Tyre options

[Dogtrousers]

One of these maybe ?
https://www.rosebikes.com/tranz-x-five-sided-release-key-114467

Tranz X five sided key for Tranz X skewers
http://www.tranzx.com/product/6quick/060-3.html

 

[vickster]

Take it to a proper bike shop to get the skewer cut

 

[Ajax Bay]

Not a hex, a pent. Skolly pointed out my innumeracy.
Go to a proper bike shop anyway - they are more likely to offer full, informed advice.
Way ahead will depend on whether you want the option of wheel security.
Gotta dash: night ride over the moor starting after dark: Dartmoor Ghost.

 

[Jenkins]

Looks like the same sort of security skewer that Whyte Bikes used to use which needed a special release key .

Key available from Winstanley Bikes: https://winstanleysbikes.co.uk/whyt...MIlPLPmr788QIVEtd3Ch0bhwQTEAYYASABEgIesPD_BwE
Or Whyte Bikes: https://whyte.bike/products/security-key

 

[I like Skol]

The grinder option isn't as drastic as it sounds, but it has to be done with care. I wouldn't necessarily be letting some spotty kid at Halfords do it!

If I was in your position I would be reaching for the grinder. Do it slowly with lots of cooling. You don't want to blister the paint or melt the grease out of the bearings.

 

[vickster]

Looks like the same sort of security skewer that Whyte Bikes used to use which needed a special release key .

View attachment 600797
Key available from Winstanley Bikes: https://winstanleysbikes.co.uk/whyt...MIlPLPmr788QIVEtd3Ch0bhwQTEAYYASABEgIesPD_BwE
Or Whyte Bikes: https://whyte.bike/products/security-key

Find a Whyte dealer who should have the key and ask them to try (Balfes with a number of branches all around Greater London sell Whyte)