Velopedia Bicycle Archive

1998 Diamondback Viper

Original specifications: 20" wheels · legacy reference geometry.

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At a glance

Archive #76768
Model year
1998
Category
BMX
Original MSRP
$175.00
Sizes
Pro XL
Colors
Blue w/chrome-plated fork, Chrome-Plated, Flat Blue W/Chrome-Plated Fork, Flat Grey W/Chrome-Plated Fork, Orange W/Chrome-Plated Fork
Geometry
Legacy reference
In this record
23 specifications · archived image · original MSRP · geometry
Model history 13 other years

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Identification clues

1998 archived details

Published colors
Blue w/chrome-plated fork, Chrome-Plated, Flat Blue W/Chrome-Plated Fork, Flat Grey W/Chrome-Plated Fork, Orange W/Chrome-Plated Fork
Frame
Chromoly main triangle/hi-tensile steel rear stays
Original equipment
N/A

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

Campaign
Original buildChromoly main triangle/hi-tensile steel rear stays · 20" wheels

Manufacturer catalog

Published sizes and colors

1 size · 5 colors

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

Published sizes

Pro XL

Published colors

Blue w/chrome-plated forkChrome-PlatedFlat Blue W/Chrome-Plated ForkFlat Grey W/Chrome-Plated ForkOrange W/Chrome-Plated Fork
+ 0 more colors + 1 more color
Orange W/Chrome-Plated Fork

Frameset

Frame ConstructionTIG-welded
Frame MaterialChromoly main triangle/hi-tensile steel rear stays
ForkDiamondback
Fork MaterialHi-tensile steel, unicrown crown

Drivetrain

Crankset1-piece 6 1/2", 44 teeth
Bottom BracketYST BB 621
BB Shell WidthAmerican 24tpi
Rear Cogs1-speed, 16 teeth
ChainTaya 410, 1/2 x 1/8"
PedalsPlatform, resin

Brakes

BrakesLee Chi ProMax linear-pull brakes, Lee Chi ProMax levers

Cockpit & Contact Points

Headset1" YST steel
HandlebarHsin Lung steel
StemHi-tensile steel
SaddleDiamondback padded
SeatpostPillar, steel, 25.4mm diameter

Wheels & Tires

HubsKing Kong aluminum, nutted
RimsKin Lin RT-6n, 36-hole
SpokesShuhn Lih steel, 2.0mm straight gauge
Spoke NipplesBrass nipples
Front Tire20 x 2.125" Comp III style
Rear Tire20 x 1.75" Comp III style
Wheel Size20" wheels

Geometry

Legacy reference · 6 measurements

Historical measurements. Frame size unknown.

All geometry measurementsLegacy reference · 6 measurements
MeasurementLegacy reference
Top tube533.4 mm
Head-tube angle75°
Seat-tube angle71°
Chainstay / rear center393.7 mm
Wheelbase967.7 mm
Fork offset / rake30.5 mm

Frame size not recorded.

Gearing

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

RPM

RPM = pedal turns per minute.

Published build44T · 16T · 1-speed
Ratio2.75:1
Estimated speed At 90 RPM Gear14.4 mph

Rear tire: 20×1.75.

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.

Your gearing setup
Gears

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

Rear tire

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).

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.

Gear, dimension and cadence changes update results automatically.

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

Parts & serviceability

Find replacement parts

Original specifications
Brake pads · Original
Lee Chi ProMax linear-pull brakes

Lee Chi ProMax levers

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Seatpost · Original
Pillar

steel, 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
Front: 20 x 2.125" Comp III style, Rear: 20 x 1.75" Comp III style
Drivetrain
1-speed
Seatpost diameter
25.4 mm
Bottom bracket / shell
YST BB 621 · American 24tpi
Campaign
Equipment inspection checks 10 checks based on 5 archived component groups Open equipment checksClose equipment checks
0 of 10 checked Progress stays in this browser for this record.

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: Diamondback · Hi-tensile steel, unicrown crown

Drivetrain

Check drivetrain wear →

Archived: Crankset: 1-piece 6 1/2", 44 teeth · Bottom bracket: YST BB 621 · Rear cogs: 1-speed, 16 teeth · Chain: Taya 410, 1/2 x 1/8"

Brakes

Inspect the brakes →

Archived: Brakes: Lee Chi ProMax linear-pull brakes, Lee Chi ProMax levers

Wheels and tires

Check wheels and tires →

Archived: Wheel size: 20" wheels · Rims: Kin Lin RT-6n, 36-hole · Hubs: King Kong aluminum, nutted · Front tire: Front: 20 x 2.125" Comp III style, Rear: 20 x 1.75" Comp III style

Controls and contact points

Archived: Headset: 1" YST steel · Handlebar: Hsin Lung steel · Stem: Hi-tensile steel · Seatpost: Pillar, steel, 25.4mm diameter · Saddle: Diamondback padded · Pedals: Platform, resin

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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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