Yes, a few have but you have to change everything: rails, footboards, brake controls, master cylinder, gear lever, the lot!
An Aussie in WA did it when parts where still available new and it was about Au$1800+ in parts a couple of years ago. They are no longer available complete from Triumph but you can check. The front footboards themselves are shared with Thunderbird 1700LT and Bonneville Americas but not the brakes, rails, mounts or foot controls.
The rear footboards off a single headlight R3Touring will fit a dual headlight Rocket III Roadster too but you have to remove the rearfoot peg frame cover and the stock pillion pegs and the R3 Touring versions will bolt straight on to the 2 holes. If you want to re-fit the cover you will need to drill a hole for the front bolt.
Otherwise the stock Rocket III Classic rear foot pillion footboards are still available too. They are identical to the Thunderbird 1700 LT ones too.
I have a new set in the shed and a used set of R3t rear ones in their too.
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Nah Im after the pillion set up. The touring boards for the pillion set about 100mm forward compared to the classic.
The classic peg is right up against the saddle bag. My wife is a stroke survivor and has difficulty getting on and off with this set up
Came with the rocket in the Panniers that came with the rocket. Have the original pegs that where on the Rocket when I got it.
Dear I say try the Harley Davidson Dealership you might be able to but a set off them that may be a straight bolt on.
If you want I can remove them from the rocket and take pictures of the extenders with measurements if you want so you could possibly move the pegs forward would take a bit of fabricating by you.
Yeah Chris they are one of the two RIVCO versions (chromed steel and chunky chromed billet Alloy like yours) for RIII dual headlight models and they sold an accessory extension which you can still find occasionally as New Old stock but other makers such as Bulldog make versions too.
I have another spare set of the single headlight R3T rear pillion boards here in the shed as well and they are very heavy with massive steel mounts that will bolt directly to the dual headlight Rockets too if you remove the rear pillion pegs (one hole) and removing the rear peg frame cover reveals another identical hole for the second bolt. Either leave the cover off or drill and extra hole in it and refit.
They weigh about 3kg a pair from memory.
I sold a set to Ozrider a year or so ago too. He had a customer with a Rocket Trike build who wanted real Heavy Duty rear pillion boards.