I've got some mud guards that I'd like to fit, but I don't have the tiny bolt that attaches the struts to the bike frame. Can anyone tell me the size and where to buy them in the UK? Halfords, Screwfix, B&Q, Wickes etc are all local, or I can order online - just don't know what to order!

Bolt holes


  • 2
    They should be standard M5 screws available at any hardware store
    – Paul H
    Commented Apr 15, 2023 at 0:53
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    @PaulH that's totally a valid answer - could you please copy-paste to the answer box instead of a comment ?
    – Criggie
    Commented Apr 15, 2023 at 1:33
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    Suggest making the question more of what to order than “where do I buy these in the UK” that can make the question and answers non-subjective and keep it from being closed.
    – Ted Hohl
    Commented Apr 15, 2023 at 4:07

1 Answer 1


They're just standard M5, often button head.

You really want stainless steel, and the choice of stainless fasteners in many UK hardware shops is poor. Unless you've got a local independent shop you may struggle to get the right length* despite having a few mm to play with.

I buy mine on ebay, always getting a few more than I need. Buying less than 10 at a time is expensive because you're paying postage (usually included in the price).

* Yes, you can cut them, but if they're going into aluminium you need to do a clean job to avoid damaging the mating thread. If you're buying, buy the right length to start with.

  • That raises a question: do you have a recommendation on what length the OP should buy?
    – Weiwen Ng
    Commented Apr 15, 2023 at 14:47
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    @WeiwenNg those black plastic fittings (if the picture is of the right mudguards) vary a bit in thickness. 12mm might not give quite enough engagement to be secure and you might want 14mm or even 16mm. OTOH if it's just bent wire stays, even 12mm can stick out inside which can interfere with the chain. Having fitted mudguards and a bunch of other accessories recently, I bought a bag of 10mm and a bag of 12mm; I already had 8mm and 16mm. Every so often I consider buying in bulk, repacking into a selection of lengths, and selling, but there's not really much profit margin
    – Chris H
    Commented Apr 16, 2023 at 8:06
  • OK. so, just a grab bag of probably 10mm, 12mm, and 16mm bolts?
    – Weiwen Ng
    Commented Apr 16, 2023 at 15:41
  • @WeiwenNg I would. I've got multiple bikes to maintain and find myself helping others, so I like being well equipped
    – Chris H
    Commented Apr 16, 2023 at 18:49

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