HT/HS ..... Shear Strength????

[BigJohn]

Somewhere recently, I read (maybe in the oil bible) that the HT/HS number indicated how strong an oil is in terms of its Shear Strenth. Is this true?

If so, I see some descrepancies that I need clarified......

For instance, I used Mobile 1 0w40 in my bike for about 500 miles. I loved the oil in terms of engine feel and shifting smoothness,etc.. But on this site, I read that Blackstone had shown it broke down quickly in motorcycles. Something about the tranny shearing it up. 0w40 has a HT/HS number of 3.6.

On the other hand, many have raved about Shell Rotella 5w40 and its solid ratings, especially resistance of shear breakdown, etc... But this synthetic Rotella only has a HT/HS number of 2.9.

Can someone explain this to me? If I am off base, what oil rating numbers point us in the right direction to the best oil for our bikes? At this time I look for an oil that has the following numbers.....

1. High Viscosity Index
2. High TBN

Pour point and flash point are of less concern to me with a water cool bike and I never ride in temps below 40 degrees.

I will say that my oil of choice at this moment for my bike is 15w50 synthetic and Mobile 1's rating for HT/HS is 5.11.

Can anyone help me with this topic?

Thanks,

 

[jmac]

Where did you get the idea that Shell Rotella 5w-40 only has an HTHS of 2.9? I can guarantee you that it is higher than that.
Though not listed in the PDS like most other manufacturers when the question was asked in the past directly to Shell the reply was that the HTHS is 4.2 for that oil, though I cannot find that post now.
The minimum specs for API CI-4 and CJ on HTHS are the same, at least 3.5. So you are assured it at least has that, but all of the direct competitor oils are in the 4.1-4.3 range with similar technology and basestocks so the 4.2 number is a credible answer and see no reason Shell would have to put out false information on it. Then there is Schaeffer's 9000 with an HTHS around 4.5,
just had to through that in...

 

[BigJohn]

Originally Posted By: jmac
Where did you get the idea that Shell Rotella 5w-40 only has an HTHS of 2.9? I can guarantee you that it is higher than that.
Though not listed in the PDS like most other manufacturers when the question was asked in the past directly to Shell the reply was that the HTHS is 4.2 for that oil, though I cannot find that post now.
The minimum specs for API CI-4 and CJ on HTHS are the same, at least 3.5. So you are assured it at least has that, but all of the direct competitor oils are in the 4.1-4.3 range with similar technology and basestocks so the 4.2 number is a credible answer and see no reason Shell would have to put out false information on it. Then there is Schaeffer's 9000 with an HTHS around 4.5,
just had to through that in...




Simply referenced off of Page 166 of The Oil Bible.

 

[jmac]

Just goes to show why I don't trust everything in that particular source. This just adds to the list of screwy things I've heard cited from that source.

 

[Quattro Pete]

Quote:
Though not listed in the PDS like most other manufacturers when the question was asked in the past directly to Shell the reply was that the HTHS is 4.2 for that oil, though I cannot find that post now.

Yup:
http://www.shellusserver.com/ubbthreads/...part=1#Post3360


Originally Posted By: BigJohn
Simply referenced off of Page 166 of The Oil Bible.

Probably not the best kind of reference for anything oil-related.

 

[jmac]

Just realized that your original question was not answered, sorry.
that the HT/HS number indicated how strong an oil is in terms of its Shear Strenth. Is this true?

Well yes and no, I think in oils that have a tendency to shear that higher HTHS can be an indicator of less shear, but we see xw-20 oils that shear hardly at all, and they start with HTHS around 2.7, then 5w-30's with VII's shear down to a 20 in a short time, or 5w-30's like amsoil or GC 0w-30 that do not shear much in long intervals at all. Dino 15w-40's from all the top manufactures (Delo, Rotella, Delvac, etc) tend to shear little, or in high shear situations shear back to heavy 30's, so the syn and Group III 5w-40's tend to shear less than their 15w-40 counterparts simply from how the products are built. Less plasticizers and VII's less shearing for sure.

 

[BigJohn]

I have read that some of the Mobil 1's tend to shear more easily. If I put the 15w50 Mobil 1 in my bike and it does shear a little, am I running the equivilant of a 15W40...after a little time has passed?