What is an A Section Belt?

With so many different types of belts, what is an A section belt. To clarify, an A section belt is a size of V-belt. What is a V-belt then? V-belts take their name from the somewhat V-shaped cross section of the belt. Whereas a flat belt has a rectangular cross section, V-belts are wider at the top than at the bottom. V-belts do not taper down to a point, only to a flat bottom that is parallel to and narrower than the top. That’s the “somewhat” in how we describe the cross section.

All of our V-belts have a 40 degree angle from the top to the bottom. Since we’re talking about two sides of a triangle and the angle that connects them, as long as we know two of those numbers we can calculate the third.

A Section V-BeltsWait, so what is an A belt then? The width of the belt determines its name or prefix. A section belts are the narrowest of the V-belts. Our A section belts are 1/2” wide at the top and 5/16” high. The next size up is – you guessed it – a B belt.

You might notice that some belts have an “X” in their category name. The X indicates belts that have notches to assist their fit into the grooves of the two components they connect.

The “wedge” shape of V-belts give them an advantage over flat belts in high torque applications. The wedge necessarily increases the thickness of the belt, contributing to higher strength per unit of length but increasing the amount of energy necessary to draw the belt around the rotor or pulley at either end. A common way of increasing the amount of power that a belt drive system can transmit is using two belts in parallel between the same components.

MDS stocks A section belts with outside lengths ranging from under 2 feet to over 15 feet on our online store. If you’re still not sure if you should use an A section belt or a B belt, give us a call before you order. We have everything you need – starting with years of experience – to ensure safe, efficient and cost effective power transmission.

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