Also depends what you want to do with them, you'd have to be an idiot to take part-worn budgets out on track, which the op has said he wants to do. I have just spent £246.something (rather than the £400+ list price) for a full set of pe2s delivered to the door, there are bargains to be had if you're willing to look. So far they've been great, I've only done about 500 miles on them, but they felt unshakeable going up prescott and communicate nicely.
The rolling radius difference between 55 and 50 profiles (ie the amount the speedo is affected by) is a little over 3%, or 2mph at 70, really nothing to worry about from that perspective.
The rolling radius difference between 55 and 50 profiles (ie the amount the speedo is affected by) is a little over 3%, or 2mph at 70, really nothing to worry about from that perspective.