I love the extra height of the tallest Wilbers, if I remember right its +50mm, so a touch under 13.5".
At 13.5", with proper spring rates, you won't drag pegs when at the edge of the tires any more, so take care if you are in the habit of using the peg feelers as an early warning system.
Bull is dead on about inseam, I'd advise against 13.5" if your inseam is under 32".
I just had the Progressive 444 HD 13" Chrome installed on my 2015 roadster. As anticipated with good quality aftermarket shocks, the ride has drastically improved. Downright cadillac comfortable on good roads and much more controlled dampening when the surface gets rough. The OEM shocks were awful and made the bike unstable on rough surface.
There are many options out there over the OEM shocks, but I can vouch for the improvement with Progessive. .
good shocks are never cheap . my suggestion try to score a set of WILBERG all the german r3 pretty much ride on them I do too here in western canada and it is a vast improvement over OEM they come in sets of front and back custom made for your own weight, the whole 4 pieces around $ 1200 last I checked in germany
Another link US$740 and in English. The same part code T18 specified for Std/Classic, Roadster and Touring modelswhich I do not think is a problemThey appear to be tuned for rider and passenger weight and % solo/pillion like Wilbers do when you order them. Twin Roadster for Triumph 2300 Rocket III Roadster - Model 2010-2016 - EMC SHOCKS US
That is NUTs Euro740 (AUD$1096) if you buy from the French language site of EMC and only US$740 (AUD$983) if you buy from USA English language site of same EMC company accessed by clicking on US flag in the French site. No wonder English has replaced French as the world's lingua Franca!
It's a sporty ride. Firm but well damped, on smooth surfaces you've phenomenal grip, on bumpy roads you get a much more composed bump and reset than stock or progressives.
Mid corner bumps become a thing you still feel but no longer upset the balance or grip of the bike. Confidence goes through the roof and suddenly your comfortable at much higher angles.
Well guess what ??? I just installed a new rear tire and after removing my right Corbin Saddle Bag I found my right Progressive 440 shock had been leaking a little bit and had accumulated a lot of dust around the bottom of the shock. Buggers. I did not buy these shocks new. They came on a bike I bought used and I transferred them to my Rocket.
I called Progressive and was told they no longer build the 440 and they only have enough rebuild parts available to do warranty rebuilds which you have to have a receipt of the purchase. He said they are only doing Warranty rebuilds. No rebuilds if you want to pay for it yourself.