To clarify RobMac, an 853 is an On One Inbred single Speed? Is that 26 or 29? Do you notice the weight penalty and what type of riding do you do? I am mostly tarmac and cycle tracks so Alloy frames are not so punishing to me.
Yes its S/S single speed and 26" wheels, it handles like a BMX for grown ups, very direct power delivery, mixed urban assault vehicle, can change direction quicker than your brain can, fitted at the moment with On One's own rigid forks bit harsh and one last thing, the B/B brackets a little low so pedal stick does happen but its got those huge flat poofy peddles on, i'll change to SPD's like all of my other bikes.
I can get a new Inbred 26 for £100 with the finish and size of my choice, I have till the end of this month to commit.
Bloody hell £100, I've been trying to buy a used one for £60, disc brake model, 26" wheel, single speed.
Yes my Coyote has the square rear tubes, not bothered me for the last 18 years though
Try looking up age hardening of aluminium.