Bike models › Mountain
Trek 820 (2010): specs, upgrades and what fits
Trek's long-running steel entry mountain bike with a 63 mm coil fork, 21 speeds on a Shimano 7-speed freewheel, V-brakes and 26 x 2.0 tires; it sold new for $329.99. The 2009-2014 820s are built the same way with small part changes. Best for: Bike paths, dirt roads and easy trails.
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My take, from the specs
A tough steel entry mountain bike that is fine for bike paths, dirt roads and easy trails. The 63mm coil fork, V-brakes and 3x7 drivetrain on a 14-34 thread-on freewheel are basic, so spend money on tires and brake pads rather than drivetrain upgrades. On a used one, check the steel frame for rust, the fork for play and the rims for brake-track wear.
Sizes: 13 in: 4′10″–5′1″ (147–156 cm) · 16 in: 5′1″–5′6″ (154–167 cm) · 18 in: 5′5″–5′10″ (164–177 cm) · 19.5 in: 5′9″–6′2″ (174–187 cm) · 21 in: 6′1″–6′6″ (185–198 cm)
Stock specs
| Type | Mountain |
|---|---|
| Year | 2010 |
| Price when new | $330 |
| Sold at | Trek dealers (discontinued; common used) |
| Wheels | 26" × 51 mm tires |
| Gears | 3×7 · 48/38/28T · 14–34T |
| Brakes | Tektro V-brake |
| Fork | SR Suntour M-2025, coil spring, 63 mm |
| Rear derailleur | Shimano TX31 (Tourney) |
| Shifter | Shimano EF40, 3x7 (integrated with brake levers) |
| Crank | Hawk DX triple (square taper est.) |
| Bottom bracket | Generic Square-taper BB (type not listed) |
| Axles | Quick release |
| Seatpost | 31.6 mm |
| Sizes | 13 in, 16 in, 18 in, 19.5 in, 21 in |
| Stock colors | Gloss Black |
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) | 51 mm | Unknown until measured. Your 30 mm internal rims suit roughly 44–78 mm tires. |
| Tubeless | Not recommended | Tubeless needs a rim built to seal (bead hook + channel) and tubeless-ready tires. |
| Valve type | Schrader | 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 | Any wheel matching axle type, spacing and brake mount fits. Rear also needs the right freehub. |
| Biggest rear cog | 34T (now 34T) | Set by the rear derailleur (Shimano TX31 (Tourney)): max low sprocket 34T, 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. |
| Brake pads (rim) | Threaded-post pads (V-brake / U-brake) | Rim brake pads are sorted by how they mount, which depends on the brake: threaded post with a nut (V-brakes, U-brakes), smooth post in an eye bolt (cantilevers), road cartridges (dual-pivot calipers) or short threaded pads (side-pull calipers). Any compound… |
| Front gears | 3x (48/38/28T) · needs 40T capacity | A 3x drivetrain needs a front derailleur and left shifter. Your rear derailleur must take up (biggest − smallest ring) + (biggest − smallest cog) = 40T. Going 1x drops the front derailleur: simpler and quieter, with a slightly smaller range. |
| Chainring size | Unknown (now 48T) | Estimated from similar frames. Measure the chainring-to-chainstay gap to confirm. Check whether your ring is bolted or riveted. Spindle length (? mm) sets chainline; a big change in ring size may need a different BB spindle. |
| Gear count upgrades | Freewheel (≤8) | Threaded freewheel: up to 7/8-speed freewheels only. More speeds needs a new rear wheel with a freehub. |
| Cranks & bottom bracket | Square taper · 68 mm shell · ? 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". |
| Stems & bars | 1-1/8 steerer · 25.4 mm bar clamp | Any stem for a 1-1/8 steerer with a 25.4 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 | No rack · No fender · 0 bottle | Threaded eyelets at the dropouts and seat stays take a rack and fenders. Fork leg mounts take cargo cages. |
| Max load (rider + cargo) | Unknown | 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 820 (2010) 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
Brakes
- Kool-Stop Salmon V-brake pads, threaded post (2 pairs), $$. threaded post pads ↔ your rim brakes
- Shimano Deore cartridge V-brake pads (2 pairs), $$. threaded post pads ↔ your rim brakes
- Jagwire Mountain Pro brake cable kit (Kevlar KEB-SL housing), $$. Made for flat bars ↔ your flat bar
- Shimano Deore BR-T610 V-brakes (front + rear), $$. threaded post pads ↔ your rim brakes · Long-pull caliper ↔ your flat-bar (long-pull) levers
- Shimano S65T V-brake pads, threaded post (2 pairs), $. threaded post pads ↔ your rim brakes
- Kool-Stop threaded V-brake cartridge holders with salmon inserts (2 pairs), $$. threaded post pads ↔ your rim brakes
- Shimano Alivio BR-T4000 V-brakes (front + rear), $$. threaded post pads ↔ your rim brakes · Long-pull caliper ↔ your flat-bar (long-pull) levers
Comfort
- Ergon GP1 ergonomic grips, $$. Made for flat bars ↔ your flat bar
- Budget ergonomic lock-on grips, $. Made for flat bars ↔ your flat bar
- 35° rise 60 mm stem, $. 1-1/8" steerer matches · Get the 25.4 mm clamp version for your bar
- WTB Volt saddle, $$. Medium-width shape that suits most riders. Measure sit bones if comfort is the goal.
- 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, $$$. 31.6 mm post ↔ your 31.6 mm seat tube
- Redshift ShockStop Endurance suspension seatpost 31.6 mm, $$$$. 31.6 mm post ↔ your 31.6 mm seat tube
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 31.6 mm (LR or XR spring), $$$$. 31.6 mm post ↔ your 31.6 mm seat tube
- Wald 8095 swept touring handlebar 25.4 mm, $$. Made for flat bars ↔ your flat bar
- Sunlite Northroad Touring alloy handlebar 25.4 mm, 3.5" rise, $$. Made for flat bars ↔ your flat bar
- Nitto B352AA Albatross handlebar 25.4 mm, 55 cm, $$$. 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), $$$. Cup-and-cone bearings are fully serviceable and last for years. Shoes with a 2-bolt SPD cleat sold separately.
- KS eTen-R external dropper 31.6 mm, 100 mm drop + KS Southpaw remote, $$$. 31.6 mm post ↔ your 31.6 mm seat tube
- TranzX YSP22 external dropper 31.6 x 450 mm, 125 mm drop, remote included, $$$. 31.6 mm post ↔ your 31.6 mm seat tube
- KS LEV external dropper 31.6 mm (100–150 mm drop) + KS Southpaw remote, $$$$. 31.6 mm post ↔ your 31.6 mm seat tube
Utility
- USB rechargeable front + rear light set, $$. 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.
Tubes
- Slime self-sealing tubes 26 x 1.75–2.125 Schrader (pair), $$. 26" wheel size matches
- Schwalbe AV13 26 x 1.5–2.4 Schrader tubes (pair), $. 26" wheel size matches · Schrader valve ↔ your Schrader rims
Drivetrain
- KMC X8 8-speed chain with Missing Link, $. 6/7/8-speed chain ↔ your 7-speed drivetrain
- KMC Z7 6/7-speed chain (116 links), $. 6/7-speed chain ↔ your 7-speed drivetrain
- KMC Z8.3 6/7/8-speed chain (116 links), $. 6/7/8-speed chain ↔ your 7-speed drivetrain
- KMC X8 EPT 6/7/8-speed anti-rust chain with Missing Link, $$. 6/7/8-speed chain ↔ your 7-speed drivetrain
Tires
- Kenda Kwest 26x1.95 reflective (pair), $$. 50 mm tire ↔ your ~51 mm clearance
- Schwalbe Big Apple 26x2.0 (50-559) (pair), $$$. 50 mm tire ↔ your ~51 mm clearance
- Schwalbe Marathon Plus 26x2.0 (50-559) SmartGuard (pair), $$$. 50 mm tire ↔ your ~51 mm clearance
- Kenda K-Rad 26x1.95 (50-559) wire (pair), $$. 50 mm tire ↔ your ~51 mm clearance
Gearing
- Shimano Tourney MF-TZ500-7 7-speed freewheel 14–28, $. 7-speed ↔ your 7-speed drivetrain · 28T biggest cog ↔ your derailleur's 34T max
- Shimano Tourney MF-TZ500-7 7-speed freewheel 14–34 (MegaRange), $. 7-speed ↔ your 7-speed drivetrain · 34T biggest cog ↔ your derailleur's 34T max
- SunRace 7-speed freewheel 13-28 (MFM3S), $. 7-speed ↔ your 7-speed drivetrain · 28T biggest cog ↔ your derailleur's 34T max
- SunRace MF-M300 7-speed freewheel 14-34, $$. 7-speed ↔ your 7-speed drivetrain · 34T biggest cog ↔ your derailleur's 34T max
- Shimano Acera RD-M3020-8 SGS 7/8-speed rear derailleur (40T max), $$. 7-speed ↔ your 7-speed drivetrain · Shimano cable pull ↔ your shifter
Fits with small changes (22)
- Suspension seatpost 27.2 mm (budget), $$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Redshift ShockStop suspension seatpost 27.2, $$$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- External dropper post 27.2 mm, 100 mm drop + remote, $$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- 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, $$$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 27.2 mm (LR or XR spring), $$$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- Cirrus Kinekt 2.1 Aluminum suspension seatpost 30.9 mm (LR or XR spring), $$$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- KS eTen-R external dropper 27.2 mm, 100 mm drop + KS Southpaw remote, $$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- KS eTen-R external dropper 30.9 mm, 100 mm drop + KS Southpaw remote, $$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- PNW Components Pine external dropper 27.2 mm (90 or 110 mm) + PNW Loam lever, $$$$. Your seat tube takes 31.6 mm: needs a 27.2→31.6 shim.
- TranzX YSP22 external dropper 30.9 x 410 mm, 125 mm drop, remote included, $$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- KS LEV external dropper 30.9 mm (100–150 mm drop) + KS Southpaw remote, $$$$. Your seat tube takes 31.6 mm: needs a 30.9→31.6 shim.
- Stan's NoTubes tire sealant 16 oz, $. In tubes: needs tubes with removable valve cores (Presta or Schrader to match your rims).
- Orange Seal Endurance tubeless sealant 16 oz, $. In tubes: needs tubes with removable valve cores (Presta or Schrader to match your rims).
- SILCA Ultimate Tubeless Sealant 16 oz, $. In tubes: needs tubes with removable valve cores (Presta or Schrader to match your rims).
- Magura HS11 hydraulic rim brakes with levers (front + rear), $$$. Replaces your brake levers. Your shifter stays.
- 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 ($330), age and condition, not live market data. If it needs tires, a chain or brakes, take off what fixing them would cost.
| Condition | Today (2010 model) |
|---|---|
| Like new | $85–$110 |
| Good | $75–$100 |
| Fair | $60–$80 |
| Needs work | $45–$60 |
See what these really sold for on eBay · Other used bike prices
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Sources: Trek bike archive (via web.archive.org): 2010 820 full spec · BikePedia (via web.archive.org): 2010 Trek 820 specs, MSRP $329.99, sizes, colour · Giant bike archive: Shimano TZ31 listed as a 14x34 7-speed freewheel