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Mudguard bolt thread

StubertStubert Posts: 7
edited April 2010 in Workshop
Hi. I'm trying to fit some sks mudguards to my bike but the M5 bolts supplied are a tad too big. does anyone have any idea what the correct thread might be?
The bike is 1978 Elswick road bike, so I'm wondering if it might be some sort of imperial thread. Any ideas?


  • sungodsungod Posts: 16,070
    sounds like it might be 2BA

    if there's an olde hardware store or decent lbs nearby they should have some bolts to try for fit
    my bike - faster than god's and twice as shiny
  • redveeredvee Posts: 11,922
    2BA is very much alike to M5 but different enough.
    I've added a signature to prove it is still possible.
  • John.TJohn.T Posts: 3,698
    It will not be 2BA. It will be coarser than that. Most British bikes had Imperial threads that were only used on bikes. Somewhere between BSF and Whitworth. Your best bet would be to get the frame tapped out to M5.
  • It will very probably be 2BA. The pitch is the same as M5, it's just the thread OD (4,7mm or so) and the thread form that is different, It will tap out M5 no problem.

    My Mum's 1979 Dawes Kingpin shopper was 2BA.

    It could conceivably be 3/16" BSF - but again, that should tap out to M5 with no problem.
  • StubertStubert Posts: 7
    Hey thanks for all the suggestions. I will try a 2BA, if not i'll just run an M5 tap down there.
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