[TowerTalk] Belt Slippage on LM-470 Towers

k0dan k0dan at comcast.net
Thu Nov 24 17:24:23 EST 2005

I have several spare belts on hand here: 4L-420 (1/2"X 42"). Not sure if that's the size I'm using, or these are leftovers after having switched to a smaller belt. I do recall switching to a smaller circumference in the past...it made things operate much better.

They're readily available from auto parts supply houses, there is nothing proprietary about the Tri-Ex/Tash one. Also, once you find a supplier of 1/2" belts, you can readily find ones that are slightly larger or smaller. 

I have used the ones with and without the teeth, doesn't seem to make much difference, the key seems to be getting a good fit to match the pulley placement. The belts do stretch so annual replacement is another maintenance item. 

GL & 73


PS From the nomenclature you list, it appears those belts are 41"
  ----- Original Message ----- 
  From: paul at w8aef.com 
  To: k2xx at swva.net ; k0dan 
  Cc: Tower Talk ; k6ll at adelphia.net ; KJ6Y at aol.com ; K9RB at bellsouth.net ; wa3gin at erols.com 
  Sent: Thursday, November 24, 2005 1:50 PM
  Subject: Re: [TowerTalk] Belt Slippage on LM-470 Towers

  It could also be that the belt is too narrow and rides in the bottom of the pulleys.  The belt dressing is a good idea.  Even if it slips when first applied it will (should) reduce slippage in the future.

  There doesn't seem to be a brand name on my belt.  There are two sets of numbers on it: 321 E 12 and 43517.  I think the 43517 is the manufacturers part number.  This is a belt that I purchased to replace the worn belt that came with the tower.  Sorry, can't remember where I obtained it, maybe an auto parts store.  This belt also has 'teeth', for lack of a better word.  It does not have the same continuous cross-section, it has teeth.

  Also, the Tri-ex bill of materials calls for either a Dayco 4L410 or Gates 2410 belt.

  de Paul, W8AEF
    ----- Original Message ----- 
    From: Joe Giacobello 
    To: k0dan 
    Cc: paul at w8aef.com ; Tower Talk ; k6ll at adelphia.net ; KJ6Y at aol.com ; K9RB at bellsouth.net ; wa3gin at erols.com 
    Sent: Thursday, November 24, 2005 7:27 PM
    Subject: Re: [TowerTalk] Belt Slippage on LM-470 Towers

    Thanks, Paul, Dan, Skip, both Daves and Roger.

    To answer several questions, I had recently changed to a new belt, applied grease to the drum via the fitting and changed the gearbox oil.  Frankly, I may have been a little lax about oiling the pulley bearings on one tower, but I know I had done it recently on the other tower.  I really don't think the issue is the pulleys or obstructions to the movement of sections.

    Usually, I can get things to work properly by simply retightening the belt.  In fact, I got it running yesterday and while it was going up sprayed Belt Dressing on the pulleys.  The slippage immediately began again.  I think that Belt Dressing is more of a lubricant and seems to make the problem worse.  The can says it is for the elimination of squeaks.

    The idea of reducing the belt size by a half inch makes a lot of sense.  In the past I had blindly replaced the belts with the identical size that came with the towers.  I bought a shorter belt yesterday and will try it out on Friday.

    Frankly, I had no idea that there was some kind of clutch mechanism associated with the large pulley.  I knew that the mounting hardware was unusual, but that information was a revelation.  I'll pay more attention to it in the future.

    I'll let you know how the shorter belt works tomorrow.

    73, Joe


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