Thread gone on Cannondale Hollowgram Si Road Crank Spider

olly49267
olly49267 Posts: 12
edited August 2019 in Workshop
I was replacing the chainrings on my Cannondale Hollowgram Si Road Crank Spider, ie one of these:

https://www.tredz.co.uk/.Cannondale-Spi ... 217408.htm

Putting the big chainring on, one of the threads had gone and the bolt just keeps turning with no grip. Do I need to replace the whole spider (expensive) or am I missing something, ie is there supposed to be a nut or something?

Also, is it safe to just carry on with one slightly unseated bolt?

Thanks.

Comments

  • Matthewfalle
    Matthewfalle Posts: 17,380
    can you just not re-tap/helicoil?

    #thread
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • Alejandrosdog
    Alejandrosdog Posts: 1,975
    Matthewfalle wrote:
    can you just not re-tap/helicoil?

    #thread

    There isnt much material there

    I'd be tempted to buy another one. you need a special tool to get the spider off the crank though
  • gezebo
    gezebo Posts: 364
    If the bolt is spinning then retapping would be unlikely to work and as you’ve said there is very little material there meaning a helicoil wouldn’t really be the answer either.

    Riding with 3 bolts will work for a short time but the chainring will soon deform.

    Sounds like a new spider is needed. How much is the tool? Cannondalespares.com may have one unless you can make your own?
  • dgunthor
    dgunthor Posts: 644
    can you just use a normal chain ring bolt? might need to drill the existing threaded hole out to a slightly larger diameter

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