everyone seems to have have a different opinion on this, but i prefer Amsoil for the crankcase / engine, and Golden Spectro Heavy Duty Platinum 6-Speed for the trans (75W-140), and im happy to say i no longer have a need for primary fluid due to my open belt drive

 

Moderators must be very busy allowing an oil topic in the Softail section.

 

Thing most important (other than lubrication) is an oil's flashpoint. Amsoil, Redline, Mobil 1 V Twin all have flashpoints higher than others, much higher than dino oils.

Flashpoint is the temp an oil breaks down at, so the higher the better.

I used Mobil 1 for a while but when I found an outlet to get Amsoil for the same price, I tried that and am very happy with the results.

 

Put some STP in it and you could have gotten 60 lbs at idle, but it wouldn't protect your engine any better than the M1 at 5 lbs. You're putting too much emphasis on pressure and not flow. A 10-30, a 5-30, & a 0-30 should have the same viscosity (10) at operating temperature, whether they're Dino or Synthetic.

 

Additive package and the quality of their base stock

 

Synthetic oil isn't "thinner". A 50 weight Dino should have the same viscosity as a 50 weight Synthetic when at operating temperature. Your Dino oil may have different additives that affect the ticking you heard. Synthetics claim to fame is that as the temperature of the oil decreases, it's viscosity increases at a much slower rate than Dino oil, resulting in increased flow on startup where most wear occurs.

 

I'm reading the softail forum and I'm interested in the subject.

 

I use amsoil. Works good in everything and fairly easy to find.

 

I have used Mobil 1 in all 3 holes with the Mobil 1 gear lube in the trans for 36,000 miles now. It is a gearbox after all. Every test report I read had Mobil 1 placing second, with the exception of the Mobil 1 test. Thats why I use it.

 

Well OP, have you gathered enough info from this thread to make an educated decision?