I put a lonestar Axcaliber rear axle on my 05 450r. I have ITP T-9 Pro Baja rims, maxxis razor mx tires. the total width side wall to side wall is 49 1/2". I want to get the total width in the rear end to 50". My question is how do I get 50" wide on the rear end.

 

Run a circular 1/4" bead of silicone around the outside of each tire at the widest point of the sidewall. You will then have your 50" overall width.

 

You can put 1/4" spacers inside of your rear wheel. Not the safest way to do it, but why would you want exactly 50" anyways? Another 1/2" isn't gonna make any difference.

 

What would an extra 1/4" do? Try a flat washer on each stud.

 

this will work
what is this a new width class for quads

 

That is a good question. Honestly why do you want 50"[img]i/expressions/face-icon-small-confused.gif[/img]