I've had this back issue for decades and I've got to know exactly what sets it off. The real problem is seat height and the degree of bend in my hips. I'm the same with car seats and armchairs in the house. If I sit too low with my hips too bent, at some point I'm going to be in deep trouble.
The mids on the LRS make this worse but even with forwards I've got too much bend in my hips. I did fit a Tallboy seat (in fact I ordered one when I bought the bike, just in case). And I rolled the bars back to bring them nearer. Both these things helped a lot but they can't eliminate that tight hip angle.

The Triumph has a higher seat height. You're much more on the bike than in it and my thighs are level or even angled downwards. The forwards aren't as far forward as most Harleys either and they're adjustable by two inches fore and aft. It's taller and you're not sitting as stretched out as a Harley and unfortunately my back dictates the seat posture.

The Triumph's suspension is pretty stiff - most Triumphs are. I can sure feel the bumps but the sitting position means they're not being transferred into my spine the way they were on the LRS. That's the difference.

 

Corbin make (very smart) hard bags and a fairing (with audio if required) that would fit it out as a bagger. For me, I prefer the pared back approach. That was why I chose the LRS. When I tour I tour light so both the LRS and the Rocket would work for me as far as luggage goes. But you're right. The Rocket would make a perfect full dress tourer. Yes it would be even heavier but a RKS and a Road Glide are pretty heavy too and they work just fine.
It's odd that Triumph didn't offer a proper bagger option. It would have widened the bike's appeal.

Funny you should say it's just a seat bolted to an engine. I've overheard people saying that a lot this weekend. And to be fair, that's kind of what it is. But I like that.

 

Variety is the spice of life

There's no law saying you can only own one motorcycle or one brand at a time.
I've owned 3 late model Triumphs in the last 10 years and they've all been great bikes.
Congratulations on your new ride.
Don't let the fanboys run you off. This site is Harley Davidson Forum, not Harley Davidson Owners Forum.

 

Gimlet, do yourself a favor, and try out a kneeling chair for office/work/home.
If you regularly sit in chairs for what you do, they can damage your back and make it hard for it to heal.
I had a mysterious back injury that left me bed ridden late 20, early 21. And could not figure out what was going on.
I tried all kinds of meds, went to the doctor and all that stuff. We assumed it was just another fibro issue I had.
But sitting in chairs always made things worse. I thought that was normal, no one likes sitting in those office chairs all day.
I tried a bunch of ergo chairs and nothing helped. Until finally out of nowhere I came across a kneeling chair.
After many months of trying it my back started to recover.
After talking with my doctor It turns out that office chairs are what damaged my back and eventually it caused it finally give out.
The kneeling chair when I remember to keep my posture straight, helped my back so much. It's worth a try since they're usually around 100$
It takes some time to get used too, but it's absolutely worth a shot.

Also purple mattresses are fantastic for people with back problems. Expensive, but they do a good job. I wish I could get one again.
Best of luck with dealing with the back problems, they absolutely suck.

 

What do you think you mean?

Hope he enjoys the ride. Sounds like fits his body.

 

For the sole purpose of pissing you off, here's a pic of a Triumph I owned...enjoy!




And you enjoy your new bike, Gimlet.

 

Congrats on your new Rocket 3. My last Brit bike was a BSA 500 Victor, which not a bad bike, for something from that era.
I'd like to see HD go back to the upright riding position they had on the pre-Evo FLs and Sportsters, or at least have that as an option. I tried to be more upright on my Road King, with a Mustang seat w/backrest and HD Touring handlebars. That setup has worked well but not like the older bikes.
Don't feel that you have to exile yourself from this forum just because you bought a Triumph.

 

That Triumph Rocket 3 is an awesome machine..Best of luck with it.

 

Ride safe Gimlet

 

Yeah.the Triumph an awesome bike. But, I missed the part on how it resolved his back problem. But, then the OP is from the UK, and so is the Triumph…so there’s that.