I see these advertised, what is the benefit of fitting these?
Would an extra 3 or 5 degrees rake make much difference?
Scouser

 

5 degree trees...

 

Looks. Reduced cornering. more stable in a straight line.

 

the 3 and 5 degree trees i think look good, but the bigger stuff like the 12 and 18 have never looked right in person to me.

as far as performance, just like the above said

 

On what bike? If you add 2 or more degrees you need longer fork tubes to maintain same height. All depends on what you are trying to accomplish.