Bike models › Hybrid
Retrospec Harper: specs, upgrades and what fits
Retrospec's best-selling steel single-speed with a flip-flop rear hub (16T freewheel on one side, 16T fixed cog on the other), a 44T ring, dual-pivot caliper brakes, a quill stem and 700 x 32 tires. Best for: City riding and simple commuting.
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My take, from the specs
A simple steel single-speed for flat city riding, with a flip-flop hub that runs a 16T freewheel on one side and a fixed cog on the other. Dual-pivot caliper brakes and 700 x 32 tires keep it easy to look after at about 12.4 kg. The 44/16 gear can feel tall on hills, and riding fixed takes practice, so start on the freewheel side.
Sizes: S (48cm): 5′3″–5′6″ (160–168 cm) · M (52cm): 5′5″–5′8″ (165–173 cm) · L (56cm): 5′7″–6′0″ (170–183 cm) · XL (60cm): 5′9″–6′2″ (175–188 cm)
Stock specs
| Type | Hybrid |
|---|---|
| Year | 2026 |
| Price when new | $300 |
| Sold at | Retrospec (retrospec.com) |
| Wheels | 700c × 32 mm tires |
| Gears | Single speed · 44/16 |
| Brakes | Retrospec Alloy dual-pivot side-pull, 47-57mm reach |
| Fork | Retrospec Unicrown steel, 1-1/8 in. threaded, fender and rack eyelets |
| Crank | Retrospec Forged aluminum, 170mm (square taper est.) |
| Bottom bracket | Generic Sealed cartridge |
| Axles | Bolt-on |
| Seatpost | 25.4 mm |
| Weight | 27.3 lb (12.4 kg) |
| Sizes | S (48cm), M (52cm), L (56cm), XL (60cm) |
| Stock colors | Navy Zion, Olive Drab, Matte Black, Grateful Dead |
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) | 32 mm | Unknown until measured. Your 19 mm internal rims suit roughly 28–49 mm tires. |
| Other wheel sizes | 700c only | Rim brakes are set to the rim height, so the wheel size cannot change. |
| 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 | Bolt-on · 100/? mm | Any wheel matching axle type, spacing and brake mount fits. Rear also needs the right freehub. |
| Brake pads (rim) | Road cartridge or road pads (dual-pivot caliper) | 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 | 1x (44T) | 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 44T) | 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 | Single speed | One cog and no derailleur. To change the gearing, swap the sprocket or the rear driver/cog (more teeth on the cog = easier pedaling). |
| 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 | 25.4 mm | Buy posts in exactly this diameter. |
| Racks, fenders, bottles | Rack ✓ · Fender ✓ · 2 bottle · Fork cargo ✓ | Threaded eyelets at the dropouts and seat stays take a rack and fenders. Fork leg mounts take cargo cages. |
| Max load (rider + cargo) | 249 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 Retrospec Harper 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
Tubes
- Thorn-resistant tubes 700x35-43 (pair), $. 700c wheel size matches
- Schwalbe AV17 700x28–45 Schrader 40 mm tubes (pair), $. 700c wheel size matches · Schrader valve ↔ your Schrader rims
Brakes
- Shimano R55C4 road cartridge pads (2 pairs), $$. road caliper pads ↔ your rim brakes
- Jagwire Mountain Pro brake cable kit (Kevlar KEB-SL housing), $$. Made for flat bars ↔ your flat bar
- Shimano R50T2 road caliper brake pads (2 pairs), $. road caliper pads ↔ your rim brakes
- Kool-Stop Dura 2 salmon road brake pads, threaded (2 pairs), $$. road caliper pads ↔ your rim brakes
- SwissStop Full FlashPro Original Black road pads with holders (2 pairs), $$. road caliper pads ↔ your rim brakes
- Shimano Sora BR-R3000 dual-pivot rim brake calipers (pair), $$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
- Shimano Tiagra BR-4700 dual-pivot rim brake calipers (pair), $$$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
- Shimano 105 BR-R7000 dual-pivot rim brake calipers (pair), $$$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
- Tektro R539 long-reach dual-pivot rim brake calipers (pair), $$$. road caliper pads ↔ your rim brakes · Short-pull caliper ↔ your road (short-pull) levers
Comfort
- Ergon GP1 ergonomic grips, $$. Made for flat bars ↔ your flat bar
- Budget ergonomic lock-on grips, $. Made for flat bars ↔ your flat bar
- WTB Volt saddle, $$. 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
- 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, $$$. Made for flat bars ↔ your flat bar
- Sunlite 2-bolt alloy quill stem 1-1/8" (25.4 quill), 25.4 clamp, 80 mm, $$. 1-1/8" steerer matches · Quill stem ↔ your threaded (quill) steerer
- Sunlite adjustable alloy quill stem 1-1/8" (25.4 quill) x 110 mm, 0–60°, 25.4 clamp, $$. 1-1/8" steerer matches · Quill stem ↔ your threaded (quill) steerer
- Kalloy Uno SP-602 alloy seatpost 25.4 x 350 mm, $. 25.4 mm post ↔ your 25.4 mm seat tube
- Thomson Elite seatpost 25.4 x 330 mm, $$$. 25.4 mm post ↔ your 25.4 mm seat tube
- Sunlite adjustable suspension seatpost 25.4 mm, $$. 25.4 mm post ↔ your 25.4 mm seat tube
Control
- Race Face Chester composite flat pedals, $$. 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
Tires
- Continental Grand Prix 5000 700x28 clincher (pair), $$$. 28 mm tire ↔ your ~32 mm clearance
- Continental Ultra Sport III 700x28 folding (pair), $$. 28 mm tire ↔ your ~32 mm clearance
- Michelin Power Cup 700x28 clincher (pair), $$$. 28 mm tire ↔ your ~32 mm clearance
- Panaracer Pasela 700x32 wire (pair), $$$. 32 mm tire ↔ your ~32 mm clearance
- Panaracer GravelKing Slick 700x32 (pair), $$$. 32 mm tire ↔ your ~32 mm clearance
- Continental Grand Prix 5000 700x32 clincher (pair), $$$. 32 mm tire ↔ your ~32 mm clearance
Drivetrain
- KMC Z410 1/8" single-speed chain (112 links), $. 1-speed chain ↔ your 1-speed drivetrain
- KMC Z1 Wide EPT 1/8" anti-rust single-speed chain, $. 1-speed chain ↔ your 1-speed drivetrain
- KMC K710 Kool Chain 1/8" (BMX / single-speed), $$. 1-speed chain ↔ your 1-speed drivetrain
Fits with small changes (12)
- RideNow TPU gravel tubes 700x32-47 Presta (pair), $$. Presta valve: a Schrader rim needs a grommet so the valve sits snug.
- Continental Ultra Sport III 700x25 folding (pair), $$. Outside the ideal range for your 19 mm rims (28–49 mm): it will mount, but the shape is less stable.
- Michelin Power Cup 700x25 clincher (pair), $$$. Outside the ideal range for your 19 mm rims (28–49 mm): it will mount, but the shape is less stable.
- Continental Grand Prix 5000 700x25 clincher (pair), $$$. Outside the ideal range for your 19 mm rims (28–49 mm): it will mount, but the shape is less stable.
- Continental Race 28 Wide 700x25–32 Presta 60 mm tubes (pair), $. Presta valve: a Schrader rim needs a grommet so the valve sits snug.
- RideNow TPU road tubes 700x18–32 Presta 65 mm (pair), $. Presta valve: a Schrader rim needs a grommet so the valve sits snug.
- Pirelli P ZERO SmarTUBE 700x23–32 Presta 60 mm (pair), $$$. Presta valve: a Schrader rim needs a grommet so the valve sits snug.
- Continental Tour 28 All 700x32–47 Presta 42 mm tubes (pair), $. Presta valve: a Schrader rim needs a grommet so the valve sits snug.
- Tubolito Tubo-CX/Gravel-All 700x30–50 Presta 42 mm (pair), $$. Presta valve: a Schrader rim needs a grommet so the valve sits snug.
- 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).
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Buying one used? Fair prices
Worked out from the price new ($300), 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 | $140–$185 | $100–$135 | $75–$95 |
| Good | $125–$165 | $90–$120 | $65–$85 |
| Fair | $100–$135 | $75–$95 | $55–$70 |
| Needs work | $80–$100 | $55–$75 | $40–$55 |
See what these really sold for on eBay · Other used bike prices
Geometry (size M (52cm))
| Standover | 782° |
|---|
Compare with
- Schwinn Discover 2 700c · compare frames side by side
- Kent Ridgeway 700c · compare frames side by side
- Trek FX 2 Gen 4 · compare frames side by side
- Specialized Sirrus 2.0 · compare frames side by side
Sources: Retrospec: Harper Fixie Bike - Single Speed (specs, sizing, 1,267 reviews) · Retrospec: product data (prices, colors, 27.4 lb weight tag) · Retrospec: adult bikes sorted by best selling