mower deck spindle pulleys??

[Brockport Bill 1,662]

i have a 42 inch side discharge mower deck being rehabbed that will have a mix of 5/8 and 3/4 spindles from my limited inventory -- however, I will need to purchase some new spindle pulleys? So if i put two 3/4 pulleys on the outside of 42" deck then typically a 3/4 shafted pulley would have a wider larger diameter than a 5/8 pulley which is smaller diameter. Logically, that would suggest a typical length belt for a 42  s.d. deck could be too short because its going around two larger outside pulleys???? Heres my question??? Would the larger radius for the standard belt to go around two wider diameter outside pulleys cause the belt to be too short??? Or would it be insigificant and the tensioner bar and spring would take up the extra belt length issue? OR, would I need a longer belt? Last question??? a solution is ---- Can a spindle pulley be purchased that is smaller diameter size like a 5/8 pulley diameter but with a center hole sized for a 3/4 shaft???? If yes, what is its part number? Thanks as always for the help!!!!!!! Bill

[8ntruck 7,006]

The difference in belt size would be close to the difference in the pulley diameters.  If it isn't too much, the belt tensioner might be able to take up the difference.

[gwest_ca-(File Mod) 11,046]

Shaft size has nothing to do with pulley diameter.

[Brockport Bill 1,662]

1 hour ago, gwest_ca said:

Shaft size has nothing to do with pulley diameter.

so you're saying a 3/4 inch spindle shaft from a 4 3/4 diameter outside pulley will fit into the center hole of a 3 1/4 inch diameter spindle pulley off a 42 sd mower deck that had a 5/8 spindle shaft?

[gwest_ca-(File Mod) 11,046]

No the center holes have to fit properly.

The outside diameter of the pulley determines the blade speed. A 42" deck will turn faster than a 48" deck because the blades are shorter. Maximum blade tip speed is approximately 19,200 feet per minute.

[Brockport Bill 1,662]

4 minutes ago, gwest_ca said:

No the center holes have to fit properly.

The outside diameter of the pulley determines the blade speed. A 42" deck will turn faster than a 48" deck because the blades are shorter. Maximum blade tip speed is approximately 19,200 feet per minute.

perhaps you would be kind enough to go back and read the start of the thread -- i tried to exlain my question as best i could - - bottom line.... is there a 3 1/4 inch diameter outside pulley for a 42 sd mower that has a center hole for a 3/4 inch spindle shaft ? If yes, what is the part number? thanks for the assistance, Bill

[ranger 1,750]

Not sure about the pulleys, but, if you assemble the parts you have, try the belt you have, to see how much shorter it appears to be. Perhaps, if it’s not too short you may be able to re-drill and thread another hole to re-position the tensioner pulley. This new hole could be either one side or the other of the original to compensate for the belt used, depending upon earlier or later deck. I’m assuming the belts would be different lengths if the cut widths are the same, but pulley sizes differ? Cast iron pulleys are available in whatever size you want, usually with ‘taper lock’ inserts for the bore of your choice. Whether this type would fit, I don’t know. I’m sure someone has already tried?

Edited October 20, 2023 by ranger

[76c12091520h 3,620]

These are your options for 42" side discharge outer pulleys . ALL are dimensionally the same except the center hole. There is no other option from Toro/ Wheel Horse unless you start swapping pulleys from other decks,  and even then the center hole choices are the same, just the outer diameter is different. 

[peter lena 8,631]

@Brockport Bill  how do related BEARINGS FEEL ?  spindle bearing failure /  increased rotational drag , is the killer of  belt driven  anything . my decks spin / move by hand at the PTO / MUEL  BELT DRIVE AREA . good opportunity for a  bearing , clean out and a re grease . 540 deg drop temp , with LUCAS EXTRA HD , GREEN CHASSIS GREASE . quiet bearings , smooth  easy rotation . you are in the area . make the problem go away , Pete

[Brockport Bill 1,662]

3 hours ago, peter lena said:

@Brockport Bill  how do related BEARINGS FEEL ?  spindle bearing failure /  increased rotational drag , is the killer of  belt driven  anything . my decks spin / move by hand at the PTO / MUEL  BELT DRIVE AREA . good opportunity for a  bearing , clean out and a re grease . 540 deg drop temp , with LUCAS EXTRA HD , GREEN CHASSIS GREASE . quiet bearings , smooth  easy rotation . you are in the area . make the problem go away , Pete

thanks Pete -- doing as you prescribe -- doing rehab now of 42 s.d. deck -- including rebuild of spindles including using your bearing suggestions I have read over the past couple years -- i just did another deck a 42" rear discharge over past few weeks -- came out terrific - of course its a nightmare getting the old pulleys off the shafts - here are some before and after photos of deck i just finished

[peter lena 8,631]

@Brockport Bill  very nice job on that !  never had a pulley hang on like that one !  was always taking advantage of a common  failure  on the decks . once I  got it zeroed in , did that to the other 2 decks . your under deck finish looks very good ,your 2nd down picture is how I prop them up to the sun after inspection , metal gets hot , breaks the grunge cycle , think thats the extra help on the decks , have also experimented with the IDLER PULLEY SPRING ,and its reaction to different tensions , has changed to a very solid / smooth action , with practically no bounce to it at all. having worked on many linkage areas , they really lacked a detail , operational tune up .spend time on any problem , with a look / see ,change / improvement  trial . basically when you firm things up ,washers , etc. And change out the lubricant , the movement goes from a rock in a garbage can , to smooth / solid . always looking for another tweak  area , to see what I can improve , love making a problem into a bombproof action of the horse ,shout back anytime , pete

[Brockport Bill 1,662]

49 minutes ago, peter lena said:

@Brockport Bill  very nice job on that !  never had a pulley hang on like that one !  was always taking advantage of a common  failure  on the decks . once I  got it zeroed in , did that to the other 2 decks . your under deck finish looks very good ,your 2nd down picture is how I prop them up to the sun after inspection , metal gets hot , breaks the grunge cycle , think thats the extra help on the decks , have also experimented with the IDLER PULLEY SPRING ,and its reaction to different tensions , has changed to a very solid / smooth action , with practically no bounce to it at all. having worked on many linkage areas , they really lacked a detail , operational tune up .spend time on any problem , with a look / see ,change / improvement  trial . basically when you firm things up ,washers , etc. And change out the lubricant , the movement goes from a rock in a garbage can , to smooth / solid . always looking for another tweak  area , to see what I can improve , love making a problem into a bombproof action of the horse ,shout back anytime , pete

i rescued that 42 rd mower deck which had been left outdoors by prior owner -- i tried EVERYTHING to get off the pulleys -- they were rusted on there like super glue -- I used one week of repeated penetrant - plus heat, plus pry bars, etc -- nothing worked so Red SQ folks said cut them off - which is real challenge to do without damage to spindle shaft - in one case i got off with no damage but damaged the other - UGH !!

[Brockport Bill 1,662]

9 hours ago, 76c12091520h said:

These are your options for 42" side discharge outer pulleys . ALL are dimensionally the same except the center hole. There is no other option from Toro/ Wheel Horse unless you start swapping pulleys from other decks,  and even then the center hole choices are the same, just the outer diameter is different. 

do you sell a 3 1/4 inch spindle pulley with the 3/4 center hole diameter? if yes - cost? Price? Part Number? thanks