When I bought my bike a few years ago I fitted these 'security' wheel clamps: https://www.decathlon.co.uk/p/seat-post-and-wheel-security-bike-clamps/_/R-p-170559

I've now managed to lose the pentagonal key that came with them. Decathlon don't sell the keys separately - they said I'll need to buy a new set, which aggrieves me as it's only the key I need.

There are other companies that make pentagonal keys, for example this: https://winstanleysbikes.co.uk/whyte-security-key.

Does anyone know if they're likely to work, or do different companies use slightly different specifications?

  • 2
    For a one-time use, it may work to use a grinder or even a hand-file to form a bolt head into a workable shape. Then lock up two nuts on the threaded part and use that to turn the pentagon bolt.
    – Criggie
    Apr 27, 2023 at 21:43
  • 4
    Not really any experience but would 100% expect security clamps and key to be sold as a set, maybe I'm expecting too much here, Kind of makes sense when you think about it. How secure is it really if you can run round with a 3rd party key and unlock these?
    – Hursey
    Apr 28, 2023 at 2:37

1 Answer 1


They're sadly uninformative, both in store and on the website.

To provide any decent security they should be different not just to other makes but between packs too - so buying a new set shouldn't even be a way to get a replacement key. However they may be less secure than that, with all sets being the same.

My Pinhead security skewers (I don't know why they call them "clamps" - they're not clamps) and other fittings have many variations for the same model. Replacement keys are available with the number printed on the key or a card you get with the set. That's normal for locks and keys.

They may be someone else's low-security product rebranded, in which case a replacement toolb(it's not much of a key if they're all the same) might be available.

If they're worth having in the first place, you're in the normal position of someone who's lost their keys, which is usually an expensive and destructive error.

On the whole, if you can just buy a replacement set and get away with it, I'd say you've got off pretty lightly. You should inspect the ones in the shop to make sure they're the same as each other, seek assurances from staff that the tool from another pack will work, and ideally try it out there and then at the shop.

  • Agree with all of this - including the illogical naming as 'clamps'. I guess I'll try popping into the store - thanks very much.
    – philipnye
    Apr 28, 2023 at 7:01
  • My guess is that Decathlon is a French chain and "clamp" is translated from French by someone who doesn't know the cycling jargon in English
    – ojs
    Apr 28, 2023 at 7:11
  • @ojs, I thought the same. Translation without checking by a native speaking subject matter expert is poor practice for a big business that can afford to do better. And costs them sales when searches fail
    – Chris H
    Apr 28, 2023 at 9:23
  • 1
    @philipnye I didn't add this to the answer because there's no picture of the head on their website, but there are some clever universal sockets that might help
    – Chris H
    Apr 28, 2023 at 9:26
  • 1
    @philipnye that sounds like a good outcome in the end
    – Chris H
    May 14, 2023 at 15:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.