Advice: Any advantage to motorcycle oil in ZTR hydrostats?

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1,587
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USA
For example, a SJ rated 20w-50 vs a SN rated 20w-50. Do hydrostats benefit more from one set of additive levels vs the other?

The reason I ask, is I recall exmark coming out with their own ZTR hydrostatic oil with "increased zinc" which is either marketing, or beefed up zinc provides better protection. :sneaky:

Thanks!
 
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965
Location
AR
Yes it is beneficial because there is metal to metal contact in a hydrostatic transmission pump. The zinc provides a sacrificial layer that reduces wear.
Personally I use Mobil 1 V-Twin 20W-50 for that reason (also its 'thick' at temperature)
 
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641
Location
WV
While I'd bet it's good for hydros, I'd stick with the recommended fluids, which I think is more based on viscosity than additives. If you look up HydroGear for instance, they list a handful of motor oils for the 730 (example from memory), On that list is 15W50 M1 and 20W50 dino oil, among others. So, I would use something on their list. I've had half a dozen or so hydro tractors and always had good service following the manufacturers recommendations. I think motor oil is one place you can marginally improve protection for an engine, but I think hydros should be fed what they were designed for.
 

SOHCman

Thread starter
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1,587
Location
USA
While I'd bet it's good for hydros, I'd stick with the recommended fluids, which I think is more based on viscosity than additives. If you look up HydroGear for instance, they list a handful of motor oils for the 730 (example from memory), On that list is 15W50 M1 and 20W50 dino oil, among others. So, I would use something on their list. I've had half a dozen or so hydro tractors and always had good service following the manufacturers recommendations. I think motor oil is one place you can marginally improve protection for an engine, but I think hydros should be fed what they were designed for.
Yes, I am trying to use exactly what is recommended... but specifically the one with the best protection even if it costs more.

The manual specifies the following: "Typically, an engine oil with a minimum rating of 9 .0 cSt (55 SUS) at 230°F (110° C) and an APIclassification of SL is recommended. A 20W-50engine oil has been selected for use by the factory and is recommended for normal operatingtemperatures . Biodegradable oils are not approved for this unit as they degrade too quickly while in service ."
 
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624
Location
Hedgesville, WV
A motorcycle oil is the only thing you will find that fits the manual recommendation. But make sure to check the bottle because someone here mentioned a motorcycle oil that was SN rated but most are not. You dont need to worry about timing chain wear, CAT posion or preignition protection so stay with the older spec.
 
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98
SL is a pretty old specification (2001) and a pretty minimal standard at that. The later SM and SN standards imply SL, and those actually specify some useful properties, such as improved deposit and oxidation control. So you can't go far wrong with a lubricant that is compliant with the newer SM and SL standards. Mower manufacturers sometimes sell and recommend their own brand of lubricant for the Hydros, some of these are synthetic. I think all of them feature a robust anti-wear additive package, Some of them are pricey.

So the way I see it, there are 3 groups of solutions:

1) Purpose build OEM hydro oils, based on some 15w50 or 20w50 starting point. Some of them are group 3, some true synthetics.
Could be rebranded motor oils w extra additives.
They all feature boosted anti-wear, anti, oxidant and anti sludge additives. E.g.:

Exmark
Ariens 15w50 #00057100 - $15 per quart. Synthetic. Claims double service intervals
Stens Shields 15w50 synthetic: Similar, but cheaper ( $10-ish per quart. )

2) Purpose built 3rd party lubes for hydros:
Triax Zero Turn 20W-50 Full Synthetic -10-14$ per quart
Amsoil AHF 20w50 synthetic base, hi zinc. Coudl be group 3 based, not disclosed what base they use, $14 / qt

3) High quality motor or bike oils matching the manufacturer's listed requirements
Mobile synthetic 20W50 or 15W50.
Castrol 10W50 or 20W50 motorcycle oil <$10
Redline powersports 20w50 or 15w50 motor oil ( $50 per gallon)

It is hard to know which one is the "best" as we typ[ically do not have sufficient info on the formulation,
and we are making educated guesses of the "useful" / "not useful" ingredients or properties.

Racing oils have maxed out wear additives, but may not have enough acid neutralizers, as they are intended for short-time use. The service interval here is extra long so.. no. I am not sure if acid formation is even a concern for a hydro, where there is no combustion. When in doubt, be extra cautious.

Motorcycle oils sometimes have some extra friction modifiers for wet clutches, I am unsure if that is harmful for the hydro use. I go by: If motorcycle oils were best choice, it would make sense for Hydrogear to call those out. And the factory fill is NOT a motorcycle oil. So when in doubt...

In the final analysis, I am going with the Ariens 15W50 synthetic. I think Amsoil may be a good choice as well, I just dislike their marketing hype.
With the Ariens/Gravely product, at least I have some assurance that someone in the possession of all the requirements and specs
took a look at the formulation and approved it.

On the motor oil for the Kawi, I am trying the redline 15W50, what the heck. I always wanted to try it.
 
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98
Update: It seems like, the Gravely/Ariens 15W50 "purpose built" hydro fluid is rebadged Mobil-1 15w50 Extended performance Synthetic oil.

Some of the older pdf manuals I can find by googling the product number and mobil-1 mention this. Stating the mobil-oil, and then giving the product number 00057100 or just 57100. The mobil-1 can be had for $22 per 5 quart jug at your local famous big box store. There is a mobil-1 $15 rebate in effect, so it can be had for little coin. The zddp content of this oil is 1200 ppm, btw.
 
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