I'm running 30t/68t sprockets and I can't remember how much belt deflection I should have with 30t front sprocket. I know Andrews says with a 30t front the factory belt deflection is to tight and hard on main shaft bearing. I was thinking it was 5/8-3/4 inch, thought maybe someone might know.

 

They make belt tensioner tools to measure the proper flex of the belt or with experience and a little pressure (without standing on it) 1/4" up and a 1/4" down

 

I can't see why a small change of tooth count should make any difference to belt tension! Use the recommended deflection in your service manual. I changed my rear pulley from 61T to 70T and have been doing that for many years.

 

First time I have heard that about using a 30T. Big Money if you have a reference on that instruction to keep the belt looser, I would love to see it - Thanks.