rear wheel spokes

in message <[email hidden]>, J.D

(') said:

Any thoughts on this one.

Have just got back into cycling and have been going out in the evenings
and at the weekends increasing the distance further each trip.
I am finding that some weeks when checking the bike on its weekly
maintenance the rear spokes are okay and appear fine, another week and
some are loose and a couple are snapped at the head.

Is anyone else suffering from this or is it just down to me being hard on
the bike?

Fingers crossed and touching wood, I've /never/ broken a spoke - but other
people do. Are these home made wheels, hand made wheels, or factory made
wheels? Are they new or old?

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

I shall continue to be an impossible person so long as those
who are now possible remain possible -- Michael Bakunin

J.D wrote on 10/09/2006 21:06 +0100:

Quoted message said:

Any thoughts on this one.

Have just got back into cycling and have been going out in the evenings and
at the weekends increasing the distance further each trip.
I am finding that some weeks when checking the bike on its weekly
maintenance the rear spokes are okay and appear fine, another week and some
are loose and a couple are snapped at the head.

Is anyone else suffering from this or is it just down to me being hard on
the bike?

Your problem is with the build of the wheel. Basically the spokes are
too loose and have not been stress relieved. You could start off by
reading Sheldon Brown's pages on wheelbuilding but until you fix the
build you will continue to have problems.
http://sheldonbrown.com/wheelbuild.html

Unfortunately many bike shops don't know how to build a good wheel so
taking it there will probably not get much joy. Try asking around at
the local cycle club as to where a good wheelbuilder is or post your
location here and someone may be able to make a suggestion.

--
Tony

"Anyone who conducts an argument by appealing to authority is not using
his intelligence; he is just using his memory."
- Leonardo da Vinci

Simon Brooke said:

Fingers crossed and touching wood, I've /never/ broken a spoke - but other
people do. Are these home made wheels, hand made wheels, or factory made
wheels? Are they new or old?

I have just had another rear one go on Saturday as I was taking the
girls for a ride along an disused railway line that has has tarmac, not
chippings put down. And what's better, it is close enough to home the
girls can ride on the pavement while I walk to it.

After the last time I have kitted myself out with a trueing stand and a
second hand bike stand, so all I needed were the spokes. It took 3 bike
shops to find any short enough (240mm), but the co-op came up trumps and
I cleaned them out of stock.

This morning I fitted the spoke & trued the wheel and while I was at it
I checked the front as well, all OK. Since the bike was on the stand, I
thought I would see if I could get rid of the annoying creak every half
turn of the pedal. I had already replaced the pedals (suspect knackered
bearings) and tightened the cranks, but it would not go away. This time
I opted for the full strip, pedals, cranks & BB. Once it was all out, I
gave everything a wipe down and put on more copper grease [1] before
putting it all back together again.

To make sure it was all working well, I needed I simple run on the flat.
Two willing girls agreed to repeat our ride, but this time we went
further. After a while the fine flat tarmac surface gives way and we
turned onto a dirt path taking us more or less back along where we had
come from. We took this as far as the girls were confident going on as
eventually it was a steep, winding, downhill and discretion took the
better part of valour so we turned round and retraced our steps back home.

The ride showed me that I had solved the BB creak problem and the spoke
was fine, but I found 2 other problems, one minor, the other a potential
biggie. The minor one was that when I had put the front wheel back on, I
had not put enough tension on the brake cable, so although it was
working to some degree, it would not be powerful enough for the daily
commute. The biggie was that some of the time when I was free-wheeling
there was this terrible sound/vibration coming from the rear hub. This
is a biggie as if this needs replacing, it is the best part of 100 GBP
(Nexus8).

After getting the girls to bed (priorities), the shed beckoned. The
braking was soon sorted out and I also gave the rear a tweak to give it
a similar feel. Looking at the rear wheel in the bike, there seemed to
be a significant amount of lateral play i.e. the it was possible to
slide the hub from side to side on the bearings. Off it came, off came
the roller brake. Under the brake, are a couple of small locknuts, these
were loose and needed a few turns to remove the slack. Phew!.

Tomorrow will tell if I have make a pigs ear out of it.

[1] At one of the LBS's I went to, they seemed to have an aversion to
copper grease, saying that it was prone to electrochemical reaction
especially where there was not a lot of expected movement and I would be
better off with silicone grease. Does this sound reasonable?.

--
Don Whybrow

Sequi Bonum Non Time

"I suppose they are vicious rascals, but it scarcely matters what they
are. I'm after what they know." (Gibson-Sterling, The Difference Engine)

in message <[email hidden]>, Don Whybrow

(') said:

After getting the girls to bed (priorities), the shed beckoned. The
braking was soon sorted out and I also gave the rear a tweak to give it
a similar feel. Looking at the rear wheel in the bike, there seemed to
be a significant amount of lateral play i.e. the it was possible to
slide the hub from side to side on the bearings. Off it came, off came
the roller brake. Under the brake, are a couple of small locknuts, these
were loose and needed a few turns to remove the slack. Phew!.

Careful. I don't know whether the Nexus has cartridge or cup-and-cone
bearings, but if cup-and-cone the adjustment is critical if you are not to
get greatly accelerated wear.

Sheldon's article:
http://www.sheldonbrown.com/cone-adjustment.html
Park Tools:
http://www.parktool.com/repair/readhowto.asp?id=105

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; 99% of browsers can't run ActiveX controls. Unfortunately
;; 99% of users are using the 1% of browsers that can...
[seen on /. 08:04:02]

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Careful. I don't know whether the Nexus has cartridge or cup-and-cone
bearings

Are any shimano hubs cartridge bearing?

cheers,
clive

Tony Raven said:

Your problem is with the build of the wheel. Basically the spokes are
too loose and have not been stress relieved.

Or you may have been a victim of the dodgy batch of spokes that were
being used by a lot of manufacturers a while back.

Don Whybrow said:

[1] At one of the LBS's I went to, they seemed to have an aversion to
copper grease, saying that it was prone to electrochemical reaction
especially where there was not a lot of expected movement and I would be
better off with silicone grease. Does this sound reasonable?.

I've emailed the expert (FIM FICorr FWeldI and so on ad nauseum) for a
definitive answer but in the mean time I am gettign splinters from
scratching my head and considering why they think that there will be
any more electrolytic problems than having aluminium alloy/steel
interfaces if there is some copper there. Trying frantically to
remember by electronegativity tables, I am not convinced that having
copper will be any worse or better than not (assuming an alu alloy
component and a steel frame). If anything I'd probably expect the
copper to protect the other components (IIRC).

...d

David Martin said:

Don Whybrow said:

[1] At one of the LBS's I went to, they seemed to have an aversion to
copper grease, saying that it was prone to electrochemical reaction
especially where there was not a lot of expected movement and I would be
better off with silicone grease. Does this sound reasonable?.

I've emailed the expert (FIM FICorr FWeldI and so on ad nauseum) for a
definitive answer but in the mean time I am gettign splinters from
scratching my head and considering why they think that there will be
any more electrolytic problems than having aluminium alloy/steel
interfaces if there is some copper there. Trying frantically to
remember by electronegativity tables, I am not convinced that having
copper will be any worse or better than not (assuming an alu alloy
component and a steel frame). If anything I'd probably expect the
copper to protect the other components (IIRC).

The expert tells me that my memory is faulty.

Copper is cathodic which means that copper/steel will degrade the
steel. Steel likewise is protected by aluminium. Adding zinc will
protect everything.

So whilst coppaslip or similar would help prevent seizing, it may not
be good for the frame in the long term. That presumes that your frame
spends a lot of time wet.

...d

In article <[email hidden]>
David Martin <[email hidden]> wrote:
<snip>

Quoted message said:

I've emailed the expert (FIM FICorr FWeldI and so on ad nauseum) for a
definitive answer but in the mean time I am gettign splinters from
scratching my head and considering why they think that there will be
any more electrolytic problems than having aluminium alloy/steel
interfaces if there is some copper there. Trying frantically to
remember by electronegativity tables, I am not convinced that having
copper will be any worse or better than not (assuming an alu alloy
component and a steel frame). If anything I'd probably expect the
copper to protect the other components (IIRC).

See the bottom table:
http://www.kovopb.cz/en/pb-plechy_p.html

J.D said:

Any thoughts on this one.

Have just got back into cycling and have been going out in the evenings and
at the weekends increasing the distance further each trip.
I am finding that some weeks when checking the bike on its weekly
maintenance the rear spokes are okay and appear fine, another week and some
are loose and a couple are snapped at the head.

Is anyone else suffering from this or is it just down to me being hard on
the bike?

It's just a bad wheel. Have someone good rebuild it with stainless
spokes, and posisbly a new rim. A good wheel will take any abuse you
throw at it, short of being twisted in a drain cover.

On Mon, 11 Sep 2006 21:33:17 +0100, Zog The Undeniable wrote
(in article <4505cbb2.0@entanet>😉:

Quoted message said:

It's just a bad wheel. Have someone good rebuild it with stainless
spokes, and posisbly a new rim. A good wheel will take any abuse you
throw at it, short of being twisted in a drain cover.

I feel a new and strong rim is very important if there are problems with
spokes braking on the rear.

The OP doesn't mention the make of the bicycle but a great many bicycles are
sold with quite weak wheels, cheap rims and being built by machine not very
much tension in the spokes.

If the rim flexes whilst riding along then it flexes the spokes and they
break through metal fatigue.

So, if one is having problems with spokes breaking on the rear wheel a
reasonably expensive strong rim will help a lot imho.

--
Patrick

My bikes: Moulton AM7 and two Moulton APBs - an R18 and a "mongrel"
Pic of R18: <http://patrickjames.mysite.wanadoo-members.co.uk/R18.jpg>

A few paragraphs about the Scottoiler chain lubrication system:
<http://patrickjames.mysite.wanadoo-members.co.uk/scottoiler.html>

Simon Brooke said:

Careful. I don't know whether the Nexus has cartridge or cup-and-cone
bearings, but if cup-and-cone the adjustment is critical if you are not to
get greatly accelerated wear.

Sheldon's article:
http://www.sheldonbrown.com/cone-adjustment.html
Park Tools:
http://www.parktool.com/repair/readhowto.asp?id=105

Fortunately, he has the entire service manual for the Nexus at
http://sheldonbrown.com/nexus8/

The assembly instructions show them as cone and locknut
http://sheldonbrown.com/nexus8/pages/24.htm - picture 17
http://sheldonbrown.com/nexus8/pages/25.htm - picture 18

Also on the parts list, parts 28 & 29
http://sheldonbrown.com/nexus8/pages/29.htm

So.. looks like I will need to do a bit of adjustment to slacken off the
cone a smidgen and then apply 25 - 30 N.m to the locknut, which I would
guess to be tight, but not gut busting tight.

--
Don Whybrow

Sequi Bonum Non Time

After things go from bad to worse, the cycle will repeat itself.

David Martin said:

David Martin said:

Don Whybrow said:

[1] At one of the LBS's I went to, they seemed to have an aversion to
copper grease, saying that it was prone to electrochemical reaction
especially where there was not a lot of expected movement and I would be
better off with silicone grease. Does this sound reasonable?.

I've emailed the expert (FIM FICorr FWeldI and so on ad nauseum) for a
definitive answer but in the mean time I am gettign splinters from
scratching my head and considering why they think that there will be
any more electrolytic problems than having aluminium alloy/steel
interfaces if there is some copper there. Trying frantically to
remember by electronegativity tables, I am not convinced that having
copper will be any worse or better than not (assuming an alu alloy
component and a steel frame). If anything I'd probably expect the
copper to protect the other components (IIRC).

The expert tells me that my memory is faulty.

Copper is cathodic which means that copper/steel will degrade the
steel. Steel likewise is protected by aluminium. Adding zinc will
protect everything.

So whilst coppaslip or similar would help prevent seizing, it may not
be good for the frame in the long term. That presumes that your frame
spends a lot of time wet.

Thanks, I will get some other grease and replace it. Any
recommendations? Zinc, Silicone, Teflon, ...

--
Don Whybrow

Sequi Bonum Non Time

Freedom defined is freedom denied. (Illuminatus)

patrick j said:

On Mon, 11 Sep 2006 21:33:17 +0100, Zog The Undeniable wrote
(in article <4505cbb2.0@entanet>😉:

Quoted message said:

It's just a bad wheel. Have someone good rebuild it with stainless
spokes, and posisbly a new rim. A good wheel will take any abuse you
throw at it, short of being twisted in a drain cover.

I feel a new and strong rim is very important if there are problems
with spokes braking on the rear.

The OP doesn't mention the make of the bicycle but a great many
bicycles are sold with quite weak wheels, cheap rims and being built
by machine not very much tension in the spokes.

If the rim flexes whilst riding along then it flexes the spokes and
they break through metal fatigue.

So, if one is having problems with spokes breaking on the rear wheel a
reasonably expensive strong rim will help a lot imho.

Even with the most flexible rim, the amount it can change spoke tension is
small compared to what the rider's weight does with even a stiff rim.
Spokes reduce in tension every time they are at the bottom of the wheel when
there is weight on the bike. (This is why heavier cyclists need better or
more spokes).

Stress relieving helps reduce fatigue, according to Jobst Brandt. Google
and Google-group for how-to.

~PB

On Tue, 12 Sep 2006 02:40:14 +0100, Pete Biggs wrote
(in article <[email hidden]>😉:

Quoted message said:

Quoted message said:

So, if one is having problems with spokes breaking on the rear wheel a
reasonably expensive strong rim will help a lot imho.

Even with the most flexible rim, the amount it can change spoke tension is
small compared to what the rider's weight does with even a stiff rim.
Spokes reduce in tension every time they are at the bottom of the wheel when
there is weight on the bike. (This is why heavier cyclists need better or
more spokes).

Stress relieving helps reduce fatigue, according to Jobst Brandt. Google
and Google-group for how-to.

All else being equal wheel strength is greatly increased when strong rims are
used for the reasons I stated in my post.

Heavier cyclists need better/more spokes and *stronger rims*.

I will quote Jobst Brandt:

"A rigid rim combined with many thin spokes will give the longest
load-affected zone and the best stress distribution. By lengthening the
load-affected zone, a strong rim distributes loads over more spokes than a
weaker rim can."

The importance of rim strength for wheel durability is also backed up very
comprehensively by the consummate wheel builder Gerd Schraner.

People who are having problems with breaking spokes are very well advised to
have the wheel rebuilt using a strong rim. This will make a very significant
difference to the overall durability of the wheel. Obviously it is essential
that the wheel is well built.

The spokes break because they are continuously being flexed continously, but
the stronger rim will spread the load and consequently spread the flexing
across a greater number of spokes.

One thing which is often noticed about small wheel bicycles is how immensely
strong the wheels are (if they are built well). 406 sized wheels with 36
spokes are thought to have the same strength and durability as 700 wheels
with 48" spokes all else being equal.

The primary reason for this massive increase in strength is that the smaller
rim is far less flexible than the larger rim. If you take a small 406 rim and
simply try to flex it in your hands you will see that it is much more
resilient. If you then take a 700 rim of the same manufacture it is very much
flexible than the smaller rim.

--
Patrick

My bikes: Moulton AM7 and two Moulton APBs - an R18 and a "mongrel"
Pic of R18: <http://patrickjames.mysite.wanadoo-members.co.uk/R18.jpg>

A few paragraphs about the Scottoiler chain lubrication system:
<http://patrickjames.mysite.wanadoo-members.co.uk/scottoiler.html>

patrick j said:

All else being equal wheel strength is greatly increased when strong
rims are used for the reasons I stated in my post.

Heavier cyclists need better/more spokes and *stronger rims*.

I will quote Jobst Brandt:

"A rigid rim combined with many thin spokes will give the longest
load-affected zone and the best stress distribution. By lengthening
the load-affected zone, a strong rim distributes loads over more
spokes than a weaker rim can."

What context is that in?

Is it to do with how the wheel deals with impacts, or how many spokes at the
bottom change by how much when weight is applied to the wheel normally?

If it's the latter then I'll accept what you say (in principle at least).
Otherwise I'm not convinced that any other flex is enough to make a
significant difference to spoke fatigue when it must be so minor in
comparison.

In practice I reckon wheels built with rims as flexible as 700C Mavic Open
Pro are easily good enough for most cyclists when it comes to spoke
reliability.

Even JB doesn't think anything stiffer than an MA2 is necessary, and that's
not mega-stiff compared to some of today's rims.

Quoted message said:

The importance of rim strength for wheel durability is also backed up
very comprehensively by the consummate wheel builder Gerd Schraner.

People who are having problems with breaking spokes are very well
advised to have the wheel rebuilt using a strong rim. This will make
a very significant difference to the overall durability of the wheel.
Obviously it is essential that the wheel is well built.

The spokes break because they are continuously being flexed
continously, but the stronger rim will spread the load and
consequently spread the flexing across a greater number of spokes.

Can you be more specific about the flexing that you are referring to?
Location and cause?

Quoted message said:

One thing which is often noticed about small wheel bicycles is how
immensely strong the wheels are (if they are built well). 406 sized
wheels with 36 spokes are thought to have the same strength and
durability as 700 wheels with 48" spokes all else being equal.

The primary reason for this massive increase in strength is that the
smaller rim is far less flexible than the larger rim. If you take a
small 406 rim and simply try to flex it in your hands you will see
that it is much more resilient. If you then take a 700 rim of the
same manufacture it is very much flexible than the smaller rim.

I know smaller wheels are stronger in general, but please can we concentrate
specifically on spoke fatigue.

~PB