Cold brakes

Can someone explain why cold brakes make the tyres lock up when the tyres / brakes are cold...?

Do cold brakes lock easier than warmed brakes?

Also, how much further do braking distances become when racing in the wet?

cold brakes make the tyres lock up
?? With most race set ups, nothing actually happens until you get some heat into them which is the opposite of your statement. All I can imagine is that as there is no initial bite when you first depress the pedal (with cold discs and pads), you apply pressure to the point where the brakes will lock anyway. Nothing to do with the temperature, more to do with the 'feel' from cold brakes.

Also, how much further do braking distances become when racing in the wet?
How long's a piece of string(twice half its length)?

This would depend on many factors; track surface grip, how wet, type of tyres fitted, weight of car etc etc. It may be the same distance heading into a corner simply because your approach speed is less in the wet.

How long's a piece of string(twice half its length)?

In this case.. a piece of wet string :)

?? With most race set ups, nothing actually happens until you get some heat into them which is the opposite of your statement. All I can imagine is that as there is no initial bite when you first depress the pedal (with cold discs and pads), you apply pressure to the point where the brakes will lock anyway. Nothing to do with the temperature, more to do with the 'feel' from cold brakes.
Agree
Different pad compounds can react in different ways, which is where the feel comes in. Some pads are quite acceptable degree of bite when cold, but are hard to modulate.
The "Coefficient of Friction" is the key, when the brakes have more than the tyres, you lock up