You may use a blend from the edges to the centre of the arrow.
And you may create a straight arrow and use that as an Artbrush, I presume that is what you are doing.
You may start with the full shape and the colour at the edge, copy it to the front, reduce the thickness proportionately, apply the colour at the centre, and Object>Blend>Make (Smooth, Align to pathin Blend Options).
I have tried the Mesh gradient, but it just mess everything... or i forgot how to use it... either way.
It sounds like the Mess gradient.
Working perfectly but i still have a question :
It seem it is limited to 2 form ( the start and the end ) what if i want to have a third step color ?. let say red to blue while goign through white ? i tryed selecting only the 2 i wanted to blend ( after a first blend with one other form ) but the "make" button stay gray.
I guess it is impossible ?
Nevermind that. my other shape wasnt right. THX !
You are welcome, Chlorale.