Yes, 6th & 65/70 mph is to low, IMHO.

 

Running a twin cam at 3k isn't going to do anything but make it happy. Lugging will lead to long term issues. You can run a twin cam at 5k all you want and won't hurt it as long as it is mechanically sound. When you constantly have to downshift to pass or climb hills you are lugging.

 

Have your GF/wife sit on the back to see if she thinks its an issue.

 

Hit 70 in third gear a few times to give yourself an attitude adjustment. When you're comfortable with that, do it in second.

Have you ever hit your rpm limiter? People have done it and lived....

 

I'll come at this from a bit of a different angle. This '13 Wide Glide is my first FI Harley, my first 6 speed, first 103, after many years on old HD iron it was all new to me. I noticed the same sort of issue you're describing along with some decel shuddering, normal or not? I've got not one clue at this point but being the curious sort willing to tear stuff to pieces that I am I started investigating the bike and found my front engine mount distorted and contacting the engine bracket pretty heavily.

I'd read about issues with the front mount being stressed and the rubber being distorted when they're mounted causing premature failure so I bypassed the dealer warranty BS and purchased and installed the new mount myself. I followed the engine alignment procedure and when I was done needed to shim out the front mount to keep it in the proper position and of course replace the bolts with longer grade 8's, the upshot was all the weird vibrations were gone, shift into 6th at 60 previously and you'd think you were for sure too slow to be in 6th but after the new mount and engine alignment, this WG feels like butter in 6th at 60 with zero decel shudders.

Same problem you've got? Hard to say, but it certainly worked out for me, this is an image of the new mount with the shims I needed to use to keep the front mount in the position the bike wanted it in...

 

Unfortunately your overall gear in 5th is 2.79:1, not good. You're gonna get weird overload vibrations in sixth unless your doin at least 80. Pick your gear up to a 3.15:1 and you will be much happier,,, stop lugging your motor....

 

I generally agree 6th should be for 70 and up however my bike being tuned and setup properly I can run it at 60mph without weird vibrations or feeling like it's lugging on a flat road. I used to worry about keeping the RPM around 2400 but now I don't care and rev it up as I please. I have a tach and I'm fine cruising at 3k rpm and shifting 4.5k-5k. Give it a shot it's more fun.

 

I have an 07 Lowrider that had bad vibes.I did the motor mount shim thing and it helped a little. Then I thought I would check the primary chain. When I got in there I found the auto tensioner very tight. I got to looking and there are two shims , one front and one on the rear between the tensiuoner and the inner primary case. Here one of the shims was missing and the chain was running crooked on the shoe.These shims are about a 1/4" thick. So I installed a M6 while I was in there and guess what! All my vibes were pretty much gone. I still have a little but I think my front mount needs replaced. I am the third owner of this bike and I think that the vibes were so bad that the other two owners got rid of the bike because nobody could figure out what was wrong. The only thing I can come up with is that this shim was missed when the motor was put together at the factory. There was not enough miles on the bike when I got it to warrent any reason to been taken apart and maybe not put back in by mistake. But my bike runs smooth as glass in all my gears. I had a 02 Electra Glide before this bike and this lowrider now rides as smooth as or better than the E Glide.

 

'09 ? .. your front motor mount is probably shot... and rear is about the same. Replace them, do an 'alignment' procedure.. and you'll probably be golden.

I've got 58k on my '08... I've ridden a lot at 60mph in 6th... no issues.. it's all about the tuning/intake/exhaust.

 

Finally did it. Going to order a tach and get that puppy on just for curiousity but ran 5th to 70 and it ran great suprisingly. Adjusted my other speeds and shifting times-had the same result. Kind of hijacked OP thread but it is a crazy difference in running the rpm's higher. Still don't lug doing 60 in 6th but from now on it'll stay in 5th. FWIW, I'm still new to HD. My Triumph didn't feel as cozy as higher rpms.