Wrong tool for the job?

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Mattoid
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Wrong tool for the job?

Post by Mattoid » 17 Nov 2009 12:58

Image

A little problem i had on my commute to work last week.
For winter duty, i have converted my original steel steed into a single speed so not to worry too much about maintenance. Keeping cost down i have used the existing chainwheel and just removed the inner ring, but it appears the additional forces (?) endured after removing the derrailleur was just too much. Chain line was good and was not tight. I have been riding it for about a month before this happened.

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GrahamGamblin
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Post by GrahamGamblin » 17 Nov 2009 13:06

Eek!
You've obviously got too much power coming out of those legs, Phil.
Graham

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John Sanderson
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Post by John Sanderson » 17 Nov 2009 14:58

I had a similar sort of thing happen to my 105 inner chain ring on my race bike - however I was entirely to blame as i'd failed to notice that one of the chainring bolts had fallen out...

Alternatively - I ALSO have too much power in my legs! :lol:
It's all about the bike.

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Johnnyc
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Post by Johnnyc » 17 Nov 2009 18:15

It's almost as if the Terminator has been pedalling your bike!

Any plans for the next version?

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paul
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Post by paul » 17 Nov 2009 18:58

is that a 1/18 chain on a 3/32 chainring?

David Cole
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Post by David Cole » 17 Nov 2009 18:59

I'm amazed, I didn't realise that the inner ring was so important in maintaining the strength of the chainset.
Hope you were'nt hurt

Dave
David Cole

Beacon Roads Cycling Club

Mattoid
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Post by Mattoid » 17 Nov 2009 19:30

paul wrote:is that a 1/18 chain on a 3/32 chainring?
Good question Paul, i really dont know :oops: is that a known cause for this type of failure?
David Cole wrote:I'm amazed, I didn't realise that the inner ring was so important in maintaining the strength of the chainset.
Hope you were'nt hurt
My dads engineering knowledge produced exactly the same statement, Dave.

Fortunately, i wasnt going for it at the time, just pulling off from an inclined standing start. Consider myself lucky to have only caught my ankle and not endangered the crown jewels :shock:

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George
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Post by George » 17 Nov 2009 22:49

In the past, I've had bikes with a single ring on a double spider and never had a problem. I had my TT bike set up like that for years; in my 20s I also rode fixed on a bike with one ring on a double spider; and for the last 5+ years I've had that arrangement on my turbo bike. No issues with any of them.

You do usually need shorter bolts though. Is it possible that you used the double bolts and there was consequently a bit of play, leading to fatigue? Otherwise, maybe it was just a defective ring, and would have happened regardless of the set-up.

Mattoid
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Post by Mattoid » 18 Nov 2009 09:37

George wrote:You do usually need shorter bolts though. Is it possible that you used the double bolts and there was consequently a bit of play, leading to fatigue? Otherwise, maybe it was just a defective ring, and would have happened regardless of the set-up.
I had no choice but to install shorter bolts. The chainset was sourced second hand and was used in its original double set up for approx 6 months before being modified. Not knowing its full history does make me wonder of any previous damage, wear or possible defect.

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George
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Post by George » 18 Nov 2009 10:14

Mattoid wrote:The chainset was sourced second hand and was used in its original double set up for approx 6 months before being modified. Not knowing its full history does make me wonder of any previous damage, wear or possible defect.
Hearing that you got it second hand does immediately make me wonder about the possibility of it having previously been weakened, e.g. in a fall. I don't think you should have any qualms about creating a similar set-up again with new components.

David Farley
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Post by David Farley » 18 Nov 2009 14:06

Having looked at the photo i would agree with George in that there may have been some damage when you bought the chainset. So you should have no problem just replacing the ring. However, one thing that i would not be too keen to do, is using a pinned and ramped chainring with a 1/8" chain

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Post by David Farley » 18 Nov 2009 14:18

On a second look at the photo i've just noticed that one of the breaks in the chainring is right where the one shift pin is ! I would definately replace with a plain type of ring

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Post by Missiles » 18 Nov 2009 15:03

Is it just me or does that look like a very very well-worn chainring anyway? The teeth seem to be very 'sharp' and worn........... am I right in thinking that would mean the chainring had seen many many miles?

Ruth

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George
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Post by George » 18 Nov 2009 15:22

Missiles wrote:Is it just me or does that look like a very very well-worn chainring anyway? The teeth seem to be very 'sharp' and worn........... am I right in thinking that would mean the chainring had seen many many miles?

Ruth
Yes, by the look of it.

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George
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Post by George » 18 Nov 2009 15:30

David Farley wrote:Having looked at the photo i would agree with George in that there may have been some damage when you bought the chainset. So you should have no problem just replacing the ring. However, one thing that i would not be too keen to do, is using a pinned and ramped chainring with a 1/8" chain
Dave, Phil isn't sure whether his chain is 1/8 or 3/32, but my guess is that it's 3/32, because it was almost certainly 3/32 before he went single-speed, and I expect he'd know if he'd gone out and bought a 1/8 chain.

David Farley
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Post by David Farley » 19 Nov 2009 00:16

George.......your right about the chain ring being 3/32" as its pinned and ramped. i was guessing about the chain size and just making a personal preference

Ruth.......i agree the chainring does look worn.....however modern outer rings look like that even when they are new

pprince3145
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Post by pprince3145 » 19 Nov 2009 09:41

that is a very worn chainring. Classic sharks teeth
Cult Racing...better than Rock Racing
www.cultracing.com

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Ringo
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Post by Ringo » 19 Nov 2009 09:57

you should see the sharks teeth on my turbo bike :lol:

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John Sanderson
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Post by John Sanderson » 19 Nov 2009 10:21

We've got an actual sharks tooth on top of our TV at home....
It's all about the bike.

Mattoid
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Post by Mattoid » 20 Nov 2009 16:24

Thanks for all comments and observations. There is certainly a lesson learnt in buying particular parts second hand (and not know exactly what i am buying :oops: )
The thing now is to get it sorted, as i miss it!

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