Velopedia Bicycle Archive
2021 Jamis Explorer A2
Mountain bicycle from the Velopedia specification archive.
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What Velopedia knows
- Model year
- 2021
- Category
- Mountain
- Original MSRP
- $589.95
- Sizes
- 15″, 17″, 19″, 21″, 14″ S/T, 16″ S/T, 18″ S/T
- Colors
- M: Deep Blue, Gloss Black S/T: Sage or Deep Blue
- Weight
- 30.50 lbs
- Geometry
- 7 manufacturer sizes · Geometry context
- Record coverage
- 24 preserved details · archived image · original MSRP · preserved geometry
- Archive ID
- 900001708
Frameset
| Frame Construction | 6061 TIG-welded aluminum, all-new sport comfort design with upright ride position, replaceable derailleur hanger |
|---|---|
| Frame Material | Aluminum |
| Fork | Hi-tensile steel unicrown, radius blades with dropout eyelets |
| Fork Material | Steel |
Drivetrain
| Component Group | Shimano TY300 rear and TY510 top swing/dual pull front |
|---|---|
| Shifters | Shimano EZ-Fire Plus, ST-EF500, 21-speed |
| Front Derailleur | Shimano TY300 rear and TY510 top swing/dual pull front |
| Rear Derailleur | Shimano TY300 rear and TY510 top swing/dual pull front |
| Crankset | Forged alloy, 48/38/28T, 170mm with chainguard |
| Bottom Bracket | Sealed cartridge, 68 x 110.5mm |
| Cassette | Shimano freewheel 7-speed, 14-34 |
| Chain | KMC Z7 |
| Pedals | Comfort platform with TPE non-slip insert |
Brakes
| Brakes | ProMax alloy direct pull brakes with Shimano levers |
|---|
Cockpit & Contact Points
| Headset | Internal cup, threaded, 1 1/8” |
|---|---|
| Handlebar | Comfort hi-rise, steel, 25.4 x 80mm rise x 15 ̊ sweep x 640mm |
| Stem | Jamis alloy, angle-adjustable, 90mm ext x 150mm quill (14 ̊18”) or 110mm ext x 180mm quill (19 ̊21”) |
| Saddle | Jamis Comfort with extra thick padding, synthetic suede top, burnished side panels and bumper springs |
| Seatpost | Alloy micro-adjust, 350mm x 27.2mm, with alloy QR clamp |
Wheels & Tires
| Wheels | Alloy 36H rims, Formula alloy hubs, QR front and rear, 14g stainless steel spokes |
|---|---|
| Front Tire | CST – 1918, 27.5 x 2.1 |
| Rear Tire | CST – 1918, 27.5 x 2.1 |
| Wheel Size | 27.5 |
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 | 15″ | 17″ | 19″ | 21″ | 14″ S/T | 16″ S/T | 18″ S/T |
|---|---|---|---|---|---|---|---|
| Effective top tube | 569 mm | 587 mm | 598 mm | 618 mm | 557 mm | 578 mm | 594 mm |
| Head tube | 155 mm | 175 mm | 195 mm | 220 mm | 160 mm | 170 mm | 180 mm |
| Head-tube angle | 69° | 70° | 70° | 70° | 69° | 69° | 69° |
| Seat-tube angle | 71° | 71° | 71° | 71° | 72° | 71° | 71° |
| Chainstay / rear center | 450 mm | 450 mm | 450 mm | 450 mm | 450 mm | 450 mm | 450 mm |
| Wheelbase | 1059 mm | 1066 mm | 1077 mm | 1097 mm | 1057 mm | 1067 mm | 1072 mm |
| Bottom-bracket height | 284 mm | 284 mm | 284 mm | 284 mm | 284 mm | 284 mm | 284 mm |
| Standover height | 727 mm | 768 mm | 808 mm | 847 mm | 478 mm | 483 mm | 486 mm |
| Fork offset / rake | 42 mm | 42 mm | 42 mm | 42 mm | 42 mm | 42 mm | 42 mm |
Geometry source: Jamis first-party geometry table (2021 GEO - EXPLORER) ↗ Measurements can vary by configuration, wheel size, or flip-chip position where noted by the manufacturer.
Geometry tools
Analyze a published size
17″ geometry
Archive context: The chainstay of 450 mm sits toward the longer rear-center end. The seat angle of 71° sits toward the more relaxed end. The head angle of 70° sits toward the steeper end.
Compared with 16 distinct mountain geometries in the XS-equivalent size cohort from model years 2021–2023 in the Velopedia archive.19″ geometry
Archive context: The head angle of 70° sits toward the steeper end. The chainstay of 450 mm sits toward the longer rear-center end. The seat angle of 71° sits toward the more relaxed end.
Compared with 48 distinct mountain geometries in the Small-equivalent size cohort from model years 2021–2023 in the Velopedia archive.21″ geometry
Archive context: The head angle of 70° sits toward the steeper end. The seat angle of 71° sits toward the more relaxed end. Its wheelbase of 1097 mm sits toward the shorter end.
Compared with 52 distinct mountain geometries in the Medium-equivalent size cohort from model years 2021–2023 in the Velopedia archive.14″ S/T geometry
Archive context: Its wheelbase of 1057 mm sits toward the shorter end. The chainstay of 450 mm sits toward the longer rear-center end. The seat angle of 72° sits toward the more relaxed end.
Compared with 44 distinct mountain geometries in the Large-equivalent size cohort from model years 2021–2023 in the Velopedia archive.16″ S/T geometry
Archive context: The seat angle of 71° sits toward the more relaxed end. Its wheelbase of 1067 mm sits toward the shorter end. The head angle of 69° sits toward the steeper end.
Compared with 43 distinct mountain geometries in the XL-equivalent size cohort from model years 2021–2023 in the Velopedia archive.18″ S/T geometry
Archive context: The chainstay of 450 mm sits toward the longer rear-center end. The seat angle of 71° sits toward the more relaxed end. Its wheelbase of 1072 mm sits toward the shorter end.
Compared with 14 distinct mountain geometries in the XXL-equivalent size cohort from model years 2021–2025 in the Velopedia archive.Parts & serviceability
Find replacement parts
ChainKMC Z7Exact archived model
CassetteShimano freewheel 7-speed, 14-34Named component · published drivetrain speed — verify exact version
ShiftersShimano EZ-Fire Plus, ST-EF500, 21-speedExact archived model
More qualified parts (2)
Seatpost27.2 mm seatpostPublished diameter — verify length and setback
WheelsAlloy 36H rims, Formula alloy hubs, QR front and rear, 14g stainless steel spokesNamed 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 →- FrameLook closely for dents and hairline cracks around welds, the head tube and bottom-bracket area. Cosmetic scratches matter less than a change in shape or a crack line.Inspect the frame and fork →
- BrakesTest each brake separately and confirm it stops firmly and releases cleanly. Inspect the pads and braking surfaces for wear or contamination, and check the cables or hoses for damage.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 Jamis Explorer A2 · Mountain · Published sizes: 15″, 17″, 19″, 21″, 14″ S/T, 16″ S/T, 18″ S/T
Frame and fork
Inspect the frame and fork →Archived: Frame: 6061 TIG-welded aluminum, all-new sport comfort design with upright ride position, replaceable derailleur hanger · Fork: Hi-tensile steel unicrown, radius blades with dropout eyelets · Steel
Drivetrain
Check drivetrain wear →Archived: Group: Shimano TY300 rear and TY510 top swing/dual pull front · Shifters: Shimano EZ-Fire Plus, ST-EF500, 21-speed · Front derailleur: Shimano TY300 rear and TY510 top swing/dual pull front · Rear derailleur: Shimano TY300 rear and TY510 top swing/dual pull front · Crankset: Forged alloy, 48/38/28T, 170mm with chainguard · Bottom bracket: Sealed cartridge, 68 x 110.5mm · Cassette: Shimano freewheel 7-speed, 14-34 · Chain: KMC Z7
Brakes
Inspect the brakes →Archived: Brakes: ProMax alloy direct pull brakes with Shimano levers
Wheels and tires
Check wheels and tires →Archived: Wheel size: 27.5 · Wheels: Alloy 36H rims, Formula alloy hubs, QR front and rear, 14g stainless steel spokes · Front tire: CST – 1918, 27.5 x 2.1 · Rear tire: CST – 1918, 27.5 x 2.1
Controls and contact points
Archived: Headset: Internal cup, threaded, 1 1/8” · Handlebar: Comfort hi-rise, steel, 25.4 x 80mm rise x 15 ̊ sweep x 640mm · Stem: Jamis alloy, angle-adjustable, 90mm ext x 150mm quill (14 ̊18”) or 110mm ext x 180mm quill (19 ̊21”) · Seatpost: Alloy micro-adjust, 350mm x 27.2mm, with alloy QR clamp · Saddle: Jamis Comfort with extra thick padding, synthetic suede top, burnished side panels and bumper springs · Pedals: Comfort platform with TPE non-slip insert
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.