Need advice on belt size for 2.4 pulley

I searched for the info but couldn't find exactly what I was looking for. I read a thread on here a while back, but I couldn't find it again when I searched.

I have a Posi ported M122 Eaton with 90mm aux idler and stock belt. I installed 2.4 pulley yesterday and now the belt is slipping occasionally. It sounds like a noisy cricket on start up. Any info on the correct belt size? Thanks for any input!

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Would this be the correct belt? Gates K100830HD

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I'm actually thinking of replacing the idler pulley with a 90mm one and use it in conjunction with the 90mm aux idler I already have. Thoughts?

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I did not change my belt when I went with the 2.40" upper on the M-122. No slip. Sorry to hear.

Thanks for the input, ya its strange. Maybe the belt is old /stretched? I don't know, but I purchased the Vmp 90mm idler, so hopefully that helps

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