Trek has added a new flip chip to its latest Top Fuel that lets riders change the bike’s geometry and the shock’s progression independently of one another. Trek has long had its Mino Link flip chip to adjust the bike’s bottom bracket and head angle, but now it’s a four-position affair that also controls how much progression the suspension generates.

Adding a four-position Mino Link is just part of a whole host of changes to a new Top Fuel, including a lighter frame, better internal storage and option to increase or reduce the travel. It’s already one of the best mountain bikes out there for down-country riders, so the real question is, just why has Trek done this? We’re not sure, but we’ve got a few ideas…

The Top Fuel has some subtle changes, including proportional geometry, better standover thanks to a straigher seat tube, and a bigger door

Trek Top Fuel 2025 need to know

• New four-pisition flip chip, to allow independent geometry adjustments and suspension progression
• Frame is 220g lighter than the old bike, across all sizes and both alloy and carbon…
• despite bigger downtube storage door (which requires more reinforcement)
• Still a 120mm travel down-country bike with 130mm fork and 29in wheels
• New door has better sealing, and comes with two bags (one padded) on carbon bikes, one with alloy
• Aftermarket option to increase the shock stroke and boost travel by 10mm to 130mm
• Bikes from $2,699.99 to $10,499.99

The Mino Link now has four positions, high and low; and high with more progresion; and low with more progression

Four position flip chip

Proportional geometry and geo adjust is still very much en vogue for the bike industry right now, Specialized practically pioneered the idea and lots of its bikes including the Turbo Levo now come with six different geometry settings, while Geometron and Trek also lead the way with the level of tweaking on offer.

The four-position Mino Link is a little different though, because you can drop the bike’s BB height and head angle, all without changing the spring curve on the suspension. It’s a really clever idea, and means riders can choose to add more progression if they want, but don’t have to if they want the lower-slacker geometry but prefer a more linear feel.

Last year’s Trek Top Fuel 8 is still a great down-country trail bike… perhaps some riders found it lacked progression?

Why bother though? When I rode the Trek Top Fuel 8 last year it proved a brilliant bike, but certainly no enduro bike in terms of both its travel and ride feel. And while the former hasn’t changed, perhaps Trek has realised just what a capable bike the Top Fuel is, and added more support for riders who really want to hammer it.

New lighter frame (but not by much)

The headline figure on the bike is a 220g drop in weight across all sizes and both alloy and carbon frame options. That’s a good start, but I still don’t think that’ll turn the Top Fuel into an XC whippet – our 2023 test bike came in at 14.89kg (32.83lb), which is about on par with a 150mm travel bike. Slice that down to 14.69kg is still a chunky ol’ bike.

Top Fuel gets a bigger door to the internal storage, while the ripstop fabric bags are now padded to deaden any noise

Storage door and shopping bags

This is a biggy for me, and also accounts for some of the extra weight the bike’s carrying. Trek has increased the size of its downtube storage door, which is great for usability and keeping your sandwiches in the same shape. There’s also a tiger seal to keep out the muck, and Trek says it’s improved the BITS bags inside: you get one padded pouch for tools and an additional one for other bits and pieces, and both are available aftermarket and on all Trek bikes now too. Oh, and the cables are reportedly better protected from snagging on the bags.

Geometry changes

Not much going on here really, the Top Fuel is half a degree slacker at 65.5 degrees, while the reach and seat tube angle remains the same. Trek has made it possible to fit longer seat posts though by ironing out the kink in that sear tube, and most importantly there are now size-specific chainstays to ensure every bike from S-XXL gets the same ride feel.

Somehow the bottom bracket height of the Top Fuel has crept up though, it’s now 4mm higher than it was last year, at 345mm.

New travel options

Travel remains fixed at 120mm with a 130mm fork, but you can now run a longer shock stroke to increase the travel by 10mm. Trek also says the bike will work just fine with a shorter 120mm fork for XC or a 140mm option for bigger trail riding.

Eight bikes in the range, and frame and shock options for both alloy and carbon frames: the Top Fuel 9.9 XO AXS at $8,500 slots in close to the top

Top Fuel range

There are eight bikes in the Top Fuel range, three with alloy frames and five sporting full carbon.

Top Fuel 5 $2,699.99

Top Fuel 8 $3,999.99

Top Fuel 9 $4,799.99

Top Fuel 9.8 XT $6,999.99

Top Fuel 9.8 GX AXS $6,249.99

Top Fuel 9.9 XO $8,499.99

Top Fuel 9.9 XX $10,499.99

Trek says the Top Fuel is for riders who want to shred the descents, and those who prefer power on the climbs