AnthonyG

Bontrager cranks appear to be made by Truvativ. The whole range of cranks look very similar to various Truvativ models but I have several sets of Truvativ ISIS Elita cranks that I've had an engineer shorten and he reckons that its some of the strongest, high quality forging that he's ever seen.

Mind you they were expensive new and the current outboard bearing model doesn't seem so strong. Then add to that the likelyhood that what Truvativ is making for Bontrager is being made to a price and the quality control may not be as high as what Truvativ sells in its own name and you see things slipping.

The cranks that broke look like Bontrager's version of the outboard bearing Truvativ Rouler crank but there is such an obvious fault in that arm that it should NEVER have gotten through quality control. Ultimately Bontrager is responsible for setting the levels of quality that any item bearing its name must meet as its the one who's paying for it, or not as the case may be.

Anthony

BananaTugger

Rouleurs are carbon, this one isn't.

Likely an Elita.

AnthonyG

Rouleurs were made with both an aluminium and a carbon model. The groove down the back of the arm say's to me that they are the Rouleur version. The Elita version are chunkier and lack such a groove.

Anthony

nachomc

How many watts were you putting out at the time of failure?

patentcad

That's what they keep asking me about my snapped D.A. 7800 crank arm. Newsflash: if your crank's going to fail, it won't necessarily take a lot of watts. I was putting out 400-500 watts, which is what many of us (of all ability levels) exert every time we climb a steep hill. But I'm convinced a crank that's going to go might also fail under 150 watts. When it's time to snap, it snaps.

Scorer75

I've got aluminum Roulers.

asmallsol

I would defiantly contact trek directly. Do not put the pieces of crank back together again. This will slightly mar up the fracture surface. They will want to analyze the fracture surface in a S.E.M. If you just contact your LBS, you will receive a new crank arm, however, will probally not contact Trek, allowing this to fail. There certainly is a forging issue that Trek will like to know about.

BananaTugger

Now, you do.

umd

Incorrect. They make a carbon and Al version. I had the Al version of my TCR, and broke a crankarm...

BananaTugger

When did they start making the aluminum version?

alanbikehouston

Back in the '70's, "superlight" cranks were made from aluminum, while "heavy-duty" cranks were made from steel. A guy who wrote a bike repair book in that era mentioned going into a bike shop where they had a large box filled with broken Campy cranks.

I've never seen a broken aluminum crank from Shimano though....knock on wood...

Benjamin11

Lesson to all to check their components.

A smart person learns from their mistakes.

An intelligent person learns from the mistakes of others.

baxtefer

Now you have
https://www.bikeforums.net/road-cycling/465175-oh-snap-ii.html

BananaTugger

Awesome.

umd

I do not know but my TCR is a 2005 or 2006 model.

Here is the broken crankarm

BananaTugger

So, Truvativ managed to make a crank that sucks, suck more by making a heavier version.

Incredible.

umd

Maybe the carbon version came after and they made it suck less by making it lighter

Edit: I have a SRAM S900 on there now...

j_amie_

As a fellow canadian I always wonder that too! you americans need to vote someone into office that will get you guys a standardized health care system like we have in canada. They are amazing! I don't know how you guys can deal with having to worry about paying for medical treatment???? That stuff is not cheap.

domestique

LOL, don't worry, he may not be paying hospital bills but it will take him 3 months to schedule an MRI

Scorer75

Universal health care:

Canada: 33.4 million people

United States: 305.2 million people

I wonder if this number includes illegal immigrants because that would add 13.9 million additional people or roughly 40% of the entire population of Canada that would also need to be insured.




Regarding pricing for this injury, assuming no MRI or X-rays were necessary and based on some recent experience, $2,500 - $3,000 would be fair.

domestique

Standardized Healthcare? No thank you. You get what you pay for, and having the freedom and efficiency to be seen when needed is much more valuable to me then getting it for free.

FYI, (this was awhile ago) There were 3 MRI machines in Lancaster county, PA (where Floyd Landis grew up).... at the SAME TIME, there were 3 MRI machines in ALL OF CANADA.

I assume things have gotten better up there, but I also have a friend who lives in Toronto, and got Giardia (a common parasite found in mountain streams, that is easy to diagnose and treat) while on holdiay in the states, and it took 2 years for the diagnosis to be made... he eventually went into the U.S to see their doctors and they made the diagnosis. Because of such a long time being infected, the Giardia damaged his kidneys enough that he had to give up playing semi-pro tennis.

Carbon Unit

It looks like the crank arm was aluminum.

bigd

True enough. However, In Alberta we do have private clinics that you can pay to do the MRI in a matter of days. So I guess you have some more options if you have the money, a lot like the way it is in the US except our middle to low income people have a free 3 month option which is better than nothing. I've read that upwards of 16% of your population has no health coverage what so ever. What happens to those people?

scorpio516

Hmmm, wonder why every one of these failure are on the left/non-drive side. I'm no engineer, but unless I start seeing some drive side failures, its looking like a trend...

Psimet2001 

Came to the party late. Definite casting defect. Porosity/sand. If it's forged then the billet they forged it from was cast - resulting in the defect.

Looks like paint in the voids meaning it was like that when it was painted. Doesn't look like a true void either - meaning it was on the sirface when painted. That means someone overlooked it. Sad.

The rest - as explained by others - is a definite classic fatigue failure. It was bound to happen at some point.

Yes it can happen with all cranks. Your odds would most likely increase with cheaper cranks though...or ones that are poorly designed.

I have seen a ton of pictures of old broken Campy cranks. It happens, and as mentioned, was quite a common thing back in the day. Seems the retro grouch post in here pinning for the good old days was grossly un-informed.