Chicken strips

[Fazerider]

As Ghostbiker says, the tyre profile has a lot of effect. The tread pattern may continue further round the tyre depending on style and manufacturer so chicken strips can't be taken as an accurate measure of lean angle unless you use a protractor.
Centre of gravity is another factor. Because the tyre has significant width, the further you lean over the further away from the centreline the contact patch is (obviously), but the effective lean angle is the line through the C of G to the contact patch... so the lower the centre of gravity the lower the cornering G force is for a given angle of lean as measured on the tyre. So lightweight riders will actually be leaning the bike over slightly further to corner at the same speed as a heavy rider.
Hopefully this crude drawing (exaggerated for clarity) may explain it better.





Of course, hanging off (or moving their body the wrong way as I witness quite often) will have a larger effect.


I just took a stroll round the bikes parked at work and of the twenty proper bikes (I ignored the learners and scooters) one had no chicken strips, one had none on the right yet a whole inch of unused rubber on the left (presumably a roundabout specialist) and the other 18 had strips of an inch or more on both sides.