How tight should my belts be??

Discussion in 'Lawn Mowing' started by STIHL GUY, Jul 21, 2008.


    STIHL GUY LawnSite Fanatic
    from CT
    Posts: 5,225

    i just replaced the old worn and stretched belts on my 48'' Bobcat Ransome mower. I was wondering how tight the belts need to be. If they are too tight i can not engage the blades. Right now when the blades are engaged it rattles and doesnt quite sound right? How tight should the belts be on this mower?? Thank you in advance for any help
  2. jiggz

    jiggz LawnSite Senior Member
    from jerz
    Posts: 646

    I have nooooo idea, hahaha but i will tell you this!

    if you call bobcat.. do a search for bobcat turff products and youll find the site

    they will print and send you a full teardown parts and owners manual for free.. just give them the model number and your set.. i got mine last week and theres a world of info in there.. if i could find where i put it i would answer you.. the guy told me all the info was on the site but i couldnt find it so he mailed it to me

    i would call them though its great info to have..

  3. Flex-Deck

    Flex-Deck LawnSite Silver Member
    Posts: 2,846

    Personally, I like my belts tight enough to hold up my pants, and my mower belts tight enough to turn the blades. Weird question.
  4. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    Yeah LOL I hate that belt tension crap, it's either just loose enough to 'slap' around or it's too tight SOB if I ain't been down this road time and again, and it can also be just tight enough where it wears the spindle bearings prematurely or the belt breaks in 3-6 months because it was too tight and other parts wear as well...

    I tell you how I do it, is I take my time, it gets a little easier every replacement but it still takes fiddling and twiddling to get it as close as possible and at least in my case it's never really perfect but such is life.

    Roughly, starting out about as tight as an alternator belt, maybe an inch of play side to side... So, tight but not super tight, hard to explain it just takes practice.

    Too tight is no good, I find if it's tight enough where it doesn't slap around at all then it's also too tight, ain't life grand.
    I like it to be where it doesn't slap a lot, the biggest issue is I watch with the cover OFF to see if it's hitting any metal objects because if it is something has to change or it will wear prematurely. So then one either tightens it or loosens it, quarter turn at a time (fun), until ya get it somewhere between minimal slapping around and not too tight, close as you can get it to that.

    Way I see things, I think you'll smoke a few, probably break one or two prematurely, then once you get 5-6 years and 3-7 belts down the road you should have it down pretty good :p
    That's how it worked out for me, I still don't always get it right, but as a rule if it is right or close to it, I've gotten 3-4 years out of such a belt before (so don't listen to what the dealers tell you that 6 months is normal lol).

    Peace out

    Other notes: On both of my mowers I removed that stupid spindle brake made of steel, the belt kept hitting it.
    Now the spindles free wheel when shutting down, always have to wait a good 30-60 seconds for them to stop, but it beats having to replace the belt more often than it really should need it.
  5. Phil G

    Phil G LawnSite Senior Member
    Posts: 843

    Nice one :laugh:
  6. themowerman

    themowerman LawnSite Senior Member
    from NJ
    Posts: 297

    You it is....1/2" deflection at 12lbs of force.
  7. dakota2112

    dakota2112 LawnSite Member
    Posts: 55

    Seems like something's missing from this equation... such as, where is this measurement to be carried out. I think you'll get different results if you try this on a short belt span vs a long belt span... :confused:
  8. mike r

    mike r LawnSite Member
    Posts: 143

    agreed with mowerman,

    10 # is what i read, but this force is measured with a force guage (15.00) at the harley
    davidson dealer. this guage is for tensioning the drive belt to rear sprocket on my bike,
    but i also use this guage on the blade to blade belts on my machine ,works perfectly.
    the measurement is taken at the halfway point between the two pulleys,then you take this guage and push it into the belt and this guage is marked for 10# by a little o-ring.
    next push on the guage till you hit 10#, hold at 10#, and measure the 1/2" difference between the back of the guage, and 36" yard stick held against the pulleys. and that should put you in the ballpark for tension. lol.


    STIHL GUY LawnSite Fanatic
    from CT
    Posts: 5,225

    thanks i hope it works lol

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