Velopedia Bicycle Archive

1999 Jamis Bossy 20

Original specifications: Juvenile Mix drivetrain · 20" wheels.

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At a glance

Archive #88105

Model year: 1999
Category: Kids
Original MSRP: $139.95
Colors: Grape Purple, Pearl Aqua
In this record: 22 specifications · archived image · original MSRP

Model history 2 other years

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Identification clues

1999 archived details

Published colors: Grape Purple, Pearl Aqua
Frame: Hi-tensile steel
Original equipment: Juvenile Mix

Clues, not proof of model year. Colors vary and components may have been replaced.

Original buildHi-tensile steel · Juvenile Mix · 20" wheels

Manufacturer catalog

Published sizes and colors

2 colors

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

Published colors

Grape PurplePearl Aqua

Frameset

Frame Construction	TIG-welded
Frame Material	Hi-tensile steel
Fork Material	Hi-tensile steel, unicrown crown

Drivetrain

Component Group	Juvenile Mix
Crankset	1-piece 5 1/2", 36 teeth
Bottom Bracket	One piece
BB Shell Width	American
Rear Cogs	1-speed, 18 teeth
Chain	KMC 410, 1/2 x 1/8"
Pedals	Union

Brakes

Brakes	Coaster rear

Cockpit & Contact Points

Headset	1" steel
Handlebar	Jamis cruiser
Stem	Alloy 4 bolt
Saddle	Jamis cruiser
Seatpost	Pillar, aluminum, 25.4mm diameter

Wheels & Tires

Hubs	Front: steel, nutted, Rear: coaster brake
Rims	Weinmann 4019, 36-hole
Spokes	Stainless steel, 2.0mm straight gauge
Spoke Nipples	Brass nipples
Front Tire	20 x 2.125" CST C-640
Wheel Size	20" wheels

Gearing

Lower gears help on climbs. Higher gears suit higher speeds.

Pedal cadence

RPM

Speed units

RPM = pedal turns per minute.

Published build36T · 18T · 1-speed

Ratio2.00:1

Estimated speed At 90 RPM Gear10.8 mph

Uses front tire 20×2.125; rear size isn’t listed.

How it works

Ratio = front teeth ÷ rear teeth. Hub gears also include the hub’s internal ratio. A 400% range means the highest ratio is four times the lowest.

Speeds are estimates from tire size and pedal cadence. Actual speeds vary.

Try other gearing

Try your current gearingChanged tires or gears? Calculate your setup.

Your changes apply to this calculation. The archived build stays unchanged.

Gears Drivetrain

Front teeth Smallest rear teeth Largest rear teeth

Use up to three front tooth counts, separated by /. For one rear sprocket, enter the same count twice.

Rear tire

Rear tire marking

Apply the marking on your rear tire or edit its dimensions below. Older or fractional inch sizes need the ISO marking (e.g. 37-590).

Rim diameter (BSD, mm) Tire width (mm)

For 32-622, width is 32 mm and rim diameter is 622 mm. Use the rear tire on mixed-wheel bikes. Leave both fields empty to compare ratios only.

Cadence (RPM) Speed units

Gear, dimension and cadence changes update results automatically.

Gearing comparison
Measure	Original	Your setup
Lowest ratio	—	—
Highest ratio	—	—
Total range	—	—
Lowest-gear speed	—	—
Highest-gear speed	—	—

Speeds are estimates. These calculations do not establish component compatibility or available tire clearance.

Parts & serviceability

Find replacement parts

Original specifications

Front tire · Original

20 x 2.125" CST C-640 Replacement search: 20x2.125 bicycle tire Before ordering: Check rim type and tire clearance.

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Seatpost · Original

Pillar

aluminum, 25.4mm diameter

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Parts and service referenceQuick reference before buying parts

Archived specifications for reference. Check the fitted parts before ordering.

Front tire: 20 x 2.125" CST C-640
Drivetrain: 1-speed
Seatpost diameter: 25.4 mm
Bottom bracket / shell: One piece · American

Equipment inspection checks 9 checks based on 5 archived component groups Open equipment checksClose equipment checks

Checks selected from the archived equipment. Confirm what is fitted today. This is not a complete safety inspection; use the full inspection guide before test riding.

Full used-bike inspection guide →

Frame and fork

Inspect the frame and fork →

Archived: Frame: TIG-welded · Fork: · Hi-tensile steel, unicrown crown

Check paint damage, vent holes and accessible internal surfaces for corrosion. Look for dents, bent tubes and cracking around welded or brazed joints.

Drivetrain

Check drivetrain wear →

Archived: Group: Juvenile Mix · Crankset: 1-piece 5 1/2", 36 teeth · Bottom bracket: One piece · Rear cogs: 1-speed, 18 teeth · Chain: KMC 410, 1/2 x 1/8"

Check chain tension and chainline, rotate the drivetrain through a full revolution and confirm the rear axle or tensioning hardware cannot slip.
Measure chain wear with a compatible gauge and inspect chainring, cassette or freewheel teeth. A new chain does not rule out wear in the remaining drivetrain.
Turn the cranks slowly, feel for rough bearings and check for side-to-side play. Inspect crank arms, chainring bolts and pedal threads for looseness or damage.

Brakes

Inspect the brakes →

Archived: Brakes: Coaster rear

Inspect pads and braking surfaces, check the complete cable or hose path, and confirm both controls feel consistent and return cleanly.

Wheels and tires

Check wheels and tires →

Archived: Wheel size: 20" wheels · Rims: Weinmann 4019, 36-hole · Hubs: Front: steel, nutted, Rear: coaster brake · Front tire: 20 x 2.125" CST C-640

Spin both wheels and watch for side-to-side and vertical movement. Check spoke tension, rim condition and hub play.
Inspect both tire casings for cuts, cracking, plugs, bulges or exposed threads and confirm the installed sizes are safe for the rims and available frame and fork clearance.

Controls and contact points

Archived: Headset: 1" steel · Handlebar: Jamis cruiser · Stem: Alloy 4 bolt · Seatpost: Pillar, aluminum, 25.4mm diameter · Saddle: Jamis cruiser · Pedals: Union

Apply the front brake and rock the bike to check for headset play or notchiness. Inspect the stem, handlebar and clamp zones, then confirm every fastener and control is secure.
Check that the seatpost moves for adjustment and that the saddle, post and clamp hold securely without cracks, severe corrosion or damaged hardware.

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Specifications are presented as a reference. Components may vary by market, size, production run, or later manufacturer revisions.

1999 Jamis Bossy 20