[Closed] XT Crank Fail

1st time I've seen that!

not the first time ive seen that

seen it before on oOOOLD xt cranks that had seen a power of miles - foot rub basically wore the front thin - but you could see it clearly - the photos above dont actually look so bad) and cracking initiated in the front judging by the colours of the material i was looking at - the rear of the crank was shiny and fresh broken the front was dull and grey looked like it had been going for a while.

Were you on the Singular?

Doh

Eeek - my xt cranks are the same vintage as those and worn pretty shiny on the fronts too, time for new ones maybe. Glad your ok though could have been nasty if you were flat out halfway down a rocky descent!

schmiken - yes, that was me!

Trying to put a positive spin on it..... I managed to do left footed pedal drills for 4 miles! 🙂

Blimey! I've got two sets of those in regular use 😐

I had an SLX crank snap like that except it was the chainring side that snapped.

Its just a sticker!

eh?

i've had a set of those crack in about the same place too.. put that down to heel rub..

and another set i managed to bend and then rip the pedal clean out of threads on a drop..

I don't buy XT cranks anymore! 🙂

I didn't realise how hollow they were. I just thought there was a little pocket in the middle. Bit nervous about getting rid of my Saints for SLX now. 😐

That wouldn't have happened with flats 😉

That's a bit worrying ....

Its just a sticker!

😆

Might be worth sending those pics to Shimano to advise them and see what they say. Cranks are safety critical kit, they need to know if they're failing.

If you look closely at the pics the out face of the arm looks to be alh the thickness of the inner. Thats a lot of heel rub!
I doubt that you can afford to lose that much material without component failure!

extraordinary spelling of half bigyinn...

Bigyinn ain't wrong:

[img] [/img]

[url= http://www.flickr.com/people/33251520@N07/ ]eddkh[/url]

[url= http://singletrackworld.com/forum/topic/have-you-ever-wondered-what-a-shimano-hollowtech-crank-looks-like-cut-in-half ]original thread[/url]

I've had some deore cranks break exactly like that, a long way from home.

It would be interesting to cut them into a section like zippy's image to see if it is local wear. If you don't have tools I'd be happy to give it a go. Left hand one might be in a similar state.

Enjoying the concern here, stuff breaks, if in 2013 you're hearing about failures of what is I think a 2009 model (?) then it's doing alright. Seen a couple of SLX do the same but then I think some people try to get SLX to do more than its paygrade.

I cut one of those, an XT M760, in half once (obviously mine is a non-drive side). This is what it looked like:
[url= http://farm9.staticflickr.com/8395/8610646958_dc1056cb74_z.jp g" target="_blank">http://farm9.staticflickr.com/8395/8610646958_dc1056cb74_z.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/33251520@N07/8610646958/ ]Shimano XT Hollowtech II Crank[/url] by [url= http://www.flickr.com/people/33251520@N07/ ]eddkh[/url], on Flickr

Apologies for the spelling of "half", I normally pick that sort of things up. Too much beer sat night!
z1ppy's pic confirms what I thought.
Not a warranty issue thats for sure!

that is a lot of missing metal compared with the 2nd pics.

do your shows have a nice metallic sheen to them?

yeah Edd's pic shows equivalent thickness on the inner and outer sides of the arms, Jo's pic shows a lot less on the outside!

(as a compulsive heel-rubber, I'm off to look in the shed ...)

Agreed, a lot of metal has worn away. The thing is, it isn't something you expect....even after years of pedalling!

Ideally, some form of wear indicator would be a good idea but I have no idea how you would do it.

I'm not sure Shimano would be interested, as mentioned previously, they are hardly new. I'd just have preferred it if they had gone nearer the end of the lap! 🙂

maybe some helicopter tape on the new ones!

Interesting.

Ms S is a serial heel rubber and has some, ooohh, 7 year old XT on her Rock Lobster.

Ooops.
Is there anyway to judge effective lifespan?
How worn is too worn?

Northwind - Member

Enjoying the concern here, stuff breaks, if in 2013 you're hearing about failures of what is I think a 2009 model (?) then it's doing alright.

You think 4 years is an acceptable life span?
Wow. I would expect them to last pretty much indefinitely unless severely damaged or heel rubbed to hell.

Seen a couple of SLX do the same but then I think some people try to get SLX to do more than its paygrade.

Not trying to be funny, just interested.

Shimano will still replace recalled cranks from the mid 1990's id contact them.

It's more about amount of use rather than lifespan. I accept I'm a heel rubber, I don't think there's anything Shimano can do about that short of making 5kg solid cranks.

A wear indicator would be handy but I suspect ain't gonna happen, so I guess the rule is if in doubt then get rid. The potential costs and consequences of a failure far outweigh the cost of replacement.

Rusty Spanner - Member

Jumping/downhilling you mean?

Yup. Tons of SLXs on dh bikes- I got on fine with mine but then I weigh as much as a child.

Bear in mind here we're not talking about a "4 year lifespan", we're just talking about a couple of items failing after 4 years, on a popular line. What's the mean time to failure going to look like? Not 4 years, that's for sure.

Maybe use some calipers to measure a new pair and then get rid after a certain (how much???) has worn off?

3dvgirl - Member

Shimano will still replace recalled cranks from the mid 1990's id contact them.

mattjg - Member
...I don't think there's anything Shimano can do about that short of making 5kg solid cranks.

deore cranks are solid (although the back of the arms are scalloped), and weigh a whopping 100g or so more than xt.

Measure from new and check occasionally seems very sensible.

Thankfully I'm not a heel rubber, but if I was I'd add cranks to the list of items that get replaced periodically to avoid a crash or injury in the event of age/use related failure, such as handlebars and helmets.

Im happy to be corrected on this point, but im not aware of any recalls on Hollowtech cranks

Found my old deore ones.

[url= http://farm1.staticflickr.com/207/441827584_040601efdf_z.jp g" target="_blank">http://farm1.staticflickr.com/207/441827584_040601efdf_z.jp g"/> ?zz=1[/img][/url]
[url= http://www.flickr.com/photos/53067724@N00/441827584/ ]snapped-deore2[/url] by [url= http://www.flickr.com/people/53067724@N00/ ]Jon Wyatt[/url], on Flickr

Now *that's* worn out. 😉

^^ !!

Wow! There's a fair bit more metal than that on mine!

samuri, were you making a prison shank?

Interesting, I've got the same old XT's fitted to my DH Bike, with a bit of heel rub, not sure how I'd gauge the level of wear without taking a hacksaw to them.

Just goes to show though everyone blathered on about needing steel pedal thread inserts to make cranks sufficiently "tough" only for them to be eroded over time by riders socks...
Probably not the predicted failure mode when they were designed...

I think I might start looking a Heli-tape for my next pair...

Wow. I think a couple of wraps of duct tape round my cransk might be in order. MAybe even a cable tie.

To be fair, all cranks are made for nancies as far as I'm concerned. None of them can withstand samuri-power.

[url= http://farm1.staticflickr.com/39/90157869_58ca47bd49_z.jp g" target="_blank">http://farm1.staticflickr.com/39/90157869_58ca47bd49_z.jp g"/> ?zz=1[/img][/url]
[url= http://www.flickr.com/photos/53067724@N00/90157869/ ]Snapped Crank[/url] by [url= http://www.flickr.com/people/53067724@N00/ ]Jon Wyatt[/url], on Flickr

[url= http://farm1.staticflickr.com/52/132536392_0b677a845f_z.jp g" target="_blank">http://farm1.staticflickr.com/52/132536392_0b677a845f_z.jp g"/> ?zz=1[/img][/url]
[url= http://www.flickr.com/photos/53067724@N00/132536392/ ]P1010498[/url] by [url= http://www.flickr.com/people/53067724@N00/ ]Jon Wyatt[/url], on Flickr

[url= http://farm6.staticflickr.com/5213/5454600810_8dc31cd2d8_z.jp g" target="_blank">http://farm6.staticflickr.com/5213/5454600810_8dc31cd2d8_z.jp g"/> [/img][/url]
[url= http://www.flickr.com/photos/53067724@N00/5454600810/ ]crack[/url] by [url= http://www.flickr.com/people/53067724@N00/ ]Jon Wyatt[/url], on Flickr

*biffer alert*

😉

I've got a set of those XTs that I've just replaced, but they've gone on a spare bike that will only see light use - they've got plenty of heel rub on them - maybe I'll do the 'tap' test to see how thin they are...

Samuri wins for most wear-like a Rizla!

I have the same model XTs as the OP, they're from about '06 are'nt they?
Mine were on my mtb, then last couple of years on the commuter. Massively polished up both sides (i only ride flat pedals).

I wonder how long they will last. Now i know what they 'should' be like, i wonder if they will sound thinner if i tapped them?