
> spokes in the rear wheel of my road bike.
>
> The first time, I could link the sanpping to hitting a pot
> hole the dul ping as the spoke head snapped off at the hub
> coincided with the impact.

The pothole was only the final straw. The spoke will have
been fatiguing all the while before that.

> Having had the spok replaced and the wheel trued, a spoke
> snapped within 25 miles. Pot holes were studiously avoided
> and there wer no significant jarring loads on the wheel
> prior to the second spoke failure. Is this just bad luck
> or should I consider having the wheel re-laced with
> heavier gauge spokes? I am still a porky 20 stone the
> wheel has a Shimano Sora hub and a Rigida rim if that is
> any help.

You may not /need/ better spokes (I don't know what you've
got) but DT Alpine III (2.3/1.8/2.0) should be ideal if you
do ever respoke the wheel or get a new wheel. Also consider
switching to a 36-spoke rear wheel if you have a 32 now.
It's important that the spokes are properly stress
relieved*. Not all builders do this, unfortunately.

* http://draco.acs.uci.edu/rbfaq/FAQ/8c.1.html

~PB

[Sandy Morton]

In article <uqhpc0tbup20qt6rfjlpcqnrs982c9ujp5@4ax.com>, "Just zis
Guy, you know?" <outlook.bugs@microsoft.com> wrote:
> All the same, a hand tensioned wheel should be
> strong enough. I know people who ride tandems with
> 36 spoke wheels,

Our hiring tandems all have heavier gauge spokes and don't
cause problems.

--
A T (Sandy) Morton on the Bicycle Island In the Global
Village http://www.millport.net (http://www.millport.net/)