M1151A1 Serpentine belt help

[Cummins50bmg]

I have a 2009 M1151A1 6.5 turbo with AC, I am trying to replace the serpentine belt and I am running into issues. The 112in belt is a bit too long belt tensioner maxes out leaving some play and the 110inch belt is a bit too short. Any help would be much appreciated

 

[DREDnot]

Are all the accessories original?
or did you have to replace something like a missing generator or A/C compressor?
Are you sure of your belt routing?
Make sure smooth pulleys are against the smooth side of the belt and grooved pulleys are against the grooved side. Ive seen them wrong this way a few times believe it or not.
Pics of your setup might help us figure out what might be the problem

 

[Retiredwarhorses]

For the 12 millionth time….the generator pulley dictates the belt size.

 

[Mogman]

For the 12 millionth time….the generator pulley dictates the belt size.

If you would be kind enough to put together a short guide I would be happy to make it a sticky!

 

[Cybul]

I have a 2009 M1151A1 6.5 turbo with AC, I am trying to replace the serpentine belt and I am running into issues. The 112in belt is a bit too long belt tensioner maxes out leaving some play and the 110inch belt is a bit too short. Any help would be much appreciated

How many AMPs do you have? If 400AMP and A/C then this one should be ok: 13013861 / 01-583-7508.
I have 1152A1 with similar config and year and it is ok.