Blade Belts breaking!!

Discussion in 'Lawn Mowing' started by kevinsky, Jul 11, 2005.

  1. kevinsky

    kevinsky LawnSite Member
    from Nevada
    Messages: 75

    On all three of my Scag Walk behinds I am constantly replacing blade belts @ 40-60 Hrs. My dealer tells me I am the only guy he knows with this problem. The belts crack through from the inside and finally break through the outside. Any thoughts?
  2. Runner

    Runner LawnSite Fanatic
    Messages: 13,497

    How many have you gone through? Where are you getting them? Your dealer? I think I would be trying a different source. Also, I would think a practicle explanation would be the pulley allignment, but it is highly unlikely on two machines. Adjustment may be another. If they are a bit loose, this causes heat whick then weakens the fiber and ultimately causes premature failure.
  3. launboy

    launboy LawnSite Senior Member
    from indiana
    Messages: 273

    i know what you mean, last year on my 36'' scag i went through 2 blade belts in 5 months. thats crazy, i've operated scag my whole mowing career and never went through belts like that. this year i haven't busted not a one. i checked the spindles and pulleys for maybe some jagged edges or something, but nothing. the only thing different that i did was not tighten the belt as much.
  4. burns60

    burns60 LawnSite Senior Member
    Messages: 291

    Don't know about the Scag (except that they are a fine product), but around here if you are consistantly breaking belts you are probably cutting grass that is very tall or wet. I would think this would be the case with any mower. In other words you are overworking the belt, and this would cause wear from the inside and breakage.

    Sounds like since you are having the same problem with both mowers you don't have a mechanical problem, but that it would be from the grass.

    Like to hear what you find out. Are you having to cut exceptionally tall grass?
  5. Mowman29

    Mowman29 LawnSite Member
    from OH
    Messages: 106

    Try a kevlor reinforced belt. Some manufactures use these belts. Don't buy manufactures belts you can usually cross the #'s with a gates or any other belt manufacture.
  6. Tn Lawn Man

    Tn Lawn Man LawnSite Senior Member
    Messages: 479

    Very common misconception about belts is that tighter is better.

    Actually you want to run the belts as loose as possbile without them falling off. You get faster blade tip speed, less wear on the engine and spindles, and you get a better cut.
  7. kevinsky

    kevinsky LawnSite Member
    from Nevada
    Messages: 75

    I have been going through three per season it seems like on all three machines. I compared the life of aftermarket belts to Scag stock belts and there is no difference in life. If anything, we probably run them loose, but I don't understand why that would wick heat.

    TURF DOCTOR LawnSite Silver Member
    Messages: 2,138

    I don,t know mabye to tight it is a inch of play do not tighten your belts it will get them smoking hot.
  9. Steppenwolf

    Steppenwolf LawnSite Senior Member
    Messages: 403

    We have the exact same problem on our three scags. This started years ago when we ran scag belts,they would break under 100 hrs and shread into the clutch,pita to clean out. We were using rotary belts,kevelar for years with no problems,175 hrs plus per belt to about 275 hrs then the dealer stoped using rotary and went to "dealers brand" which is also kevelar and is "the same belt as rotary" but the best I have gotten is 109 hrs. We also are the only ones having this problem I am told. I adjust belts once a week after initial break in with one inch of deflection in the belt as told by scag rep. The best part about the kevelar is that they will chunk out and vibrate like crazy so you have time to kill your blades before they break and foul your clutch and knock off the pump belt,or break the idler pulley or as what happened last week it also took out the hydro filter. But just like you, apuzzled look and " No one else ever has had that problem."
    If you find the cure,let me know and I will enlighten my dealer. I am at wits end with this problem. We have 11,000 plus on these three machines( by hr meter) and they should last awhile longer.
  10. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,203

    I still use Scag belts on our 36" WB and no problem and our load is great because we mulch with plate on outlet. No adjustment on our Scag, it has spring loaded idler? Belt failures have always been cracks across the belts but sometimes they run many hours with cracks, so don't understand. I did replace the bearings in the idler pulley pivot because I could see that the Idler was not running square to the belt. I also adjusted the idler down so the belt runs in the center of the idler pulley with the unit adjusted at normal cut height. As normal maintenance I do this type of stuff on all our units. No problem on our Scag Cougar...ran two years 1400hrs on belt.

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