Low blade tip speed a problem?

Discussion in 'Lawn Mowing' started by brucec32, May 30, 2004.

  1. brucec32

    brucec32 LawnSite Platinum Member
    Posts: 4,403

    I've been operating a Lazer hp with a blade tip speed over 18,000 and love the cut. When I mow with my 32" and 44" toros which I believe have lower speeds I can tell the difference in terms of some stringers and lack of uniformity in cut at times to a minor degree.

    Would a Wright Stander 48" /23hp with a blade tip speed of only 15,576fpm cause problems? (especially if used to mulch with their new mulching baffles). The 48" is the only model available to me at a very good price, unfortunately, or I would pick a 52" or 42".

  2. tiedeman

    tiedeman LawnSite Fanatic
    from earth
    Posts: 8,745

    that is a tough question to call, you seem to have great horse power and ok blade tip speed with it, the only problem is the baffle kit that you have on. I would personally think that the 23hp would be more than enough to supply the power and tip speed that you need for the baffle kit and still leave a good cut
  3. Fareway Lawncare

    Fareway Lawncare LawnSite Silver Member
    from Canada
    Posts: 2,222

    Your Toros Have Almost Identical Blade Tip Speed as the eXmark....The reason the cut Sux on the Toro is the SFS Deck...Horrible Deck...Shallow, baffleless....Antique....
  4. brucec32

    brucec32 LawnSite Platinum Member
    Posts: 4,403

    Actually one of the toros is the old style toro deck (before sfs) and the 32" is the Exmark fixed deck design. Toro's website is such a mess and full of so many innacuracies I can't be sure what the numbers are on that mower. The 44" is w/o baffles and dates from '98, so yeah, I'm looking to make a change for that reason. The 32" won't cut high enough for the grass here. The chart on it says it will cut at 3.5" with the spindle spacers where I need them to mulch, but measuring it's really more like 3.25".
  5. Fareway Lawncare

    Fareway Lawncare LawnSite Silver Member
    from Canada
    Posts: 2,222

    You have the 32" in the Top aXle Position...

    Try using a Solid or Notched Blade w/2 Blade Spacers for a 3.5" Cut...Still a Good Cut Mulching...

    You're Saying your 44" Predates SFS & it's a '98?....Can you post a Pic of that Deck...It Should Be an SFS if it Floats!?
  6. Doc Pete

    Doc Pete LawnSite Gold Member
    Posts: 3,469

    Yes, I hear you.
    I've been experimenting with blades for the last few years. Currently, I've begun experimenting with blade sail. From my testing, I've found that "suction/vacuum" is a much larger factor than deck design.
    I began by welding a sail tab to a old set of blades. Then, after a first "disaster", but much gained input, I bent the tab and have been getting terrific results. More info will follow.
    Also, I've spun low lift blades faster and high lift blades slower, and checked the results. Again, suction power seems to be the biggest factor for a good cut.
    So, at the moment blade speed mainly helps the cut, not from the actual speed of the blade cutting the grass, but from the increase in vacuum/suction.
    At the moment, the blades I’m using seem the cut and vacuum/blow as well as doubles, but the unexpected benefit is the deck is not loading with grass, even “high speed force cutting” damp grass at 2.75”, which uncut was 8”.
    In fact, this Saturday (Morris county, New Jersey) at the end of the day after doing 17 lawns, with still a few “mini clumps”, the deck was as clean as if I had scraped the underneath (most areas) of the deck. Needless to say, if I was using the stock blades, I would have had to clean the mower more than once.
    Wow, that was a real surprise. I’ve got a lot more testing to do, but right now the results are good.
    So far, if we can get the same results from “modified stock blades” as with Megmo’s, and not have the streak problem of the Megmo’s folding under load, I’m sure everyone will benefit.
  7. Fareway Lawncare

    Fareway Lawncare LawnSite Silver Member
    from Canada
    Posts: 2,222

    It's Not Just Blade Lift...If your Deck isn't Properly Baffled or Blades Set Too Low or High in the Cutting Chamber a Blade w/too much Lift will Cause Too Much Disturbance...Solid Foils Create Less Disturbance & Lift than Notched but Leave a Nicer Cut in Normal Growth Conditions...!
  8. brucec32

    brucec32 LawnSite Platinum Member
    Posts: 4,403

    lol, no, I know there are newbies galore here but I have it in the lowest frame hole position. Also I am using 3 spacers above the blade and under the deck for good lift (2 or fewer and the cut is noticeably worse when mulching with more windrowing of mulched clippings) and one above the deck. And all front caster spacers under the caster arm. So it's maxed out. The height of cut chart that is in the manual is, typical for Toro, all wacky and formatted, wrong (example. It looks like 3 1 / 2 ). But the Exmark one I downloaded as well as some Toro info says 4.25" is the max height. Subtract the three 1/4" spindle spacers that I have under the deck, lowering the blade, and it "should" mow at 3.5", so I was wrong earlier. The tires could be pressured up more than they are currently (trying to improve mediocre traction of narrow tires) so it probably does match what it should as per Toro, which would be 3.5". Still, that is on the low side of what I need to mow St. Augustine at this time of year. It shows drought and heat stress more noticeably at 3.5" than at 4". And I'm sure some customers will want it even higher if they have thatch or a really thick healthy lawn that will look good at that height. So the net result is I need to either get taller tires or a new mower. Combined with the low productivity of the belt drive 32" I have decided to just sell it and use a 21" on any small gated areas I can't get with the others.

    The 32" doesn't mulch poorly, just noticeably less clean than my 48" lazer does. It performed acceptably at 2-3" on Bermuda and Fescue back in Atlanta.

    I may also be mistaken about the SFS designation. I thought that referred to the decks with vertical height adjust pins and the bullnose guard welded to the front of the deck for strength. My 44" looks just like the ones I had back in '94 or so. But it does just chop and shoot the stuff out, which in tall grass means long clippings lying on top of the grass. I actually prefer it for mowing tall rough areas, but the clippings in nicer lawns are noticeably less attractive than with the Exmark 48" even disharging.

    The St. Augustine grass here is a very upright "stiff" bladed grass, it doesn't sag and need to be stood up like some grasses. The Bahia, however, is very tough and has tall seedheads at times of the year, so I would assume a faster tip would help cut it better, and extra lift would stand the seedheads back up after the deck front edge passes over.

    My original question just boils down to "how much speed is enough" ?

    Hey Doc Pete, do you ever have traction problems with your SWB's and a bullrider? I had never used a sulky that swings you around with it, and the proslide definitely had too much friction and momentum to overcome with me on it. I'm sure the castering wheels are better, but I can't have a situation where the wheels of the mower lose traction and damage the turf trying to spin me around in turns.
  9. MikeLT1Z28

    MikeLT1Z28 LawnSite Bronze Member
    Posts: 1,732

    you checked your rpms on the other mowers? if the rpms are too low your tip speed will decrease.
  10. Fareway Lawncare

    Fareway Lawncare LawnSite Silver Member
    from Canada
    Posts: 2,222

    The Proline 21" Only Goes to 3 1/4"!

    & Yes the Proline 21" will Be Faster & Less Fatiguing than a Belt 32" in those Tight Areas....But that Briggs Proline is a Brute to Turn & Pull Backwards...try & find a a Suzuki if there's any Left!


Share This Page