How about another £5.. the challenge change the rear tire in 3 minutes... off the bike , new tyre and tube and back on the bike again... well 20 minutes then!
The rear tyre has two rim locks and even Brixham tyres struggled with it, punctured the tube, charge ME for a new one and vowed to never touch this wheel again.
Think it would prove costly in tubes.....
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I have a hacksaw, welder and a grinder, and I'm not afraid to regret using them!