Speed of blade set on a 48" deck

[Anvil 9]

I would like to check with you guys about the pros and cons of increasing the speed of the deck blades, possibly by increasing the diameter of the drive pulley on the PTO clutch. Anybody do this????? I'm not so worried about the spindle shafts on the deck as I grease the heck out of them on a regular basis. The Mule longevity however, without a grease fitting concerns me. Your thoughts????

[gwest_ca-(File Mod) 11,033]

First thing I would do is put a tachometer on the engine and find how fast it is running. Then see what rpm the spindles are turning with the engine at operating speed. That way you can calculate how far off the 19,200 maximum feet per minute the blade tips are travelling.

 

Garry

[JoeM 7,871]

There is a pretty good thread on this subject here. Not sure what the title was maybe someone will know.

gwest is right, you need to avoid excessive blade tip speed. All the engineering is done using the pulleys installed from the factory.

I have two different decks, 42 and 48 side, both run and cut great. Checking the RPM of the engine is a great place to start.

 

[Marv 919]

 

Marv

[953 nut 55,078]

The engineers at Wheel Horse and other manufacturers didn't just randomly decide what size pulleys to use. I think they actually used laws of physics and a bit of common sense. You have to take into consideration the fact that our mower blades are not dynamically balanced and any imbalance will be magnified with increased speed. The resulting vibration can crack the deck and destroy bearings.

Slow down, relax and enjoy some quality seat time.

[wallfish 16,985]

All of the above and sharp blades will do wonders as well.

To increase the size of the PTO pulley, you'll need to machine a whole new bell. Smaller pulley on the deck will probably be much easier to do.

Why are you looking for more blade speed?

[Anvil 9]

Thank you all for your input. I will begin with the basics as suggested. I did move the PTO drive belt out to the outer pulley, which is slightly smaller and it appeared to cut better. Which pulley should the drive belt be on? The C-141, 312-8, and 417-8 all had the belts on the second or inner pulley. When I moved the belt to the outer or smaller pulley the belt appeared to ride just fine so aside from a bit more tension against the PTO shaft bearing I didn't see any negative effects. I also know that the effects can be cumulative over time increasing wear but to what extent....2%???

[953 nut 55,078]

The larger PTO pulley is for mowing, the outer on for snow blowers. If you are finding the smaller one gives you better results then stick with it.