[SONiC MOjO]

I have a Mag2650 and a 9.1 lower pulley.
Can someone please help with a belt length or
A chart of some sort.

I’ve contacted Magnuson and they’re unable to help.

[laynlo15]

What is your upper pulley? What belt was sent with the kit?

[SONiC MOjO]

Originally Posted by laynlo15

What is your upper pulley? What belt was sent with the kit?

It’s just the stock upper, 90mm
Belt is for a stock lower pulley. . .

[toohighpsi]

Longest that Magnuson will have is a 80865 (80 is 8 rib, 865 is 86.5" length) you'll need longer than that (as you know).

You'll have to make an estimate of length and hit up your local auto parts store. Quick back of envelope calcs show the stock lower has a circumference of 25.1", your 9.1" lower has a circumference of 28.6". Since the belt wraps around about 2/3 of the lower you my guess that you need a belt that is about 2.3" longer.

Check the belt that Magnuson sent you, and add 2.3" to the last 3 numbers - so if you have a 80865 you need an 80888 - plus or minus about .5 (the last number). There is also a good chance you won't be able to get an 8 rib from your store, so just go with a 7rib (70888) or even 6 rib (60888) to make sure you end up with the right size. Once you dial in exactly right length (tensioner at nearly full tight with new belt) then you can go online and order the correct length 8 rib belt.

I normally buy a few belts around the correct length when I visit the store, then return the once that were incorrect later to save trips back a fourth.

Mike

[SONiC MOjO]

Originally Posted by toohighpsi

Longest that Magnuson will have is a 80865 (80 is 8 rib, 865 is 86.5" length) you'll need longer than that (as you know).

You'll have to make an estimate of length and hit up your local auto parts store. Quick back of envelope calcs show the stock lower has a circumference of 25.1", your 9.1" lower has a circumference of 28.6". Since the belt wraps around about 2/3 of the lower you my guess that you need a belt that is about 2.3" longer.

Check the belt that Magnuson sent you, and add 2.3" to the last 3 numbers - so if you have a 80865 you need an 80888 - plus or minus about .5 (the last number). There is also a good chance you won't be able to get an 8 rib from your store, so just go with a 7rib (70888) or even 6 rib (60888) to make sure you end up with the right size. Once you dial in exactly right length (tensioner at nearly full tight with new belt) then you can go online and order the correct length 8 rib belt.

I normally buy a few belts around the correct length when I visit the store, then return the once that were incorrect later to save trips back a fourth.

Mike

Perfect, Thank you

[laynlo15]

Thanks Mike I was just about to chime in and you got it taken care of.

[laynlo15]

I bought mine from Napa, they have their own line that is made by Gates and you want to use the FLeet Green belts.