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View Full Version : Crank blowout


stephenmarklay
09-06-2010, 08:08 AM
Over the last few rides I notice my cleat felt a bit loose. I increased the tension on my pedals and torqued down the cleat on the shoe but nothing.

I was riding my rollers on Saturday and finally I figured it out :crap:

This may have been a result of a crash early in the season. I guess it is about time to upgrade the bike.

Chris
09-06-2010, 09:08 AM
mmm...carbon

skijoring
09-06-2010, 09:15 AM
Alloy cranks break also... but FSA hasn't the best record with cranks and their inserts.

Seott-e
09-06-2010, 12:29 PM
Alloy cranks break also... but FSA hasn't the best record with cranks and their inserts.


I 2nd that, I have a set of FSA Carbon mtb cranks that I had insert problems with. As a matter of fact, I putting my replacement set on right now !

jhcakilmer
09-06-2010, 01:02 PM
Alloy cranks break also... but FSA hasn't the best record with cranks and their inserts.

Really, show me. The only alloy cranks that I've seen failures with resulted from a crash, or 15 + years of use. Those carbon cranks are how old?

You need to compare apples to apples......alloy cranksets have a much better track record than do carbon. I can find you dozens of photos of failed carbon cranksets, but not many alloys.

rice rocket
09-06-2010, 01:11 PM
Alloy cranks break also... but FSA hasn't the best record with cranks and their inserts.

FSA hasn't had the best record with much.

bfd
09-06-2010, 01:13 PM
Really, show me. The only alloy cranks that I've seen failures with resulted from a crash, or 15 + years of use. Those carbon cranks are how old?

You need to compare apples to apples......alloy cranksets have a much better track record than do carbon. I can find you dozens of photos of failed carbon cranksets, but not many alloys.

You must be young?! Alloy cranks have been breaking for years - prime example, old Campy Super Record. Here's a list of many types of broken ALLOY cranks:

http://pardo.net/bike/pic/fail-001/000.html#Crank

Good Luck!

MattTuck
09-06-2010, 01:23 PM
stephen,

lay off the gym this off season, ok? Your strength has clearly exceeded the bounds of human engineering ;)



Seriously, glad you were indoors and not sprinting up a hill. Could have been a lot worse... as in, serious bodily injury instead of just serious bike injury.

AndrewS
09-06-2010, 01:40 PM
You must be young?! Alloy cranks have been breaking for years - prime example, old Campy Super Record. Here's a list of many types of broken ALLOY cranks:

http://pardo.net/bike/pic/fail-001/000.html#Crank

Good Luck!
You know, I just looked through that list. While 1970s failures and exotics are very common, 1980s and later Shimano, Sugino (Suntour) and Campy are pretty under-represented. Despite their popularity amongst racers, not a single Ultegra or 105 crank is shown. I've spent a lot of time in shops, and have seen more cracked frames than cranks - in fact, I can't remember ever seeing a nice alloy crank broken.

csm
09-06-2010, 01:46 PM
I think it's safe to say that alloy cranks are used much more than carbon cranks and still the number of alloy cranks that have failed is easily exceeded by the number of carbon cranks that fail.

dvs cycles
09-06-2010, 01:57 PM
My friend just had the pedal inserts on bothe sides of his FSA cranks start to wiggle before a ride and decided to quit before having what happened in the picture happen out on the road.

skijoring
09-06-2010, 02:00 PM
Really, show me. The only alloy cranks that I've seen failures with resulted from a crash, or 15 + years of use. Those carbon cranks are how old?

You need to compare apples to apples......alloy cranksets have a much better track record than do carbon. I can find you dozens of photos of failed carbon cranksets, but not many alloys.


Over on V-salon someone posted a new-ish set of TA cranks with a crack right above the pedal hole. 18,000 KM on 'em. That is a low number for an alloy crank. Like the pardo pictures, there are quite a few older alloy cranks that had sub par design features and forgings, and we all hope the manufacturers learned from those lessons - certainly Shimano does their homework.

godfrey1112000
09-06-2010, 02:37 PM
FSA hasn't had the best record with much.

their customer service leaves much to be desired, I had a crank, that would not tighten on crank arms, they would be loose after 200 miles, just 3 years into the deal, when I had the lbs contact them, the response was "tough luck", funny never heard of a DA or Campy problem like this,
oh by the way I love my DA 7900

would not buy FSA ever again

Peter P.
09-06-2010, 09:15 PM
Stephen,

I'd shy away from carbon cranks, regardless of all the positive feedback you read about them.

Cranks are easily scuffed up and scratched at the pedal end, and carbon doesn't like that one bit. Not saying that's what happened in your situation, but that carbon cranks don't like it, but the WILL see it.

If you upgrade, I suggest an alloy crank. Sure, they can crack, but the reliability factor is much greater.

konstantkarma
09-06-2010, 09:26 PM
Speaking of alloy crank failures, does anyone remember the Ritchey WCS compact failures a few years ago? Although Ritchey replaced and staged a recall.

AndrewS
09-06-2010, 09:42 PM
The some of the mid run of certain Ritchey cranks were too thin in one dimension on the left crank arm. I had two replaced without incident. The replacements were just the correct spec again.

I love my Ritcheys.

bfd
09-06-2010, 09:54 PM
You know, I just looked through that list. While 1970s failures and exotics are very common, 1980s and later Shimano, Sugino (Suntour) and Campy are pretty under-represented. Despite their popularity amongst racers, not a single Ultegra or 105 crank is shown. I've spent a lot of time in shops, and have seen more cracked frames than cranks - in fact, I can't remember ever seeing a nice alloy crank broken.

I think you need to look closer at pardo's site again as Shimano is not immune from failure:

Dura Ace 9 crank:
http://pardo.net/bike/pic/fail-001/FAIL-010.html

Shimano 105:
http://www.pardo.net/bike/pic/fail-001/FAIL-029.html

Good Luck!

bfd
09-06-2010, 09:57 PM
Speaking of alloy crank failures, does anyone remember the Ritchey WCS compact failures a few years ago? Although Ritchey replaced and staged a recall.

Here's a photo of a broken Ritchey crank:

http://pardo.net/bike/pic/fail-001/FAIL-051.html

Good Luck!

ahumblecycler
09-06-2010, 10:26 PM
I like how the OP is using a broken/failed crank as an excuse to upgrade the bike ... sounds like a good reason to me :D

I'm glad you are okay. Any material can be questionable after a crash or some type of impact.

Charles M
09-06-2010, 11:19 PM
I like how the OP is using a broken/failed crank as an excuse to upgrade the bike ...


Grst thing that popped into my head... :D


As for the metal is perfect bull*****, yeah it had to get said.


Minds and roads are never wide enough...

AndrewS
09-06-2010, 11:34 PM
"Underrepresented" is different than "immune". I didn't see the 105 listing, but did see the Dura Ace. Either way, underrepresented. There was a period when nearly every crank was Shimano. Yet no Deore, Ultegra, etc, and only 1 each for the racers' darling and the ubiquitous 105.

It would seem that your claim that aluminum cranks are no better than carbon is based largely on periods when manufacturers attempted to make weights really low - like the drillium '70s and all the pre-carbon ultralight stuff from custom houses in the '90s. It's hardly compelling.

Good luck!I think you need to look closer at pardo's site again as Shimano is not immune from failure:

Dura Ace 9 crank:
http://pardo.net/bike/pic/fail-001/FAIL-010.html

Shimano 105:
http://www.pardo.net/bike/pic/fail-001/FAIL-029.html

Good Luck!