The Trek Top Fuel trail bike sees more travel — and more options — compared to the previous version that launched less than three years ago. With separate flip chip adjustments for geometry and leverage rate, a lighter frame, improved in-frame storage, and the ability to run a longer shock, it seems the fourth generation Top Fuel is designed to be whatever mountain bike riders want it to be. What started out as an XC bike is now a bike that sits solidly inside trail bike territory.
Frame updates
The latest Top Fuel is highly adaptable thanks to a new four-position Mino Link (flip chip) with independent geometry and leverage rate adjustments (more progressive, or less). The geometry adjustment not only allows riders to raise the bottom bracket height and steepen the head tube angle a bit, it also enables an aftermarket mixed wheel configuration for sizes medium and larger. (The size small bikes ship with matched 27.5″ wheels, and are not designed to run a 29er wheel in front.)
The Top Fuel is a 130/120mm bike out of the box, which is up from 120/120mm previously. Buyers are cleared to run forks with up to 140mm of travel or as little as 120mm. The brand has also designed the bike to work with a longer stroke shock so that buyers can add 10mm of additional rear suspension travel if they want it, which would give the bike 140/130mm of squish front/rear.
Overall, Trek says they managed to shave about 220g off the carbon and aluminum frames, with some of the lightest builds weighing as little as 28.33lbs. With the previous version of the Top Fuel, Trek gave their Knock Block steering limiter a wider sweep. Now, Knock Block is gone altogether thanks to a modified down tube that clears the fork stanchions even at extreme steering angles.
Rounding out the frame updates, Trek has revamped their in-frame storage solution by improving the frame door and latch and updating the included BITS storage bags. The upshot, according to the brand, is fewer snags and better fitment.
Trek Top Fuel 4 geometry
Have we reached peak trail bike geometry? Looking at the changes to the Trek Top Fuel, there’s a case to be made. The head tube angle on the latest bike is just half a degree slacker at 65.5° while the effective seat tube angle and reach are unchanged.
| S | M | ML | L | XL | |
|---|---|---|---|---|---|
| ST Length (mm) | 360 | 410 | 420 | 435 | 470 |
| Reach (mm) | 417 | 447 | 462 | 477 | 507 |
| Stack (mm) | 570 | 603 | 607 | 612 | 630 |
| BB Height (mm) | 342 | 345 | 345 | 345 | 345 |
| CS Length (mm) | 435 | 435 | 440 | 440 | 445 |
| Eff ST Angle (deg) | 76.0 | 76.9 | 76.2 | 75.9 | 75.2 |
| HT Angle (deg) | 65.5 | 65.5 | 65.5 | 65.5 | 65.5 |
| Wheelbase (mm) | 1151 | 1188 | 1210 | 1227 | 1271 |
| Front Center (mm) | 717 | 755 | 772 | 789 | 827 |
| Trail (mm) | 115 | 125 | 125 | 125 | 125 |
| Fork Offset (mm) | 43 | 43 | 43 | 43 | 43 |
| Standover Carbon (mm) | 700 | 750 | 752 | 753 | 758 |
With this release, Trek has moved to size-specific chainstay lengths, ranging from 435mm up to 445mm for extra large frames.
Pricing for the Trek Top Fuel 4 builds range from $3,999.99 to $10,499.99. It appears that frame-only options will be available for purchase as well. Check out all the builds and get more info on the Trek website.
