rear axle breakage -warning signs?

[patrick mitchel]

Broke the rear axle (unnoticed by me until a hadda flat- am assuming the
axle was still "solid" until the last time of levering the skewer) on my
rans stratus lwb recumbent. The original part I think). I was changinge the
tube after a second flat and mounted the wheel and noticed a severe wobble
(loose) in the wheel . Thought it might be a loose cup/cone. When taken
apart, the axle was broken through at the inner adege of the threaded
section-drive side (freewheel hub). Looks from the shine that the majority
of the break had been in place for a while. Over 2/3 of the circumferance
had the shine. Are there any signs of impending failure other than the
drunken rider look? TIA Pat

 

[[email protected]]

Patrick Mitchel writes:

> Broke the rear axle (unnoticed by me until a hadda flat- am assuming
> the axle was still "solid" until the last time of levering the
> skewer) on my rans stratus lwb recumbent. The original part I
> think). I was changinge the tube after a second flat and mounted
> the wheel and noticed a severe wobble (loose) in the wheel .
> Thought it might be a loose cup/cone. When taken apart, the axle
> was broken through at the inner adege of the threaded section-drive
> side (freewheel hub). Looks from the shine that the majority of the
> break had been in place for a while. Over 2/3 of the circumferance
> had the shine. Are there any signs of impending failure other than
> the drunken rider look? TIA Pat

Not to worry, the true test is to spin the axle and see whether either
end (usually the sprocket end) wobbles. Axles don't bend, they break.
If it wobbles it is cracked. If the ends rotate independently, it is
broken. This can be done with a QR skewer in place.

What does recumbency have to do with broken axles?

Spell check!

Jobst Brandt

 

[Johnny Sunset aka Tom Sherman]

[email protected] aka Jobst Brandt wrote:
> Patrick Mitchel writes:
>
> > Broke the rear axle (unnoticed by me until a hadda flat- am assuming
> > the axle was still "solid" until the last time of levering the
> > skewer) on my [RANS] tratus lwb recumbent. The original part I
> > think). I was changinge the tube after a second flat and mounted
> > the wheel and noticed a severe wobble (loose) in the wheel .
> > Thought it might be a loose cup/cone. When taken apart, the axle
> > was broken through at the inner adege of the threaded section-drive
> > side (freewheel hub). Looks from the shine that the majority of the
> > break had been in place for a while. Over 2/3 of the circumferance
> > had the shine. Are there any signs of impending failure other than
> > the drunken rider look? TIA Pat
>
> Not to worry, the true test is to spin the axle and see whether either
> end (usually the sprocket end) wobbles. Axles don't bend, they break.
> If it wobbles it is cracked. If the ends rotate independently, it is
> broken. This can be done with a QR skewer in place.
>
> What does recumbency have to do with broken axles?

The RANS Stratus [1] will put typically put 60-70% of the combined
bicycle/rider weight on the rear wheel. Unless the rider learns the
technique of pushing with both feet on the pedals to slide
himself/herself up the seat back just before traversing a bump, the
rear wheel on a LWB recumbent will also tend to be more heavily loaded
over bumps than one on a standard single diamond frame upright. All
else being equal, the rear axle on a LWB recumbent will see higher peak
stress than one on a single upright bicycle.

> Spell check!

A proper spell checker should know that RANS is always in CAPITAL
LETTERS.

[1] <http://www.ransbikes.com/Stratus.htm>.

--
Tom Sherman - Here, not there.
1999 RANS Wave to Tailwind Conversion (LWB recumbent)
2000 RANS Rocket (SWB recumbent)

 

[Matt O'Toole]

On Sun, 01 Oct 2006 14:59:09 -0700, Johnny Sunset aka Tom Sherman wrote:

> [email protected] aka Jobst Brandt wrote:

>> What does recumbency have to do with broken axles?

> The RANS Stratus [1] will put typically put 60-70% of the combined
> bicycle/rider weight on the rear wheel. Unless the rider learns the
> technique of pushing with both feet on the pedals to slide
> himself/herself up the seat back just before traversing a bump, the
> rear wheel on a LWB recumbent will also tend to be more heavily loaded
> over bumps than one on a standard single diamond frame upright. All
> else being equal, the rear axle on a LWB recumbent will see higher peak
> stress than one on a single upright bicycle.

Recumbents also have very low gears, and correspondingly high chain
tension.

Matt O.

 

[Johnny Sunset aka Tom Sherman]

Matt O'Toole wrote:
> On Sun, 01 Oct 2006 14:59:09 -0700, Johnny Sunset aka Tom Sherman wrote:
>
> > [email protected] aka Jobst Brandt wrote:
>
> >> What does recumbency have to do with broken axles?
>
> > The RANS Stratus [1] will put typically put 60-70% of the combined
> > bicycle/rider weight on the rear wheel. Unless the rider learns the
> > technique of pushing with both feet on the pedals to slide
> > himself/herself up the seat back just before traversing a bump, the
> > rear wheel on a LWB recumbent will also tend to be more heavily loaded
> > over bumps than one on a standard single diamond frame upright. All
> > else being equal, the rear axle on a LWB recumbent will see higher peak
> > stress than one on a single upright bicycle.
>
> Recumbents also have very low gears, and correspondingly high chain
> tension.

Torque from the freewheel gears is transferred to the spokes through
the hub shell, not the axle.

--
Tom Sherman - Here, not there.

 

[[email protected]]

Matt O'Toole writes:

>>>> Broke the rear axle (unnoticed by me until a hadda flat- am
>>>> assuming the axle was still "solid" until the last time of
>>>> levering the skewer) on my rans stratus lwb recumbent. The
>>>> original part I think). I was changinge the tube after a second
>>>> flat and mounted the wheel and noticed a severe wobble (loose) in
>>>> the wheel. Thought it might be a loose cup/cone. When taken
>>>> apart, the axle was broken through at the inner adege of the
>>>> threaded section-drive side (freewheel hub). Looks from the
>>>> shine that the majority of the break had been in place for a
>>>> while. Over 2/3 of the circumferance had the shine. Are there
>>>> any signs of impending failure other than the drunken rider look?

>>> What does recumbency have to do with broken axles?

>> The RANS Stratus [1] will put typically put 60-70% of the combined
>> bicycle/rider weight on the rear wheel. Unless the rider learns
>> the technique of pushing with both feet on the pedals to slide
>> himself/herself up the seat back just before traversing a bump, the
>> rear wheel on a LWB recumbent will also tend to be more heavily
>> loaded over bumps than one on a standard single diamond frame
>> upright. All else being equal, the rear axle on a LWB recumbent
>> will see higher peak stress than one on a single upright bicycle.

> Recumbents also have very low gears, and correspondingly high chain
> tension.

That has no effect on detection of broken axles, which is what was
under discussion.

Hey, if I don't have the right answer, let's change the question!

Jobst Brandt

 

[[email protected]]

patrick mitchel wrote:
> ... Thought it might be a loose cup/cone. When taken
> apart, the axle was broken through at the inner adege of the threaded
> section-drive side (freewheel hub). Looks from the shine that the majority
> of the break had been in place for a while. Over 2/3 of the circumferance
> had the shine. Are there any signs of impending failure other than the
> drunken rider look? TIA Pat

For riders who are anything other than fairly light, or
climb a lot, and use more than ~120mm rear spacing,
a freewheel hub is a warning sign of a broken axle.
They all get there eventually.

 

[Helmut Springer]

Johnny Sunset aka Tom Sherman <[email protected]> wrote:
>> Recumbents also have very low gears, and correspondingly high
>> chain tension.
>
> Torque from the freewheel gears is transferred to the spokes
> through the hub shell, not the axle.

Which is why he wrote "chain tension" which is trying to bend the
axle, whereas "torque" tries to spin the wheel...

--
MfG/Best regards
helmut springer

 

[Qui si parla Campagnolo]

patrick mitchel wrote:
> Broke the rear axle (unnoticed by me until a hadda flat- am assuming the
> axle was still "solid" until the last time of levering the skewer) on my
> rans stratus lwb recumbent. The original part I think). I was changinge the
> tube after a second flat and mounted the wheel and noticed a severe wobble
> (loose) in the wheel . Thought it might be a loose cup/cone. When taken
> apart, the axle was broken through at the inner adege of the threaded
> section-drive side (freewheel hub). Looks from the shine that the majority
> of the break had been in place for a while. Over 2/3 of the circumferance
> had the shine. Are there any signs of impending failure other than the
> drunken rider look? TIA Pat

Ensuring the dropouts are aligned will help in reducing broken
axles...but with freewheels, kinda a fact of life.

 

[Qui si parla Campagnolo]

[email protected] wrote:
> Patrick Mitchel writes:
>
> > Broke the rear axle (unnoticed by me until a hadda flat- am assuming
> > the axle was still "solid" until the last time of levering the
> > skewer) on my rans stratus lwb recumbent. The original part I
> > think). I was changinge the tube after a second flat and mounted
> > the wheel and noticed a severe wobble (loose) in the wheel .
> > Thought it might be a loose cup/cone. When taken apart, the axle
> > was broken through at the inner adege of the threaded section-drive
> > side (freewheel hub). Looks from the shine that the majority of the
> > break had been in place for a while. Over 2/3 of the circumferance
> > had the shine. Are there any signs of impending failure other than
> > the drunken rider look? TIA Pat
>
> Not to worry, the true test is to spin the axle and see whether either
> end (usually the sprocket end) wobbles. Axles don't bend, they break.
> If it wobbles it is cracked. If the ends rotate independently, it is
> broken. This can be done with a QR skewer in place.

Can I send ya the axle I replaced this last saturday? Certainly bent,
not cracked...
>
> What does recumbency have to do with broken axles?
>
> Spell check!
>
> Jobst Brandt

 

[jim beam]

[email protected] wrote:
> Matt O'Toole writes:
>
>>>>> Broke the rear axle (unnoticed by me until a hadda flat- am
>>>>> assuming the axle was still "solid" until the last time of
>>>>> levering the skewer) on my rans stratus lwb recumbent. The
>>>>> original part I think). I was changinge the tube after a second
>>>>> flat and mounted the wheel and noticed a severe wobble (loose) in
>>>>> the wheel. Thought it might be a loose cup/cone. When taken
>>>>> apart, the axle was broken through at the inner adege of the
>>>>> threaded section-drive side (freewheel hub). Looks from the
>>>>> shine that the majority of the break had been in place for a
>>>>> while. Over 2/3 of the circumferance had the shine. Are there
>>>>> any signs of impending failure other than the drunken rider look?
>
>>>> What does recumbency have to do with broken axles?
>
>>> The RANS Stratus [1] will put typically put 60-70% of the combined
>>> bicycle/rider weight on the rear wheel. Unless the rider learns
>>> the technique of pushing with both feet on the pedals to slide
>>> himself/herself up the seat back just before traversing a bump, the
>>> rear wheel on a LWB recumbent will also tend to be more heavily
>>> loaded over bumps than one on a standard single diamond frame
>>> upright. All else being equal, the rear axle on a LWB recumbent
>>> will see higher peak stress than one on a single upright bicycle.
>
>> Recumbents also have very low gears, and correspondingly high chain
>> tension.
>
> That has no effect on detection of broken axles, which is what was
> under discussion.
>
> Hey, if I don't have the right answer, let's change the question!
>
> Jobst Brandt

like you just did?

 

[Qui si parla Campagnolo]

[email protected] wrote:
> patrick mitchel wrote:
> > ... Thought it might be a loose cup/cone. When taken
> > apart, the axle was broken through at the inner adege of the threaded
> > section-drive side (freewheel hub). Looks from the shine that the majority
> > of the break had been in place for a while. Over 2/3 of the circumferance
> > had the shine. Are there any signs of impending failure other than the
> > drunken rider look? TIA Pat
>
> For riders who are anything other than fairly light, or
> climb a lot, and use more than ~120mm rear spacing,
> a freewheel hub is a warning sign of a broken axle.
> They all get there eventually.

Not so-I am .1 offa ton, use C-Record freewheel rears exclusively at
130mm spacing and altho I have broken axles after smacking
something...broken axles are not automatic JRA....

 

[jim beam]

patrick mitchel wrote:
> Broke the rear axle (unnoticed by me until a hadda flat- am assuming the
> axle was still "solid" until the last time of levering the skewer) on my
> rans stratus lwb recumbent. The original part I think). I was changinge the
> tube after a second flat and mounted the wheel and noticed a severe wobble
> (loose) in the wheel . Thought it might be a loose cup/cone. When taken
> apart, the axle was broken through at the inner adege of the threaded
> section-drive side (freewheel hub). Looks from the shine that the majority
> of the break had been in place for a while. Over 2/3 of the circumferance
> had the shine. Are there any signs of impending failure other than the
> drunken rider look? TIA Pat
>
>
there's no way to detect. the axle fatigues, then breaks. the chances
of detection in the cracked but pre-failure stage is slim to zero unless
you want to strip and spend a bunch of money testing.

best thing is to prevent failure completely by using a hub with
shimano-type outboard bearing, not inboard like freewheel designs, or
use a hub with an oversize axle like some of the boutiques.

 

[jim beam]

[email protected] wrote:
> Patrick Mitchel writes:
>
>> Broke the rear axle (unnoticed by me until a hadda flat- am assuming
>> the axle was still "solid" until the last time of levering the
>> skewer) on my rans stratus lwb recumbent. The original part I
>> think). I was changinge the tube after a second flat and mounted
>> the wheel and noticed a severe wobble (loose) in the wheel .
>> Thought it might be a loose cup/cone. When taken apart, the axle
>> was broken through at the inner adege of the threaded section-drive
>> side (freewheel hub). Looks from the shine that the majority of the
>> break had been in place for a while. Over 2/3 of the circumferance
>> had the shine. Are there any signs of impending failure other than
>> the drunken rider look? TIA Pat
>
> Not to worry, the true test is to spin the axle and see whether either
> end (usually the sprocket end) wobbles. Axles don't bend, they break.

that's not true. i've bent a whole bunch of axles - not least of which
was an oversize titanium 98 campy axle.

> If it wobbles it is cracked. If the ends rotate independently, it is
> broken. This can be done with a QR skewer in place.
>
> What does recumbency have to do with broken axles?
>
> Spell check!
>
> Jobst Brandt

 

[patrick mitchel]

Ok, a related question. Would a solid axle be a more reliable component?
Pat

 

[[email protected]]

On Mon, 2 Oct 2006 09:49:12 -0700, "patrick mitchel"
<[email protected]> wrote:

> Ok, a related question. Would a solid axle be a more reliable component?
>Pat
>

Yes, given that all else was equal.

All else meaning material, finish, heat treatment (if any), etcetera.

Good quality solid axles are not difficult to find.

 

[Matt O'Toole]

On Sun, 01 Oct 2006 17:08:29 -0700, Johnny Sunset aka Tom Sherman wrote:

> Matt O'Toole wrote:

>> On Sun, 01 Oct 2006 14:59:09 -0700, Johnny Sunset aka Tom Sherman
>> wrote:
>>
>> > [email protected] aka Jobst Brandt wrote:
>>
>> >> What does recumbency have to do with broken axles?
>>
>> > The RANS Stratus [1] will put typically put 60-70% of the combined
>> > bicycle/rider weight on the rear wheel. Unless the rider learns the
>> > technique of pushing with both feet on the pedals to slide
>> > himself/herself up the seat back just before traversing a bump, the
>> > rear wheel on a LWB recumbent will also tend to be more heavily
>> > loaded over bumps than one on a standard single diamond frame
>> > upright. All else being equal, the rear axle on a LWB recumbent will
>> > see higher peak stress than one on a single upright bicycle.
>>
>> Recumbents also have very low gears, and correspondingly high chain
>> tension.
>
> Torque from the freewheel gears is transferred to the spokes through the
> hub shell, not the axle.

Chain tension bends the axle, especially when the drive side wheel bearing
is toward the middle of the axle. Some hubs, like Campy and Hugi, have
beefed up axles to prevent this. Others may not. Shimano solved this
problem with their cassette hubs by moving the drive side wheel bearing
out to the end of the axle. So broken axles with Shimano cassette hubs
are practically unheard of.

Anyway, lower gears = more chain tension = more bending force on the
axle.

Matt O.

 

[patrick mitchel]

> Chain tension bends the axle, especially when the drive side wheel bearing
> is toward the middle of the axle. Some hubs, like Campy and Hugi, have
> beefed up axles to prevent this. Others may not. Shimano solved this
> problem with their cassette hubs by moving the drive side wheel bearing
> out to the end of the axle. So broken axles with Shimano cassette hubs
> are practically unheard of.
>
> Anyway, lower gears = more chain tension = more bending force on the
> axle.
>
> Matt O.
Sansin freewheel hub BTW- Pat

 

[Pete Grey]

I used to think that from the old Suntour/Shimano days when I bent a few,
but now I'm not so sure.

I've been running 7-speed 135mm Phil freewheel hubs on our loaded tourers
since the mid-90's now, the first of which is still in service.
No signs of bending/breaking, despite X-country tour, a tour up theAK hiway
and numerous other tours over mixed paved/rough terrain. This is with a
bike/rider/panniers/gear combo weighing in at over 270 lbs, sometimes over
300.

I think that the Phil axles are so over-built that the service life is very,
very long. Now that I've said that, I'm sure one will break next summer in
the middle-of-nowhere! ;-]

-pete

"Qui si parla Campagnolo" <[email protected]> wrote in message
news:[email protected]...
>
> patrick mitchel wrote:
>> Broke the rear axle (unnoticed by me until a hadda flat- am assuming the
>> axle was still "solid" until the last time of levering the skewer) on my
>> rans stratus lwb recumbent. The original part I think). I was changinge
>> the
>> tube after a second flat and mounted the wheel and noticed a severe
>> wobble
>> (loose) in the wheel . Thought it might be a loose cup/cone. When taken
>> apart, the axle was broken through at the inner adege of the threaded
>> section-drive side (freewheel hub). Looks from the shine that the
>> majority
>> of the break had been in place for a while. Over 2/3 of the circumferance
>> had the shine. Are there any signs of impending failure other than the
>> drunken rider look? TIA Pat
>
> Ensuring the dropouts are aligned will help in reducing broken
> axles...but with freewheels, kinda a fact of life.
>

 

[Mike Jacoubowsky]

>I used to think that from the old Suntour/Shimano days when I bent a few,
>but now I'm not so sure.
>
> I've been running 7-speed 135mm Phil freewheel hubs on our loaded tourers
> since the mid-90's now, the first of which is still in service.
> No signs of bending/breaking, despite X-country tour, a tour up theAK
> hiway and numerous other tours over mixed paved/rough terrain. This is
> with a bike/rider/panniers/gear combo weighing in at over 270 lbs,
> sometimes over 300.
>
> I think that the Phil axles are so over-built that the service life is
> very, very long. Now that I've said that, I'm sure one will break next
> summer in the middle-of-nowhere! ;-]

I doubt it. As you note, the Phil axles are quite over-built. You'll have a
very difficult time destroying one, primarily due to the very large (and
unthreaded) diameter.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"Pete Grey" <[email protected]> wrote in message
news:[email protected]...
>I used to think that from the old Suntour/Shimano days when I bent a few,
>but now I'm not so sure.
>
> I've been running 7-speed 135mm Phil freewheel hubs on our loaded tourers
> since the mid-90's now, the first of which is still in service.
> No signs of bending/breaking, despite X-country tour, a tour up theAK
> hiway and numerous other tours over mixed paved/rough terrain. This is
> with a bike/rider/panniers/gear combo weighing in at over 270 lbs,
> sometimes over 300.
>
> I think that the Phil axles are so over-built that the service life is
> very, very long. Now that I've said that, I'm sure one will break next
> summer in the middle-of-nowhere! ;-]
>
> -pete
>
> "Qui si parla Campagnolo" <[email protected]> wrote in message
> news:[email protected]...
>>
>> patrick mitchel wrote:
>>> Broke the rear axle (unnoticed by me until a hadda flat- am assuming the
>>> axle was still "solid" until the last time of levering the skewer) on my
>>> rans stratus lwb recumbent. The original part I think). I was changinge
>>> the
>>> tube after a second flat and mounted the wheel and noticed a severe
>>> wobble
>>> (loose) in the wheel . Thought it might be a loose cup/cone. When taken
>>> apart, the axle was broken through at the inner adege of the threaded
>>> section-drive side (freewheel hub). Looks from the shine that the
>>> majority
>>> of the break had been in place for a while. Over 2/3 of the
>>> circumferance
>>> had the shine. Are there any signs of impending failure other than the
>>> drunken rider look? TIA Pat
>>
>> Ensuring the dropouts are aligned will help in reducing broken
>> axles...but with freewheels, kinda a fact of life.
>>
>
>