Solid_Spoke

Stopped at an intersection waiting for the green. As soon as it turned green, I started pedaling and heard a SNAP!. Coudln't pedal the bike, had to coast to the other side. When the inner ring snapped it swung around...dragged its teeth into my Co-Motion frame! There is a deep dent where you see the red arrow...and all around the the bottom bracket. Dropped the bike off at the bike shop and will wait to see what happens. All I'm praying for is that Co-Motions lifetime warranty will cover this.

6/6/14 @ 4PM Updates:

I received a call this morning from Bike Gallery. The manager there said that structurally the frame is safe to ride, that it is a small dent, and that there are no cracks. He informed me that Shimano shipped a new Ultegra crankset to the shop. As to Co-Motion's lifetime warranty, he says that they do not cover "acts of God". He said he would contact the owner of the Bike Gallery and see what else could be done for me.

A few hours later, I got another call saying that Bike Gallery is going to have Co-Motion repair and repaint the frame, at no cost to me! The repair time will take 2-4 weeks.

otg 

uuhh!

Nachoman

super bummer.

Pirkaus

Did the chain ring bolt break or come out first? Just curious
Pirk

velocity

Metal fatigue caused by a stress riser. How old were the components?

alexaschwanden

Wow!

Solid_Spoke

Chainring bolt broke. The bike is 6 months old.

macca33

Ouch nasty. Good luck with it all.

cheers

RollCNY

How, pray tell, can you tell that from a bad photo that doesn't show the fracture? And then please let me know how a stress riser "causes" metal fatigue. I was taught cyclic loading causes fatigue failure.

fstshrk

Wow.

With all the problems that Shimano is having with shifting on the 11 speed drivetrains and now this?

I guess I am getting a SRAM bike.

Pirkaus

Any creaking or clicking before this happened? Are the chain ring bolts tight?

Solid_Spoke

No odd sounds prior to this event, the bolts were tight.

Pirkaus

Wow that is scary to have with no warning at all, good luck.
Pirk

kleng

Don't think Co-Motion will honor any warrantee, its not a failure with their frame but shimano's part.

Solid_Spoke

and $10 that Shimano won't cover my $1800 frame. Just great. I'll have to see what the shop says tomorrow after they contact Co-Motion.

clydeosaur

I'd be willing to bet there was a loose chainring bolt that caused this.

DXchulo

That sucks. I hope they can piece together what happened.

Co-Motion really has nothing to do with this. I wouldn't ask them to replace it even if they wanted to.

cmschmie

Bad batch of steel on the inner ring? I hope the shop is contacting Shimano as well.

kaliayev

That's what it looks like to me. Have to remember with only 4 arms in the 6800 crank and at the bolt where the stress occurred half the diameter of the chainring would not have an arm for support.

shelbyfv

My guess is Co-mo, Shimano and the LBS will all say a loose chainring bolt. Sorry.

rpenmanparker 

I depends upon who assembled the bike, Co-Motion or OP or the LBS. If the bike came finished from Co-Motion, they might replace the frame. Otherwise, nah.

gsa103

I'm voting for over tightened bolt. Almost the same as too loose, but there would be no warning.

zymphad

What problems other than this one? I read far more issues with SRAM than Shimano.

As others have said, looks like it's a problem of whoever assembled the bike, not Shimano.

What?!?!? The 4 arm design is stiffer and stronger than the previous 5 arm. Also Campagnolo revamp of their groups also use 4 arm. Guess both Shimano and Campagnolo engineers are morons. They didn't stress test these properly, sucks so much that their top three groups use them.

vwchad

I'm curious. Was this possibly the result of a really bad chain drop incident? Did you downshift right before stopping and not realize that the chain had become lodged between the chainring and frame or between the two chainrings somehow? Or, did you have a previous incident like that and maybe damaged the chainring without knowing it? Seems to me that there must be more to this than just going from 100% flawless operation to a failure of this magnitude.

zymphad

If my car or laptop had a component that caused frame damage, regardless if the component was manufactured by the frame designer or not, I'd expect them to replace the product if it's under warranty. I don't see why a bike frame designer who sells bikes as complete bikes shouldn't be held to the same standard as everyone else.

If Co-Motion only sold the frame, and OP assembled bike with parts he bought himself, yeah. But if Co-Motion sold a complete bike, they should be liable for all parts of the bike as well. Meaning if they want to recoup costs for frame damage, then they should be responsible to resolve issue with Shimano's warranty dept.

If I bought a bike from LBS and it was under warranty, I wouldn't call Shimano to warranty the part. I'd bring the bike to LBS and have them do it, and they better do it for free. It's their fault for selling me a bike with a faulty crank.

How would dropped chain cause the small chainring to detach from the crank and break? Also if it was dropped, he wouldn't have been able to pedal after he stopped at the intersection. When chain drops, your pedal stroke halts immediately, he would have noticed.