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**Pulley belt size - demystify - Sheet ready**

**All info and sheet on my last post**

So... I've made a quick search and found out that there is no general consensus in what regards belt sizes for different pulleys, and even for even sized pulleys.

Well, this sure ain't rocket science and I think a quick guide would avoid many mistakes on the time of choosing the correct size for our setup.

We have 3 changeable pulleys that will contribute to the correct final size of the belt:

- Supercharger pulley

- Crank Pulley

- Alternator Pulley

Having the original size of these 3 parts, and the original belt size, it would be a simple exercise.

So, if someone can provide me with these sizes I ask, then it will just be a matter of doing the math.

I will take the values Fisher once provided to calculate the Supercharger speed at a given RPM with different pulleys.

Stock Supercharger pulley size (mm) - 65,5

Stock Crank pulley size (mm) - 134,93

Alternator pulley size (mm) - ?? I will put 100, just for the example.

I will also consider that the original belt has 1350mm

So, with a simple 15% reduction on the supercharger pulley we would have about 9,82mm (65,5 x 0,15) to compensate for… So, the ideal belt size would be 1360mm.

With a 19% reduction on the supercharger pulley we would have about 12,44mm (65,5 x 0,19) to compensate for… So, the ideal belt size would be 1363mm.

Now a more complicated one… with a 17% reduction on the Supercharger, +5% on the Alternator, and + 2% on the Crank, we would have: -11,14mm + 5 mm + 2,7mm = -3,44mm; which results in 1350 + 3,44mm = 1354mm.

We also have to take in account that there are no belts per mm, so we must get the closest match.

Note, these values are (until someone provides me the accurate data) merely indicative.

Thanks in advance,

Citro