Saturday was the first good ride for me and a bud on our new HD. I have a 08 Ultra that is a tuned up 103 he has a 2010 limited with the stock 103.
328 miles and you would have to drain the tanks to find a difference in our mileage. We matched that closely. 162 miles and still had a 1/4 tank left.
Now we both were running 6 gear out and back around 65. My neighbor has an 08 SG and he said that we would have probably gotten much better mileage had we run 5th at those speeds. He said he avoids 6 unless running steadily at or above 70 mph.

So what is the consensus on 6th gear?

Do you think neighbor is right that had we run 5th at 65mph we could have done even better?

 

I'm with your neighbor. I've done it both ways and do better mpg waiting until 70 to hit 6th.

 

Ya know, I don't agree, I think the '07 to '10 primary and secondary ratio's are the same and both of you should have the same gear sets for your 103's. If you can use it and you have thre torque to pull it then you are better in the higher gear. I like to think our large displacement 2 cylinder motors are designed for torque not HP therefore more efficient at low RPM's or this case 6th gear at 65 MPH.

 

I don't run 6th gear unless i can run at 3000 to 3200 rpm and that usually running 80 mph and get better millage. Just a thought ,next time you go ridding don't tell him you are running in 5th gear and see who gets better millage,keep your's at 3000 rpm no matter what gear it takes.

 

The 07 and 08 gearing was different. Not the actual gears, the pulleys.
Those bikes hated 6th gear...

 

And the frowning man wins the internet

My wife has an 08 RG. 6th gear is pretty much a dog.

 

Yep, I agree with you completely. For me I hit 3k rpm between 70 and 72 and that's when I go to 6th.

 

Once you get over 3000rpms the gas seems to disappear.

I run 65 miles to work one way, 8 days straight. About 20 miles of that is 75mph speed limit, traffic runs 80+

I run 6th gear. If I take the "back road" home, the speed limit varies between 55 and 60, and get WAY better mileage...

The biggest factor in MPG at speed is wind resistance. There is a sweet spot, but above a certain speed, trying to slice through the air drags it down.

 

Agreed, all my baggers over the years seemed to drop MPG once you get over 65MPH. Never had one of the early 6 speeds so never experienced the lack of torque. Stricktly talking gearing and assuming you have enough torque, lower RPMS will always generate more MPG

Assuming a stoichiometric AFR of 14.7Grams of Air to 1 Gram of Gasoline and your motor running 3000 RPM's in 5th gear or 2500 in 6th, the motor could consume about 0.044 drops of gasoline per engine revolution. Using this logic running 65 MPH the engine will consume 110 drops of gasoline per minute at 2500 RPM and 132 drops of gasoline at 3000 RPM. Basically 12 more drops per minute or 720 more drops per hour or 11.7 more drops per mile in 5th gear. There are 58369 drops per gallon so it may be hard to detect in average MPG

 

On my '08, 6th is only used on the interstate if I'm running at least 70mph.
But, I will also say the answer is "it depends". Depending on the modifications done to the bike (cams, pulley/sprockets, etc) 6th gear may become more usable.