How cold is too cold for 20w50?

not an oil thread

let's call this a "state of matter" thread

what is the coldest average temp you'd run dino 20w50 in an airhead?

i'm gonna do an oil change tomorrow, this is my winter oil, i guess, i'm probably just gonna stick with 20w50 as it doesn't really get super cold here (figure avg winter startup is gonna be in the 30-45 degree range) from what i know this is probably fine, but i sometimes feel my bike's a bit "fragile".

i used to run lighter oils in my oilhead in the winter, but that was massuchusetts "highlands" colder winters (regularly rode in the teens) and a newer bike.

BubbaZanetti said:

not an oil thread

let's call this a "state of matter" thread

what is the coldest average temp you'd run dino 20w50 in an airhead?

i'm gonna do an oil change tomorrow, this is my winter oil, i guess, i'm probably just gonna stick with 20w50 as it doesn't really get super cold here (figure avg winter startup is gonna be in the 30-45 degree range) from what i know this is probably fine, but i sometimes feel my bike's a bit "fragile".

i used to run lighter oils in my oilhead in the winter, but that was massuchusetts "highlands" colder winters (regularly rode in the teens) and a newer bike.

Click to expand...

I used to run 10W40 in the winter. One year when Mobil 1 first came out I ran 5W30 or whatever it was then. That way my bike would start sitting outside the lab all day in 10 deg F. It used a quart about every 500 miles with that stuff that winter. But it started. When I took it apart years later, everything looked like new incl the cyl bore. Any oil is better than no oil.

also a synth user

Also a synth user ...

but the /7 factory Repair Manual
has an "Engine Oil viscosity Chart"
(Oil grades to use at various outside temperatures)
at the beginning of the book ...

according to that chart,
20w50 is suitable from @ 16??F to @ 110??F

15w50 from @ –5??F to @ 85??F
and 10w50 gets you down to @ –21??F to 50??F

I think you'll be safe with 20w50 year round.

Derek, your MOM will tell you that the range for 20W50 is about 15F to 105F. 15W50 goes -5F to 90F, and 10W40 goes -20 to 40F. My feet are only good to about 20F or so, and with a 30 mile commute, and speeds around 70 as common for much of it, i rarely push even to that 20 deg mark. i run 20W50 all year round.

Not an oil thread, but...

I run 20/50 dino in one of my airheads. It gets kind of "stiff" below 30 degrees F.

That said, my "guy" recommends Mobil 1 synthetic, 15/50, all year 'round. That's what I've been using in my '77 RS for the last 3 years, and have been very satisfied.

15W-50 Mobil 1 would be perfect for winter and not because it's 15 but because it's synthetic. Its cold pour point is almost the same as any other grade of Mobil 1. You can look it up.

I switch a couple bikes to the Maxxim 10/40 for winter. We are talking teens in the morning, high maybe to low 50's at most. The dual plug one would start better with the 20/50 than the other. But really, the bike was groaning with the thicker oil, especially at startup. And even 30 minutes in a store in the afternoon would leave it quite cold again. I feel the 10/40 was much easier on the motor, especially at startup, during these cold temperatures.

My winter airhead oil was 10W-40.

I use 10w40 in the winter here in Iowa.

ÔÇ£State of MatterÔÇØ

IsnÔÇÖt this the key question for either dino or synthetic oils in terms of temps? The SAE rating is related to how the oil behaves at a given temp and its ability to deliver the protective and lubricating nature of the stuff.

The lubricating ability of any oil has to do with its ability to first penetrate and cover the surface (bearings is the big concern at startup) while providing the proper sheeting and adherence at the current operating temperature both ambient and of the engine itself.

Single viscosity oil will provide a certain ability to penetrate a bearing gap while providing a defined lubricating ability to that surface. Multi grade oil is a multi personality oil. The two numbers combined give a temperature range over which the oil is designed to have a viscosity to penetrate the gap deliver the sheeting and lubricating benefit of the higher number.

Multi grade oils of any kind give a wider range of safe range of start up and operating temperatures than single grade oils. If a multi grade oil meets all of the alphabet soup requirements for the engine it is put in and covers the operating temperature range at start up that you anticipate encountering you should be fine. At least that is the promise as I understand it.

What is the ambient temp where you are is an important question in selection. I donÔÇÖt know about the temp ranges in NY. When I Roundered my airhead in Chicago temperature differences between what was reported for lake side v at OÔÇÖHare varied by 15 degrees normally. In the Lilydale suburbs of the Twin Cities the temperature range varied between 5 and 10 degrees. What I paid attention to was did my oil meet the low temp requirements of where I would be starting my engine again after it was sitting for a while.

Effect on Ease of Starting?

While we all know the charts say it's *acceptable* to use 20W50 down to ~15F, the better question is:

Would you be better off going to 10W40 in the winter because the thinner oil will make turning a cold engine over easier?

(consider this oil thread pot freshly stirred )

What I paid attention to... was the low temp requirements...Mika

Click to expand...

That was my focus, as well, when I had my airhead. And airheads can be a bit difficult to start at colder temperatures, which I think is caused by pumping losses from their high capacity oil pumps, and because of the vacuum carbs. They need a good spin at startup to before they'll light off.

That was my experience with my RS, anyway.

mneblett said:

While we all know the charts say it's *acceptable* to use 20W50 down to ~15F, the better question is:

Would you be better off going to 10W40 in the winter because the thinner oil will make turning a cold engine over easier?

(consider this oil thread pot freshly stirred )

Click to expand...

Another way of putting this is, "How far are you willing to walk back from wherever you are when your 20W oil is too thick for your cold battery to stir?"

535is said:

Another way of putting this is, "How far are you willing to walk back from wherever you are when your 20W oil is too thick for your cold battery to stir?"

Click to expand...

what i'm basically getting to, my oilhead cranked over with a bit of difficulty at 18 f with 20w50 dino, a bit better with 15w50 dino, WAY better (like it was 75 out) with 5w40 rotella, which i used as my "winter oil" on the R11S. the "slow to start" nature of this airhead when it gets cool seems like it'd only be further hampered by oil that was too thick. the other reasons i don't want to go with a "winter oil" on the airhead is 1. runing 10w40 on a weird 88 degree day next april in a bike that gets significantly hotter than my oilhead used to, on a bridge, in traffic, in nyc, does not sound good. 2 it seems all the "pros" are against the thinner oil in the hotter running airheads.

have not considered synth only in deference to the 25 year old seals, don't want the thing to resemble the bsa and norton parked along side it.

Not sure of your situation at home/work but...could you preheat the oil somewhat for the Airhead, as in put a light bulb under the oil pan? I've heard of people doing that and the bulb providing enough heat to keep the oil at a higher temp for easier starting.

Now you’re starting to hit the second part of winter or cold weather starting issues – cold cranking power of our electrical systems. We (myself included) compensate for old batteries and not charging them by using lighter oil when it gets cold.

Mika said:

Now youÔÇÖre starting to het the second part of winter or cold weather starting issues ÔÇô cold cranking power of our electrical systems. We (myself included) compensate for old batteries and not charging them by using lighter oil when it gets cold.

Click to expand...

I was thinking of making the switch, when this morning, my R90 was reluctant to start. It was probably still in the low 50's.

About 4 attempts, 4 seconds each, and it started. Smelled something funny, and saw my negative battery post had melted.

cool x oil

I am in NYC too and I was asking my self the same questions this week.
Now I have 20w50 semi-synthetic oil but i will wait to see how this winter will turn out. at the momenti have semi-synthetic 10w40 because my bike is cold blooded and I dont want to take chances stressing my battery.

How about this, Derek:
Your engine is cold when it starts, and when it starts only. The rest of the time, it is running under the conditions the oil will be working hardest at. If you're going to start it and ride at freeway speeds for half an hour+ every day, you'll probably want different oil than if you're going to start it and scoot around a few city blocks at half that RPM for half as long. Pick the oil that suits your riding needs and adjust your starting/warm-up habits accordingly.

Located in Texas here so may not be much help.
But I run 20/50 year around, there is a good chance we will have high 80's in Jan. and Feb. But with a good battery and starter my RS cranks over just fine in the few mid 20 mornings we have also.
I do give the bike time to warm the oil as well as its self before making it work or turning over 3,000 RPM.

When I started riding I lived in Ill, and loved 2strokes because they would start more reliably in cold temps. With 10/40 and temps in the single digits could not even spin a 4stroke over fast enough to start with the kick starter. This was pre magic button.