Velopedia Bicycle Archive
2021 Polygon ZENITH TOWN-i3
Hybrid bicycle from the Velopedia specification archive.
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What Velopedia knows
- Model year
- 2021
- Category
- Hybrid
- Original MSRP
- $679.00
- Sizes
- S, M
- Colors
- Black
- Geometry
- 2 manufacturer sizes · Geometry context
- Record coverage
- 18 preserved details · archived image · original MSRP · preserved geometry
- Archive ID
- 900001899
Frameset
| Frame Construction | AL6 Commuter Nexus |
|---|---|
| Fork | HI-TEN Steel Rigid Fork |
| Fork Material | Steel |
Drivetrain
| Shifters | Shimano Nexus SL-3S41E |
|---|---|
| Crankset | Alloy Crank 44T, 170mm |
| Bottom Bracket | Cartridge Bearing |
| Cassette | Shimano Nexus 18T |
| Chain | KMC Z-610RB |
| Pedals | VP Component, VP-191, Alloy |
Brakes
| Brakes | Caliper Brake (F) Shimano Roller Brake BR-IM31R (R) |
|---|
Cockpit & Contact Points
| Headset | Internal Thread ID:44mm |
|---|---|
| Handlebar | Alloy, 695mm |
| Stem | Alloy, 80mm |
| Saddle | Selle Royal Ondina, Steel Rail |
| Seatpost | Alloy, 27.2X300mm |
Wheels & Tires
| Wheels | Araya TX-633 Rims with Shimano Nexus-3 HUB |
|---|---|
| Front Tire | 26”X2.35” |
| Rear Tire | 26”X2.35” |
Size-specific frame data
Geometry
Manufacturer-published geometry normalized for consistent archival comparison. Effective top tube and reach remain separate measurements because they describe different aspects of fit.
| Measurement | S | M |
|---|---|---|
| Seat tube | 406 mm | 456 mm |
| Effective top tube | 570 mm | 585 mm |
| Head tube | 230 mm | 250 mm |
| Head-tube angle | 66° | 66° |
| Seat-tube angle | 66.5° | 66.5° |
| Actual seat-tube angle | 66.5° | 66.5° |
| Chainstay / rear center | 490 mm | 490 mm |
| Wheelbase | — | 1102 mm |
| Bottom-bracket drop | 33 mm | 33 mm |
| Bottom-bracket height | 307 mm | 307 mm |
| Reach | 301 mm | 308 mm |
| Stack | 590 mm | 608 mm |
| Standover height | 719.28 mm | 763 mm |
Geometry source: Polygon first-party metric geometry table ↗ Measurements can vary by configuration, wheel size, or flip-chip position where noted by the manufacturer.
Geometry tools
Analyze a published size
S geometry
Archive context: The chainstay of 490 mm sits toward the longer rear-center end. The head angle of 66° sits toward the slacker end. The seat angle of 66.5° sits toward the more relaxed end.
Compared with 18 distinct hybrid geometries in the Small-equivalent size cohort from model years 2021–2023 in the Velopedia archive.Want to go deeper?Open this exact published size and configuration in the Velopedia Geometry Analyzer, then complete any measurements the manufacturer did not provide.
Analyze S geometry M geometry
Archive context: The head angle of 66° sits toward the slacker end. The seat angle of 66.5° sits toward the more relaxed end. The chainstay of 490 mm sits toward the longer rear-center end.
Compared with 17 distinct hybrid geometries in the Medium-equivalent size cohort from model years 2021–2023 in the Velopedia archive.Want to go deeper?Open this exact published size and configuration in the Velopedia Geometry Analyzer, then complete any measurements the manufacturer did not provide.
Analyze M geometry Parts & serviceability
Find replacement parts
Brake padsCaliper Brake (F) Shimano Roller Brake BR-IM31R (R)Brake model identified — verify pad shape
SaddleSelle Royal Ondina, Steel RailNamed archived component — verify exact version
ShiftersShimano Nexus SL-3S41EExact archived model
More qualified parts (2)
Seatpost27.2 mm seatpostPublished diameter — verify length and setback
WheelsAraya TX-633 Rims with Shimano Nexus-3 HUBNamed archived component — verify dimensions
Searches use the archived manufacturer specification, not the components currently installed on a particular bicycle. Confirm the exact model, size and fit before ordering. As an Amazon Associate I earn from qualifying purchases. Velopedia may also earn from qualifying eBay purchases. Velopedia may also earn from qualifying retailer purchases. Commercial relationships do not influence Archive specifications or analysis.
Used-bike inspection
If you’re buying this bike used
Before any test ride: both brakes should stop the bike firmly and release cleanly; both wheels should run true and be securely attached; tires should have no casing damage; and the headset, handlebar, stem, cranks and pedals should have no looseness or play.
Follow the full used-bike inspection order →- FrameInspect the complete frame and fork in bright light for cracks, dents, distortion, corrosion, impact marks, suspicious paint differences or signs of repair. Check the head tube, bottom-bracket area, dropouts, joints and clamped surfaces especially closely.Inspect the frame and fork →
- BrakesInspect pad condition, cable movement and the rim sidewalls or brake tracks for wear. A concave or heavily worn braking surface can mean the wheel also needs replacement.Inspect the brakes →
- DrivetrainShift through the full range under light load, measure chain wear and inspect the cassette or freewheel teeth. Skipping or hesitation can indicate wear, poor adjustment or mismatched parts.Check drivetrain wear →
- Wheels & tiresSpin both wheels and watch the rims for side-to-side or vertical movement. Check for dents, cracks, loose or uneven spokes and hub play, then inspect both tire casings for cuts, cracking or exposed threads.Check wheels and tires →
Bike-specific inspection checklist 19 checks based on 5 archived component groups Open checklistClose checklist
This checklist uses the archived equipment for this bike. It cannot confirm the condition, service history or later component changes of the example in front of you.
Identity and fit
Follow the full used-bike inspection order →Archived: 2021 Polygon ZENITH TOWN-i3 · Hybrid · Published sizes: S, M
Frame and fork
Inspect the frame and fork →Archived: Frame: AL6 COMMUTER NEXUS · Fork: HI-TEN STEEL RIGID FORK · Steel
Drivetrain
Check drivetrain wear →Archived: Shifters: SHIMANO NEXUS SL-3S41E · Crankset: ALLOY CRANK 44T, 170MM · Bottom bracket: CARTRIDGE BEARING · Cassette: SHIMANO NEXUS 18T · Chain: KMC Z-610RB
Brakes
Inspect the brakes →Archived: Brakes: CALIPER BRAKE (F) SHIMANO ROLLER BRAKE BR-IM31R (R)
Wheels and tires
Check wheels and tires →Archived: Wheels: ARAYA TX-633 RIMS WITH SHIMANO NEXUS-3 HUB · Front tire: 26”X2.35” · Rear tire: 26”X2.35”
Controls and contact points
Archived: Headset: INTERNAL THREAD ID:44MM · Handlebar: ALLOY, 695MM · Stem: ALLOY, 80MM · Seatpost: ALLOY, 27.2X300MM · Saddle: SELLE ROYAL ONDINA, STEEL RAIL · Pedals: VP COMPONENT, VP-191, ALLOY
Before and during the test ride
Follow the full used-bike inspection order →Build relationships are limited to the archived manufacturer specifications. Confirm exact fit and standards before ordering parts or performing service.
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Specifications are presented as a reference. Components may vary by market, size, production run, or later manufacturer revisions.