Narrowing a track down

[edgeracer1]

ok so i bought a 15x121 cobra track and i want to fit it to my phazer what is the best way to narrow it.

 

[yamahas]

I really like this idea

http://www.ty4stroke.com/viewtopic.php?t=97180

also

http://www.ty4stroke.com/viewtopic.php? ... sc&start=0

 

[Ruckus]

 

[who8that]

Ruckus;s way was the cleanest I have seen.