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Smaller pulley on Grasshopper vac?

Discussion in 'Lawn Mowing' started by J.T.M., Sep 28, 2007.

  1. J.T.M.

    J.T.M. LawnSite Member
    Posts: 31

    I put a smaller pulley on the impeller shaft of my vac system and it increased the suction tremendously. But the belt and pulleys seem to be getting pretty hot. Every thing seems to be lined up o.k. so could it just be the increase in speed? If anyone has ever done this your feedback would be appreciated. Thanks, J.T.M.
  2. JimQ

    JimQ LawnSite Bronze Member
    Posts: 1,139

    Two thoughts.

    The blower is consuming more power because of the increased RPM. Your belt is now carrying more load.

    It is also forced to flex around a smaller diameter sheave. This also generates heat.
  3. razor1

    razor1 LawnSite Bronze Member
    Posts: 1,985

    What made you think of changing the pulley and how much smaller? Is there a spring loaded tension pulley to keep the belt tight? I'm asking because I may be altering my vac too.
  4. J.T.M.

    J.T.M. LawnSite Member
    Posts: 31

    razor1, I was never satisfied with the power and the fact that it clogged all the time. I read on this site that some people switch to a smaller pulley for clean ups, so i'm givin it a try. The pulley I used is 2-3 sizes smaller than the original. I had to get a smaller belt and I also changed the drive pulley ( kept that the same size) because I couldn't find A belt or pulley with the same channle size as the original.
  5. jpiwowar

    jpiwowar LawnSite Member
    Posts: 43

    The reason everything is getting hot is this: The vac housing has 2 sealed bearings in a cast iron spindle. Notice how the deck spindles are aluminum? Aluminum will dissipate the heat better. That vac housing is designed to spin at a certain RPM. When you increase that RPM, you are putting adding more friction to a bearings and a spindle that it was not intended to take. A product of friction is heat. I'm curious as to what blades you are using with your collection system prior to changing your pulley that were leaving material on the grass.

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