Rider Files 32: Need for Speed Carbon

Up until now, I have only ridden bikes with alloy frames and parts, my only experience was lifting my friend’s carbon hard tail with three fingers and lifting a carbon fat bike frame with one finger. So in the pursuit of greater speeds, both climbing and descending, mountain bikers often turn to carbon frames and parts. Carbon fibre can be lighter than metal alloys, but possess the same structural integrity as metal. It can be built to flex in certain ways to provide dampening, and people swear that carbon handlebars can reduce trail noise. My reservations on carbon have been down to price and the fact that carbon can spontaneously fail and break while alloy visibly shows signs of fatigue to indicate when crunch time might happen. Carbon fibre framed bikes have become cheaper and more reliable in recent years as manufacturing has improved, allowing carbon fibre to become a mainstay of mountain biking culture.

In the next few months (or years, can’t rush these things), I would like to start building a project bike that vastly differs from Titan or Warpath. A few ideas are swirling in my head about trail bike versus enduro bike; 27.5 versus 27.5+ versus 29er; Transition versus Trek versus Orbea; and now whether carbon is a worthwhile investment? And to an amateur rider, does a carbon fibre bike actually pose significant advantages? And the bike to test, once again happens to be a Trek Fuel EX…

Back in Rider Files 15, I rode the 2017 Trek Fuel EX 8 29er which was my first time pedaling a dual suspension 29er and taking on the trails at You Yangs. I like the alloy Fuel EX, and got along with its trail geometry, 29er wheels and 130mm travel front and rear. But I always had the feeling that I never pushed the limits of the bike since I didn’t know the trails too well. So with the new test Fuel EX, it would be preferred if I knew the trail system before hand. For that reason, the test trails for the carbon Trek is Bright Victoria, home to Mystic MTB Park. With a combination of green, blue and black trails, technical features and the legendary Hero flow trail, and having ridden there in the dry and wet, I would have no excuse to not get the most out of this bike.

The 2018 Trek Fuel EX 9.7 in front of the majestic alpine mountain range.

The 2017 EX 8 is conservative compared to the 2018 Trek Fuel EX 9.7 29. With a carbon fibre frame, Fox Rhythm Float 34 out front, Fox Performance Float driving the Active Braking Pivot rear end linkage, Sram NX 1×11 drive train, Bontrager Drop Line dropper post, and Sram Guide R brakes. Everything else to make a bike comes courtesy of Bontrager.
With the carbon frame and higher spec parts, you’d expect the 9.7 to be kilograms lighter than the EX 8, but in reality it is only 400 grams or so lighter. While the figures seem impressive for tech and not so stellar for weight, what really matters is how a bike rides.

Bontrager XR4 Team Issues hugging a Bontrager Line Comp rim set, the Fox Rhythm 34 130mm and Sram Guide R with 180mm rotor to complete the front end.

Sram NX cranks, Jet Black pedals (same as on Titan), Fox Float Evol with ReActiv tuning and MRP chain guide. 

Bontrager Drop Line with 125mm as the seat post, always welcome in my books.

Same wheel set as the front, with the Sram NX 11 speed cassette and a 160mm rotor. The Active Braking Pivot linkage system providing 130mm of travel.

With the variety of trails on hand and wanting to test everything I could for this bike, I selected three specific sections and made loops around them. Tombstone is a cross country flow loop that features tight switchbacks and tight berms, so Playground and Rapids were incorporated to provide slippery rocks and roots in a mellow setting. Corkscrew is a black diamond downhill section with chronically wet roots and off camber corners on a steep gradient, which linked into Charos Trail and Deer Stalker which are blue descent trails with slippery rocks and roots and tight corners. Finally the Hero Trail is the golden child of Australian mountain biking tourism, a prolonged flowing descent with jumps, large berms, and greasy corners to test brakes and suspension. In order to reach Hero, I would need to climb Up DJ, Hades, and Grevid’s Way; which are an assortment of switchback and technical climbs. Aside from a 15 meter drop and a boner log, Bright has enough to test the EX 9.7…

The EX 9.7 relishes in technical features, both climbing and descending. With a majority of the trails being littered with rocks and roots, your wheels are constantly sliding and jolting. With the 29×2.4 inch tyres floating over smaller rocks and roots, the wagon wheels work well at Bright. I never felt the wheels getting caught in between crevices, so that either means I was perfect at picking lines (highly unlikely) or this is a magic tyre size that isn’t too thin to get wedged but not too fat to pinch flat (more likely). In the event that you need to climb slippery roots or carve down wet rocks, the tread pattern works alright. I would like a bit more aggressive pattern than the XR4 Team Issue, but once the rocks and roots of Bright are out of the picture the tread pattern rolls fast and grips on hard pack surfaces such as on Tombstone. The moderately slack head tube, wide bars, powerful Guide R brakes and the Active Braking Pivot makes technical descending a fast but controlled affair. Corkscrew can be merciless in the wet with loam further reducing traction, but the set up of the EX 9.7 worked well to slow down or bomb it when I wanted. On the other hand, since the carbon frame is so much lighter and stiffer than an alloy frame, for technical climbing sections you can easily lift your wheel up and over certain features and keep chugging on. Anything technical, whether fast and downhill or slow and uphill, is easily met by the Fuel EX 9.7.

While technical trails are where the EX 9.7 excels, steep climbs and prolonged downhill flow trails are where it suffers in my opinion. With a 32 tooth chain ring but only a 42 tooth low gear out back, and that same moderately slack head angle, once the gradient gets steep uphill the EX kind of sucks. If you have weak legs or have had a long day of riding, the gear ratio will be the first thing to stall you on steep climbs. I know 32 teeth is small for some riders, but at Bright you climb all day to get places and it wears you down. In the event that you have incredible leg stamina, then the head tube angle and short chain stays precipitate the tendency for the front wheel to wander and lose traction. And if by some miracle the first two problems are compensated for by skill and power, then the back wheel usually spins loose and you stall. Infarct Hill was where these three problems came to fruition and no matter how many attempts I made, it just didn’t seem planted on the incredibly steep, chest pounding climbs. On the Hero Trail, while it did corner well and held onto the greasy berms for dear life, over the whole run my hands and shoulders died from the vibration of the braking bumps and small embedded pebbles. Whoever said carbon frames reduced trail noise must be dreaming! Maybe carbon bars might aid things, but the first myth busted was carbon dampening vibrations. And with the 32 tooth chain ring, I never reached the 10 tooth high gear on the cassette. You can’t get up to speed on the Hero Trail or Tombstone, and they are flowing downhills. To slightly remedy these gripes, either fit a smaller chain ring or use the highly praised Eagle 1×12. This appraisal was backed up by Cycle Path employees who have used the same bike on the same trails.

The bike handles well across multiple areas thanks to the stiff frame, powerful brakes, and modern geometry. If you point the front wheel in a certain arc, then it will track that way without any disobedience and the rear wheel predictably follows. This is good to know on technical downhill trails where line choice is paramount and wet noodle frame design calls for banishment. Having absolutely control over wheel speed is another key component in handling, and the Guide R’s do well to stop run aways. The single finger levers mean the remaining three fingers and thumb can hold on for the ride, while the four pot callipers have modulation and momentum halting power on their part. The handling exhibited by this bike is great in my opinion.

In mountain biking, climbing is inevitable and climbing sucks for some. Running out of breathe, sore legs, grinding gears, under steering on tight switch backs and slippery roots are the bane of most’s existence. The EX 9.7 is not the cure for any of those things. It does well on technical climbs for sure, but otherwise it is tame when climbing tight switchbacks and with the 32 tooth chain ring it does cause bodily fatigue in the end. Up DJ and the climbing section of Tombstone prove that this bike doesn’t have ascending super powers, rather it sits as a mediocre example of how “long, low and slack” modern geometry doesn’t breed mountain goat terrain traversal.

People swear that Fox suspension is better than Rockshox by a long shot, but I didn’t find anything mind blowing about the Rhythm fork and Float rear. I am aware that every Fuel EX comes with a Fox shock of some sort with ReActiv tuning, but I wasn’t hit with awe and wonder as the rear linkage displayed amazing handling. It worked well and I’ll give it credit for that, but for proprietary tuning from Trek and Fox you would think it would leave a greater impression than “it might have been why technical downhills were so easy…” The 130mm Fox 34 Rhythm is not leagues above everything else either. It felt supple and worked well, but with the same tuning options as a Rockshox Recon or Yari, the fork isn’t irreplaceable. The suspension works well and doesn’t need to be upgraded, so maybe it is perfect for the EX 9.7? Whatever the case, it sits as another average example of what you should expect on a mid/high end trail bike from a big manufacturer.

The Bontrager Drop Line and the saddle are great as always. Seeing as my saddle and dropper post on my Farley haven’t failed yet, it’s good to see that Trek equipped their solid dropper post and good saddle on their “low price” point carbon dual suspension trail bike. No complaints here.

When I consider everything that the EX 9.7 achieved in the test period, I would like to say it is a very technical trail bike. It can jump and dance up hill, and fly and slide down hill like any other high end trail bike. It wants to impress you with how daring it can be floating over roots and slaying flow trails, but it can still be ridden on mellow trails with copy paste switchbacks. When you think the back tyre is about to slip off the wet root, it somehow finds that ounce of grip needed to get you over. When you think you’re out of control on he down hills, the wide handle bars give you the leverage to turn, the suspension plants both wheels on the ground and the brakes feather the wheels so they hold onto the dirt and get you down. The EX 9.7 allows amateurs to push their limits on technical rough stuff. But like that friend that helps you move the couch and fridge up stairs to the third story, it doesn’t help you any more or less than any other friend. It flows like a normal dual suspension, you feel the nerve numbing vibration of the trail like any other bike, and it possesses the same geometry as the Fuel EX 5 and the Fuel EX 9.9. When everything is considered, the brakes and suspension elevate it above the lower spec Fuel EXs, but the drive train and alloy rear triangle and handlebar ensures it doesn’t over shadow the true carbon dual suspensions of the Trek family.

Would I buy one? If I didn’t have Titan then probably. But with 10mm suspension travel more front and rear, better brakes, a better dropper and a carbon frame, I can’t justify buying this bike. It doesn’t cause my jaw to hit the floor and my wallet to empty, it just leaves me with the impression that it is a cool bike. I will consider carbon frames for my project bike for sure, but I won’t be sourcing the 9.7 frame for the build. Then again, maybe this bike and I aren’t made for each other. I’m an Aires and it’s a carbon trail bike. I like craft beer or a hot cup of tea, it likes having its suspension serviced every 50 hours of ride time. Jokes aside, the 2018 EX 9.7 sold out across Australia and Trek riders wait with baited breathe for the 2019 model, hopefully coming with the NX Eagle 1×12 to shut down my criticism. And if that were the case, I still won’t be the first person to slap down a deposit for the new season model. If I did want one, I would want it as a 27.5+ like they have in the UK and US, and I would like a 30 tooth with 1×12 shifting at the rear. But that’s just how I would want a great trail bike to suit me. Otherwise it wouldn’t have sold out last season.

But the EX 9.7 was not the only one taking on the mountain this test period. I also took Warpath up to Bright to run it through its paces seeing as its last big day out was when I sprained my AC joint. So next Rider File will be Trek versus Trek to see if a burly alloy fat hard tail can stand against a racy carbon/alloy dual suspension trail bike.


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