Shear Resistance - Delo 15w40 vs. Delo 5w-40

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Jim 5

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My motorcycle calls for a 10w-40 or 15w-50 synthetic.

I have often run a 15w-40. I am going on a longer bike trip in a few days and I am deciding whether to use Delo 15w-40 or Delo synthetic 5w-40.

Could anybody offer any advice as to which would be the most shear resistant? I intend to do about 3k OCI in reasonably hot temperatures. I think I can get away with 15w-40 if they would be close, but if the 5w-40 would be significantly better, I will shell out the extra money.

My bike is a 955cc fuel injected water cooled triple with a shared sump.

Thanks to everyone for their advice!
 
For a 3000 mile OCI I'd used the 15w40. There won't be any significant difference in shear resistance between 15w40 and 5w40 in 3000 miles.
 
That's what I had thought.

Out of interest, is it safe to say however that the synthetic offering would be more shear resistant than the 15w-40?

I'm wondering if the fact that the 5w-40 is a synthetic more than compensates for the larger spread in viscosity between the 5w-40 and the 15w-40.
 
Look at the VI of both oils and compare each to the VI of Group 2 and 3 basestocks, respectively. The one that has a larger difference between VI of motor oil and VI of basestock is probably less shear stable.
 
Quote:

I'm wondering if the fact that the 5w-40 is a synthetic more than compensates for the larger spread in viscosity between the 5w-40 and the 15w-40.

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Not necessarily. Remember, Group III base oil is only made in roughly three grades with the heaviest being about 8 cSt--that's 20 weight. Depending on what other base oils are used in the blend, a Group III 5w40 may (and probably does) have more VI improver than a 15w40 made from Group II.
 
The 15w40 unless Delo 5w40 is a different formula that I am aware of a year ago.
 
Based on Chevron's spec sheets:

Chevron Delo 400 15w-40 VI = 125
Chevron Delo 400 5w-40 VI = 172

I've been around Bitog for a while now, but I will confess that this discussion is above my head at this point.

The 5w-40 40degree Cst is attractive to me compared to the 15w-40 as well, but in choosing between that and shear resistance, I'll take shear resistance. Hopefully those contributing to this thread (who obviously know more than I do) can guide me.
 
15/40 much better will have much lower viscosity shear loss compared to about any 5/40 other than perhaps RL and afew other high PAO blends.
bruce
 
If shear loss is your bottom line, some cheap chevron supreme straight 40 held up better than delo in my V8 ski boat, which usually chews oil up.
 
At least you are going the right direction looking for stability from shearing, since you are going on a long trip (meaning fewer cold-starts). Before reading the expert's opinions, I would have guessed the 15-40 would be more stable. Now that I read some of the expert's opinions, I have a better understanding as to why 15-40 would be more stable.
 
That was my thought as well. For a long trip, I anticipate only 1 cold start per day, followed by long periods of full temperature cruising (stopping only for fuel for me and the bike).
 
Quote:

If shear loss is your bottom line, some cheap chevron supreme straight 40 held up better than delo in my V8 ski boat, which usually chews oil up.

Click to expand...


That's true. A straight 40 would be fine for summer use.
 
I didn't think there was an exact corrolation between viscosity index and amount of improvers in any given oil. Doesn't it depend on the base stock, synthetic by nature needing much less if any viscosity improvers to make the wider multigrades because it naturally doesn't thicken as much when cold? Wouldn't that make synthetics always more stable?
 
That's true Todd, my comment was based on a UOA of the oil at the end of the season, as compared to previous runs of delo and rotella. Not just speculation.

There is the labeling for the intended market thing, I think also. If I had an 30 that tested 10w30, I might label it 10w30 for cars in one bottle, and sae30 for lawnmowers in another. The guy who bought the 30w thinking he's not getting VII's may be wrong.
 
Why is shear resistance a critical issue with motorcycles? Will there be significant metal wear in an air-cooled bike engine when the synthetic 5W-40 shears down?
 
I have run several of the HDEOs in my ST1100 (water cooled 4 cyl. shared trans) for 8,000 mile OCIs

Here is the Data on a few of them at 8,000 miles.

Delo 15W40 = SUS Visc 68.1
Rotella 15W40 = SUS Visc 71.5
Rotella 5W40 = SUS Visc 66.1

I have been happy with all of the HDEOs.

Rick
 
I didn't run a VOA on these oils but I am pretty sure that there are VOAs in that forum that you could search on.

Rick
 
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