Trek Fuel EX – Evolution of a legend (Part 1)

Criterium Cycles Trek Fuel X Main Image
Jan 13 2017

Trek Fuel EX – Evolution of a legend (Part 1)

by Paul Bowker


Design icons stand the test of time. The basic platform or even just the core concept remains constant but despite technology advances over the years, the DNA of the product remains unchanged. The Porsche 911 is a great example. Air cooled engines may have given way to water cooled, a multiplicity of technological driver aids may now ensure the car’s rear end isn’t going to step out and try and kill you (unless you want it to of course) and the whole package has got rather bigger. But look at a current generation 911 and compare it to the car from the 1960s. Unmistakably 911.


The mountain bike has evolved a great deal over the past 30 years and since 1986, Trek has been at the forefront of mountain bike technology the world over. Mountain biking is a notoriously fashion conscious sector. Even more impressive then that Trek has created a bike that has evolved into a global sales success for well over a decade. In bike terms, it is an eternity. The bike in question is the Trek Fuel EX.

A true all rounder

There is a tendency these days for some riders to ‘over bike’ themselves, buying kit that looks terrific but is never going to be put to full use in the majority of situations. It is always worth taking a step back to analyse what you really need because we think for most circumstances and for most riders, the Trek Fuel Ex is just about the fastest way to cover ground. When we say “for most riders”, we are assuming that you are not highly specialised such as a dedicated cross country racer or downhill specific rider. Where a Fuel EX really shows its credentials is the ability to climb fast, pedal fast on the flatter sections and descend fast. You’ll note the word ‘fast’ appeared plenty of times there! To put together a fast lap at your favourite trail centre, you need a bike that will be great at all these disciplines and not just a bike that will be super quick when gravity takes hold.


What makes the Fuel EX so good?

The secret to the Porsche 911’s longevity and superb handling, no matter what wheels, tyres, brakes and suspension are fitted, is the chassis. The chassis is the beating heart around which the components and tuning of the rest of the car are optimised.


Move over to the world of bikes and we are talking about the frame. Trek has used the same design philosophy as Porsche do to create all of their road and mountain bike frames i.e. employing some of the finest engineering minds around to research and design some of the most technically advanced bike frames. It is worth bearing this approach in mind when considering your next bike. It is wonderful to have a bike with plenty of shiny components all over it but if the core frame isn’t the best it could be, those fancy components aren’t going to do their job as well as they could. Always think frame first, everything else afterwards.


The second element to the success of the Fuel EX is the sheer number of variants that are available in 2017 but we’ll come to that in Part 2. First, let’s look at the evolution of the models in the Fuel EX story.


2005 – 2007 Model Years


Criterium Cycles Trek Fuel Ex 2005

Trek Fuel Ex 2005

Constructed only in Alloy, the Fuel EX began with a recipe that has evolved but largely stayed the same. The main frame was light and stiff with a swing arm and rear suspension based on an efficient single pivot design. Unlike some manufacturers, Trek used a rocker and a seat stay that dramatically increased the overall swing arm stiffness. The design enabled the shock to be placed in a vertical position. This in turn allowed designers to optimise the suspension geometry to pedal uphill efficiently. Despite this, the bike had a plush and bottomless feel during descending.


2008 – 2012 Model Years

Major suspension revisions appeared with an option for a carbon fibre main frame in 2009. Lighter weight and stiffer swing arm architecture came about thanks to the new one piece cast Magnesium rocker arm (now called Evo link). However, one idea above all others transformed Trek full suspension swing arms forever. Called ABP (Active Braking Pivot) it introduced a totally new idea to remove a phenomenon in full suspension systems called brake jack.


To understand exactly what the mechanics of brake jack are, it’s worth reading this excellent ABP technical description. In summary though, before the introduction of ABP, when the rider applied the brakes, the brake calliper rotated round the brake rotor causing the contact patch between tyre and ground to want to move relative to the suspension. The intervention of friction meant the contact patch couldn’t easily do this so the result was a skidding, skipping feeling as the suspension bounced over bumps.


ABP allows the brake caliper to keep a near constant relationship to the brake rotor so the caliper doesn’t rotate around the brake disk as the suspension moves through its range of travel. The skidding sensation disappears and the suspension remains active throughout braking giving the rider constant control, whether on the brakes or not.


2013 – 2015 Model Years

2013 Fuel EX 9.8_26er (Blog)

2013 Trek Fuel EX 9.8 26er

By 2013, Trail riders were demanding more from their bikes, and starting to ride more progressive and challenging terrain whilst still wanting to climb back up to the top again as efficiently as possible. A tapered steerer and slacker geometry sorted this, and once again Trek had innovated ahead of the game.


However, turbulent times hit the world of mountain biking thanks to a confusing development. Up to the 2014 model year, mountain bikers had been quite content with around 120mm of suspension travel and 26” diameter wheels. Now we had to contend with the arrival of different wheel sizes.


2014 saw two options for the Fuel EX. You could opt for 130mm of travel and a 26” wheel diameter version to suit the more jumpy and aggressive rider. Alternatively, there was 120mm of travel and a 29” wheel diameter version for the rider wishing to be smoother with a more confidence inspiring ride.

Criterium Cycles 2014 Trek Fuel EX 9.8 29er

2014 Trek Fuel EX 9.8 29er

This would have been perfect had all manufacturers had the budget to offer both wheel sizes in their ranges. However, the adoption of a third wheel size (650b or 27.5”) allowed some manufacturers to take an easy route and offer the customer ‘the best of both worlds’. At least that’s how they pitched it. In reality it was trying to do things on the cheap as 650b did save manufacturers the cost and bother of developing a range of 26” and 29” wheel bikes. Almost overnight, the 26” wheel was dead after nearly 25 years.


Trek adapted and for 2015, the dual theme continued but this time with 650b and 29” wheel options. The 29er option outsold the 650b version but it was not until 2016 that we got perhaps the greatest evolution of the 29er platform yet.


2016 Model Year

Criterium Cycles 2016 Trek Fuel EX 9.8_29er

2016 Trek Fuel EX 9.8_29er

For 2016, the 29er version got a slacker geometry that was adjustable using the mino link system for an even slacker trail geometry. Stiffer 34mm diameter forks graced the front end whilst another Trek invention, ‘boost axle spacing’, was introduced to the wheels. Boost increases the width of the front axle from 100mm to 110mm and the rear from 142mm to 148mm. By increasing the bracing angle of the spokes, the the 29er lateral wheel stiffness was now the same as a 27.5” and put the Fuel EX back on the top of the all round trail weapon step.


2017 Model Year

Criterium Cycles 2017 Trek Fuel EX 9.8 27.5 Plus

2017 Trek Fuel EX 9.8 27.5 Plus

That was until the launch of the all new 2017 Model year Fuel EX. In summary, what Trek have done for 2017  is introduce a number of new technologies, such as Knock Block and straight down tube. Knock Block is a keyed headset system that ultimately limits the amount of handlebar turn, so that the fork crown can’t impact the downtube. With Knock Block, Trek can now build a straight down tube, without the risk of owners damaging their frames in a crash. Just these two new revolutionary ideas have allowed Trek engineers to redistribute frame material, which has created the stiffest frame in class, whilst not impacting frame weight. Genius!


Our new Trek Fuel EX 9.8 Plus

We have just taken delivery of our new Trek Fuel EX 9.8 Plus and three rides in, it’s fair to say we are blown away. First impressions and a more detailed technology review will follow soon but to whet your appetite, here are some headlines:


  1. On my first ever ride on the bike at Glentress (and first night ride of the winter), I bagged three third fastest and a second fastest of all time segments
  2. On my second ride at Ae Forest Red Route (also my first day time ride), I managed third fastest time on a natural technical descent, and a personal record on the 1.5km Zig Zag Climb. This climb has an average 6.1% gradient and I was nearly a minute faster than my previous best.


This bike is fast, both up and down.


In Part 2……

Watch out for Part 2 in our story of the Evolution of Trek’s Fuel EX. Part 2 will include an explanation the 2017 model range along with reviews of our own Fuel EX 9.8 Plus a guest review from a very special guest!


Share Post
No Comments

Post a Comment

We'd love to keep in touch!

If you'd like to receive news, views and the occasional very special offer, just enter your details below to subscribe to our mailing list. You can unsubscribe at any time.

* indicates required