A couple of years ago I was doing a long-term review on the latest Trek Top Fuel, and the opening line talked about how many big changes had been made to the platform. This time around, the changes are much more subtle, as the bike seems to be settling firmly into the light trail category rather than the cross-country category in which it was born. How does it compare to the last generation? Letโs dive in to find out.

Geometry-wise, not much has changed compared to the previous version. Two generations ago, at 6 feet tall, I had to ride an extra large to get the appropriate amount of reach but, like the previous generation, Iโm on a large now. The head tube angle drops to 65.5 degrees, not from a difference in the frame but from bumping the front fork up to 130 mm of travel, whereas the previous bike came outfitted with a 120 mm fork. Weโll talk more about the fork change later, as travel isnโt the only thing that changed. The reach has grown 22 mm out to 482 mm, a welcome change, as I prefer my bikes to be longer than most since my arms are disproportionately long for my body. The wheelbase has grown by 10 mm, as has the bottom bracket height. These changes are very hard to differentiate from the old frame.


One of the biggest selling features of the new Top Fuel is that the frame is 250 g lighter than the previous version. Lighter, stronger, stiffer: pretty standard claims across the board from any manufacturer these days. I know that in-frame storage can be divisive, but I am a huge fan of it. Not only did they retain it while making the frame lighter, there is quite a bit more of it, including a larger opening, which is great for accessing whatever you might have stowed inside. Making the frame lighter helps overall, but this bike has gained weight in other areas, much more than the 250 g they shaved off the frame. The frame can still only take one water bottle, which, as Iโve said in previous reviews, is a negative for me. I realize this is a limitation of the shock placement but at this point in time, Iโd trade this suspension design for another water bottle, as this is a bike that is equally at home on rowdy trails as it is on epic endurance rides.

One of the biggest changes on the 2025 Top Fuel is that it now comes with a 130 mm RockShox Pike, whereas before it came with a 120 mm RockShox SID. This accounts for most of the geometry change and adds an extra 400 g of weight to the bike. Ouch. This is the move that firmly brings the bike into the trail category and out of the cross-country category in my eyes. The Pike is not only significantly stiffer, the damper is far more robust with proper tuning options. On the SID Ultimate, you could adjust preload with air and rebound. Thatโs it. If the stock tuning didnโt work from the factory, cโest la vie. Outside of the additional tuning options, what I noticed most with the Pike is how much better it handled small bumps on the trail. In Edmonton, our trails are about as rooty as you can get, and small bump compliance is a really big deal. With the front wheel being more planted through the smaller, rougher sections, you can maintain higher speeds with more comfort and control. The fork also feels like it dives less under heavy braking; this is likely due to the adjustable low-speed compression. Again, this is super noticeable on the Edmonton trail network, as our trails are very undulating with a lot of corners that require heavy braking.

The rear shock, an Ultimate Deluxe, is effectively the same as it was on the previous Top Fuel. The shock performs quite well but is less adjustable than the piggyback-equipped shocks youโd find on the Fuel and other enduro bikes. Iโve never felt the need for extra tuning on rear shocks for my XC bikes, as Iโm not a rider who spends a lot of time in the air or seeking out big drops. Around Edmonton, the shock never feels overworked and performs flawlessly. With that being said, when youโre in the mountains, the Top Fuel is so capable that itโs easy to find yourself on terrain where the shock starts to struggle. When the descents are long and rough, the shock does not feel as responsive. This is likely due to the minimal amount of fluid and air in the shock heating up, making the damper feel quite different. The Pike up front only encourages you to head to larger terrain, so itโs easy to see why some riders opt to put a piggyback-equipped shock on the back. The 120 mm of travel has never felt insufficient, and the bottom outs are soft enough that I canโt say exactly how many or how few Iโve had. I donโt even think about it, which speaks to how well the damping curve suits this bike.



The groupset is the other large change on this model, as the bike comes equipped with SRAM Transmission. Typically, I buy XX-equipped bikes, but this year I decided to roll with the lower-tier XO. The extra couple thousand dollars for the few hundred grams saved just didnโt make sense to me, especially with the shifting performance being the same. The XO came with the same seatpost, bar, suspension, and wheels, so there was no other reason to consider stepping up to XX. I did add the XX power meter and a 34t chainring, as the 30t it came with doesnโt suit my riding style. The new Level brakes, formerly the Guide brake line, have been flawless, although I miss the pad contact adjust that my previous brakes had. This is nitpicking, but it should be mentioned, as that is one less adjustment you can make to really dial in the feel of the bike.




Initially, the shift performance of the groupset was extremely underwhelming. Sure, you could shift while sprinting, but if you needed to grab or drop more than one gear at a time, youโd need to schedule it in your calendar and plan for it. As I mentioned earlier, the trails in Edmonton are either straight up or straight down, so youโre always shifting through the entire cassette in a hurry. If you hadnโt ridden the previous generation AXS, you probably wouldnโt be as disappointed with the performance, as you wouldnโt be used to the shift speed. Thankfully, SRAM released a firmware update this fall that significantly improved shift speed. At last, the derailleur is shifting as fast as youโd expect an electronic one to. The firmware entirely changed how the bike felt, especially when riding at race pace. Being able to shift under load takes some time to get used to after years of easing off the pedals when you shifted. How much time this saves on the trails is hard to measure, but it does feel faster. The Reverb post is the older style, as the new version was released after the bike was shipped. I had a few issues with sag on my previous bike, but so far this post hasnโt exhibited any of those symptoms.



The wheels are one of my biggest gripes on the Top Fuel. They are Line Pro 30s, Trekโs enduro wheel. While this bike is capable of light trail riding, these wheels are absolutely overkill and really take away from how the bike could feel. Kovee Pro wheels, at least for Alberta riding, would be a much better choice. Despite being much lighter, they are still plenty strong and would really increase how snappy the Top Fuel can be. Iโm running the same wheels that I had on my last bike, Kovee RSL. These are sub-1200 g wheels and have entirely changed how this bike feels, bringing it much closer to being an endurance XC bike than a light trail bike. Two generations ago, Trek specced the Kovee Pro wheels, and Iโm really not sure why theyโve since changed this.


Other than the wheels, the only other thing I changed was the cockpit. The Top Fuel ships with a shorter stem with a rise which, if youโre using this as a trail bike, makes a lot of sense. I swapped it out for the more aggressive version with a negative rise and longer stem. This poses a bit of a problem, as Trek has removed Knock Block from this generation. This means the bars can spin all the way around, and with my lower stem, the shift pod hits the top tube. Iโve added a few layers of paint protection film here, and it has saved my bacon a couple of times, not when riding, but when Iโm washing the bike and the bars spin around or the bike falls over trailside.

With the Top Fuel being the next bike up in terms of travel and geometry after the Supercaliber, it has big shoes to fill in terms of the gap between this and the Fuel. If youโre looking for an all-out XC race bike, this is likely not the bike for you. It doesnโt come with remote lockouts and is a bit portly when you weigh it. With the RSL wheels, mine weighs just over 26 pounds with pedals. If youโre looking for a bike that is fast enough to chase cross-country KOMs on Strava while making the odd trip to the mountains, where the terrain is quite a bit gnarlier, then this would be a very good option for you.
Despite this generation of Top Fuel continuing to get slacker, it hasnโt given up any of its climbing prowess, and I believe this is largely due to the steeper seat tube angle. This really keeps your weight forward when the going gets vertical. The Pike is noticeably better when it comes to the slow speeds of climbing on technical terrain, thanks to its small bump sensitivity. With the previous generation, I found the SID fork to be harsh at the slower speeds associated with technical climbing.
The greatest strength of the current generation of Top Fuel is that it is extremely versatile. Wheels and tires can take this bike from a trail machine to an XC ripper. Trek has since released the Top Fuel RSL, which swaps out the 130 mm Pike for a 120 mm SID Ultimate with Flight Control, as well as adding Flight Control to the rear shock. The cockpit is swapped to what I changed mine to, and it comes with Kovee wheels, not Lines. Had this been an option available when I ordered my bike, I would have gone this route.
Where is the Top Fuel headed from here? I hope that they bring this bike closer to its XC roots, as the Supercaliber is a pure XC bike that Iโd argue isnโt enough bike for modern XC courses, and the Top Fuel, without modifications, isnโt as racy as it could be. I look forward to seeing what they come up with, likely released in the fourth quarter of 2026 as a 2027 model.
Photos and words by Nick Croken








































































































































































