Mowing Greasing Frequency MMM

[Runner]

it really depends on the bearing or bush I were always told by the bearing experts more high speed bearings were damaged by over greasing than under greasing

I've heard this before too, but other than maybe displacement of the seal, can't figure out what damage you could cause by "overgreasing" a bearing.

I would go by the manual. The manual for my RFM says grease everything every 9 hours, so every fourth mowing for me.

 

[JJT]

The rear U-joints on the Kubota ZD mowers are awful to access.

I put my Kubota ZD on my lift, lower the mower as low as it will go and the zerks are pretty easy to access. Without the lift - major pita.

 

[DarkBlack]

I've heard this before too, but other than maybe displacement of the seal, can't figure out what damage you could cause by "overgreasing" a bearing.

It’s true with ball and roller bearings. You can cause the rolling elements to slide between the races instead of rolling, and it can flat spot them and cause early failure.
Grease is good for over a thousand hours of use. Unless your seals are bad, and you’re loosing the grease, and/or ingesting dirt into the bearings, it makes no sense to grease every 20 hours. Better time and money would be spent fixing the leaky seals.
Remember, off the shelf sealed ball and roller bearings are spec’d to around 2,000 -10,000 hours, with just the original grease in them.
Plain bearings aren’t sealed as well, and will force out grease though, and do merit more periodic replenishment

 

[sixdogs]

Thanks TBN'ers,,,,,,, looks like i'll be be safe to extend the MMM greasing to at least 20 hrs........belt spindels... and U-joints. The front Gage wheels are easy to get at.........but that duo rear center gauge wheel set is very difficult to get at....as well as the U-joints.

Mike

Something interesting that I learned was that my B7800 with a MMM had small wheel bearings in the mower wheels. I thought it was just metal to metal. I learned this as I was selling it and had I known would have greased at 10 hours rather than every other time.

The spindles were greased more frequently as well, but longer or on schedule for the U joints and things under the mower. In fact, one of the reasons I sold it for a Grasshopper was to have more accessible grease fittings.

I've mowed since the '60's and never had any spindle, wheel or u-joint failure by using just a little more grease.

 

[Runner]

Grease is good for over a thousand hours of use. Unless your seals are bad, and you’re loosing the grease, and/or ingesting dirt into the bearings, it makes no sense to grease every 20 hours. Better time and money would be spent fixing the leaky seals.
Remember, off the shelf sealed ball and roller bearings are spec’d to around 2,000 -10,000 hours, with just the original grease in them.
Plain bearings aren’t sealed as well, and will force out grease though, and do merit more periodic replenishment

Logically, I agree with all that, but then, why does the mower manufacturer say grease it every 8 (24) hours?

Actually, double checked the manual - it says u-joints and wheel spindles every 8 hours, blade spindles 24 hours. Nevertheless, I've been greasing everything, every 9 hours for the last 18 years and no issues....

 

[DarkBlack]

Logically, I agree with all that, but then, why does the mower manufacturer say grease it every 8 (24) hours?

Actually, double checked the manual - it says u-joints and wheel spindles every 8 hours, blade spindles 24 hours. Nevertheless, I've been greasing everything, every 9 hours for the last 18 years and no issues....

I’m not familiar with your machine. It must use somewhat crude bearing sealing methods. Why else would you need to push out fresh 8 hours old grease? Good U-joints employ roller bearings and cup seals, and are good for over 1,000 hours.
How often do you change/add grease to your PTO shaft U-joints? Your vehicle’s driveshaft U-joints? Vehicle wheel bearings? Electric motor bearings?
I’m guessing your manufacturer wasn’t confident in their bearing seal design, to keep grease in and dirt out

 

[sixdogs]

Logically, I agree with all that, but then, why does the mower manufacturer say grease it every 8 (24) hours?

Actually, double checked the manual - it says u-joints and wheel spindles every 8 hours, blade spindles 24 hours. Nevertheless, I've been greasing everything, every 9 hours for the last 18 years and no issues....

Mower companies want to sell mowers and some people might choose one mower over another. They need competitive standards to survive.

Much the way most car makers all went to a 10,000 mile oil change interval. It's because others did. Most mechanics will say a 5,000 mile oil change if you want your car to last.

 

[DarkBlack]

Much the way most car makers all went to a 10,000 mile oil change interval. It's because others did. Most mechanics will say a 5,000 mile oil change if you want your car to last.

You don’t think the technology of engines, fuel , and motor oils, have improved?

 

[Runner]

I’m guessing your manufacturer wasn’t confident in their bearing seal design, to keep grease in and dirt out

Perhaps, but I don't think Woods is known for making poor quality equipment.

 

[DarkBlack]

Perhaps, but I don't think Woods is known for making poor quality equipment.

Not saying it’s poor quality. Just saying, that a quality grease is still “new” condition after 8 hours use. Your Woods implement must not retain it within adequate sealing methods, if it either leaks out so fast, or requires you to push out 8 hour old grease, because it’s contaminated with dirt? Again that’s a sealing issue.
I’m only talking of ball and roller bearing assemblies.
Plain sleeve bearings are the exception , like in your loader arms. No seals and grease gets displaced externally, so require frequent additional grease