chain stress

recycled

Is there any deleterious effect on a chain if you start from a dead stop in
a high gear such that you are putting a large strain on the chain and cog
wheels, chain rings and crank arms for that matter?

Serious question.

Has anyone snapped a chain in this manner?

Roger Zoul

"recycled" <u-lock@hotmail.com> wrote
>
> Is there any deleterious effect on a chain if you start from a dead stop
> in a high gear such that you are putting a large strain on the chain and
> cog wheels, chain rings and crank arms for that matter?
>
> Serious question.
>
> Has anyone snapped a chain in this manner?

Who cares about the chain....has anyone snapped a knee?

Tom Keats

In article <g32ubs$afk$1@news.datemas.de>,
"recycled" <u-lock@hotmail.com> writes:
>
> Is there any deleterious effect on a chain if you start from a dead stop in
> a high gear such that you are putting a large strain on the chain and cog
> wheels, chain rings and crank arms for that matter?
>
> Serious question.
>
> Has anyone snapped a chain in this manner?

In my own experience, I've broken more rear axles
than chains. I really don't fully understand the
dynamics of how it happens, but apparently (to me)
it's the rear axle that bears the brunt of such
stresses.

Lower gears (in which it's easier to attain higher
torque) seem to contribute more to axle breakage
than higher gears.


cheers,
Tom

--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca

peter

On Jun 15, 4:27 am, "recycled" <u-l...@hotmail.com> wrote:
> Is there any deleterious effect on a chain if you start from a dead stop in
> a high gear such that you are putting a large strain on the chain ...

Note that the strain you can put on the chain will be greatest when
using your smallest chainring

jobst.brandt@stanfordalumni.org

Peter Rathman wrote:

>> Is there any deleterious effect on a chain if you start from a dead
>> stop in a high gear such that you are putting a large strain on the
>> chain ...

> Note that the strain you can put on the chain will be greatest when
> using your smallest chainring

And MTB riders do that all the time with no ill effect. This sounds
like one of those:

"If I hang my bicycle from the front wheel, won't that ovalize it?"

Troll!

Jobst Brandt

PK

<jobst.brandt@stanfordalumni.org> wrote in message
news:4855a4f9$0$17144$742ec2ed@news.sonic.net...
> Peter Rathman wrote:
>
>>> Is there any deleterious effect on a chain if you start from a dead
>>> stop in a high gear such that you are putting a large strain on the
>>> chain ...
>
>> Note that the strain you can put on the chain will be greatest when
>> using your smallest chainring
>
> And MTB riders do that all the time with no ill effect. This sounds
> like one of those:
>
> "If I hang my bicycle from the front wheel, won't that ovalize it?"
>
> Troll!
>
> Jobst Brandt


The one time I broke a chain was trying to pull away from a dead stop on a
hill on my mtb, where I had arrived in far too high a gear as the road
junction was immediately following a blind corner. I stood on the pedals and
the chain snapped. Granted it was a new chain <200 miles, and therefore the
problem was possibly a faulty chain, but it did break in the exact
circumstance the op describes.

pk

recycled

<jobst.brandt@stanfordalumni.org> wrote in message
news:4855a4f9$0$17144$742ec2ed@news.sonic.net...
> Peter Rathman wrote:
>
>>> Is there any deleterious effect on a chain if you start from a dead
>>> stop in a high gear such that you are putting a large strain on the
>>> chain ...
>
>> Note that the strain you can put on the chain will be greatest when
>> using your smallest chainring
>
> And MTB riders do that all the time with no ill effect. This sounds
> like one of those:
>
> "If I hang my bicycle from the front wheel, won't that ovalize it?"
>
> Troll!

I hope you aren't suggesting that I'm a troll.

jobst.brandt@stanfordalumni.org

someone wrote:

>>>> Is there any deleterious effect on a chain if you start from a
>>>> dead stop in a high gear such that you are putting a large strain
>>>> on the chain ...

Oops! lets look up the meaning of "stress" and "strain" first:

http://www.m-w.com/

>>> Note that the strain you can put on the chain will be greatest
>>> when using your smallest chainring

>> And MTB riders do that all the time with no ill effect. This
>> sounds like one of those:

>> "If I hang my bicycle from the front wheel, won't that ovalize it?"

>> Troll!

> The one time I broke a chain was trying to pull away from a dead
> stop on a hill on my MTB, where I had arrived in far too high a gear
> as the road junction was immediately following a blind corner. I
> stood on the pedals and the chain snapped. Granted it was a new
> chain <200 miles, and therefore the problem was possibly a faulty
> chain, but it did break in the exact circumstance the op describes.

Cut the fog! What broke? The way you say that it seems a side plate
failed. If a pin extracted, it was most likely an installation
assembly problem, the most common cause of chain separation.

Lets not fuel the chain failure rumor mill!

Jobst Brandt

jobst.brandt@stanfordalumni.org

anonymous wrote:

>>>> Is there any deleterious effect on a chain if you start from a
>>>> dead stop in a high gear such that you are putting a large strain
>>>> on the chain ...

>>> Note that the strain you can put on the chain will be greatest
>>> when using your smallest chainring

>> And MTB riders do that all the time with no ill effect. This
>> sounds like one of those:

>> "If I hang my bicycle from the front wheel, won't that ovalize it?"

>> Troll!

> I hope you aren't suggesting that I'm a troll.

You are a troll, possibly unwittingly. I suppose remainng anonymous
helps you live with it.

Jobst Brandt

PK

<jobst.brandt@stanfordalumni.org> wrote in message
news:48569d6c$0$17236$742ec2ed@news.sonic.net...
> someone wrote:
>> The one time I broke a chain was trying to pull away from a dead
>> stop on a hill on my MTB, where I had arrived in far too high a gear
>> as the road junction was immediately following a blind corner. I
>> stood on the pedals and the chain snapped. Granted it was a new
>> chain <200 miles, and therefore the problem was possibly a faulty
>> chain, but it did break in the exact circumstance the op describes.
>
> Cut the fog! What broke? The way you say that it seems a side plate
> failed. If a pin extracted, it was most likely an installation
> assembly problem, the most common cause of chain separation.
>
> Lets not fuel the chain failure rumor mill!
>
> Jobst Brandt



Is there some fine point of semantics I am missing?

Instead of being a continuous loop, my chain was a single length: ie it
broke!
I'm not particularly bothered if a joint failed or if a metal part snapped:
the chain broke!

pk

Frank Krygowski

On Jun 15, 7:27 am, "recycled" <u-l...@hotmail.com> wrote:
> Is there any deleterious effect on a chain if you start from a dead stop in
> a high gear such that you are putting a large strain on the chain and cog
> wheels, chain rings and crank arms for that matter?
>
> Serious question.

It should cause no problem.

The tension in the chain isn't hard to calculate. Your crank arm has
a radius of about 170mm. In "high gear," your chainring has a radius
of about 100 mm. So to find chain tension in high gear, multiply your
pedal force by 175/100. (The choice of rear cog doesn't matter.) And
your pedal force is probably about equal to your weight in that
situation. If you weigh 175 pounds, that's a chain tension of 306
lbs.

It's worse when your chain's on a small front cog. A triple crank's
small cog might have a radius of 50mm, so if you're standing hard on
the pedal in that gear, you get about twice the chain tension: 612
lbs. And my chain's stood up to that situation thousands of times.

>
> Has anyone snapped a chain in this manner?

I once broke a chain mountain biking, but never road riding. I was
trying to grind past a sudden, steep obstacle and was in the process
of changing to the smallest front cog. I imagine the bending &
twisting of the chain during the shift is what tore the side plate off
the pin.

I've had to start in a high gear many, many times (and always kicked
myself for forgetting to "pre-shift"). But it's never, ever harmed my
chain. Don't worry.

- Frank Krygowski

DennisTheBald

On Jun 15, 6:27 am, "recycled" <u-l...@hotmail.com> wrote:
> Is there any deleterious effect on a chain if you start from a dead stop in
> a high gear such that you are putting a large strain on the chain and cog
> wheels, chain rings and crank arms for that matter?
>
> Serious question.
>
> Has anyone snapped a chain in this manner?

I can't believe that a bicycle chain can be broken by the weight of a
human & a bicycle, regardless of the gearing.

recycled

<jobst.brandt@stanfordalumni.org> wrote in message
news:48569e2a$0$17236$742ec2ed@news.sonic.net...
> recycled at u-lock@hotmail.com wrote:
>
>>>>> Is there any deleterious effect on a chain if you start from a
>>>>> dead stop in a high gear such that you are putting a large strain
>>>>> on the chain ...
>
>>>> Note that the strain you can put on the chain will be greatest
>>>> when using your smallest chainring
>
>>> And MTB riders do that all the time with no ill effect. This
>>> sounds like one of those:
>
>>> "If I hang my bicycle from the front wheel, won't that ovalize it?"
>
>>> Troll!
>
>> I hope you aren't suggesting that I'm a troll.
>
> You are a troll, possibly unwittingly. I suppose remainng anonymous
> helps you live with it.

Believe what you wish.

I had that thought whilst taking off from a traffic stop in a high gear and
wondered about it.

I'm sorry it doesn't meet your posting standards.

I wonder what you find so trollish about the question.

BTW: I do not post as 'anonymously'. I post as 'recycled' at email
u-lock@hotmail.com and have done so on this ng for years. Though I haven't
posted much at all recently. T'is true this is not my real name nor even a
fake name that would have the appearance of a real name. I'm sorry that does
not meet your posting standards either but I don't indiscrimately release
personal information on the internet. Identity theft and net-cook
cyber-stalkers might be a low order probability but I won't take that risk
simply to please you or anyone else.

Stephen Harding

DennisTheBald wrote:
> On Jun 15, 6:27 am, "recycled" <u-l...@hotmail.com> wrote:
>
>> Is there any deleterious effect on a chain if you start from a dead stop in
>>a high gear such that you are putting a large strain on the chain and cog
>>wheels, chain rings and crank arms for that matter?
>>
>> Serious question.
>>
>> Has anyone snapped a chain in this manner?
>
>
> I can't believe that a bicycle chain can be broken by the weight of a
> human & a bicycle, regardless of the gearing.

I had two SRAM PC-48 chains break at the side plates.

I think its just cheap manufacturing for that model of
chain. I now use PC-68s.

Probably most likely chain failure is because the pin
wasn't properly installed. Chains for the most part
don't break, no matter how much torque you are able to
apply to it.

I stay away from "pinned" chains now too. The master
link is much superior IMHO.


SMH