Pulley size

PACub100 · Oct 4, 2020

On my 1450 I have a 5" main deck pulley from the PTO. I understand that there were 4-1/2" pulleys on these as well. My question is, has anyone has swapped out the larger pulley for a smaller diameter one and if it made a noticable difference? I've noticed that my deck leaves some grass uncut. Not in any particular spot but at random. It also doesn't "throw" the clippings very far at all... generally the distance of one pass - 44". It also leaves clippings on the pass I just made.
Curious if speeding up the rotation of the blades by using a smaller diameter pulley will be good...

kphill · Oct 4, 2020

The pulley is actually 4" and yes they make a differance.. I have one on my 169 but they are getting hard to find.. My deck would leave lines in the yard but that faster pulley gave the deck more lift and made a big differance.. You will need a 3/8 x 79" PTO belt if you don't already have one.. I just bought a new belt last month..

PACub100 · Oct 4, 2020

For my pulley now I have the 3/8 x 79. For the smaller pulley I'd need a 3/8 x 78", correct?... and I'm measuring from outside of the flange diameter...5" by my tape measure.

kphill · Oct 4, 2020

Yes, My mistake.. I was going by the wrong belt sleeve.. I have the bill from the dealer in front of me.. IH-59971 is the part number.. 3/8 x 78 belt..

danderson · Oct 4, 2020

IIRC the smaller pulley was standard on the A series decks for the Quietlines due to the larger pulley on the electric clutch. The bigger pulley was used on the decks for the wide frames with the smaller manual PTO pulley. The purpose was to keep the blade speeds where they wanted them.