jay clock said:
42-622 is the size shown on that site. Must say, for the conditions in the UK, I think having these tyres on would be like having a car with studded tyres on the off chance it might snow. Overkill. Unless you plan to change tyres when you go out for a ride and it is icy, then change back again
It's a case of what's available.
I was originally going to get the Nokian's Joe mentions, but
Chain Reaction are out of stock, while they do have the Continental I linked to above.
I was in Reading at the weekend, I tried two of the local bike shops, and unsurprisingly neither carried spiked tyres.
Hopefully I'll be in Newbury tomorrow, and if possible I'll order some of the Nokians, but I did wonder if the UK distributor (Windwave?) might be out of stock.
As to overkill. When I fell off the roads were empty. Any car on that stretch of road would have been unable to stop, and I'd have been jam. So, given that not cycling isn't really an option for me, I'd rather go for some spiked tyres, whether it's overkill or not.