Crankarm bolt cover bolt size? Fitting ?? Torque Settings ???

bilabonic
bilabonic Posts: 299
edited May 2019 in Workshop
Hi All

Looking to fit an blue alloy crank arm bolt but unsure what thread it is ? M20 or smaller??

I have also always wondered that the thread size obviously changes depending on the torque setting of the arm.

I currently have Dura Ace 7900 with nothing in 'hole' in the arm?

What is the purpose of the bolt?

Do i tighten arm first then fit bolt? Or loosely tighten until bolts fits, the fully tighten/torque??

Also is there a chart anywhere for torque settings for such things as i can not find one and my Giant is all Carbon and i'm afraid of over tightening (had it secondhand)..Eg bars, seat post etc...

I was looking at get one of these -

https://www.ebay.co.uk/itm/Anodized-Arm ... e7q8_U96tg

Why is it needed, why have i not got one??

Thanks
Specialized Epic FSR Carbon Comp

Comments

  • sungod
    sungod Posts: 16,532
    https://media.canyon.com/download/manua ... 950_EN.pdf

    i'd guess it's there to make sure the crank arm is pressed fully onto the spindle before tightening

    presumably yours has been lost
    my bike - faster than god's and twice as shiny
  • crankycrank
    crankycrank Posts: 1,830
    Same as your threadless headset cap. Tighten the large nut to get the right tension on the crankarm spindle so that there is no play but not too tight to bind the bearing. Tighten the clamp bolts on the crankarm and you're done. Do a search for the Dura Ace manual and read the procedure if you like. Very simple to adjust properly and with the correct tool, (Shimano makes an inexpensive plastic one that is all you need), and finger tight.
  • svetty
    svetty Posts: 1,904
    Remember to clean the thread in the spindle properly before fitting the pre-load bolt.
    FFS! Harden up and grow a pair :D