I keep eating deck belts even after replacing the pully bearings. Is there another reason? Thanks Ron

Clay it may be time to replace the pulleys,including the engine pulley, check all bearings and blade spindles for wear and free movement and if the tensioner is on an arm lube the arm so it move freely.
Check the attached links,instruction and guides, Good luck
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Why am Breaking So Many Belts on My Mower
http://www.tractorforum.com/f166/burning-up-deck-belts-21199
Craftsman lawn tractor breaking belt after each use
Why Does My Yard Man Mower Keep Destroying the Belt That Is on the Deck to...

The tentioner could not be applying the right preasure. Make share it is not sticking and that it is moving free.

The belt tentioner is loose.

If you removed the harmonic pulley, make sure its all the way back in. Otherwise inspect the pulleys surface.

I just had a problem with my belts smoking also. Replaced belt and the same thing happened. Removed deck, flipped it over and their it was. I large stick had somehow gotten wedged between one of the blades and the deck frame, causing the belt to turn but the mandrel would not. Removed the stick and problem solved. I don't know if your problem will be solved as easily as mine but for me it was just a reminder to ALWAYS check the simple things (and normally the ones that doesn't cost) first and you may be surprised.

Looks like your mowers have a little age on them. I recommend that you remove the decks for inspection. I bought one recently that the deck was rusted out in the middle causing it to flex and throw the belt. Check for good alignment all around and make sure that the blade guides around the pulleys are as they should be. If not that will cause them to eat the belt. Make sure everything moves as it should including the blade engagement mechanisms.

I hope this helps you get going.

The input shaft on the transmission is snapped.The shaft is snapped off from its fitting.This causes the belt to slip/ wobble.The belt should not wobble.There should be zero wobble.Only the belt should smoothly spin, but not wobble.---- Check the shaft.------- This should help.Thanks.Helpmech.

You didn't indicate what model of tractor you have. usually if you're eating the drive belts there is a problem on how they are installed. Make sure the belt is correct belt and not too long or too short. Without model number it would not be possible to show a diagram, but typically the belt should go around the drive pully about 180 degrees, When the tensioner is tight the belt should not rub on any guides, or bolts. It should only ride on the pully, and the flat side of the idler(s). The other posibility is that one of your spindles has bad bearings, causing extra strain on the belt or if it's "locked" up then it will burn right through the belt. If there is a cover over the belts ( and there should be) make sure it's not rubbing the belt.

There is something out of alignment. look at all the pullies with belt on and engine running. use a strong flashlight to see. they all should be in alignment. if any of them are out even a little replace them. including altenator, power steering pump, a/c

check the alignment of the ideler pully to make sure it is even withe the drive pulleys. if not in line it will cause the belt to break. There is a spacer that is on the idler that should be on top and not on the bottom of the pully.