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Inside Dassi: British manufacturer using graphene in UK-made frames

Peter Stuart
27 Jan 2017

The world of carbon bike building revolves around the Far East, but Hampshire-based brand Dassi has grand ambitions to change that

Walking through an industrial estate in Banbury, Oxfordshire, there’s a sense of expectation in the air.

We’re here to visit the manufacturing facility for Dassi, a company that aims to make the first mass-production carbon frame in the UK, the first frame to use a material 300 times stronger than carbon and the first 3D-printed carbon bike components.

Nestled somewhere between a chocolate factory and a heavy tool factory, it’s not obvious which one of the dozen anonymous-looking warehouses is being used to achieve these various technological wonders.

Dassi’s production is currently handled by Brick Kiln Composites, a company more at home with F1 and aerospace components than bicycle frames.

The factory is just one part of the global hub of F1 businesses in Oxfordshire.

How exactly Dassi owner Stuart Abbott has turned its space-age tech towards the business of bike building is the question that has brought us here today.

 

I’ve barely spotted his Dassi-branded car before Abbott leaps out and excitedly shares his vision as he ushers me towards Brick Kiln’s building.

He’s partnered with numerous UK firms to produce his bikes, and this is the centrepiece.

One at a time

While we’ve seen some innovative and impressive UK-based carbon framebuilders, the complexities of the process has often meant production involves one man in a room crafting bespoke frames.

Dassi’s ambition is somewhat greater – a large-scale custom carbon project akin to Parlee and Alchemy in the US, and something never before done in the UK.

It’s a claim we felt had to be seen to be believed.

I’ve had to submit my passport in advance as the factory deals with secretive carbon projects and visitors have to be appropriately vetted.

Now I’m here it seems somewhat understated – a standard redbrick building in a nondescript industrial park. Inside, though, is a different world altogether.

The engine room

Nick Brew, production manager at Brick Kiln Composites, talks me through the process of building a Dassi frame, but unfortunately he won’t be able to show me a finished product.

‘Making a frame takes two or three days, and today we’ll be staging certain parts of the process,’ he says.

Brick Kiln deals with aerospace, F1, and defence projects in carbon, making it a secure site.

We’re not allowed to photograph much and it’s little wonder – it looks like a cross between a laboratory and space station, and it’s quite striking that Abbott will be able to command its resources ahead of high-profile F1 and aerospace projects.

‘Dassi is going to be quite a big part of what we do,’ says Brew.

‘In the layup room alone we’ll probably end up having four guys working on bikes. It’s a totally different budget, though.’

Race against time

While the costs and fees may be greater for the likes of F1 teams or aerospace companies, that’s largely as a result of the extreme time demands.

‘F1 want it there and then that day, whereas we get a bit more time with this sort of thing. F1 has always been aggressive.

The price they pay for it is because they want it to go straight through inspection and onto the car so they pay a premium rate for a premium part.

Although Dassi is getting a premium part, the lead time is much longer. Rather than a four to five-day lead time on car parts, Dassi has a four to five-week lead time on most bikes.’

The process is very different from what we’re used to with bike construction, which is usually done in the Far East using a hot press moulding process and internal mandrels to shape the frame.

Here at Brick Kiln, the moulds themselves are carbon, and the bike is formed in an enormous autoclave. How did Dassi find its way here?

Homeward bound

Stuart Abbott founded Dassi in 2012 with a focus on British manufacturing, but until very recently his dream hung ever so slightly out of reach.

With a background working for Rolls-Royce, and having done a stint as a management consultant, Abbott felt the time was ripe to create a new bike brand, based in Britain, manufactured in Britain and sold in Britain.

‘We have a unique environment in the UK,’ he says. ‘We have an awful lot of aerospace industries here, and about 70% of the F1 industry is also based here. Why the hell do we have to go anywhere else to produce leading technology?’

 

His initial dabblings in cycling were based, as most are, in Taiwan.

‘I got a number of frames from the Far East and cut them in half to understand how they’d gone about making them. I picked one design I liked based on various requirements I had set,’ Abbott says.

‘I made a few design changes to make it our own, and that became the Dassi variant.’

The variant was similar in look to a popular open-mould Taiwanese offering, but Abbott claims he tweaked the design to improve aerodynamics and structural performance.

It was still Taiwanese, though, and it’s the variant of that variant that Dassi hopes to make in the UK.

Just add graphene

Desperate to move from small steps into bounding leaps of progress, though, Abbott quickly hatched plans to enhance his very own design with a space-age additive – the miracle substance called graphene.

‘I’ll show you something that’s been made with it,’ Abbott says before reaching back behind him and pulling out a stunning carbon fibre guitar.

‘We drove over this last week in the car park – we literally drove straight over it in a Range Rover, it’s that tough.’ There’s not a scratch on it.

That’s not to say Dassi’s bikes are made entirely of graphene.

‘It’s very difficult to take a single atom-thick piece of graphene and weave it into a material. Weaves are about this big at the moment,’ he says, forming a square-inch with his fingers.

‘So anybody who’s using graphene to make anything is doing it in conjunction with another material.’

Dassi’s frames add graphene to the resin that’s used to bond the carbon fibres.

In total the graphene makes up less than 1% of the overall frame.

Light but strong

The consequence, Abbott argues, is significant. ‘We’re expecting that an 800g frame will go down to 350-400g, just because the strength properties are off the charts.’

Speaking before the graphene frame reached fruition, Abbott’s estimates seem a little grand.

The eventual frame is 750g, but still has a valid claim to be the lightest aero frame on the market.

That weight point won’t sell a £5,995 frame by itself, though, and Abbott is quick to wax lyrical about graphene’s other qualities.

 

‘Because you’ve chemically altered the graphene and epoxy, it will improve the resistance to break apart by 75%,’ Abbott says.

‘Cracks only form where you have a soft material. Say you’ve used a T300 [type of carbon fibre] to save money, butting up against a high-grade Toray T800 fibre at a joint. As with anything that begins to work hard, it starts to fracture or break in some way.

‘You’ve got no real way of stopping that unless you make the whole bike out of the same material, as we do, or you use something like graphene that inhibits cracks.

‘So it’s not just about strength gains and weight loss, but also some fundamental chemistry that helps the bike last longer.’

I’ve met engineers who would suggest that high-end frames require a mix of different carbon fibres and they would probably take issue with the suggestion that frames with multiple grades of carbon are doomed to crack, but Abbott clearly places a lot of confidence in the superiority of his process.

Abbott equally prides himself on the homegrown element of Dassi’s production – even the carbon and graphene are mixed on British soil by a company in Wales.

The production process is made no easier by graphene’s wondrous qualities, though.

Pride and process

We’re in the cutting room, where the carbon sheets take shape.

This is the closest room to the cold-storage vault where the sheets are stored at -18°C.

The temperature is necessary to preserve the resin, which will later bond the carbon together.

It currently sits pre-impregnated in the sheets, but at any higher temperature it will begin to set.

The vault holds all grades of carbon, from low-grade Toray T300 costing around £10 a metre, to the likes of M55J, which runs into thousands of pounds per metre.

Soon it will also house Dassi’s graphene-impregnated carbon.

Once in the cutting room the sheets are cut by laser to the various shapes that will be placed together in the mould, which happens down in the lay-up room.

Controlled climate

‘The lay-up facility is an acclimatised place so you have to go in through two separate doors,’ Brew says.

Here, technicians place the carbon into moulds, which themselves are carbon fibre.

It’s a highly unusual approach for bicycles, one normally done with aluminium moulds, and Abbott claims it improves the finish of the bike.

The carbon mould, he says, will cool at the same rate as the frame and so reduce the risk of cracking or having to hammer the frame out of the mould.

 

The moulds have to be carefully heat-treated by freestanding post cure, essentially making them more heat-tolerant, to avoid deformation in the autoclave.

Despite the high level of work here, bikes do present a new challenge.

‘We’ve never laid up a bike before, so it’s quite long-winded at the moment,’ says Aaron, a composite laminator who will be working on Dassi’s bikes.

‘But we’ll work out how to make things quicker. The first frame we did took two days, but it’s all very similar to lots of other parts that we do.’

New challenges

Will graphene present new challenges, mixing a form and material new to the technicians?

Abbott says the treatment is nearly identical, differing only in the specifics of the heating temperatures and curing process.

Once the carbon has been laid into the mould, the mould is sealed and placed in a vacuum bag that will force the carbon into place.

Then comes the autoclave – a giant pressurised oven, which will heat the carbon and resin, bonding them into hard carbon fibre.

We wander over to the main autoclave, which looks like the jet engine of an enormous rocket and is where one frame has recently finished its cycle. It’s tentatively opened, but nothing is inside.

‘Ah, that frame has gone upstairs already for finishing,’ Brew says with a chuckle. 

The custom customer

Despite not having witnessed the creation of any actual frames, the process certainly looks impressive.

The relatively chunky £6,000 pricetag doesn’t seem over the top when you consider the technology involved, but you might be excused for wondering whether a bicycle needs the same finishing as an F1 car, or if consumers will side-step the big brands for something more home-grown.

Abbott doesn’t entertain such doubts.

‘I want to make a new market for a luxury custom product,’ he says, and that extends beyond the frame itself.

 

‘Wouldn’t it be great if you could get a service plan for your bike that means that we’ll service it, replace chains and cassette – whatever and whenever it’s needed?

Most of our customers won’t even know the bike is gone because we’ve been dealing with their PAs.’

Elite club

For Dassi, the vision of the future is about being an elite club that bonds motorsport and cycling.

‘The relationships we’re trying to forge aren’t with the people who are going to make the next greatest chainset.

‘The relationships we’re trying to forge are with companies like Maserati,’ Abbott says.

His vision of this luxury service includes the finer points of the bike too, which will also boast extensive customisation.

‘We’re essentially making 3D-printed components, but it’s a carbon powder created under pressure using a laser to essentially sinter the powder with an epoxy,’ he says.

The pieces will be totally customisable to within one tenth of a millimetre. For now it’s been put into practice with seat clamps and spacers, but Abbott believes handlebars and stems are not far off.

‘I can customise every individual part if I want. They will be typically lighter and more durable than most normal components.’ 

Dassividaniya

There’s no doubt Dassi has broken new ground in creating a moulded British carbon frame.

We have to ask, though, why not go the whole hog? Its miracle graphene frame is a thing of beauty, but boasts similar curves and geometry to its variant of a Taiwanese catalogue order.

Couldn’t Abbott have thrown the rulebook aside and redesigned the very idea of a bicycle?

‘There’s a huge cost in bringing back a bike that’s made in the Far East, making it work and manufacturing it without having to worry about changing things too radically,’ he says.

‘It’s like anything in life – if you fundamentally change too many things in one go then how do you firefight if there’s a problem? So we changed the geometry slightly, we changed the rear stays – they’re different for a reason.

We changed the headset, we changed the arch of the top tube then we sat back and said, for now, that’s fine.

'Let’s crack that manufacturing problem, then we can begin to tune stuff. But actually, does it need to look that much different if the actual advancement is in the material science not in the aero science?’

Innovation or complication?

It’s a fair point. I can’t quite decide if Dassi has taken an unnecessarily complex approach to creating something that looks fairly generic, or whether it’s blazing a trail across unchartered technological terrain.

I settle on the idea that it may be both.

Before leaving, Abbott nearly bursts with excitement over his plans for the future.

‘We’ll get the first frame that is completely instrumented up. Riders will be able to come in and, literally, we’ll log the data of their position on the bike and all the power they’re producing in relation to the stress and strain that’s measured in the frame.

‘It might work, it might not. I believe it will. It’s research, but we can do that here – that’s off the back of work done with Rolls-Royce and F1, because they’re used to measuring stuff to improve it.

‘Not a great deal of measuring goes on in the cycling world, as far as I can see.

‘Wouldn’t it be better if it was tuned to the individual from either a size or layup perspective rather than being just aerodynamically shaped?’

He takes a moment to catch his breath. ‘I would have said so,’ he calmly concludes.

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What is graphene?

 

It’s the carbon fibre of the future, only better and already here. Sort of

An ultra-strong and light material, a superconductor, a superlubricant, energy storage system, 3D printer powder and thermal insulator – graphene can do everything, short of cooking your dinner for you.

The material comprises a single-atom-thick chain of carbon atoms formed into a hexagonal lattice, making it 100 times stronger than steel.

As yet it is purely a nanomaterial, meaning it works on an atomic scale, not as a large structure.

When Dassi says that its frame is graphene, it’s truer to say that the frame is carbon fibre, with a small degree of reinforcement from graphene.

The graphene fragments, added to the resin, are intended to reinforce and enhance the frame, and Dassi claims it reduces weight while increasing impact strength as well as stiffness.

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The bikes

 

What you get for your money

The Graphene Interceptor is Dassi’s flagship frame, and comes in at £5,995.

It’s created in the UK, contains graphene, weighs around 780g and its carbon fibre lay-up can be customised to the rider.

The geometry is set by the existing moulds, so it is currently available in five sizes, from 50cm to 58cm.

Next in the hierarchy sits the standard Interceptor, which is what we saw in construction, and it weighs an extra 200g.

Both are made to order, and custom painted to request.

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