Fixed or Adjustable Auxiliary Idler?

[V8Flexin]

I have a 2.6 metco pulley that I plan to install. I know that a auxiliary idler will give me better belt wrap than just using a 90mm idler. I've seen a few that are adjustable but most are fixed. My question is it better to stick with the fixed one's or get the adjustable one's for even more belt wrap? My only concern with the adjustable one's are possible failure due to slotting of the mounting bracket. I also plan on installing a 15% OD in the future.

 

[einehund]

I've got a 2.59 upper, 10% lower and just put on an evolution adj. aux idler. I would be amazed/dumbfounded if the mounting hardware failed. It is a very robust, HEAVY peice of metal. I imagine all the others are similar. I've had no issues since the install.