blade tip speed ?

Discussion in 'Lawn Mowing' started by lawn storm, Feb 27, 2003.

  1. lawn storm

    lawn storm LawnSite Member
    Posts: 39

    blade tip speed is any where from 15,000 to over 19,000 on most ztr's . even with the same motor.
    can you increase blade tip speed your self ?
     
  2. Phishook

    Phishook LawnSite Bronze Member
    Posts: 1,143

    I'm sure you could.
    Change the pulley size, bump the rpm's up. But I'm no engineer.
    Why would you want to mess with it?
     
  3. lawn storm

    lawn storm LawnSite Member
    Posts: 39

    my great dane cloggs up unless, i cut completly dry grass( no dew)the dbl. blades help but not enough.
    i wouldnt want to mess with the pulleys but i did idle it up more .but it still does it.
     
  4. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    A deck clogging up is usually the result trying to get too much grass through a given designed deck. Increasing BTS can sometimes help but it has been my experience that other factors are involved. Some of those factors are blade depth in the deck, baffling, blade offset and discharge. Most of the problems occur at the left blade, at the verticle point where the rear baffles meet each other and the rear of the discharge opening.
     
  5. Thompson Lawns

    Thompson Lawns LawnSite Member
    from OK
    Posts: 21

    I know this is a little off the subject, but is the tip speed that important as long as its between 17,000 and 18,500? I have noticed that exmark claims one of the highest tip speed is this the reason most think it has clean cut? besides keeping the blades sharp!
     
  6. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    I think that grass blade lift and blade sharpness are as important a part of the equation in achieving a clean cut as BTS. High BTS comes into play as the mower moves faster across the lawn. If you have a mower that goes 5 MPH there will be twice as many chances to cut all of the blades of grass as a mower that is moving at 10 MPH given the same BTS.

    Walker mowers have a relatively slow BTS, in the order or 14 to 16,000 FPM, but you never hear of complaints about the quality of cut. Why? Because they are slow moving mowers. Compared to a Dixie or a Hustler they are turtles. The limiting factor in a Walker mower isn't the deck or the BTS, it's the ability of the GHS to handle the larger volumes of grass that moving faster would generate.
     
  7. John Gamba

    John Gamba LawnSite Fanatic
    from ct
    Posts: 10,812

    Lawnstorm
    Do You have a FRONT FLOW CONTROL BAFFLE In Your deck? If Not Put One In, Just look At Others Like Hustler It's Not Hard That Should Help.
    John.
     
  8. Thompson Lawns

    Thompson Lawns LawnSite Member
    from OK
    Posts: 21

    Richard, Thanks I did not think of it like that.

    larry thompson
     
  9. Doc Pete

    Doc Pete LawnSite Gold Member
    Posts: 3,469

    Not that you can't increase blade speed, but since I'm the experimenting "king":p , you could easily run into changing the "resonance" of the deck and the resulting vibrations will make it impossible to stand being next to the machine, even with hearing protection. The easiest way to "attempt"to fix the problem is add another set of blades and run doubles. The added amount of air volume should keep the deck clean under almost any circumstances.......
    Pete
     
  10. MOW ED

    MOW ED LawnSite Fanatic
    Posts: 5,028

    God and your pocketbook help ya if you do crank it up, throw a blade and injure someone.
    Not sayin it can't happen with the designed speed but that type of incident would be covered most times by insurance as long as negligence isn't involved.
    If that mower is knowingly cranked and an investigation finds that you did it. Well, you are on your own to defend that one.
    Besides that, unless you are a real good engineer I wouldn't even consider it. Like Switchless said, the vibrations could change everything with the deck. The things that worry me are the spindles ability to handle a speed up for. Once that spindle no longer wants to stay, it is leaving at how many feet per minute you cranked it to.
     

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