Trek Marlin 6 review

Smooth start turns shockingly bruising in the rough

Our rating 
2.5 out of 5 star rating 2.5
GBP £450.00 RRP | AUD $749.00 | USD $610.00

Our review

Violently uncontrolled fork and blunt frame lead a list of reasons that Trek’s Marlin is best kept away from real off roading
Buy if, You're a glutton for punishment looking to get into mountain biking
Pros: Size-specific wheels, range of paint jobs available
Cons: Punishingly stiff frame and handlebars, undamped fork, some poor finishing kit
Skip to view product specifications

Trek is one of the world’s largest and most successful bike makers, but its entry-level mountain machine offers something of a bruising introduction to the global superstar brand.


Multiple choice

If you like a choice of paint jobs, then the Marlin 6 is a refreshing rarity at this bargain-basement price point, in that it offers an alternative (orange) paint option and comes in a class-leading range of sizes. It also switches wheel size depending on frame size with 13.5 and 15 bikes rolling on 27.5in wheels and 17.5 through 23in frames fitted with 29in wheels.

The thinking behind this is that most mountain bikes now use 27.5in wheels for a balance of easy handling and smooth roll, but going 29in on larger sizes can offer a more proportionate, smoother ride.

We found the handlebar to be brutally unforgiving:

We found the handlebar to be brutally unforgiving

According to this theory, the shallower contact angle of the bigger wheels when they roll into a root or rock on the trail should make for a significantly smoother ride in the rough. The increased wheel weight and smoother roll should also give better speed sustain.

Because 29er wheels don’t intrinsically cost any more to build than 27.5in wheels it’s potentially a great solution for making budget bikes easier and more efficient to ride on more technical terrain.

Unfortunately the relatively small volume – particularly rear – Bontrager treads minimise the smoothness and momentum gains of the Marlin. Despite longer chainstays and a skinny seatpost, which should create more flex, the Alpha alloy rear frame is still a super stiff and inert structure that batters rather than bounces over even slightly rough surfaces.

Add the slow response of the heavier wheels and high overall weight, and the Marlin is something of a slog to get going and then keep going.

Aches and pains

Unfortunately the front end actually compounds the control and comfort problems of the rolling chassis. On mellow trails the softly sprung SR Suntour fork with 85mm of useable travel seems like a pleasantly plush companion.

Initially positive thoughts literally explode in your hands off the first drop or sizeable obstacle though. That’s because the return stroke of the fork is totally undamped and there’s no softening top out bumper either. That means the fork cannons back with a brutal metal-on-metal smash that was loud and violent enough that we genuinely thought it had snapped off the bike going down the first set of steps.

Low-volume bontrager tyres nullify the smoothness and momentum gains of the marlin:

Low-volume Bontrager tyres nullify the smoothness and momentum gains of the Marlin

Braking or turning places more stress on the skinny 28mm fork legs, causing them to stick rather than move smoothly. The inch-diameter handlebar is also so unforgiving that we checked it with a magnet in case it was steel rather than alloy. The ergo-shaped grips don’t have locking collars either so they twist and potentially slide off 660mm wide handlebars that are already too narrow to provide enough technical terrain leverage.


While Trek’s concept of appropriate wheel sizing is a basically good idea, the high weight reduces responsiveness to an unacceptable degree. Add those under-width bars, loose grips, undamped suspension and the brutally stiff frame and the Marlin 6 really isn’t a catch – even at this price.

Product Specifications


Name Marlin 6
Brand Trek

Description Geometry based on size - 18.5"
Rear Derailleur Shimano Altus M280
Top Tube (in) 23.62
Standover Height (in) 30.59
Seat Tube (in) 17.48
Chainstays (in) 17.52
Bottom Bracket Height (in) 12.44
Trail 8.3
Stem Bontrager alloy, 25.4mm, 15-degree
Shifters Shimano Altus M310, 8-speed
Seatpost Bontrager SSR, 2-bolt head, 27.2mm, 12mm offset
Seat Angle 72.3
Saddle Bontrager Evoke 1
Rims Bontrager AT-550 36-hole alloy
Rear Tyre Bontrager XR2, 29x2.00" / (Bontrager XR2, 27.5x2.20")
Rear Hub Formula DC22 alloy
Pedals Wellgo nylon platform
Available Sizes 13.5in 15.5in 17.5in 18.5in 19.5in 21.5in 23in
Headset Type 1-1/8" threadless, semi-integrated, semi-cartridge bearings
Head Angle 69.6
Handlebar Bontrager alloy, 25.4mm, 15mm rise
Grips/Tape Bontrager Satellite Plus, ergonomic
Front Tyre Bontrager XR2, 29x2.20" front / (Bontrager XR2, 27.5x2.20")
Front Hub Formula DC20 alloy
Front Derailleur Shimano Altus
Frame Material Alpha Silver Aluminium w/semi-integrated head tube
Fork Offset 5.1
Fork SR Suntour XCT
Cranks Shimano M131, 42/34/24
Chain KMC Z7
Cassette Shimano HG31, 11-34, 8-speed
Brakes Tektro M290 hydraulic disc
Wheelbase (in) 44.41