Making of the Trek Session

What goes into one of the world's most expensive downhill bikes

‘Misty’ was going about the normal business of welcoming in clients before breathing out an intoxicating current of deep red spray from which there was no escape, except via the oven. Deeper inside, Angel was drawing the scalpel through sticky sheets of paper which the professor would soon bring to life, Sabrina was cackling with a cordless drill and Moreira was clouting the living daylights out of what seemed to be a plastic drainpipe.  

It might come as a surprise but the Session 9.9 is an American made frame. The sight of the 9.9 certainly knocked me for six as I walked the long, high white corridors of the Wisconsin headquarters and frame building plant of Trek Bicycles.

It was the distinctive red that caught my eye, the Viper coloured embrocation emanating from a break dancing nebulizer, the skinny white limbs of the racked-up frame turning to an almost living red before further synthetic work, a drop of laquer and personal touch. As a salon, ‘Misty’ was working in one of the finest, and certainly one of the more exclusive.

The goings-on in a paint shop had not been high on my list of priorities when visiting the brand that holds many world titles in several disciplines of bicycling. All I knew was that high end carbon road bikes were made and painted here, and that I was on a mission to report on technology not cosmetics.

It then dawned on me that there was much more than ‘finishing’ in the air. I began scanning the workshops and in each one a new piece of the Session downhill bike would appear. A man buffing a rocker link, a front triangle being glued. Holy shit, I never knew the Session was a frame wholly created in America. My walk turned into a trot, and before I knew it I had a hat and glasses, long coat and notebook chatting to every single person who’d breathed on the Session during its making.

Media reports of ‘boutique’ bikes came into my conscience, a history of Californian hand made. High jinks and the handmade rife in an industry that’s rattling towards… hell had ‘Misty’ doused me with hallucinogens?

It’s well known that most mountain bike frames and components get made in Asia. Economies of scale and a skilled labour force or cheap labour and steel, whichever way you look at it, that’s the reality. It’s partly the reason why an Asian made Trek Slash frame is £2900 and the American made Session frame is £4800. But they’re all handmade frames, they’d all sit pretty in a boutique shop. And in terms of quality, I’ve seen the love, I’ve seen the skill.

Here then is every person involved in the physical creation of the Session 9.9 at Trek HQ, Madison.

Words and Photos: Steven Jones

Where it all begins. Rolls of unidirectional (UD) ready to begin its journey to World Cup glory.
The Session is made of fabric (left) and UD (right)
The UD is impregnated with resin, pretty much like sheets of sticky paper. It's called 'pre-preg'.
Stage one. The UD is stacked and cut to basic shapes

LAY UP – Audrey Grunewald

Audrey takes the first steps in the process of taking what is essentially a roll of sticky paper and transforming it into a World Cup winning machine, one of the most successful downhill race bikes of all time. The material arrives ‘pre-preg’ in form, this means the material is already impregnated with resin. The material is a bit like thin, sticky liquorice to touch.

She stacks up the sheets of material and makes the first cut of the basic shapes of uni-directional (UD) and cloth before arranging onto shelves so that they can then be cut out. The uni-directional material and the cloths are graded depending on weave and density so each bike from road to downhill will be composed of different amounts of each.

Audrey making first cut on UD


This is one of the few processes where a machine features quite heavily but Angel very much calls the shots here by organising different materials for different parts of the bike. The CNC machine cuts up the material into many component shapes which will finally be arranged in the mould. Some parts of the frame require many layers of the same shape material, for example the downtube has many layers of UD plus a stronger T graded cloth.

Angel will make up to 400 individual shapes of UD and cloth that will be arranged into a tray as a frame kit that are then ready to be thrown into the mould and cooked. There is a kitting room which has trays of what’s essentially a flat pack bike ready to be made into the real thing.

Flat packed Session ready to be shaped in the mould
Cutting out the shapes of each and every Trek carbon bike
First stages in laying up the UD into the Trek Session front triangle mould
Just one piece in a huge puzzle
The Session frame alone is made up of hundreds of individual pieces
...even in the top and downtube alone.
Chris Moreira, with material layed up in the mould almost ready to be cooked

MOULDING – Chris Moreira 

This is where the Session frame really starts to take shape. Moriera takes a tray of pre-cut material and begins layering the pieces sequentially into the mould. Each frame and frame size has its own mould and each is layered differently.

You have to work quick here, there is already heat in the mould which makes the pieces more pliable and fit more easily into the tight spaces. The head tube and bottom bracket are quite complex areas made up of many different grades and shapes.

It takes about half and hour for Chris to lay up the mould, before inserting a custom formed bladder that, once inside the oven it will be inflated and force the material into every crevice. The mould is closed and locked and then put into the oven to cook. In the oven the layers and shapes of carbon fibre material synthesize to become one.

After cooking for a short period the mould gets pulled out, opened and the frame cleaned of surplus resin. The difference between pre and post cook is dramatic.

Apart form the finishing you could now bolt a front triangle into a frame and head down Val Di Sole (in fact there are some brands who actually don’t do a ton more than this!). He quickly smashes off the remaining drops of resin and racks it. Chris will mould the rocker link, seat stay and chainstay separately.

MACHINING – Ricardo Castellon

There is still much to be done although its remarkable how clean the Session comes out of the moulding process. Downstairs in the machine shop the Session gets cleaned up and all its holes drilled for cable routing, the headset, bottom bracket cleaned and surfaced. Any of the heavy machinery and lathe work will be done here and Ricardo has tooling for each and every frame requirement.

BONDING – Dan Evenson

Dan is now the fifth person to run his fingers over the Session. By the end of the process over twenty people will have been involved. The Session front triangle is moulded out of two separate parts and its Dan’s job to bond the downtube/toptube section to the seat tube, bottom bracket. It seems a quick, simple process not too dissimilar to adding an extension to a hoover but with a bit of glue involved. I’m sure Dan will tell you differently as here there is no room for error. But then there’s no room for error in any of the processes.

Dan Evenson before the front triangle becomes one
You really don't want that on your hands
Machine shop hard at it
The machine shop, like every section has custom tooling
That'll be Travis Mead in Domingo's jacket.....

FINISHING – Travis Mead

Its back to the machinery. This is where the frame gets prepped ready to go into the paintshop and where the frame gets a real rub down of all surface imperfections. The rocker link is a particularly complex area requiring Travis some time to get every area ready for paint.

INSPECTION – Francisco Mendoza

Fransciso takes smooth parts and makes sure they are velvet. The Session frame components leave Francisco in perfect unblemished condition.


The man in charge of licking the Session into life, of letting the viper loose onto the raw Session structure.

Mike in engine room of ‘Misty’

WHITE COAT – Feliciana Perez

Anything can happen in between the frame leaving Franciso and it entering one of the most clinical areas of the Trek facility. In here there is no food and each person has to wear specific clothing. After final rub down and cleaning Feliciana racks up each Session onto the conveyor before communicating to the paintbooth via radio of what’s coming down the line.

Feliciana with a Session ready for final coat and white coats (right) just coming out of the oven


Misty is an enigma and behind this machine lies a complex and incredibly colourful system of paint and pipework. Project One paint alone fills a whole room but each mix has to be carefully measured out.

The Session gets a couple coats of paint, first the white coat before circling back around for the Viper red and then final laquer, which will eventually roll out of the factory as the the top of the range 9.9. Yet this is one bike in many, and it’s here that all the custom ‘Project One’ bikes are sprayed too.

The paint shop has a multitude of paint colours ready to be dripped into Misty’s paint pot to be applied to the bikes that swarm the paintshop at any given time. Each time a frame comes through the lines have to cleaned and the pumps primed with a particular blend of colour. While this feature is all about each person that touches the Session remember behind the scenes there are designers who, like the suspension and engineering, have agonised over the colours of each Trek.

‘Project one’ is s system whereby the rider can create a custom paintjob for their bike and there’s a list of standard options also to choose from. The range is staggering.

In operation it’s as if Misty has a mind of its own as it dances around the frame, not too much not too little, the red bringing life to the Session, and the frame certainly comes off the carousel pumping ready for action.

The Session moves down a conveyor belt into the sealed off world of Misty. The frame will pass through here three times. Once for white coat, then main coat before final laquer.
Tuned for each and every Trek frame
Misty is always in the right place at the right time
Raised by humans, war paint by machine.
Finished by hand


Its not all about Misty, because behind the scenes is a man who makes sure that each Session is armed perfectly and it’s a human touch which does has the final spray on the Session. Priewe is arguably one of the most behind-the-scenes of behind-the-scenes in Rachel Atherton’s success. The invisible man adds his touch before sending the Session into the oven to bake.

DECAL MASTER – Amanda Radloff 

Before the decals get to Amanda there are a number of people involved from design, to decal library but it’s Amanda who is relied on for the steady hand to get the Trek and Session 9.9 decals applied perfectly each time. Once applied she uses a scalpel to trim up the graphic to a faultless standard and from here the Session gets shipped onto the line for a last coat of lacquer and final bake.

INSPECTION/RE-WORK – Sebastian Klarer 

You’d think it’s unlikely that anything has been missed, and by and large this is true, however there’s the odd occasion when there’s a blip in the process and this is where Seb comes in to make sure the Session is coated evenly and correctly and all graphics aligned correctly.

It requires a fine eye so that any person buying one of the most expensive downhill bikes in the world is actually getting the real deal. The attention to detail is exacting.

BUFFING – Joann Bauer 

Out of the heat of the oven the 9.9 makes its way to Joann who turns a sparkling frame into a dazzling one. Joann makes it even. She  is now the fourteenth person to have handled the Session since it began its journey as a sheet of sticky paper a few hours ago.

HARDWARE – Sheena Wehrmann 

Up until now the Session has been making its journey in separate parts, the front triangle and swingarm not always in the same place the same time, and possibly in different parts of the building at any given moment, but it’s here that the frame begins to take form as one. It’s here that the limbs of the Session get a means of articulation. Sheena muscles in the bearings and fittings that will ultimately allow her colleague a few yards away assemble the Session into one.

Like all the other staff she has to work quick, they even put up a sign letting us know this fact. Again there’s no room for error and by this point with so much time having been spent it could all go horribly wrong in a split second. It’s a job that requires nothing but perfect concentration.

ASSEMBLY – Sabrina Marinaro 

This is where, after sixteen pairs of hands, the Session finally gets assembled into one frame. Sabrina takes, front triangle, rocker link, chainstay, seat stay and with a fittings kit assembles it into a 9.9 frame. No person has a tool shop quite like Sabrina’s and surgeon-like she puts the 9.9 together.

WAREHOUSE – Albert Bolden

Not every 9.9 gets built up immediately, for after the frame has been assembled Albert racks it up yet again where it sits until an order is made, whereby it then gets moved back to assembly where the components are built onto the bike. A box of Fox dampers, Shimano gears and brakes, Bontrager wheels and finishing kit has been stacked with the bike in the warehouse waiting for this moment where it finally becomes alive and able to roll.

WAREHOUSE – Richard Raisbeck

Sending the Session on its way is Richard Raisbeck

Many hands make light work, and a light bike. One of the most striking aspects of the visit was the proximity of the designers to the makers. This is one of the areas where we will see advancement in the next few years, how designers of frames, not just from Trek but any carbon bike, learn from experience of how to blend the perfect flex/stiffness character of a bike.

There are around two dozen people involved in the Session before it even gets to the production stage outlined above, but Colegrove and his team have over a quarter of a century knowledge behind them in constructing this frame. An intimate knowledge of a material that many have yet to get to grips with.

Many thanks to everyone at Trek in US with putting up with the camera in their faces….

One Trek Sesison 9.9 every inch ready for the big bad world of downhill.


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