Moly lowers Timken OK load

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I am looking at Mystik JT6 Hi Temp grease specs and it has an Timken OK load of 80; but the same grease with 3% moly has a Timken OK load of 60. I thought moly would always increase load capacity, but apparently not always true. Anybody have insight on why moly would lower the load carrying ability of this grease?
 
What matters is how much EP additive is in each formulation.

Moly is primarily a friction modifier but in larger treatment levels contributes to some (not the only) EP activity.
 
Moly is for helping things that "slide against each other" to not wear.. (Like cam lobes & rockers)

Roller bearings aren't supposed to do any "sliding". Just rolling.
 
The percentage of moly in a grease is not directly correlated to EP performance. A grease with less or no molybdenum and a higher EP test result contains some additional non-moly EP additives to boost performance.
 
Originally Posted By: MotoTribologist
The percentage of moly in a grease is not directly correlated to EP performance. A grease with less or no molybdenum and a higher EP test result contains some additional non-moly EP additives to boost performance.


Lithium Complex greases are typically "extreme pressure"
 
Originally Posted By: Linctex
Originally Posted By: MotoTribologist
The percentage of moly in a grease is not directly correlated to EP performance. A grease with less or no molybdenum and a higher EP test result contains some additional non-moly EP additives to boost performance.


Lithium Complex greases are typically "extreme pressure"

If they contain EP additives they certainly are. Lithium complex thickener offers little to no inherent EP performance though.
 
Not only moly is the part of the formula you would have to exclude a lot of factors.

1. EP testing is relevant for EP conditions they are rare.
2. Moly in greases is antiwear additive.
3. Moly oxidizes readily in a presence of air and moisture turning into abrasive Molybdenum Oxide (III)
 
Originally Posted By: TriboTEX

3. Moly oxidizes readily in a presence of air and moisture turning into abrasive Molybdenum Oxide (III)

Good mentioned. In era of MOS2 hype people forget there is no single wonderful material for all the problems that we have.

Some basics from WIkipedia - https://en.wikipedia.org/wiki/Molybdenum_dioxide
Molybdenum oxide is a constituent of "technical molybdenum oxide" produced during the industrial processing of MoS2

2 MoS2 + 7O2 → 2MoO3 + 4SO2
MoS2 + 6MoO3 → 7MoO2 + 2SO2
2 MoO2 + O2 → 2MoO3
 
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Originally Posted By: Mainia
I thought I heard 3% moly is ok for ball bearings, but 5% and above is not?? Going by Caterpillar specs.


I am inclined to think that most people who have used moly grease in a roller application ended up using a 3% moly formula that is very commonly bought at the auto store.
 
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