6 Speed Trans

[joel]

I had a 03 RKC and also felt it needed 1 more gear.
Never had any problems cruising at 70 or more, I think rpm at the high side was just fine.
As for your sometimes seems ok and sometimes seems to be high rpm's might just be pressure block in your ears.
Happens to me more and more as I get older.

 

[biscuit]

On my 08 96” FLSTN I changed my gearing to about 9.6% shorter to raise rpms because the 6 speed HD box is woefully overgeared. You can’t really use it at 100kph.
I did this by going smaller on the front pulley( 30T) larger on the rear. (68T).This kept my belt length about the same as standard.
However, IF you want to go a bit longer and drop the rpm’s; you could fit an Andrews 34T front


This would give you a 6.25% reduction in engine speed in 5th gear. Everywhere in the rev range.
Acceleration and pick-up may be slower and you’d want to ensure your belt wouldn’t be too short.
One option for you.