Making the Wheels

A very British motorbike

We spent the day at Dymag to see how composite wheels are made. This is what we found out. Thanks to all at Dymag for their time, the cups of tea and the chocolate.

Dymag wheel designer Mike Wilson

Dymag wheel designer, Mike Wilson, who has been with the company for most of his working life, works out all the engineering aspects of a wheel using CAD software before any manufacture takes place.

Computer simulation of motorcycle wheel cornering stress
TThe design software allows Mike to simulate the real world stresses to which a wheel will be subjected. Here we can see the stress exerted on a wheel as a result of cornering forces.
carbon fibre sheet used in the manufacture of Dymag wheels for Enigma 1050

The main body of the wheel starts life as pieces of woven carbon fibre sheet which are cut to shape ready to be laid up by hand into a two piece mould.  The individual strands of carbon fibre are D-shaped in section which gives optimum bonding.

Lay up technician Craig Butler at Dymag

We cannot show you this bit as the actual lay up procedure used by Dymag is a closely guarded secret. Craig Butler (pictured) was working on a wheel when we arrived. All lay up is done by hand. The process is similar to that used in the making of fibreglass components.

Dymag composite wheel in mould

Once the lay up is complete, the two halves of the mould are bolted together. The resulting pressure ensures proper bonding and uniform thickness. The initial curing takes place overnight and is done at a controlled room temperature. Further curing is then carried out at 100 degrees Centigrade once the wheel has been removed from the mould.

Dymag carbon fibre wheel removed from the mould Enigma 1050

When the wheel is removed from the mould, the exposed edges are razor sharp. After heat curing, the blanks are machined to remove all of the flashing which results from the moulding process. Once cured, carbon fibre is extremely hard and the tools required to succesfully machine it are expensive.

Allo centre for Engigma 1050 Dymag carbon fibre composite wheel

Alloy centres, like the component shown here, are prepared and bonded into the machined blank. They will provide the location for the sprocket and brake disc carriers.

Dymag carbon wheel enigma 1050 machining

Andrew Moore prepares to load a wheel into the lathe so that the alloy centre can be machined true to the wheel rim and be prepared to accept the carriers (disc carriers in this case as it is a front wheel)

Carbon fibre wheel dymag being checked for run-out

After machining, the centre is checked for truth using a Dial Test Indicator (DTI). Look closely and you can see the register machined into the centre to provide a positive location for the brake disc carrier.

Dymag cad design for wheel sprocket carrier

CAD software is used to design the brake disc and sprocket carriers. Pictured here is the on-screen rendering of a rear sprocket carrier, which, like the brake disc carriers, also serves to house wheel bearings.

Dymag carbon wheel sprocket carrier being machined in Haas CNC mill

The carriers are machined from HE 30 aluminum alloy which is highly corrosion resistant, has excellent elongation properties and is commonly used in highly stressed applications, including beer barrels.

Overheated mill tool after machining HE30 alloy for Dymag carbon wheel

Machining aluminium alloy at high speed generates a great deal of heat. Cutting fluid (suds) are used to both lubricate and cool the tool and the work. This is what happens to the tool if it gets too hot.

Dymag wheel sprocket carrier takes 5000 line of code to describe to the Haas CNC millAndrew Moore at the controls of the HAAS CNC mill. He is resetting the mill to the exact line of code (from 5000) so that he can resume the machining process from the point at which it was temporarily paused.

Dymag carbon fibre wheel sub assemblues

Disc and sprocket carriers and the corresponding lumps of HE 30 aluminium alloy from which they are machined. Modular construction makes it relatively straightforward to build a wheel for any motorbike.

Dymag carbon wheel sprocket carrier being pressed into position

A sprocket carrier is pressed into the centre of a rear wheel. The blue stuff you can see around the circumference of the centre is the adhesive used to bond the carrier to the centre. It’s strong glue. Once bonded, the carrier can withstand a force of 12 tons per square inch.

Dymag carbon wheel bearing being pressed into position for enigma 1050

The disc and sprocket carriers also serve as wheel bearing housings. Here a wheel bearing is being pressed into the brake disc carrier of a front wheel. Making a composite wheel is labour intensive. Much of the work is done by hand and a single wheel takes a full person day to produce

Finished dyamg carbon fibre wheel for Enigma 1050

Wheel assembly technician Simon Hardisty (right) and designer Mike Wilson with a finished composite front wheel. Simon will be responsible for assembling the wheels which will be fitted to the Enigma 1050. Light, beautifully made and British – Dymag composites are the perfect choice for our project.

So that’s how it’s done. We hope you found this description of the process interesting. It takes a full person day to make one wheel and all the people involved in the process have to be highly skilled. Raw materials cost a lot and as well as the highly skilled staff, you also need expensive machine tools. Compared to alloy wheels, the production process is labour intensive. These factors mean that composite wheels are pricier than their alloy counterparts. Lightness costs but we reckon it’s worth it.

Enigma 1050 – a very British motorcycle being built in Hampshire, Derbyshire, Leicestershire, Berkshire, Wiltshire, Surrey, Sussex, Suffolk, Shropshire and Cambridgeshire.