They're nice bikes and well specced, but there's a few components and the wheelset that are a bit heavy. ANd a few heavy bits makes the bike a bit heavy....
The IO SS weighed in at just over 26lb IIRC. My Inbred with gears, cheapish wheels and coil forks is only 29lb, and my 18 year old Cindercone SS is 22.5lbs, admittedly with vee brakes, but it gives you some idea.
I reckon the worst of the weight is in the wheels. Tyres I've already done, but the spokes are plain gauge and rebuilding the wheels with some DB spokes would save 5oz alone...
But I've got a spare front wheel (Hope XC/Mavic 717) and I'm thinking of rebuilding the rear with a Mavic 717 and DB spokes, which by my calculations will lop 250-300g off the wheelset and take the bike down to around 24.5lb
I'll explain why I'm thinking like this - Mrs PP bought the bike on Bike to Work for us both to use. She rode it standard a few times before I rode it, and I was rather disappointed by how sluggish it was, and I did notice the badly draggy tyres more than anything. So I weighed it, and was even more disappionted. So the weight weenie in me started looking at the bike a bit closely, and the bits I had lying around. Tyres and post saved 1lb and some internetting told me the rims, the PG spokes, and the front hub are a bit weighty: Nothing too bad, but a little bit here and there soon adds up, especially in the wheels..... Which explains the sluggishness.
I rode it for the second time this week and the tyres have made a big difference: It feels quite lively now in comparison. That said, you don't get a much faster rolling tyre than a SB8!
So I'm gonna rebuild the rear wheel with a 717 and fit the front wheel I already have, and see if that helps!