I ran my first 7000 miles , and shifted into 6th at 60 (single) and 65 (two up).
Engine was happy with these speeds.
I added the SE compensator at 7000 miles and can now shift at 55 (single) and 60 (two up).
Engine is now happy with these speeds.
This would be on flat ground and not a big headwind.
Just listen to your machine and it will let you know what it likes.
My engine is at about 10,000 miles now and it seems more relaxed at lower speeds without balking at all.
Mine is darn close to bone stock and I weigh in at about 156 pounds.
40 lbs front and rear tire pressure , and running a 15" windshield.
YMMV
Mick

 

I have an '07 and run 6th grade at when maintaining 70 for an extended period.

 

I have an '07 and run 6th gear when maintaining +70 for an extended period.

 

Good stuff - thanks for the feedback!

 

I usually pop her into 6th at or around 65+. I don't have a tach so I have no idea where my rpm's fall in line with the speed. It varies with the grade I am running and so I listen to my motor and shift when she tells.

 

SG 1
You are correct. Thats what I was trying to explain. I really don't know where emwolb got his math from. HD six speed is 1:1. Where as a transmission with a ratio of 89:1 is considered an overdrive meaning overdriven. You can put the smallest sprocket you want on the rear to give it a high output ratio but, it still isn't an overdrive transmission.
Hope this helps Jonnierock

 

Mine is happy in 6th at any speed over 55mph.