Sarto Seta Plus Tri-composite
Cutting-edge carbon fibre and razor-sharp performance
Just when you thought you were safe… bang. The cafe doors crash open and a man in weirdly tight clothes clacks in like a deer in high heels. He’s pushing a bicycle; he insists on having it inside with him because, just like the bicycle he brought in last month, this one is waaay too expensive to leave outside. Or to ever leave anywhere except tucked up in bed with a hot mug of epoxy resin and a story about The Little Carbon Frame That Could.
Yes, may I introduce the Sarto Seta, which like last month’s Spoon Customs Vars costs £13,000 (OK, the Spoon was £100 cheaper, but if you’re looking at a bike at this sort of price, who’s counting?).
Smooth operator
So how does this bike justify its price? Well, it’s built in Italy by Sarto in the tube-to-tube fashion, allowing for custom geometry, and Sarto also makes its own tubes in-house too. Both these things add cost. But where this Seta is concerned, a defining feature is the carbon material itself, in particular those red bits…
‘The red threads running through the carbon are actually copper filaments woven into the carbon fibres,’ says Sarto’s Davide Libralesso. ‘They’re just coloured red. This is the reason this version of the Seta Plus is the Tri-composite.’
This isn’t the first time I’ve come across this – eagle-eyed readers may recall that the Passoni Fidia (issue 74) uses carbon woven with titanium filaments. But this is the first time I’ve heard tell of copper, or seen it employed to such effect. The stem plate and saddle hull use it too, and Sarto also offers the copper in a blue and a green tint.
It’s all jolly pretty, but there is a reason beyond the aesthetic. Tri-composite is supposed to make for a smoother-riding and stronger frame. But how? Hang on, let me just roll the sleeves up on my layman’s overalls…
Imagine a table on which is perched a glass of water and a glass of oil. Depending on how hard you thump the table, either the oil or the water ripples most. This is because each substance has a specific resonant frequency, the point at which it vibrates most. By vibrating, the substances are helping to dissipate the thump energy, and this is what we want bike frames to do – absorb the frequencies of thousands of different bumps and thumps from the road before they reach the rider. What Sarto has done is add an extra absorbing element.
The Seta tracks near-perfectly through corners before pinging out of them with pronounced pedalling stiffness
It’s also stronger. Tri-composite is more impact-resistant, claims Sarto, because the smoothness of the filaments’ surface means they can slide inside the resin, such that in a highimpact strike they don’t shatter like carbon can.
It all sounds compelling, but does it work?
Sticking power
I stopped short of hitting this bike with a brick, so I can make no judgements on strength, but what I can attest to is that the Seta is smoother than a greasy conga, and as a result it corners beautifully, making all kinds of little flexible concessions to the road surface as it goes, thus keeping as much rubber in contact with the ground as possible.
I’d wager a regular Seta Plus would ride with less elan, however I’d also wager that while the Tri-composite material is certainly doing something, it is vastly outperformed by the Seta’s tube shapes and tyres.
The tube profiles are very close to being round, and in my experience round-tubed bikes have a better ride feel, something I’ve always attributed to round tubes being prone to flexing the same amount in all directions. This pairs nicely with the fact that, in this case, said tubes are also quite narrow by today’s standards, and this provides an extra amount of spring that carbon frames so often lack.
The result is a decent amount of give over big hits and a huge helping of compliance over rough, buzzy tarmac. Then, even more edifyingly, the Seta is imbued with a spring and flex that helps the frame track near-perfectly through corners before pinging out of them with pronounced pedalling stiffness. It’s like the best of carbon meets old-school steel racer. Still, all this would come to nought without good tyres.
One day I’ll shut up about tyres, but look, these are 32mm! And they say ‘gravel’ on them. Yes, these are Panaracer’s lightweight Gravelkings, and while I might opt for 28mm race tyres in summer, for spring UK riding these tyres are a stroke of genius. The width means a wide contact patch for lots of grip, the volume helps the Seta glide like a Slinky on a magic carpet. Perfect for crap roads in crap weather.
Add all this up and once again I’m left scratching my head looking for flaws. But honestly, I can’t find any. For anyone looking to spend this kind of cash, you’d be happy to spend it here. The Seta is a truly exceptional bike.