It's a fine line we walk with drive belts. Too tight, just right, or too loose.
Too tight can wear the pulley and belt and also create some unwanted noise.
Just right is somewhat subjective. In the Harley world, and suggested many years ago on this forum, in mid belt being able to twist it 90 degrees is about right. There's also the deflection method, but in the case of the M3W, there really is no reference to the amount of deflection based on a certain pounds/kgs of pressure. I have a couple spring tension devices that will measure the deflection at a certain amount of force. But again, twisting the belt is probably about the closest method of tensioning. AND yes, they do feel very tight even with that method.
Too loose. I know that if they're too loose to a point that they can jump teeth, but that does have to be very loose to do that. But the main problem with running, in some cases too loose, is that if the Polychain lugs are fully seated on the sprocket teeth, there's a straight pull force on the belt and that's good. But when you run too loose, the belt tends to climb the lugs out of the teeth and that creates a mechanical advantage between the two and puts WAY too much force on the length of the belt when the teeth climb with that leverage. Many Harley belts have snapped by running too loose and with the belt climbing out of the sprocket the stretch force on the belt is tremendous.
I know Supermax has lots of experience and knows their product inside and out, but again, running loose is very subjective and borders on letting the belt climb the teeth of the sprocket putting way too much tension force on the belt. Those that have the Supermax sprockets have surely by now developed a technic to get it right as 18000 miles is very nice to say the least.
I'm just throwing this all out there to possibly add just a tid bit more information and help make good choices.
On Harleys, the belt pivot point is forward of the swingarm pivot, so from time to time with loading and unloading of the rear wheel when riding, the belt tension does vary some. But as it appears on the M3W, the centerline of the swingarm and the centerline of the BB is about the same, so once tensioned, the belt tension will not vary much at all during use, regardless of weight load.
Sorry if I'm being redundant in this post, but you all have to be careful and follow proven setup practices from other M3W owners. Experience is worth its weight in gold. Bad experience, don't repeat, Good experience becomes the norm!
I hope you are all staying safe and healthy in these very trying times!
Dan
