Velopedia Bicycle Archive

2021 Jamis Explorer A1

Mountain bicycle from the Velopedia specification archive.

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What Velopedia knows

Model year
2021
Category
Mountain
Original MSRP
$729.95
Sizes
15″, 17″, 19″, 21″, 14″ S/T, 16″ S/T, 18″ S/T
Colors
M: Palladium, Riptide S/T: Palladium or Teal
Weight
34.50 lbs
Geometry
7 manufacturer sizes · Geometry context
Record coverage
24 preserved details · archived image · original MSRP · preserved geometry
Archive ID
900001707
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Manufacturer catalog

Published sizes and colors

7 sizes · 2 colors

Manufacturer-published sizes and colors; availability and exact size/color pairings may vary by market or production run.

Published sizes

15″17″19″21″14″ S/T16″ S/T18″ S/T

Published colors

M: PalladiumRiptide S/T: Palladium or Teal

Frameset

Frame Construction6061 TIG-welded aluminum, all-new sport comfort design with upright ride position, replaceable derailleur hanger
Frame MaterialAluminum
ForkSR Suntour XCE 27.5”, coil spring, external preload adjustor, 28mm stanchions, aluminum lowers, 80mm travel
Fork MaterialAluminum

Drivetrain

Component GroupShimano TX-800 rear, Shimano TY710 31.8mm top swing/ dual pull front
ShiftersShimano EZ-Fire Plus, ST-EF510, 24-speed
Front DerailleurShimano TX-800 rear, Shimano TY710 31.8mm top swing/ dual pull front
Rear DerailleurShimano TX-800 rear, Shimano TY710 31.8mm top swing/ dual pull front
CranksetShimano TY301, 48/38/28T, 170mm with chainguard
Bottom BracketSealed cartridge, 68 x 110.5mm
CassetteShimano HG20, 8-speed, 12-32
ChainKMC Z7
PedalsComfort platform with TPE non-slip insert

Brakes

BrakesTektro forged alloy direct pull brakes with Shimano levers

Cockpit & Contact Points

HeadsetInternal cup, threaded, 1 1/8”
HandlebarComfort hi-rise, alloy 25.4 x 80mm rise x 15 ̊ sweep x 640mm
StemJamis alloy, angle-adjustable, 90mm ext x 150mm quill (14 ̊18”) or 110mm ext x 180mm quill (19 ̊21”)
SaddleJamis Comfort with memory foam, synthetic suede top, burnished side panels and bumper springs
SeatpostSuspension, alloy micro-adjust, 350mm x 27.2mm, with alloy QR clamp

Wheels & Tires

WheelsDouble-wall alloy rims, 32H, alloy hubs with QR, 14g stainless steel spokes
Front TireCST – 1918, 27.5 x 2.1
Rear TireCST – 1918, 27.5 x 2.1
Wheel Size27.5

Size-specific frame data

Geometry

7 sizes · 9 measurements

Manufacturer-published geometry normalized for consistent archival comparison. Effective top tube and reach remain separate measurements because they describe different aspects of fit.

Measurement15″17″19″21″14″ S/T16″ S/T18″ S/T
Effective top tube565 mm587 mm598 mm617 mm555 mm577 mm594 mm
Head tube135 mm165 mm185 mm210 mm140 mm150 mm160 mm
Head-tube angle69°70°70°70°69°69°70°
Seat-tube angle71°71°71°71°72°71°71°
Chainstay / rear center450 mm450 mm450 mm450 mm450 mm450 mm450 mm
Wheelbase1055 mm1066 mm1077 mm1097 mm1057 mm1067 mm1072 mm
Bottom-bracket height284 mm284 mm284 mm284 mm284 mm284 mm284 mm
Standover height718 mm784 mm824 mm870 mm481 mm487 mm484 mm
Fork offset / rake42 mm42 mm42 mm42 mm42 mm42 mm42 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

Choose a 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.

Parts & serviceability

Find replacement parts

3 top part searches
CassetteShimano HG20, 8-speed, 12-32Exact archived model
CranksetShimano TY301, 48/38/28T, 170mm with chainguardNamed archived component — verify exact version
More qualified parts (2)
ShiftersShimano EZ-Fire Plus, ST-EF510, 24-speedExact archived model
Seatpost27.2 mm seatpostPublished diameter — verify length and setback

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.

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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 →
  • SuspensionAsk when the fork was last serviced. Check the stanchions for damage, look for oil at the seals and make sure the fork moves smoothly without bushing play.Evaluate the suspension →
  • 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 20 checks based on 6 archived component groups Open checklistClose checklist
0 of 20 checked Progress stays in this browser for this bike.

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.

Archived: 2021 Jamis Explorer A1 · Mountain · Published sizes: 15″, 17″, 19″, 21″, 14″ S/T, 16″ S/T, 18″ S/T

Archived: Frame: 6061 TIG-welded aluminum, all-new sport comfort design with upright ride position, replaceable derailleur hanger · Fork: SR Suntour XCE 27.5”, coil spring, external preload adjustor, 28mm stanchions, aluminum lowers, 80mm travel · Aluminum

Archived: Fork: SR Suntour XCE 27.5”, coil spring, external preload adjustor, 28mm stanchions, aluminum lowers, 80mm travel

Archived: Group: Shimano TX-800 rear, Shimano TY710 31.8mm top swing/ dual pull front · Shifters: Shimano EZ-Fire Plus, ST-EF510, 24-speed · Front derailleur: Shimano TX-800 rear, Shimano TY710 31.8mm top swing/ dual pull front · Rear derailleur: Shimano TX-800 rear, Shimano TY710 31.8mm top swing/ dual pull front · Crankset: Shimano TY301, 48/38/28T, 170mm with chainguard · Bottom bracket: Sealed cartridge, 68 x 110.5mm · Cassette: Shimano HG20, 8-speed, 12-32 · Chain: KMC Z7

Archived: Brakes: Tektro forged alloy direct pull brakes with Shimano levers

Archived: Wheel size: 27.5 · Wheels: Double-wall alloy rims, 32H, alloy hubs with QR, 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, alloy 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: Suspension, alloy micro-adjust, 350mm x 27.2mm, with alloy QR clamp · Saddle: Jamis Comfort with memory foam, 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.

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