Is Trek Marlin 4 the Right Beginner MTB for You?

Review of Trek Marlin 4: Beginner Mountain Biker’s Dream

Trek Marlin 4 2020
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Trek Marlin 4 is an affordable mountain bike ideal for anyone who wants to get back in shape or test the waters of trail riding.

Mountain biking is an expensive sport, right?

You’ve always wanted to ride the trails but you never had enough money for it. Well, that’s no longer a valid excuse thanks to Trek Marlin 4.

Trek Marlin 4 is a cheap bicycle that costs less than $700 but has all the important features to earn the status of a real trail bike.

New riders looking to be more active, have fun on backroads, or do some rugged commuting will find lots of value in this versatile 29er.


Trek Marlin 4 Quick Overview

In short, Marlin 4 Gen 2 is an excellent starter bike. First-timers will find it to be comfortable, fun, and efficient. It sports a lightweight aluminum frame, a decent fork with plenty of travel, 27.5″ or 29″ wheels, and disc brakes.

It is characterized by excellent handling, progressive geometry that gives you control, and great Bontrager parts that get the job done when you get off the paved roads.

Key Specs:

  • Frame: Alpha Silver Aluminum
  • Fork: SR Suntour XCE 28, 100 mm (80mm for XS)
  • Front Derailleur: Shimano Tourney TY300
  • Rear Derailleur: Shimano Tourney TY300
  • Number of Gears: 21
  • Brakes: Tektro mechanical disc, 160mm rotors
  • Rims: Bontrager Connection, double-wall
  • Tire Size: 27.5″/29″ x 2.20″ or 29″x2.00″
  • Weight: 31.75 lbs / 14.40 kg


See on Trek


Marlin 4 Main Features

Trek Marlin 4 has a lot to offer in terms of looks, durability, build quality, and on-trail performance. It’s a versatile bike that’s ready to assume different roles and serve as a daily commuter or a mountain explorer.

Marlin 4's rear rack

Its long list of features includes lots of pleasant surprises, but some inevitable points for improvement as well.


Progressive Geometry Aluminum Frame

The most important element of Marlin 4 is definitely its frame. This Trek’s Alpha Aluminum frame is seen on more expensive bikes and features high-tech solutions such as internal cable routing, rack and fender mounts, a kickstand mount, progressive geometry, and more.

Namely, the top tube on smaller frames (XS, S) dips down to provide more standover height, which is great news for shorter riders. The frame itself is available in three vibrant colors, so it’s perfect for both men and women.

This Trek’s frame comes outfitted with an SR Suntour fork with 100 mm of travel. It’s a heavy fork, no doubt, but for $490 it’s a decent feature. You’ll be happy to have it when you hit the trails.

This fork does not have a lockout feature,  so you can’t lock it when you’re riding on paved roads to avoid power loss.


Shimano Tourney Components

Entry-level Shimano Tourney components will provide you with 21 gears on a 3×7 drivetrain. The cassette has a 14×28 tooth range, which is not ideal for steep hills. This is one area where Trek could improve in the future.

Shimano Tourney components

Tourney is Shimano’s cheapest groupset, so don’t expect much in terms of precision or durability. However, if your plan with Marlin 4 is to ride casually without testing anyone’s limits, you don’t need much more.


Highpoint: Trail-Ready Disc Brakes

Marlin 4’s Tektro mechanical disc brakes are good value for the money. They significantly extend the capabilities of this bike and present one of its main selling points.

These brakes are matched with 160 mm rotors on both wheels, so they are definitely trail-ready. Mechanical disc brakes don’t offer the precision of a hydraulic setup, but they are pretty much equal in terms of stopping power.

If you tackle big descents or hit the brakes hard at a traffic light, mechanical discs will respond well.


Double-Wall Rims and Wide Tires

Trek equips all of its bikes with Bontrager wheels and tires. Bontrager is Trek’s sister company, which means Marlin 4’s wheels and tires are built in-house.

Smaller frame sizes (XS, S) come with 27.5″ wheels, whereas all others roll on 29er wheels. This way, the bike will fit better for both short and tall riders.

The Bontrager XR2 Comp tires are 2.20″ on both wheel sizes. They’re quite knobby and have a wire bead which makes them more durable and less prone to flats.


SEVEN Frame Sizes

Trek Marlin 4 Gen 2 is available in seven frame sizes, which is much more compared to other popular brands — most manufacturers offer bikes in four or five sizes.

Choose the perfect frame size for your height based on the Trek’s size chart below:


Frame size number Frame size letter Wheel size A — Seat tube B — Seat tube angle Effective seat tube angle C — Head tube length D — Head angle E — Effective top tube F — Bottom bracket height G — Bottom bracket drop H — Chainstay length I — Offset J — Trail K — Wheelbase L — Standover M — Frame reach N — Frame stack
13.5″ XS 27.5″ 34.3 73.5° 73.5° 9 69.3° 54.4 29.2 5.8 43.8 4.2 8.8 104.9 65.8 37.6 56.5
15.5″ S 27.5″ 36.8 73.5° 73.5° 9 69.3° 55.5 30.2 4.8 43.8 4.2 8.8 106.6 68.6 38.5 57.4
17.5″ M 29″ 41.9 71.9° 73.0° 9 69.5° 60.2 31 5.8 43.8 4.2 9.3 110 74.8 41.8 60.2
18.5″ ML 29″ 44.4 71.9° 73.0° 9 69.5° 61.8 31 5.8 43.8 4.2 9.3 111.6 75.8 43.4 60.2
19.5″ L 29″ 47 71.9° 73.0° 10 69.5° 63.8 31 5.8 43.8 4.2 9.3 113.7 75.7 45.1 61.1
21.5″ XL 29″ 52.1 71.9° 73.0° 12 69.5° 65.9 31 5.8 43.8 4.2 9.3 115.9 76.9 46.6 63
23.0″ XXL 29″ 55.9 71.9° 73.0° 12 69.5° 67.3 31.1 5.8 43.8 4.2 9.3 117.3 80.4 48 63


Sleek and Modern Appearance

Last but not least is Marlin 4’s sleek and modern appearance. This is by far one of the best-looking bikes in this price range. Internal cable routing provides a clean look and the colors are suitable for both men and women.

Without taking a closer look at the components, Marlin 4 looks like a more expensive bike, especially due to massive 29″ tires and well-designed Bontrager parts.

It would win any beauty pageant.


Is Trek Marlin 4 the Right Choice for You?

suggestedTrek Marlin 4 will not find a place in everyone’s bike rack. It’s a bike built with beginners and first-timers in mind.

If you’re completely new to mountain biking and trail riding and you want to see if this type of cycling is the right choice of hobby for you, Marlin 4 is an excellent choice.

This bike also doubles as a rugged commuter that you can ride to work, school, or around the campus. If you plan to take the long way home when you’re done with your obligations, then it’s an even better choice.

However, don’t purchase Marlin 4 if you’re the type of person to blame everything on the equipment and if your expectations are way too high. It’s an entry-level trail bike after all.


Other Marlin Models

Trek Marlin Series Bikes

  • Marlin 4MSRP $630- Has a lightweight aluminum frame, 21 gears, 100 mm of front suspension, and strong mechanical disc brakes.
  • Marlin 5MSRP $740 – Combines a light aluminum frame, plush SR Suntour suspension, entry-level Shimano drivetrain, and powerful hydraulic disc brakes in a good-looking trail package.
  • Marlin 6MSRP $850 – This model is built with an Alpha Silver Aluminum frame, a 1×10 mid-range Shimano drivetrain, burly tires, and comes with 100 mm of front suspension travel with lockout.
  • Marlin 7MSRP $1,030 – Trek’s race-worthy model with an Alloy frame, superior RockShox front suspension, quality 1×10 drivetrain, Shimano components, and improved Shimano hydraulic disc brakes.


Verdict: Worth the Money?

Trek Marlin 4 proves to be worth the money once you consider the amount of fun to be had and the number of miles to be ridden by an average trail cyclist.

It’s an affordable bike that fits everyone’s budget and meets the needs of different types of rides. If you’re a beginner and a first-timer on the trails, we definitely recommend it.

Get From Trek

Trek Marlin 4













  • Lightweight aluminum frame
  • Great disc brakes
  • Affordable price
  • Capable knobby tires
  • Breathtaking looks


  • Entry-level components

12 thoughts on “Review of Trek Marlin 4: Beginner Mountain Biker’s Dream

  1. For a website that calls itself “bicycle guider” I expect to read insightful and current information on bicycles. Unfortunately, this article, although informative when written in 2020, is somewhat misleading in 2022. The Trek Marlin bike you describe is not a 2022 model and most of the specs listed no longer apply. There are actually too many differences to mention but suffice to say Trek has greatly updated the entire Marlin line – and the prices as well. I look forward to reading your amended article soon. Thank you

    1. Hi Tim,
      We always update our articles especially when newer models arrive. In fact, we are working on new articles 😉

    1. Hi Zachary,
      They are available in different sizes. You simply need to indicate the size you make when ordering.

  2. Hi Jeff

    I have one OEM Marlin 4, i would like to change the transmission to an Acera model. Do you think is advisable, maybe to increase to 9 or 10×3?

    1. Hi Jose,
      Interesting question as I have never explored that before. I would suggest you contact your LBC to see if there is compatibility issues. Aceras are mid-level components for MTBs, and in terms of performance they do ok but no so much to worth the trouble. But, Shimano is always reliable.

  3. Hi, is there a big difference between te 12-32 cassette on the Marlin 5 and the one on the Marlin 4? Would you recommend choosing the Marlin 5 because of the better cassette and the hydraulic disk breaks? Thanks a lot!

    1. Hi Erik,
      I doubt it will have an impact to your riding if you are not racing etc…But yes, the Marlin 5 is an improvement from the previous one. Hydraulic disck breaks are more efficient.

  4. Hi, I’m doubting between the Marlin 4 and the Marlin 5. Would you recommend the Marlin 5 because of the hydraulic breaks and the better cassette? Thank you very much!

  5. hello i have the marlin 4 and i broke the back derailleur do you know where i can get that same one or another derailleur that will work with it and for how much

    1. Hi Arjun,
      Any Shimano derailleur is compatible with the bike. Visit your LBS so you can get a better recommendation. A common Shimano brand is around $30.

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