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2000 GT Thumper

Original specifications: 20" wheels · legacy reference geometry.

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At a glance

Archive #45341
Model year
2000
Category
BMX
Original MSRP
$478.00
Colors
Gangreen, Propane
Geometry
Legacy reference
In this record
23 specifications · original MSRP · geometry
Model history 3 other years

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Identification clues

2000 archived details

Published colors
Gangreen, Propane
Frame
Chromoly
Original equipment
N/A

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

Campaign
Original buildChromoly · 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

GangreenPropane

Frameset

Frame ConstructionTIG-welded
Frame MaterialChromoly
ForkGT
Fork MaterialChromoly, unicrown crown

Drivetrain

CranksetGT 3-piece chromoly, 44 teeth
Bottom BracketSealed cartridge
Rear Cogs1-speed, 16 teeth
ChainKMC, 1/2 x 1/8"
PedalsGT aluminum platform

Brakes

BrakesDiaTech 996 U-Brake rear brakes, Dia-Compe MX-101 rear levers

Cockpit & Contact Points

Headset1 1/8" threadless Aheadset SB-1 w/SST Oryg detangler
HandlebarGT Freestyle
Handlebar ExtensionsNot included
StemGT Johnson
SaddleGT
SeatpostGT aluminum micro-adjust

Wheels & Tires

HubsGT Mohawk
RimsWeinmann ZAC-X, 48-hole
Spokes2.0mm
Spoke NipplesBrass nipples
Front Tire20 x 2.125" Powerlite Retro Tread
Rear Tire20 x 1.75" Powerlite Retro Tread
Wheel Size20" wheels

Geometry

Legacy reference · 5 measurements

Historical measurements. Frame size unknown.

All geometry measurementsLegacy reference · 5 measurements
MeasurementLegacy reference
Top tube527 mm
Head-tube angle73.5°
Seat-tube angle70°
Chainstay / rear center381 mm
Wheelbase967.5 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 and service referenceQuick reference before buying parts

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

Front tire
Front: 20 x 2.125" Powerlite Retro Tread, Rear: 20 x 1.75" Powerlite Retro Tread
Drivetrain
1-speed
Bottom bracket / shell
Sealed cartridge
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: GT · Chromoly, unicrown crown

Drivetrain

Check drivetrain wear →

Archived: Crankset: GT 3-piece chromoly, 44 teeth · Bottom bracket: Sealed cartridge · Rear cogs: 1-speed, 16 teeth · Chain: KMC, 1/2 x 1/8"

Brakes

Inspect the brakes →

Archived: Brakes: DiaTech 996 U-Brake rear brakes, Dia-Compe MX-101 rear levers

Wheels and tires

Check wheels and tires →

Archived: Wheel size: 20" wheels · Rims: Weinmann ZAC-X, 48-hole · Hubs: GT Mohawk · Front tire: Front: 20 x 2.125" Powerlite Retro Tread, Rear: 20 x 1.75" Powerlite Retro Tread

Controls and contact points

Archived: Headset: 1 1/8" threadless Aheadset SB-1 w/SST Oryg detangler · Handlebar: GT Freestyle · Stem: GT Johnson · Seatpost: GT aluminum micro-adjust · Saddle: GT · Pedals: GT aluminum platform

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Campaign

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

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