1975 Triumph Trident T160 review

Faced with the imminent arrival of 750 superbikes from the East, Triumph needed a multi. They built the Trident, which was pretty good by the time they stopped building it

Mainstream British bikes in The Great Golden Age were predominantly twins, twins of ever-greater capacity. They usually started out as 500s and then expanded in both internal dimensions until they reached their limits, mostly 750, although Norton went one better with their 850 Commando. Sounds good? Maximise return while minimising investment? It was. Riders were happy – usually because the Brit twins were familiar and because the riders knew no better. And if the engines grew increasingly temperamental and vibratory as their capacities expanded, well, that was all part of the heroism, macho culture and things like that.

And then the captains of industry (and eventually the Press of the day) understood that the unfairness that was genuine competition was headed their way, in the shape of the famous Four from Honda.

All serious engineers understood the diminishing returns law of stretching a basic design. Up to a point it’s OK, because engineers are no fools and allowed for capacity increases in their original specs, but there comes a point where the original tooling cannot cope with the strengthening which needs to go with increased power, increased reciprocating mass and the beefy bearings required to cope with it all. Your average trad Brit twin’s bottom end was built like a skipping rope with the crank and its mighty and only partially successful balancing flywheel being whirled around between a bearing at each end. They could (and did) whip, and they could (and occasionally did) break. This is bad. Even the most die-hard of marque fans will struggle when his P&J clatters to a broken ruin after just a few thousands of miles. Hands up if you know why Norton’s Combat Commando was famous.

Turning a twin into a triple was both simple and highly complex

However, although it’s long been fashionable to pour scorn upon the simple idea that a triple would be a logical step to take and would permit the old BSA / Triumph chaps to continue to use the plant and techniques they already owned, rather than buying posh and expensive new kit, it was in fact completely sensible. And in any case it was intended to be a temporary, gap stopper to hold the fort while the Bright New Future Range of modular engines was developed. Which never happened.

Right then. 1.5 500cc twins equals a 750 triple. Plain enough. So that was the plan, and that is what they built. So far so sensible. The problem was the bottom end. Remember that skipping rope crankshaft idea? Well, that was plainly not a sane option for a 750, no one could even dream of hanging three big end journals between just two main bearings. Very silly. But… as always in the old Brit business, there is a big BUT… the old plant in the factory was intended to produce crankcase halves, and only if they were split vertically, which is sensible for a single, possibly sensible for a twin, but improbable for a triple. And so they designed the Trident to have three crankcase halves, with the middle half [sigh] containing a pair of shell main bearings to sit either side of the centre big end and supporting the whole thing. Sounds insane? Must have been easier and would certainly have been better to follow car practice and hang the crank assembly from a single crankcase, with an unstressed oil sump beneath. But they didn’t. Stiff upper lip, chaps.

When it first appeared, Triumph’s 750 triple was (almost) a rival for Honda’s world-beating CB750/4

The other notable insanity was that the engine was based around the Triumph twin, which is an ohv design and carries its flickery little pushrods in chromed tubes, external to the cylinder block. Very 1930s. So instead of two tubes to leak happily, as on the twin, there are four. They don’t in fact leak. Much. Often.

The engine sounds like an appalling cobble job, but is in fact a delight. It is. So there. I ran a T160 like the one in the pics for many years. It was the most expensive motorcycle I have ever tried to keep on the road. Honest. I loved it. Ridden anywhere near its limits – which are high; BSA / Triumph twins were world class racing engines, remember – mine managed 30mpg. Also 30mppint, because it was utterly dipso regarding the oil.

The T160 was the last of the triples – following the T150. Logic in numerology if in little else. The company was already bust when they started building them, and they built them at the near-deceased BSA works at Small Heath in Brum rather than at Meriden, home of Triumph. I know why, but I’m already writing over-length…

Price

Scary stuff. A decent T160 Trident will make £10k on a good day. Even a half-decent example is heading that way. Buying a cheaper imported machine (because they were almost all sold in the US and places like that) for a bargain basement £6500 or so and rebuilding it yourself will rapidly teach you the twin delights of patience and poverty. In the long run it’s cheaper to buy a good one.

Spares are plentiful and pricey; modifications and improvements abound; they’re mostly good ideas which work and they cost a lot. Lots and lots. Once you have become a true believer you just won’t care, and in any case you can either afford one or you can’t. Earlier kickstart-only T150 Tridents are generally less expensive – you’ll find them around two-thirds the T160 price. But they don’t look so utterly ace and they demand kicking, which is undignified.

If you’re suddenly sold on the idea – and why not? – buy the best you can afford. If you’re not already an expert, buy from a trader, and buy with a warranty. This is the best advice you’ll have read today.

Unless you enjoy tinkering more than riding, buy the best one you can afford

Power and torque

To anyone familiar with British twins, and especially Triumph twins, climbing aboard a Trident for the first time can be a peculiar experience. To anyone familiar with Japanese multis – less so. The T160 Trident – as seen here – is the least odd for a rider used to the rival 750s of the day, not least because its pedals are the current way around and its engine can start itself without that kicking nonsense.

When it was launched in 1968, the original Trident stamped out 58bhp at 7250rpm, which was certainly competitive. The white heat of progress resulted in the last of the same line producing 58bhp at 7250rpm. But before you collapse with the sneering, noise regs had grown seriously strict between the two dates, and both induction and exhaust silencing was stringent by 1975.

The odd thing is that the Trident engine feels like it’s buzzy and high-revving, but only to anyone too familiar with a twin. The T140 Bonneville developed maybe 50bhp at 6800rpm, so the Trident certainly felt faster and indeed revvier, as there are three cylinders firing and not two. And of course the power gain from three cylinders was largely absorbed – on the road bikes – by greater weight. So the triple feels much more modern, even if in reality it’s not. Not much.

Torque? How does a figure of 45lb/ft sound? OK? But peak torque is around 6900rpm, so you need to work the engine a little to get that figure. These stats compare well with the T140 Bonnie, which managed a notional 40lb/ft at 6000rpm. The difference lay in the manner of the delivery. The triple is much more buzzy, much more modern, much more ‘multi’.

A possibly useful comparison is with Yamaha’s almost contemporary XS750 triple, which was dohc rather than ohv like the Triumph. That pushed out 64bhp at 7500rpm, and 45lb/ft at 6000, and they are remarkably different to ride, with the Yam being the less buzzy by far. Go figure. Myths ignore this.

Electric start is welcome…when it works

Engine, gearbox and exhaust

Relatively few were actually built – the best estimate puts the figure at around 7000. Which isn’t bad, given that the T160 was in production for only a year.

Let’s start at the top. The engine is ohv – pops its valves, two per cylinder, by short pushrods. This was primitive, even for 1975, but has advantages, one of them being that the engine need not be tall to accommodate camboxes. And it isn’t tall. The T160 lump is a little lower than the preceding T150 Trident because the cylinder bank is canted forward a little, in theory to allow space for the starter motor to fit behind the block, but that seems unlikely as I’ve seen several T150s fitted with the starter kit for the T160. I think Triumph cranked the top end forward because it looked better. More modern.

Top end design is still primitive, with external tubes to contain the pushrods and separate rocker boxes, one each for inlet and exhaust, bolted to the top of the head. Plenty of opportunity for Joe Bodgit to introduce leaks by stripping the threads when playing at fixing one. Oil to the rockers was delivered by a messy pipe outside the rocker boxes. Sophisticated it’s not.

The block and head are both beautifully cast in alloy, with closely pitched fins. Below this handsome air-cooled top end lives the 3-piece crankcase, as mentioned already. The timing side and drive side contain monster conventional ball/roller main bearings, with a further pair of shell bearings clamping the 120° crank in place. On the right side of the engine is a case containing the timing gears which drive the camshafts, with an extension from the exhaust shaft spinning the cam which operates the three sets of contact breakers. The first thing any sane Trident owner does is replace this idiotic set-up with an electronic alternative. There are a few of these and they are all an improvement.

Also at home in the timing chest is the Lucas alternator, moved from the trad Brit location inside the primary chaincase to ease the width a bit. The engine is still wide, but not as wide as it could have been. And a seriously hefty and usually effective oil pump lives down inside, as does a decent oil filter. The crank has five plain shell bearings, and they really do like clean oil. Change that filter a lot.

Drive is taken from the left end of the crank via a duplex chain, itself adjusted by a slipper tensioner and driving a slightly unconventional clutch. Unlike all Triumph twins, which use Brit-standard coil springs to clamp the plates together, the triples use a diaphragm spring instead. Set up properly and with decently meaty clutch plates to preserve the important stack height, this works very well. A neat bit of design has the Lucas starter motor driving the engine via a gear on the back of the clutch.

Five speeds in the box, and a left-side lever to shift them, then a single-strand chain to the rear wheel.

Amal carbs need tickling to wake them up, Honda’s Mikunis didn’t require a sense of humour to live with

Breathing in is accomplished using a bank of three Amal Concentric 626 26mm carbs, which appreciate a tickle to help fire up a cold engine. Don’t we all? Exhalation is handled by a truly handsome set of four exhaust headers; the middle pot using two pipes, one heading off to join the single pipes from the outer cylinders. There’s an engineering reason for this, but basically it looks like the engine’s a four. This possibly did not hinder sales in those shiny chrome days. The four headers merge into a pair of silencers, which really did chop the crackle from the exhaust note. These are accurately referred to as ‘annular discharge’ silencers, but more folk call them ‘bean cans’ or ‘black caps’. They work really well, and the engine works well with them. Of course, lots of enthusiasts replace them with the bonkers ray gun efforts from the original 1960s Tridents. The same guys switch from Amal to Anything Else, usually Mikuni carbs. There are several reasons for this, many of them imaginary.

Handling, suspension, chassis and weight

All the Tridents use what is basically a development – mostly strengthening and a little geometric fiddling – of the pre-1971 T120 Bonneville’s frame. This is a good thing, as it’s a good frame. Neither BSA nor Triumph triples followed the singles and twins down the path of the oil-bearing frame, which may also be a good thing, not least because the triples were hard on their oil, necessitating a cooler for it mounted under the nose of the fuel tank. The twins got by on a 4-pint capacity, while the triples carried six pints, which is another good thing.

As we’ve already said, the engine is low-slung, and so is the rest of the bike, with a seat height of between 29 and 31 inches, depending on your source material. Rear bounce is controlled by Girling shocks – or was when the bikes were new. Plenty of modern alternatives are available, some of them better than the originals. But not all.

The frame is quite simple, with just a single front down tube splitting into a cradle beneath the engine. The seat and shocks mount to a rear subframe, and the swinging arm is entirely conventional.

Front forks are the handsome slimline variety fitted to almost all BSA and Triumph machines from the 1971 season until the end of T140 Bonneville production in 1983. They’re good forks, too, and work well with a steady predictability which is reassuring if you press on – which you surely will if you want to get the beast out of a Trident. They provide 5.75 inches of travel, which may not sound like a lot but is enough. There were a few upgrades to the same fork on the T140 twins after the T160 slipped into the history books, so if you want to upgrade a little you can. You can also fit progressive springs and fiddle with the dampers should you wish, but the factory offered no adjustments at all at the front, and only preload at the rear, so if you enjoy a decent fiddle, feel free to spend more money. The T160 weighs in at a porky 502lbs, and the frame handles this with ease. Both rims are 19-inch, running 4.10 tyres, so the steering can feel fairly vintage, although it’s all part of the charm, part of the reasons for riding a bike like this.

Handling and steering are excellent. Really. No reservations. If you want to exploit the fine road holding, and modern rubber ware encourages this, you’ll need better ground clearance, which means ditching the centrestand and fitting rear-set rests. Racing Tridents used this frame to lap the IoM at terrifying speeds, so feel confident. Did anyone mention braking?

Brakes were as good as the competition, but 502lb is a lot of weight for two 1970s discs to stop – a twin disc conversion is worth having

Brakes

A front disc brake had replaced the two types of 2ls drum stoppers already, at the same time as the disc appeared on the twins for 1973. No surprises there. In the mid-70s the single 10-inch disc was viewed as OK, but it’s marginal, given the speed and the weight of the Trident. The T160’s engineering team took advantage of the shifting of the brake pedal from left to right to replace the sls rear drum with another disc, intelligently exactly the same as the front and gripped by the same 2-pot caliper. Both brakes feel wooden and weak when compared to modern anchors but work OK. However, among the very many upgrades available for Tridents are several excellent brakes and fitting at least a second front disc is recommended. It is impossible to have brakes which are too effective.

Export fuel tank was prettier – but smaller. Taller ‘export’ handlebars offered more comfort too

Comfort

Basic stuff here. There are two fuel tanks – home market and export. Most of the Tridents you’ll find will be export models, because most of them were exported. This makes sense. The UK tank is a notional 4.8 gallons, which is not a lot if you’re pressing on and returning around 35mpg. The export tank is just over a gallon smaller, but looks a little nicer. And export tanks were typically supplied with export handlebars, too, which are tall and wide. They work well and suit the fixed footrest position too. UK bars are less dramatic and produce that peculiar forward slump familiar to Brit riders down the years.

The stock seat is not a place to sit for a long time. There are few advantages to fuel-swillers like this engine, but the need to get off every hundred miles or so to fill up is one of them. Alternatives are of course available, which is a good thing. Most of them will be an improvement over the original.

The engines also tend to vibrate, which a 120-degree three should not. But they do, in strange spots throughout the rev range. It’s not harsh, but can be tingly. I always blame the carb set-up. Triumph acknowledged this by offering rubber-mounted footrests, which are very effective.

Equipment

There’s an electric starter! It usually works! Other than that, equipment spec is modest: two big Smiths clocks do the mile and revolution counting, and there’s a neat binnacle to hold them – rubber-mounted too, because of the unexpected tingles. A small array of loonie lights tells you the usual things about flashing lights, main beam and whether the battery is charging. There’s also a neutral light, in one of those endearing moments of optimism. Neutral is in fact easy to find. The light is … sporadic.

Paranoid owners fit oil pressure gauges; also known as the blood pressure indicator…

Still a great looking bike and still relatively affordable too

1975 Triumph T160 Trident Verdict

These are great bikes for anyone who wants a classic ride which will go like stink, handle brilliantly, make fabbo noises and turn heads wherever it’s parked. The barely contained ‘whooooo…’ as the revs build is a great roar and encourages you to go far too fast, which is a rare thing with bikes of this generation.

Downsides are several, mostly involving the cost of the thing, but if your wallet is not of the weary kind T160 Tridents – the last of their line – can be awesome. This is why they are still so popular. Try one. Buy one. Try to love it. If you don’t you can move it on with little loss – if any. They’re great. I have no idea why I don’t own one myself…

Three things I loved about the Triumph T160 Trident

• Excellent performance

• Outstanding looks

• Superb handling

Three things that I didn’t…

• Killer seat

• Vibration

• Riding position

1975 Triumph T160 Trident spec

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