Are these 30 or 100 weight?

[Richard]

My cutters manual says to use:

Exxon Nuto H-100 or
Gulf Harmony 100 AW or
Shell Tellus 100 or

and this is what's confusing me "or an approved equivalent 30 weight oil"

Are the first three listed 30 weight or 100 or other? When I looked up Shell Tellus I interpret it to be saying the 100 means it's got a viscosity of 100

https://www.mil-specproducts.com/Documents/908_PDS-TELLUS%20PREMIUM%20OIL%20100.pdf

What am I missing?

I'm likely going to flush the mower and want to be sure I get the right stuff.

 

[dodge man]

You say cutter? Are we talking push mower, brush hog gear box? A little more info.

 

[Richard]

Hydraulically powered flexwing mower. (hydraulic pump attached to PTO powering hydraulic motors above each blade spindle)

 

[LD1]

The technical answer is both. They are both 100w viscosity AND 30w. And no I dont mean multi-viscosity like 10w30 motor oil.

It has to do with scale. Hydraulic oil is ISO viscosity scale. Motor oil is SAE scale.

10w motor oil (SAE scale) is equivalent to ISO 32
20w is a broader range that encompasses both 46 and 68 on the iso scale
30w on the SAE scale is the same as 100w on the ISO.

Gear oils are different too.....

Sever charts out there but something like this might help What is Oil Viscosity? | Comparative Oil Viscosity Chart

 

[Richard]

Excellent, thank you.

I was really scratching my head thinking that a viscosity of 100 (I'm accustomed to SAE) would be pretty darn thick for this....

I had no idea there was a different scale.

 

[the old grind]

It's really this simple ..