Tyres went on, rode home about 8 miles on icy roads.
Took bike out for a ride to scrub them in, absolutely belted down for the whole trip so rode full-on Jenny Upright!
Next trips were back on the commute in minus 4-8c temps. Definitely took the nobbly bits off the centre line but not much else.
Bit more commuting and I think they're now mostly scrubbed in! Tonight's ride was in torrential rain and not a single wibble so I reckon I can relax now.
Tyre review? Had a few moments at first before I realised that the weird, falling sensation when going round a bend was because they had
a) curved bits instead of flat bits
b) grip!
They are infinitely grippier when on uneven surfaces, like tramline repairs, drain covers, knackered road surfaces etc and grip is maintained strongly when braking, even along wet white lines.
Overall confidence is much higher and will increase now that I've got rid of most of the nobbles (these were seriously hairy tyres when put on!
). Only query is whether they have a bit of extra vibration when riding around 80-85 but that might have been road surface or I just need to amend the pressures. No issue above (on a track of course) or below that speed...
