Have you ever wondered what a Shimano Hollowtech crank looks like cut in half?

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  • Have you ever wondered what a Shimano Hollowtech crank looks like cut in half?
  • Interesting.
    I want to know how they make them now.

    DrP
    Member

    Interesting.
    I want to know how they make them now.

    They get Edd to post them to them, and sugru them together. Et voila…!

    DrP

    oldnick
    Member

    Looks like a tube that’s been squashed flat, and if you look at the tip of the pedal end there’s a line in the metal that could be the join*

    * Looking at my cranks, not the photo

    Premier Icon woody2000
    Subscriber

    Was it knackered? I’ve been after a 170mm NDS XT crank arm for a while 🙁

    Premier Icon edd
    Subscriber

    MidlandTrailquestsGraham – Member
    Interesting.
    I want to know how they make them now.

    I think that oldnick has it. I believe that they are cold forged in a multi stage process from an aluminium tube. Then machined to produce the splines, pedal threads etc.

    woody2000 – I had stuffed the pedal threads and, rather than using a HeliCoil, I replaced it with this: (Granted it looks a bit weird with one side XT and the other SLX but it works.)
    http://www.chainreactioncycles.com/Models.aspx?ModelID=41814

    bencooper
    Member

    Some of them are tubes forged around a core that’s then removed and the end squished flat. Others are hydroformed and have a little hole somewhere to let water out. From my memory of some cutaway ones Shimano had on a stand at a show…

    stumpy01
    Member

    Nice. I’d be tempted to sand that down to s smooth finish & hang it in the garage. Might take a while though…!

    How ‘flat’ is the cut or is it wibbly wobbly?!

    I might be interested in it, if no one else wants it?!

    Premier Icon cookeaa
    Subscriber

    I reckon it’s worth polishing up the cut faces and getting some close up shots, I want to see the grain structure and if there’s any indication of how the material behaved when formed in different areas, it’s a pretty complex form for forging .

    I’ve got a pair of 170mm hones with a frigged Driveside pedal thread I think, I was also going ot look at helicoiling that, but now I’m tempted to cut up the driveside arm for a look… Hmmm.

    Anyone want the Non-drive arm if I do chop it up?

    Premier Icon edd
    Subscriber

    Over the weekend, to satisfy my curiosity, I cut a Shimano Hollowtech crank in half. This is what it looks like (please excuse my lack of skill with a hacksaw):

    Shimano XT Hollowtech II Crank by eddkh, on Flickr

    For reference it is a Shimano Deore XT M760 non-drive side crank, 170mm long. If anyone desperately wants it I could send it for the cost of postage.

    beefheart
    Member

    Do you have any XTRs you can cut in half?

    I’d like to see how they differ.

    Premier Icon househusband
    Subscriber

    Could be that its inflated in a semi-solid state – in the same way that some turbine blades are made?

    Premier Icon edd
    Subscriber

    stumpy01 – Member

    How ‘flat’ is the cut or is it wibbly wobbly?!

    I cut from each end so where I “met” in the middle isn’t that pretty.

    cookeaa – Member
    I reckon it’s worth polishing up the cut faces and getting some close up shots, I want to see the grain structure and if there’s any indication of how the material behaved when formed in different areas, it’s a pretty complex form for forging.

    You’re welcome to have a go (and I would be very interested to see the results) but I’ll leave it for someone else to do.

    beefheart – Member
    Do you have any XTRs you can cut in half?

    I’m not made of money. 😉

    perthmtb
    Member

    In a similar vein, I took apart an old brake caliper the other day to see what was inside. I was quite surprised how little there was to it…

    twohats
    Member

    Was it knackered? I’ve been after a 170mm
    NDS XT crank arm for a while

    Think I may have one knocking about!

    Premier Icon aracer
    Subscriber

    IIRC some of the Hollowtech cranks were made by welding a plate onto the back of the forging – though I understand they’ve used a variety of different methods.

    Premier Icon woody2000
    Subscriber

    @twohats – if you have one, drop me an email. It’s this generation (760) I’m after 🙂

    teasel
    Member

    Perthmtb – which areas did you actually cut on that caliper ?

    perthmtb
    Member

    Nothing cut, its a two piece caliper, just dis-assembled. In fact its back together now as a spare.

    ndthornton
    Member

    The caliper is just bolted together isnt it?

    So you were expecting more from XTR – More branding and more money is all you get

    ndthornton
    Member

    Anyone want the Non-drive arm if I do chop it up?

    Can I have the outside half – Mine is all scuffed

    perthmtb
    Member

    Actually its an SLX, the XTR caliper is a single piece.

    ndthornton
    Member

    Wow even less bits!!

    teasel
    Member

    its a two piece caliper

    I thought as much when I inspected my XT, though I suspected they’d use some sort of ‘weld’ to stop folk having a prod about.

    Thanks for clarifying…

    twohats
    Member

    @woody2000, aye that’s what I’ve got, need to double check when I get home later.

    perthmtb
    Member

    I thought as much when I inspected my XT, though I suspected they’d use some sort of ‘weld’ to stop folk having a prod about.

    Thanks for clarifying…

    If your XT is the M785 then the caliper is identical to the SLX above (except painted a different colour and with those magic letters ‘XT’). There’s nothing other than two bolts holding the two halves together. The long bolt in the picture goes through the top hole (in the top picture), and the banjo bolt which attaches the hose to the caliper goes through the bottom one. The banjo bolt has the ‘O’ ring pictured to seal the two halves (note the recess for it), but the top one doesn’t even need that as there’s no oil around it.

    Very simple to take apart, just make sure you force the pistons out as far as you can while its still attached to the lever, as they’re a bu@@er to get out otherwise (learnt the hard way 😳 ) Re-assembly is even easier, but needs a good bleed to get air out of the small oil passages drilled through the caliper body (see bottom picture – the passage on the left goes to the bleed nipple, and the one on the right to the banjo bolt).

    teasel
    Member

    Thanks, man. Good shout on the piston, too.

    brakes
    Member

    wowsers! so that’s why they call it Hollowtech 😉

    andrewh
    Member

    ndthornton – Member
    Wow even less bits!!

    Posted 18 minutes ago # Report-Post
    FEWER!

    Could have saved you the trouble:

    Legs of iron, me.

Viewing 29 posts - 1 through 29 (of 29 total)

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