PDA

View Full Version : Greasable/sealed bearings


DaveVB
10-23-2009, 04:18 PM
There is currently a discussion about this subject here on lawnsite. Everyone has an opinion based on experience, but I got to wondering about how they are made; How can a sealed bearing go for 1k plus hours?
So I am going to my preferred zero-turn manufacturer- What kind of engineering goes into a sealed bearing? Better grease? better seals?
Will my next 72" zero-turn have sealed bearings? Why or why not? Thanks for your time.

The Toro Company
11-13-2009, 09:42 AM
Very good questions, DaveVB. From a technical perspective, both sealed and greasable bearings can perform very well. In fact, at Toro we utilize both types of bearings depending upon the application.

Some people prefer sealed bearings from a routine maintenance perspective -- they obviously don't have to worry about adding grease (or relying on their employees to do it). Sealed bearings generally utilize a different seal design than do greasable bearings, largely because it is even more imperative to keep contaminants out of the bearing when new grease cannot be added to purge debris or replace grease that has broken down over time. Although virtually everyone is in favor of lower routine maintenance requirements, many of our commercial customers believe that certain parts of a machine simply won't survive if you can't add fresh grease periodically. This belief is confirmed by our testing, which has demonstrated that well-maintained greasable bearings will in fact outlive sealed bearings by a significant margin in some of the more demanding applications (i.e. - high-speed rotation in moist and dirty environments -- like the deck spindles on a 72" zero-turn rider).

Your next 72" Toro Z Master will likely contain both sealed bearings (in areas like the front caster wheel axles) and greasable bearings (in the deck spindle assemblies). As stated above, the choice of bearing type depends upon the specific application. With regard to deck spindles on Toro Landscape Contractor Equipment, you can currently expect to find greasable bearings on cutting decks that are 48" and wider on products with ground speeds of 8 miles per hour or higher. On products where the top end ground speed exceeds 10 mph, the greasable spindle assemblies receive a further upgrade from ball bearings to tapered roller bearings because of the potential for the spindle bearings to see even higher loads.

Also note that differences in seals and grease exist not only between greasable and sealed bearings, but also between different designs of the same type (greasable or sealed).

Hopefully this provided some assistance. Please let us know if you have additional questions.

-The Toro Company