Bike models › Mountain
Trek Marlin 7 Gen 3: specs, upgrades and what fits
The step-up Marlin: the same Alpha Silver aluminum trail hardtail as the Marlin 5, but with a 100mm RockShox Judy air fork, SRAM 1x12 Eagle gearing, a dropper post and tubeless-ready Maxxis Rekon tires. Best for: Trail riding and singletrack on a budget, with room to grow.
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My take, from the specs
A trail hardtail to start on and grow with, with a RockShox Judy air fork, SRAM 1x12 Eagle on an 11-50 cassette, Shimano MT200 hydraulic brakes and a dropper post, at about 14.2 kg. It keeps quick-release style axles (100 mm QR front, 135x5 rear), which limits future wheel upgrades. The MT200 brakes are basic for long steep descents.
Sizes: XS: 4′9″–5′1″ (145–155 cm) · S: 5′1″–5′5″ (155–165 cm) · M: 5′5″–5′10″ (165–177 cm) · ML: 5′8″–5′11″ (173–180 cm) · L: 5′10″–6′2″ (177–188 cm) · XL: 6′2″–6′5″ (188–195 cm) · XXL: 6′5″–6′8″ (195–203 cm)
Stock specs
| Type | Mountain |
|---|---|
| Year | 2026 |
| Price when new | $1400 |
| Sold at | Trek dealers / trekbikes.com |
| Wheels | 700c × 61 mm tires |
| Gears | 1×12 · 30T · 11–50T |
| Brakes | Shimano MT200 |
| Fork | RockShox Judy Silver, Solo Air, rebound adjust, TurnKey lockout, 100mm, 46mm offset, 100mm QR |
| Rear derailleur | SRAM NX Eagle 12-speed |
| Shifter | SRAM SX Eagle 12-speed |
| Crank | SRAM SX Eagle, PowerSpline interface, 170mm |
| Bottom bracket | Truvativ PowerSpline 73mm threaded cartridge, 118mm spindle |
| Axles | Quick release |
| Seatpost | 31.6 mm |
| Weight | 31.2 lb (14.15 kg) |
| Sizes | XS, S, M, ML, L, XL, XXL |
| Stock colors | Magic Mint, Crystal White, Fury Red/Lithium Grey Fade, Matte Dark Web/Clear Gloss Fury Red Fade |
Upgrade limits
How far each part can go on this frame, and why. Measure your own bike to confirm the estimated ones.
| Part | Limit | Why |
|---|---|---|
| Widest tire (current wheel size) | 61 mm | No measurement yet. Estimate from owner reports and frame design. Your 23 mm internal rims suit roughly 34–60 mm tires. |
| Other wheel sizes | 650b up to ~68 mm | Disc brakes don't care where the rim sits, so a 650b wheel with a fatter tire fits. A 650b × 47 is about the outer size of a 700 × 28, so the bottom bracket sits about 12 mm lower than on 700 × 40 (watch pedal strikes). |
| Tubeless | Yes (tubeless-ready) | Tubeless needs a rim built to seal (bead hook + channel) and tubeless-ready tires. |
| Valve type | Presta | Decides which tubes and pump heads fit. Presta tubes fit Schrader rims with a grommet; not the other way. |
| Replacement wheels | Quick release · 100/135 mm · 6-bolt disc | Any wheel matching axle type, spacing and brake mount fits. Rear also needs the right freehub. |
| Biggest rear cog | 50T (now 50T) | Set by the rear derailleur (SRAM NX Eagle 12-speed): max low sprocket 50T, total capacity ?T. A hanger extender can add a few teeth (hit-or-miss on non-Shadow derailleurs); a new derailleur is the reliable way to get more. |
| Front gears | 1x (30T) | One ring, no front derailleur. Adding a front derailleur needs a mount on the seat tube and a 2x crankset, so most riders change the ring size or cassette instead. |
| Chainring size | Unknown (now 30T) | Estimated from similar frames. Measure the chainring-to-chainstay gap to confirm. Check whether your ring is bolted or riveted. Spindle length (118 mm) sets chainline; a big change in ring size may need a different BB spindle. |
| Gear count upgrades | 12-speed (HG body) | Shimano HG 8/9/10-speed freehub: takes 8, 9 or 10-speed cassettes, Shimano 11-speed MTB and CUES/LinkGlide cassettes (7-speed needs a 4.5 mm spacer; most 11/12-speed road cassettes need an 11-speed road freehub, though the 11-34 HG700/HG800 fit). Shifter,… |
| Cranks & bottom bracket | Square taper · 73 mm shell · 118 mm spindle | Any square-taper crankset fits with the right spindle length. Upgrading to Hollowtech II needs a new BB (same threaded shell). |
| Pedal thread | 9/16" × 20 | Every adult multi-piece crank uses 9/16". One-piece kids/cruiser cranks use 1/2". |
| Brake pads | SHIMANO B01S | Disc pads only fit calipers with the matching shape. |
| Rotor size | 180/160 mm now | 6-bolt rotors. Going bigger needs a caliper adapter: post mount +20 mm adapter. Most steel forks allow 180 mm; check the fork if a max rotor is printed on it. |
| Caliper upgrades | Hydraulic system | Hydraulic: match the brand of lever and caliper. |
| Stems & bars | 1-1/8 steerer · 31.8 mm bar clamp | Any stem for a 1-1/8 steerer with a 31.8 mm clamp fits. You can cut a bar narrower but not wider. |
| Drop-bar conversion | Possible with mods | Needs road brake/shift levers (microSHIFT R8 makes 8-speed ones that pull Shimano 8-speed cable correctly), a drop bar, tape, and road-pull brake calipers because road levers pull less cable. Usually $250+. |
| Seatposts | 31.6 mm | Buy posts in exactly this diameter. |
| Racks, fenders, bottles | Rack ✓ · No fender · 1 bottle | Threaded eyelets at the dropouts and seat stays take a rack and fenders. Fork leg mounts take cargo cages. |
| Max load (rider + cargo) | 300 lb | Wheels are usually the weak point under heavy loads. Stay under this with rider plus luggage. |
Best upgrades by area
Three options that fit the Trek Marlin 7 Gen 3 as-is in each area, from budget to best. ★ marks the one most worth the money. How we pick. Typical US prices, checked October 2026. They change often: check the price at the store.
Upgrades that fit as-is
Tires
- Panaracer GravelKing Slick 700x35 (pair), $$$. 35 mm tire ↔ your ~61 mm clearance
- Kenda Kwest 700x35 (pair), $$. 35 mm tire ↔ your ~61 mm clearance
- WTB Byway 700x40 (pair), $$$. 40 mm tire ↔ your ~61 mm clearance
- Panaracer GravelKing SK 700x40 (pair), $$$. 40 mm tire ↔ your ~61 mm clearance
- Schwalbe Marathon 700x38 (pair), $$$. 38 mm tire ↔ your ~61 mm clearance
- WTB Riddler 700x45 TCS Light (pair), $$$. 45 mm tire ↔ your ~61 mm clearance
- Maxxis Ardent 29x2.25 EXO TR (pair), $$$. 57 mm tire ↔ your ~61 mm clearance
- Panaracer Pasela 700x35 wire (pair), $$$. 35 mm tire ↔ your ~61 mm clearance
- Panaracer Pasela 700x38 wire (pair), $$. 38 mm tire ↔ your ~61 mm clearance
- Schwalbe Marathon Almotion 700x38 (40-622) V-Guard Addix (pair), $$$. 38 mm tire ↔ your ~61 mm clearance
- Continental Contact Urban 700x40 (40-622) wire (pair), $$$. 40 mm tire ↔ your ~61 mm clearance
- Panaracer GravelKing Slick 700x40 (2025, pair), $$$. 40 mm tire ↔ your ~61 mm clearance
- WTB Riddler 700x37 TCS Light (pair), $$$. 37 mm tire ↔ your ~61 mm clearance
- Pirelli Cinturato Gravel M 700x45 (pair), $$$. 45 mm tire ↔ your ~61 mm clearance
- WTB Trail Boss Comp 29x2.25 wire (pair), $$. 57 mm tire ↔ your ~61 mm clearance
- Continental Race King ProTection 29x2.2 (pair), $$$. 55 mm tire ↔ your ~61 mm clearance
- Maxxis Minion DHR II 29x2.4 WT EXO 3C MaxxTerra (pair), $$$. 61 mm tire ↔ your ~61 mm clearance
Brakes
- Shimano B05S resin disc pads (B01S shape, 2 sets), $. Shimano B01S pad shape ↔ your calipers
- Tektro E10.11 resin disc pads (2 sets), $. Shimano B01S pad shape ↔ your calipers
- Kool-Stop D620S sintered disc pads, Shimano B01S / Tektro E10.11 shape (2 pairs), $$. Shimano B01S pad shape ↔ your calipers
- SwissStop Disc 15 RS organic disc pads, Shimano B-type / Tektro E10.11 shape (2 pairs), $$. Shimano B01S pad shape ↔ your calipers
- Shimano SM-RT56 180 mm 6-bolt rotor (1 rotor), $. Disc-brake part ↔ your disc brakes · 180 mm rotor ↔ your 180 mm front rotor
- Galfer Wave 180 mm 6-bolt rotor, 1.8 mm (1 rotor), $$. Disc-brake part ↔ your disc brakes · 180 mm rotor ↔ your 180 mm front rotor
- Shimano SM-RT86 Ice-Tech 180 mm 6-bolt rotor (1 rotor), $$. Disc-brake part ↔ your disc brakes · 180 mm rotor ↔ your 180 mm front rotor
Comfort
- Ergon GP1 ergonomic grips, $$. Made for flat bars ↔ your flat bar
- Budget ergonomic lock-on grips, $. Made for flat bars ↔ your flat bar
- 35° rise 60 mm stem, $. 1-1/8" steerer matches · Get the 31.8 mm clamp version for your bar
- WTB Volt saddle, $$. Medium-width shape that suits most riders. Measure sit bones if comfort is the goal.
- Race Face Chester riser bar 31.8 x 740 mm, 25 mm rise, $$. Made for flat bars ↔ your flat bar
- Brooks C17 All Weather saddle, $$$. Vulcanized rubber top that flexes like a hammock, and this All Weather version is fully waterproof. No break-in like leather. Firm, not padded: made for long…
- Bikeroo oversized comfort saddle, $. Wide, soft and sprung for short upright rides on cruisers and hybrids. On rides over an hour wide padding can chafe; a firmer saddle that fits your sit bones…
- Ergon GA3 lock-on grips, $$. Made for flat bars ↔ your flat bar
- Selle Royal Respiro Moderate saddle, $$$. Made for a 60° "moderate" back angle (most flat-bar hybrids). Very upright cruisers suit the wider Respiro Relaxed. Standard round steel rails.
- Fizik Terra Argo X5 saddle (150 or 160 mm), $$$. Pick 150 mm for narrower sit bones, 160 mm for wider. Round 7 mm alloy rails fit every standard clamp.
- Ergon SR Allroad Core Comp saddle (men's or women's), $$$. Comes in S/M and M/L widths (measure your sit bones) and men's and women's shapes. Round CroMo rails; 120 kg rider limit.
- Ergon GP5 ergonomic grips with built-in bar ends (S or L), $$$. Made for flat bars ↔ your flat bar
- SR Suntour NCX suspension seatpost 31.6 x 350 mm, $$$. 31.6 mm post ↔ your 31.6 mm seat tube
- Redshift ShockStop Endurance suspension seatpost 31.6 mm, $$$$. 31.6 mm post ↔ your 31.6 mm seat tube
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 31.6 mm (LR or XR spring), $$$$. 31.6 mm post ↔ your 31.6 mm seat tube
- Race Face Ride riser bar 31.8 x 710 mm, 25 mm rise, $$. Made for flat bars ↔ your flat bar
- SQlab 30X alloy riser bar 31.8 x 780 mm, 12° backsweep, $$$. Made for flat bars ↔ your flat bar
Control
- Race Face Chester composite flat pedals, $$. Big platform with pins. Feet stay put on bumps and in rain. Install with an 8 mm hex key (no wrench flats).
- ROCKBROS aluminum flat pedals, $$. Budget metal platform with pins. A big step up from stock plastic.
- Shimano PD-M520 SPD clipless pedals (cleats included), $$. Nearly indestructible two-sided SPD pedals. You also need SPD (2-bolt) shoes, about $60–100 more. Set the release tension low and practice unclipping before…
- Crankbrothers Stamp 2 aluminum flat pedals (small or large), $$$. Sized by shoe: small for US men's 5–10, large for 10 and up. Grease the threads and tighten to about 35 Nm.
- OneUp Components Aluminum flat pedals, $$$. Bearings and bushings can be serviced with a cheap kit instead of replacing the pedal. Grease the threads and tighten to about 35 Nm.
- Shimano PD-EH500 dual-sided SPD / flat pedals (cleats included), $$$. Comes with SM-SH56 multi-release cleats, which are easier to get out of in a panic. You still need 2-bolt SPD shoes to clip in.
- Shimano Deore XT PD-M8100 SPD pedals (cleats included), $$$. Cup-and-cone bearings are fully serviceable and last for years. Shoes with a 2-bolt SPD cleat sold separately.
Utility
- Topeak Explorer rear rack (disc mount), $$. Uses your frame's rack mounts
- USB rechargeable front + rear light set, $$. Daytime flashing lights cut collisions. Required by law at night.
- Pletscher adjustable kickstand, $$. Handy for errands. Check it clears the rotor and chainstay.
- Lisen clamp-style handlebar phone mount, $. Cheap and tool-free for maps on paved rides. On rough gravel or trails a locking mount (Quad Lock or Peak Design, about $45–70 plus a case) is much safer.
- Topeak TopLoader top tube bag (0.75 L), $$. Keeps snacks, keys and a multi-tool within reach. Straps on, with a rain cover. Check your knees do not rub it when you stand up.
- Knog Oi Classic bell, $. Slim ring bell that wraps the bar. Large fits 23.8–31.8 mm bars; Small fits 22.2 mm kids and BMX bars. Required by law in some places.
- Wald 137 front basket, $$. Made for flat bars ↔ your flat bar
- Planet Bike Beamer 200 + Blinky Squared USB light set, $$. USB rechargeable, tool-free mounts. Use flash mode in daylight. Rear light is 30 lumens: good for town, modest on fast roads.
- Cygolite Metro Plus 800 + Hotshot Pro 150 USB light set, $$$. Nine headlight modes including a daytime flash. Aim the beam slightly down so you do not blind oncoming riders.
- Trek (Bontrager) Ion Pro RT + Flare RT light set, $$$. Daytime-running flash modes on both lights. ANT+ lets a Garmin or Wahoo show battery and switch them. Full power runs about 1.5 hours; medium lasts much longer.
- Topeak Super Tourist DX Tubular rear rack (disc), $$$. Uses your frame's rack mounts
- Tubus Disco steel rear rack for disc brakes (26" or 28"/700c), $$$. Uses your frame's rack mounts
Drivetrain
- KMC X12 12-speed chain with Missing Link, $$. 12-speed chain ↔ your 12-speed drivetrain
- Shimano Deore CN-M6100 12-speed chain (126 links), $$. 12-speed chain ↔ your 12-speed drivetrain
- Shimano Deore XT CN-M8100 12-speed chain (126 links), $$. 12-speed chain ↔ your 12-speed drivetrain
Tubes
- Stan's NoTubes tire sealant 16 oz, $. For your tubeless setup
- Orange Seal Endurance tubeless sealant 16 oz, $. For your tubeless setup
- SILCA Ultimate Tubeless Sealant 16 oz, $. For your tubeless setup
Wheels
- WTB ST i30 TCS 29er disc rear wheel, QR 135, 6-bolt, HG 10, $$$. Disc-brake part ↔ your disc brakes · 700c wheel size matches
- Stan's NoTubes Crest S2 29 rear wheel, QR 135, 6-bolt, HG, $$$$. Disc-brake part ↔ your disc brakes · 700c wheel size matches
Gearing
- SRAM SX Eagle PG-1210 12-speed cassette 11–50 (HG), $$$. Cassette ↔ your Shimano HG freehub · 12-speed ↔ your 12-speed drivetrain
- SRAM NX Eagle PG-1230 12-speed cassette 11–50 (HG), $$$. Cassette ↔ your Shimano HG freehub · 12-speed ↔ your 12-speed drivetrain
- SunRace CSMZ90 12-speed cassette 11–50 (HG, alloy spider), $$$. Cassette ↔ your Shimano HG freehub · 12-speed ↔ your 12-speed drivetrain
Fits with small changes (29)
- microSHIFT Advent 1x9 kit (shifter, clutch RD, 11–46 cassette) + 9-speed chain, $$$. Installs as a set: shifter, derailleur, cassette and chain together.
- Suspension seatpost 27.2 mm (budget), $$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Redshift ShockStop suspension seatpost 27.2, $$$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Continental Grand Prix 5000 700x28 clincher (pair), $$$. Outside the ideal range for your 23 mm rims (34–60 mm): it will mount, but the shape is less stable.
- Continental Ultra Sport III 700x28 folding (pair), $$. Outside the ideal range for your 23 mm rims (34–60 mm): it will mount, but the shape is less stable.
- Shimano CUES U6000 1x11 kit (SL-U6000-11R shifter, RD-U6000 clutch RD, CS-LG400-11 11–50 LinkGlide cassette, chain), $$$$. Installs as a set: shifter, derailleur, cassette and chain together.
- Shimano BR-MT420 4-piston hydraulic brakes + BL-MT401 levers (pair), $$$. Replaces your brake levers. Your shifter stays.
- Shimano SM-RT66 203 mm rotor + 203 adapter (front), $$. Needs a post +23 mm adapter (included).
- Ritchey Comp 2-Bolt alloy seatpost 27.2 mm, $$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Thomson Elite seatpost 27.2 x 330 mm, $$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Ergon CF Allroad Pro Carbon flex seatpost 27.2 mm, $$$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- SR Suntour NCX suspension seatpost 30.9 x 350 mm, $$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- Redshift ShockStop Endurance suspension seatpost 30.9 mm, $$$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 27.2 mm (LR or XR spring), $$$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 30.9 mm (LR or XR spring), $$$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- Wald 8095 swept touring handlebar 25.4 mm, $$. Clamp is 25.4 mm; your bike's is 31.8 mm. Needs a shim or a matching stem/bar.
- Sunlite Northroad Touring alloy handlebar 25.4 mm, 3.5" rise, $$. Clamp is 25.4 mm; your bike's is 31.8 mm. Needs a shim or a matching stem/bar.
- Nitto B352AA Albatross handlebar 25.4 mm, 55 cm, $$$. Clamp is 25.4 mm; your bike's is 31.8 mm. Needs a shim or a matching stem/bar.
- Michelin Power Cup 700x28 clincher (pair), $$$. Outside the ideal range for your 23 mm rims (34–60 mm): it will mount, but the shape is less stable.
- Panaracer Pasela 700x32 wire (pair), $$$. Outside the ideal range for your 23 mm rims (34–60 mm): it will mount, but the shape is less stable.
- Panaracer GravelKing Slick 700x32 (pair), $$$. Outside the ideal range for your 23 mm rims (34–60 mm): it will mount, but the shape is less stable.
- Continental Grand Prix 5000 700x32 clincher (pair), $$$. Outside the ideal range for your 23 mm rims (34–60 mm): it will mount, but the shape is less stable.
- Shimano Deore BL-M6100 + BR-M6120 4-piston hydraulic brake set (pair, levers included), $$$$. Replaces your brake levers. Your shifter stays.
- Shimano SLX BL-M7100 + BR-M7120 4-piston hydraulic brake set (pair, levers included), $$$$. Replaces your brake levers. Your shifter stays.
- Shimano CUES U4000 1x9 kit (SL-U4000-9R shifter, RD-U4000, CS-LG300-9 11–46, CN-LG500 chain), $$$. Installs as a set: shifter, derailleur, cassette and chain together.
- Shimano Deore M5100 1x11 kit (SL-M5100 shifter, RD-M5100, CS-M5100 11–51, CN-HG601 chain), $$$. Installs as a set: shifter, derailleur, cassette and chain together.
- Kalloy Uno SP-602 alloy seatpost 25.4 x 350 mm, $. Your seat tube takes 31.6 mm: needs a 25.4→31.6 shim.
- Thomson Elite seatpost 25.4 x 330 mm, $$$. Your seat tube takes 31.6 mm: needs a 25.4→31.6 shim.
- Sunlite adjustable suspension seatpost 25.4 mm, $$. Your seat tube takes 31.6 mm: needs a 25.4→31.6 shim.
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Buying one used? Fair prices
Worked out from the price new ($1400), age and condition, not live market data. If it needs tires, a chain or brakes, take off what fixing them would cost.
| Condition | 1 year old | 3 years old | 5 years old |
|---|---|---|---|
| Like new | $790–$1040 | $640–$845 | $520–$685 |
| Good | $695–$915 | $565–$740 | $455–$600 |
| Fair | $570–$750 | $460–$605 | $375–$490 |
| Needs work | $435–$575 | $350–$465 | $285–$375 |
See what these really sold for on eBay · Other used bike prices
Geometry (size M)
| Stack | 609° |
|---|---|
| Reach | 440 mm |
| Head angle | 66.5° |
| Seat angle | 74° |
| Chainstay | 438° |
| BB drop | 60 mm |
| Wheelbase | 1163 mm |
| Head tube | 105 mm |
| Seat tube | 420 mm |
| Standover | 747° |
Compare with
- Huffy Stone Mountain 26 · compare frames side by side
- Schwinn High Timber ALX 29 · compare frames side by side
- Trek Marlin 5 Gen 3 · compare frames side by side
- Specialized Rockhopper Sport · compare frames side by side
Sources: First Stop Board Barn: Trek Marlin 7 Gen 3 2026 full spec, weight, limit, price · Bike Insights: Marlin 7 Gen 3 M geometry · Flow Mountain Bike: 2026 Marlin 7 review (66.5 HTA, 74 STA, 440 reach on M) · SRAM: PG-1210 cassette (11-50 cog list)