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-   Clydesdales/Athenas (200+ lb / 91+ kg) (http://www.bikeforums.net/clydesdales-athenas-200-lb-91-kg/)
-   -   I sheared my chain ring bolts today! (http://www.bikeforums.net/clydesdales-athenas-200-lb-91-kg/474435-i-sheared-my-chain-ring-bolts-today.html)

Tom Stormcrowe 10-07-08 08:39 PM

I sheared my chain ring bolts today!
 
Riding the fixed gear. Talk about an ouch! I made contact with the stem with a very sensitivee area of my anatomy and have no idea how I avoided a faceplant! Chain ring came off the crank and I basically dropped the chain and went from a sprint to recovery in an instant. I will say my voice was higher pitched than Geddy Lee's singing voice while I was cussing a blue streak! :p.

How much force does it take to shear track chainring bolts and mount hubs?

Joe Gardner 10-07-08 08:46 PM

401 watts, Tom.

Mr. Beanz 10-07-08 08:52 PM

Steel or aluminum? I placed aluminum bolts on our tandem cause the color matched the bike. Thought it was cool till we sheared 2 of them!

Glad the nutty buddies survived!:thumb:

zpl 10-07-08 08:53 PM

I think someone is putting something in your morning coffee, Tom. Glad to hear you weren't seriously injured.

Tom Stormcrowe 10-07-08 08:59 PM

Steel track bolts, Beanz. Grade 8 Tempered steel. Same with the inserts.
Quote:

Originally Posted by Mr. Beanz (Post 7623038)
Steel or aluminum? I placed aluminum bolts on our tandem cause the color matched the bike. Thought it was cool till we sheared 2 of them!

Glad the nutty buddies survived!:thumb:


gearhead82 10-07-08 09:00 PM

It's hard to imagine that human force could shear those bolts unless they were perhaps a tad bit loose to begin with. Maybe they backed themselves out a little? Or I suppose you could just be superhuman! :)

Mr. Beanz 10-07-08 09:02 PM

Quote:

Originally Posted by Tom Stormcrowe (Post 7623078)
Steel track bolts, Beanz. Grade 8 Tempered steel. Same with the inserts.


Then you Da Man!:thumb:

127.0.0.1 10-07-08 09:04 PM

you was robbed and got crap metal. they just do not break

Tom Stormcrowe 10-07-08 09:08 PM

I suppose it's possible, but they were retorqued just a few days ago with a torque wrench to 95 inch/pounds Shimano specs for a steel bolt).

As to superhuman, nope, not at all.

Maybe one was flawed and when it went, they cascade failed?
Quote:

Originally Posted by gearhead82 (Post 7623089)
It's hard to imagine that human force could shear those bolts unless they were perhaps a tad bit loose to begin with. Maybe they backed themselves out a little? Or I suppose you could just be superhuman! :)


JKing 10-07-08 09:14 PM

When I read the title my brain saw that you "shared" your bolts, and I thought geez what a nice guy. Then I read the post and got a little tummy ache, same thing happened to me when I broke a very old chain on my MTB. It now has a new SRAM and my boys appreciate it.

tomdaniels 10-07-08 10:51 PM

Congrats, Tom. If it weren't bedtime, I'd make you up a "Bolt Shearing" or "Glad you saved the twins" award.

I'd love to see the look on the faces at Hodson's when they hear about this one!

scrapmetal 10-08-08 12:39 AM

Glad you are OK!

As far as why they sheared, maybe you have a colleague structural engineer in your school? I would suspect the retorquing as of know.

But, still, they should not shear.

markhr 10-08-08 01:32 AM

Quote:

Originally Posted by zpl (Post 7623041)
I think someone is putting something in your morning coffee, Tom. Glad to hear you weren't seriously injured.

+2

Glad your okay, Mr. Tom "Legs of Steel" Stormcrowe.

bautieri 10-08-08 07:36 AM

Yeotch, hopefully you were wearing padded shorts or tights. My boys ached just reading that.

wayne pattee 10-08-08 07:41 AM

Holy crap Tom.
Hope you're OK
I think that I told you to be carefull with that thing.

Neil_B 10-08-08 07:46 AM

Quote:

Originally Posted by Tom Stormcrowe (Post 7623127)
I suppose it's possible, but they were retorqued just a few days ago with a torque wrench to 95 inch/pounds Shimano specs for a steel bolt).

As to superhuman, nope, not at all.

Maybe one was flawed and when it went, they cascade failed?

Pardon my ignorance, but are these new bolts, or are they original to the 35 year old bike?

HandsomeRyan 10-08-08 08:26 AM

Shearing chainring bolts with your pedaling fury- you have truely raised the bar for all of us clydes who ride fixed gear bikes!

Did it shear all 4/5 bolts or just enough to "drop" the chainring?

You sir, are hardcore.

cod.peace 10-08-08 11:53 AM

Quote:

Originally Posted by Tom Stormcrowe (Post 7623127)
Maybe one was flawed and when it went, they cascade failed?

Bingo. They'd be spec'd to take the forces from pedaling and normal bike movement, but if one failed the shock to the others at a moment of very high torque (a sprint, were you standing too?) was way more than they were designed to take. Tempered steel is hard and strong but prone to fracture due to brittleness, as compared to say annealed steel (which is softer and weaker).

Perhaps finding a more reputable manufacturer would be a wise move, considering your near-miss with eunuch-hood!

Jtgyk 10-08-08 11:54 AM

Quote:

Originally Posted by Tom Stormcrowe (Post 7623078)
Steel track bolts, Beanz. Grade 8 Tempered steel. Same with the inserts.

eeeeeeeeeyikes!!!!
(Though we did think your gear ratio was way high.)
I hereby dub thee "King of Torque!"
:eek:

CliftonGK1 10-08-08 01:38 PM

They didn't shear. After all the abuse from that gigantic gear you're pushing on that bike, they saw their chance and tried to escape. :lol:

Bone Head 10-08-08 01:39 PM

YOU DA MAN !!!! If you can generate that kind of torque, I'll bet you can do this:

http://www.youtube.com/watch?v=6GNB7xT3rNE

cohophysh 10-08-08 02:08 PM

Quote:

Originally Posted by markhr (Post 7624076)
+2

Glad your okay, Mr. Tom "Legs of Steel" Stormcrowe.

More like kahuna's of steel:D

Tom Stormcrowe 10-08-08 04:20 PM

Quote:

Originally Posted by The Historian (Post 7624829)
Pardon my ignorance, but are these new bolts, or are they original to the 35 year old bike?

New bolts, retorqued just a few days ago. The bike is a conversion from a road bike, it used to have a double chain ring. Now it has a new crank and sealed bottom bracket.

Quote:

Originally Posted by cod.peace (Post 7626567)
Bingo. They'd be spec'd to take the forces from pedaling and normal bike movement, but if one failed the shock to the others at a moment of very high torque (a sprint, were you standing too?) was way more than they were designed to take. Tempered steel is hard and strong but prone to fracture due to brittleness, as compared to say annealed steel (which is softer and weaker).

Perhaps finding a more reputable manufacturer would be a wise move, considering your near-miss with eunuch-hood!

The bolts I have in now are track spec bolts from Shimano. ;) They meet aviation standards as well for high torque apps...... ;)

Tom Stormcrowe 10-08-08 04:22 PM

There were a couple of chins on the floor....

By the way, I put a 17 tooth cog on the back, 98 was fun, but not as good for sprint and slow down riding I do on campus. I'm running 68 GI now.

Quote:

Originally Posted by tomdaniels (Post 7623718)
Congrats, Tom. If it weren't bedtime, I'd make you up a "Bolt Shearing" or "Glad you saved the twins" award.

I'd love to see the look on the faces at Hodson's when they hear about this one!


EasyEd 10-08-08 05:54 PM

Tom, If you are man enough to shear those bolts, I'd check the stem on your bike and make sure you didn't dent it.....


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