Trek

Marlin4 Gen 3

Claimed weight14.90 kg / 32.85 lb (size M)Complete bike

FrameAlpha Silver Aluminum (XX…XXS: SR Suntour XCM 30, coi…

GroupsetShimano M315, 8-speedShimano HG300, 8-speed, 1…

WheelsBontrager Connection, d…Bontrager Montrose Comp, wi…

The third-generation Trek Marlin marks a deliberate shift from its cross-country and hybrid origins toward a modern trail hardtail. Trek designed this aluminum frame to serve a dual purpose, catering to newer mountain bikers exploring singletrack while retaining the utility needed for rugged commuting. The defining update is a significantly longer and slacker profile, bringing current trail bike proportions to an entry-level price point.

Despite the aggressive new silhouette, the Marlin Gen 3 remains deeply practical. The frame includes integrated mounts for racks, fenders, and kickstands, acknowledging that many riders will use it for daily transportation as well as weekend recreation. Trek also updated the frame standards to include internal dropper post routing and increased tire clearance. It is positioned as a versatile, durable starting point for riders who want a capable off-road machine that does not sacrifice everyday usability.

Trek Marlin

Build

Size

$630See deal

01 / Buy

Where to get it.

1 retailer · size M.

Size

1 retailer · Size M

Brand directTrekBest price

Trek Marlin 4 Gen 3

In stock

$630

02 / Specifications

Spec sheet.

Every component shipped with this build.

01Frameset

3 components

FrameAlpha Silver Aluminum (XXS, XS: curved top tube), internal derailleur & dropper post routing, rack and kickstand mount, 135x5mm ThruSkew

ForkXXS: SR Suntour XCM 30, coil spring, preload, hydraulic lockout, 42mm offset (26"), 100mm QR, 100mm travel; XS: SR Suntour XCE 28, coil spring, preload, 42mm offset (27.5"), 100mm QR, 80mm travel; S: SR Suntour XCE 28, coil spring, preload, 42mm offset (27.5"), 100mm QR, 100mm travel; M/ML/L/XL: SR Suntour XCE 28, coil spring, preload, 46mm offset (29"), 100mm QR, 100mm travel

Weight14.90 kg / 32.85 lb (size M)

02Drivetrain & brakes

10 components

Shift leversShimano M315, 8-speed

Rear derailleurShimano ESSA U2000

CassetteShimano HG300, 8-speed, 11-45T

ChainKMC Z8.3, 8-speed

CranksetProWheel alloy, 30T narrow-wide steel ring — XXS/XS: 160mm; S/M/ML: 170mm; L/XL: 175mm

Bottom bracketThreaded cartridge

Front brakeHydraulic disc — XXS/XS/S: Tektro HD-M276; M/ML/L/XL: Tektro HD-M275 (also listed: Power BH-M286TF)

Rear brakeHydraulic disc — XXS/XS/S: Tektro HD-M276; M/ML/L/XL: Tektro HD-M275 (also listed: Power BH-M286TF)

Front rotorTektro, 6-bolt — 160mm (XXS–XL), 180mm (M–XL listed)

Rear rotorTektro, 6-bolt — 160mm (XXS–XL)

03Wheels & tires

4 components

Front wheelBontrager Connection, double-wall, 32-hole, 20mm width, Schrader valve; Formula DC-20, alloy, 6-bolt, 100x5mm

Rear wheelBontrager Connection, double-wall, 32-hole, 20mm width, Schrader valve; Formula DC-22, alloy, 6-bolt, Shimano 8/9/10 freehub, 135x5mm

Front tireBontrager Montrose Comp, wire bead, 30 tpi — XXS: 26x2.35; XS/S: 27.5x2.4; M/ML/L/XL: 29x2.4

Rear tireBontrager Montrose Comp, wire bead, 30 tpi — XXS: 26x2.35; XS/S: 27.5x2.4; M/ML/L/XL: 29x2.4

04Cockpit & contact

5 components

StemBontrager Comp, 31.8mm, 7° — XXS/XS/S: 35mm; M/ML/L: 50mm; XL: 60mm (M–XL Blendr compatible)

HandlebarsBontrager alloy, 31.8mm — XXS/XS: 5mm rise, 690mm; S: 15mm rise, 720mm; M/ML/L/XL: 15mm rise, 750mm

SaddleBontrager Verse Short, stainless steel rails

SeatpostBontrager alloy, 31.6mm, 12mm offset — XXS: 300mm; XS/S/M: 330mm; ML/L/XL: 400mm

Grips/TapeTrek Line Comp, nylon lock-on

03 / Geometry

Geometry & fit.

8 sizes published.

The Marlin Gen 3 adopts a distinctly modern trail posture, defined by a slack head tube angle and a lengthened reach. This pushes the front wheel further out, stabilizing the steering on descents and preventing the twitchy feel common to older cross-country designs. To maintain pedaling efficiency, Trek steepened the seat tube angle, placing the rider in a neutral, upright position that centers their weight over the bottom bracket for seated climbing.

Trek utilizes size-specific wheel sizing to keep handling consistent across rider heights. The smallest frames roll on 26-inch or 27.5-inch wheels and feature a heavily curved top tube to maximize standover clearance, while medium through XXL frames use 29-inch wheels. The cockpit setup reinforces the bike’s trail intentions, pairing wide handlebars with a short stem to provide leverage and responsive steering inputs. While the seated position is comfortable for touring and commuting, some taller riders may find the reach slightly cramped during long, flat pedaling efforts.

Reach × Stack · size Mmm

Where the handlebar sits relative to the bottom bracket — the single most important fit pair.

01Fit geometry6 values

Stack609 mm

Reach440 mm

Top tube615 mm

Headtube length105 mm

Standover height747 mm

Seat tube length420 mm

02Component geometry4 values

Crank length170 mm

Handlebar width750 mm

Stem length50 mm

Seatpost offset12 mm

03Handling geometry8 values

Headtube angle66.5°

Seat tube angle73.4°

BB height308 mm

BB drop60 mm

Trail110 mm

Offset46 mm

Wheelbase1163 mm

Chainstay length438 mm

Which size should I buy?

Slide your height to see the recommended size. GearWise's fit algorithm works from the published stack, reach, and ETT — the brand's own recommendation may differ.

Your height

5'8"173 cm

5'0"5'5"5'10"6'3"6'7"

Recommended sizeMBased on stack, reach & ETT for your height · score 94/100.

→Calculated from GearWise's own stack / reach / ETT algorithm — the brand's size chart may recommend a different size, and a proper bike fit beats any calculator.

04 / Other builds

The lineup.

4 builds, ranging $630 – $1,400.

The Marlin Gen 3 lineup spans four aluminum builds, with significant component shifts dictating each model's off-road capability. The entry-level Marlin 4 and 5 utilize basic coil-sprung forks and rigid seatposts. The Marlin 4 relies on an 8-speed drivetrain and Tektro hydraulic brakes, while the Marlin 5 steps up to a 9-speed Shimano CUES system.

The Marlin 6 and 7 represent a major jump in trail readiness, introducing TranzX dropper posts and tubeless-ready Bontrager Kovee wheels. The Marlin 6 features a 10-speed Shimano CUES drivetrain and a RockShox Judy coil fork. The flagship Marlin 7 offers the most refined ride, upgrading to a lighter RockShox Judy Silver air fork with adjustable rebound and a 12-speed SRAM Eagle drivetrain.

While the frame offers excellent durability and a threaded bottom bracket, long-term upgrade potential is inherently limited. The straight head tube restricts aftermarket fork options, and the reliance on quick-release and ThruSkew axles prevents riders from easily swapping to modern thru-axle wheelsets. Consequently, the higher-tier builds offer the best out-of-the-box value for dedicated trail riding, as upgrading the lower-tier models later will prove difficult.

— · Currently viewing4 Gen 3

—

$630On this page

05 / Reviews

From the press.

14 reviews from the cycling press.

Reviewers consistently praise the Marlin Gen 3 for its modernized geometry, noting that the longer footprint translates to a highly predictable ride on moderate singletrack. On flowing descents, the updated frame delivers "calmer handling" (BikeRadar), allowing newer riders to navigate green and blue trails without feeling pitched over the front wheel. Testers also found the aluminum chassis surprisingly forgiving, highlighting a "compliant character" (Ambmag) that helps mute trail chatter at lower speeds.

However, critics agree that the bike has clear limits when pushed hard. The combination of a quick-release front axle and Trek’s ThruSkew rear system introduces noticeable flex under heavy cornering loads. When taken onto steep, rocky, or high-speed descents, the chassis feels "easily overwhelmed" (Ambmag). Multiple testers also pointed out that the internal cable routing can become "rather noisy and rattly on more challenging terrain" (YouTube), detracting from the otherwise solid ride quality.

While the bike is an efficient climber on smooth fire roads, its overall weight can feel sluggish on steep, technical ascents. Ultimately, reviewers view the Marlin as an excellent gateway mountain bike that balances off-road capability with pavement manners, provided riders stay within its intended light-trail scope.

Review image

Staging