Trek Marlin 6 Bike Review [2021 Guide]

Trek Marlin 6 Bike Review [2021 Guide]

The Trek Marlin 6 women’s-specific frame after a day of light trail riding

What are you looking for in a mountain bike? Are you a new rider interested in cutting your teeth on trail riding without spending a fortune? Or are you searching for a rugged commuter that uses familiar, comfortable, mountain bike geometry?

If you answered yes to the questions above, or find yourself somewhere in between, the Trek Marlin 6 is worth your consideration.

The Trek Marlin 6 is an entry level cross-country mountain bike that packs a lot of value into an affordable package.  Well suited for some light trail riding or ready to be fitted out as a burly commuter, the Marlin 6 offers plenty of versatility, making it a good choice for a variety of riders.

As an aluminum hardtail, the Marlin 6 effectively blends performance and value. The hardtail provides the added comfort of a front suspension, without the additional expenses associated with full-suspension bikes, and the aluminum frame provides a lightweight build at a fair price.

A hardtail, such as the Marlin 6, makes for a great first trail bike. Hardtails build good riding technique and still provide compliance for trail riding at a much more approachable price. As commuter bikes, hardtails are rugged and comfortable, and offer a fun ride to the office when kitted out with racks and fenders. The Marlin 6 is an excellent value for the price and certainly a bike that I would recommend. Read on for the detailed breakdown of this bike.


The frameset for the Marlin 6 utilizes Trek’s Alpha Silver Aluminum with a front suspension fork, the SR Suntour XCT 30. The Marlin 6 comes in seven different sizes for the men-specific design, and 4 different sizes for the women-specific design. The fork on the XS sizes offers 80mm of travel, and the fork on all larger sizes offers 100mm of travel.

The SR Suntour XCT 30 is a reliabe, affordable suspension that handles moderate trail riding well.

The front suspension also features a hydraulic lockout that can easily be manipulated by the rider while riding. This is a crucial feature for any bike with a front suspension and is quite an impressive offering at this price point!

The hydraulic lockout is key feature of the Marlin 6, making it an even better commuter bike when locked.

While the front suspension isn’t the lightest of offerings on the market, it performs well on trails and off-road terrain. The suspension provides a smooth, comfortable ride, and the hydraulic lockout is highly effective in totally locking out the suspension and providing stiffness for efficient power transfer.

The frame also has some impressive features for such an affordable build. Most notably, the frame utilizes internal cable routing, providing a sleek aesthetic while also protecting the cables and keeping them clean and organized.

The internal cable routing is a surprising and welcomed feature for this budget-friendly frame!

The frame features mounts for racks and fenders, as well. This provides the Marlin with the ability to be kitted out with racks and fenders and transformed into a comfortable, yet burly commuter bike. Having a front suspension on a commuter bike can make for comfortable, fun rides into the office. There is even a mount available for a kickstand if you do choose to build out the Marlin as a commuter bike.

As an important safety note, it is not recommended to do any trail riding with a kickstand on your bike. There is the potential that the kickstand could open, due to the rough terrain of a trail, causing a dangerous crash. Kickstands should only be mounted for strict commuting and cruising purposes.


The Marlin 6 features the geometry of a slack cross-country mountain bike. Designed for more moderate terrain, this geometry is not as slack as a devoted trail bike, but it does place the rider in a good position for cross country terrain without being overly steep.

This geometry can be attributed to why the Marlin is so effective for mixed use; it allows the rider to do some light trail riding without completely sacrificing efficiency on the paved or limestone paths that are likely to be encountered when commuting.

The men-specific and women-specific versions of the bike rely on almost identical frame geometry. The main difference between the two is the standover height. The women’s version features a slight dip in the top tube, providing addition standover clearance.

The Marlin may be a bit more sluggish on paved terrain than a devoted commuter (it is a mountain bike, after all), but the cross-country geometry is one of my favorites for a mountain bike. I do not consider myself a hardcore trail rider by any means, but I do enjoy the ability to ride some moderate trails. The versatility of a cross-country bike like the Marlin is excellent for riders like me.


The Bontrager Connection wheels and XR2 tires perform well as an all-arounder, but they are the area of this build that is in most need of improvements.

The wheel size on the Marlin depends on which frame size you purchase. The XS and S, for both the men’s and women’s, use 27.5” wheels, whereas all larger sizes use 29” wheels. The larger wheels provide a better riding experience on tougher terrain, but the smaller wheels are needed for the standover height on the smaller frames.

The wheels used on the Marlin are the double walled Bontrager Connection. These are durable wheels and can undoubtedly handle rougher terrain, but they are quite heavy. The added weight of the wheels can make the bike feel sluggish at times.

The Bontrager Connection wheels are also not tubeless ready, so you will not be able to set up your Marlin 6 to be tubeless right out of the box. You will need to upgrade your wheels if you intend on running tubeless tires: a small tradeoff but one to be expected at this price point.

The tires on the Marlin 6 are Bontrager’s XR2 tires. They are grippy and damage resistant, allowing them to function well for all-terrain use, without flat tires being too much of a concern. Since these cannot be set up as tubeless, the durability is an added benefit. However, the wheels and tires would be one of the first areas in need of an upgrade on this bike.


The Marlin 6 features an efficient 2×8 drivetrain and is one of the biggest reasons to choose the Marlin 6 over the Marlin 5. (Trek just released the 2022 Marlin 6 that features a 1x drivetrain, but it comes in at a higher price; we will focus on the 2021 Marlin here).

The 2×8 drivetrain on the Marlin 6 is much lighter and more efficient than the 3x that comes on the Marlin 5.

For just a $100 price increase over the Marlin 5, you get a 2×8 Shimano Altus drivetrain that is better suited for both trail riding and commuting. The Altus is an entry-level drivetrain, but it still features the quality and reliability of a well-calibrated Shimano design.

The Shimano Altus derailleurs are an entry-level drivetrain that provides the reliability and durability Shimano is known for.

The drivetrain is limited for more advanced trail riding, but it performs well for light trail riding and commuting. The gearing offers enough flexibility to tackle the mixed-use riding that the Marlin is designed for and will prove to be reliable in the long run.

Brakes & Shifters

The shifters on the Marlin 6 are comfortable right out of the box. They are angled downwards at an ergonomic angle that provides a firm grip without any wrist strain whatsoever. The shifting is controlled by thumb and index finger levers, and the shifters are crisp and smooth. The shifters on the Marlin also provide an analog readout, signifying to the rider which gears they are currently riding in.

The analog readouts on the shifters are a nice touch for newer riders, though rarely seen on more advanced bikes.

The brake levers are Tektro hydraulic brake levers that provide reliable stopping power and easy operation. That’s right, the Marlin 6 has hydraulic disc brakes! Hydraulic disc brakes are undoubtedly the best braking option on the market, and I think it is amazing to get their dependability on such an affordable bike.

The shifters and brakes that come on the Marlin 6 further add to the already outstanding value of this build. Trek clearly paid attention to the details when trying to design an affordable, mixed-use cross-country bike, and the set-up out of the box truly delivers great performance at a surprisingly low price.


The handlebars on the Marlin 6 are flat bars that find themselves somewhere between a true mountain bike flat bar and a commuter flat bar.

From above, the slight sweep of the handlebars is noticeable, providing a balance of comfort and control when steering.

They feature an ever-so-slight back sweep towards the rider, putting them in a more comfortable ride position. However, they are not as back swept as we often see on commuters, which still makes them a functional trail biking bar, as well. Handlebars on mountain bikes sometimes feature no back sweep at all, but the Marlin 6’s handlebars still prove effective on the trails, the back sweep almost unnoticeable.

The handlebars are wide, as would typically be found on a mountain bike, providing reliable control and instilling confidence in the rider on off-road terrain. The slight back sweep to the bars makes them feels slightly less wide and bulky when commuting, so I find that they strike a good balance between trail performance and commuting comfort.

The grips that come stock on the Marlin 6 are also comfortable. They stray from the traditional round grip design, featuring an extended flat pad on the outside of the grip. This provides additional contact for the hand and prevents any hot-spots or hand discomfort on longer rides.

Where is the Trek Marlin 6 lacking?

Not for Advanced Trail Riding

While the Marlin is a great entry-level cross-country bike, it does not have the geometry nor the components for advanced trail riding. Once the trails get overly technical, require a lot of jumps, or turn into downhill trails, the Marlin finds itself out-gunned by the technical demands of the terrain. The shifting would start to feel clunky or slow due to the demands of the trails, and the geometry would feel too steep for serious off-roading. Furthermore, the travel of the front suspension is too short for serious trail riding

Not the Fastest Commuter Bike

The Marlin 6 is a good all-arounder, functioning well as a commuter while also handling moderate trails on the weekends. However, for long distance commutes, or for use as strictly a commuter bike, the heavy wheels and burly frame may start to feel sluggish. The Marlin offers a level of robustness that is not required for typical commuting, so bikes that are designed strictly for commuting will feel lighter and quicker comparatively. If you plan to only commute on this bike, you would be better suited by a bike in Trek’s FX line of fitness hybrids.


The Trek Marlin 6 is a great all-around bike. It’s designed for dual purpose use as a commuter that can also handle some moderate off-road terrain, and, for that purpose, it excels. Trek provided an excellent value at an affordable price for this bike, with impressive features throughout the build.

The Marlin 6 adapts well to off-road terrain while still performing on flat paths and pavement.

The Marlin 6 includes hydraulic disc brakes, a front suspension with lockout, internal cable routing, and a 2×8 drivetrain, all for under $700. Compared to many other mountain bikes on the market, this truly is an incredible value for what you pay, and it leaves plenty of room for upgrades and growth as a cyclist.

My girlfriend purchased her own Marlin 6 about a year ago, and it has proven to be a great choice for her. She was just beginning to ride more and did not want to invest too much money initially. The Marlin 6 has provided her with a reliable bike that she has taken on gravel rides and cross-country trails, instilling a sense of confidence that all newer riders need and allowing her to enjoy riding.

After reading the specifications online, I was already impressed with the offerings of this bike, considering the low price. Now, having ridden it and seeing it in action over the past year, I can confidently say that it has met my expectations and delivered on Trek’s marketing promises.

As we approach MTB season, I would highly recommend this bike to new mountain bikers or people looking for an affordable, versatile mountain bike.

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