Amsoil 20W-50 VS 10W-40

[rraiderr]

I contacted Amsoil regarding what weight oil I should run at the track and this is the response I got below.

Most guys at the track run the 50W as they say it holds up better when the oil starts to sheer down a grade after a weekend of racing.

What do you guys think? Run 40W or 50W for a track bike?

Thanks


From Amsoil Tech

We do not make specific recommendations for racing as there are too many variables. That said, unless you are having excess wear with the 10W40, I would continue using it as you will have more available power and speed if you are using it instead of the thicker 20W50.

Thank you for this opportunity to respond to your question(s). As always, please feel free to contact us again if we can be of further assistance.

Sincerely,
Byron Selbrede

Technical Services

 

[addyguy]

It's a reasonable response....what's the issue?

 

[rraiderr]

Most racers seem to run 50W so it would seem they must be dong it for a reason that maybe the Amsoil tech is not aware of but someone on the forum may be aware of.

 

[demarpaint]

Looks to me like he is offering an opinion and nothing more. Not that there is anything wrong with what he is saying, but it looks to me like his opinion, along with a disclaimer. Pretty smart actually. Backing those statements up with facts would be interesting, for the 10W40 camp as well as the 20W50 camp. My guess is the 10W40 would allow for slightly more power and speed as he mentioned.

As always in these cases JMO.

 

[CourierDriver]

Was at Advance in Lakeland Fl recently,,they had 80 wgt aircraft engine oil,,,I have never seen it there before,,its to thick for autos, but its a thought

 

[edhackett]

Aircraft oil is on a different scale than SAE automoive oil. Aviation 80=40 SAE, 100=50 SAE, etc.

Ed

 

[KernelK]

Originally Posted By: CourierDriver
Was at Advance in Lakeland Fl recently,,they had 80 wgt aircraft engine oil,,,I have never seen it there before,,its to thick for autos, but its a thought


Please do not even think of using aircraft oil in a track bike. Either grade of the Amsoil is a much better choice for this application.

 

[whitesands]

I think the real issue is what are you more concerned about, the extra drag of a 50 wt, or the possibility of a 40 sheering down to a high 30wt ? Really, the drag of a 50 wt will not make a difference unless you are racing at a top level..Were talking maybe a reduction in 2 or 3 hp max vs 40wt...At the same time there's no reason to worry about running a 40 wt...The only thing I can think of is if it does sheer and a 40 wt is recommended for your bike, a 50 wt will give you more room if you want to continue using it after your track day.

 

[Craig750]

I would make my choice depending upon the ambient temperature at the racetrack. That is, are you racing in winter or summer?

What the cooling capacity is of the bike and what the oil temperatures are reaching.

Whether you want to compromise wear to gain a few percent of horsepower by running a thinner oil.

 

[Craig750]

Just to add, oil pressure has to be kept above a minimum, so it is wise to not go to thin at the risk of doing damage.

 

[Norm Olt]

Despite all the "racing" hype, I can't believe that in anything other than a fuel dragster there would be any appreciable difference. Between a 10W-40 & a 20W-50.

It's kind'a like golf clubs: Jack Nicklaus could beat 99% of the non-pro golfers on any given day and on any given course using a women's forged 5-iron as his only club.

Off the tee, in the fairway, out of the occasional trap & putting with just one club...

"It is the _ick, not the STICK!" Or, the rider, not the oil viscosity!

Cheers!

Now, using a 15W-40...

 

[rraiderr]

Thanks for all the responses, I will stick with 20W-50 as it has been working great over the last several seasons and the bikes seem to run well with it.

 

[Craig750]

Originally Posted By: Norm Olt
Despite all the "racing" hype, I can't believe that in anything other than a fuel dragster there would be any appreciable difference. Between a 10W-40 & a 20W-50.

It's kind'a like golf clubs: Jack Nicklaus could beat 99% of the non-pro golfers on any given day and on any given course using a women's forged 5-iron as his only club.

Off the tee, in the fairway, out of the occasional trap & putting with just one club...

"It is the _ick, not the STICK!" Or, the rider, not the oil viscosity!

Cheers!

Now, using a 15W-40...


I suppose golf is a lot like oil.

On oil you can do a UOA.
And in golf you can do a UA.

Not a lot of difference there in my opinion.

 

[Craig750]

Originally Posted By: rraiderr
Thanks for all the responses, I will stick with 20W-50 as it has been working great over the last several seasons and the bikes seem to run well with it.


If it is a track bike that's what I would be using.

More resistant to shearing than 10w40s.
More optimal viscosity due to higher oil temperatures experienced when racing. Most race bikes and classes don't allow increased cooling capacity, i.e larger radiators and oil coolers, so the oil is going to run hotter.