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? |
401 watts, Tom.
|
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: |
I think someone is putting something in your morning coffee, Tom. Glad to hear you weren't seriously injured.
|
Steel track bolts, Beanz. Grade 8 Tempered steel. Same with the inserts.
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: |
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! :)
|
Originally Posted by Tom Stormcrowe
(Post 7623078)
Steel track bolts, Beanz. Grade 8 Tempered steel. Same with the inserts.
Then you Da Man!:thumb: |
you was robbed and got crap metal. they just do not break
|
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?
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! :)
|
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.
|
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! |
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. |
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.
Glad your okay, Mr. Tom "Legs of Steel" Stormcrowe. |
Yeotch, hopefully you were wearing padded shorts or tights. My boys ached just reading that.
|
Holy crap Tom.
Hope you're OK I think that I told you to be carefull with that thing. |
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? |
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. |
Originally Posted by Tom Stormcrowe
(Post 7623127)
Maybe one was flawed and when it went, they cascade failed?
Perhaps finding a more reputable manufacturer would be a wise move, considering your near-miss with eunuch-hood! |
Originally Posted by Tom Stormcrowe
(Post 7623078)
Steel track bolts, Beanz. Grade 8 Tempered steel. Same with the inserts.
(Though we did think your gear ratio was way high.) I hereby dub thee "King of Torque!" :eek: |
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:
|
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 |
Originally Posted by markhr
(Post 7624076)
+2
Glad your okay, Mr. Tom "Legs of Steel" Stormcrowe. |
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?
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! |
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.
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! |
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.....
|
Good lord Tom! I winced reading that! I feel your pain though, I sheared a crank off my old MTB many years ago and bounced off my twins.
Upon closer inspection... the metal was already fatigued as the cast aluminum had a hairline crack in it. Your bolts may have already been fatigued, got a bad batch of steel, or you over torqued them without knowing it and stripped the head a touch. V |
OK, I used a torque wrench, ratchet type. I torqued them to the spec required for the steel ring bolts. The conversion to single speed was done this year, and the bolts were relatively new.
It's very possible the metal was from a bad batch though, and once the bad one failed, the rest cascaded, as I mentioned before. |
Also torguing is a bit of a science. For instance, if you apply any kind of lubricant to the bolt, the original numbers do not apply.
I lube every thread, except those where I have to use locktite (like steering on my jeep) - since I prefer to be able to loosen it up when needed. As far as to tighten, I do it the german way - gutntight:) - seldom use the book values - like for engine head bolts or flywheel bolts. |
I'm glad that you did not get hurt too bad. It could have been terrible. It takes A LOT of pressure to shear bolts like that. Wow.
I have this picture in my head, for some reason, of Tom unintentionally popping wheelies at every red light, and having to stand and lean forward over the front tire to keep from landing on his butt. That was some power you were laying down, dude! |
WADA will be in touch soon, and your invite to the 09 TdF could be in jeopardy as well.:D
I think I'll go assume the fetal position and hide in a corner now. OUCH!!!!!!!!!!!!!!!!!! |
All times are GMT -6. The time now is 01:45 PM. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.