In the Triumph naming system, the TR numbers indicated a new body. Not the TR8.
The ’65-67 TR4a had a four-cylinder 2.1 litre unit. The ’67-68 TR5 had a straight six 2.5 litre unit as did the TR6 which ran to 1976. Then Triumph reverted to a 2.0 litre four with the TR7. Oddly then the TR8 name served to indicate a new engine, the Rover V8 and not a new body. But it’s the disappointing ashtray that we’re here todiscuss. It’s door mounted which is an unusual touch. It looks like a horizontal lower hinged device, and singularly badly located for smoking and driving. They did that on the other side too.
Driven To Write 
“They did that on the other side too.”
Very droll indeed.
It was a joke waiting to be used.
Good one though – given that in the first decade of this century swept-down side swages seemed to take over the world, Harris Mann got the last laugh.
The TR numbering system is not as straighforward as the header paragraph suggests (A Boring Slag writes). Nothing at Standard-Triumph ever is.
The TR3 got a shiny grille in place of a gaping unadorned intake to differentiate it from the less powerful TR2. The “wide-mouthed” treatment arrived mid-term for the TR3.
The first proper re-body came with Michelotti’s 1961 TR4. The 1967 TR5/TR250, with the 20S six was only distinguished from the four cyinder TR4A by badging.
The TR5/TR250 lasted only 13 months until the Karmann-designed TR6 arrived, itself a nose-and-tail job on the TR4 body, with the centre section and interior changed only in minor details.
That is fabulously messy. Something of that could be gleaned from toggling through Wikipedia but it was too much data for me to compress. As I outlined, the new number seemed to come with a change to the body. The TR8 body differs in no important way to the TR7 body. Also, those TR numbers are sequential. Up to the TR7 and TR8 the TR´s did no co-exist. That´s another way the TR7 and TR8 numbering is a bit off. Did TR stand for anything or is it as meaningless as the A in Audi A3, A4, A6 et cetera? Triumph Racing perhaps?
As far as I understand, from someone who’s done several V8 conversions the TR7 and TR8 bodies are identical, and there’s no metal-bashing needed.
The whole TR7 / 8 is oddly alien to everything else BL were doing at the time; Marina, Allegro, Princess, SD1. The rear suspension is very GM-like, and the dashboard looks as if it would be more at home in a Volvo than a sports car.
As for TR, I don’t think it has any significance other than the first two letters of Triumph. Post WW2, the once illustrious Triumph was pretty much a zombie brand under thrusting, ambitious Standard. The abject failure of the Triumph-badged Mayflower nearly killed the nameplate off, the TR cars turned the tide.
Incidentally, there was also a TR10, but it was just a re-badged Standard 10 for the US market. A quite impressive 9910 were sold.
The Mayflower has no sporting character at all. It’s a kind of miniaturised Rolls-Royce. There’s a touch of Allegro Van Den Plas about it. Then Triumph became a name for sportscars. How peculiar.
I really wish Rover had been closed instead of Triumph. The way the market turned out you can see someone selling Triumphs today but not Rovers. Even Jaguar has a hard time selling Britishness. Sportiness is international and timeless. Britishness is forever 1967.
I have always understood TR to stand for ‘Triumph Roadster’, but that is purely what I have picked up at one point or another over the years – I’ve no reference to substantiate that.
Stevemckelvie.wordpress is a bit of a Triumph enthusiast. He suggests it’s arbitrary. There is no official explanation from company documents as “TR stands for x”. It seems like a working name that escaped into the wild. Interestingly there was no TR1. The name was created afterwards for a one off sportscar.
Tr7 (etc) ash tray might have been a parts bin fitment, possibly from the Landcrab/Maxi fitment from the early 70s (as were the door arm rests made by Marley Foam, albeit in different colours).
There was a previous example of co-existence. The TR3B was produced for a while for the US market for those who found the TR4 shape too shockingly modern or its’ wind up windows too soft!