Velopedia Bicycle Archive

Compare Bicycles

Compare published geometry, gearing and specifications for up to three bicycles.

1 of 2 bicycles

At a glance

Key differences

Supported differences are shown below. Data limitations are labeled separately.

  1. Data limitation

    No geometry is recorded for 1999 GT Bump and 2003 GT Bump.

Gearing comparison

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

RPM

RPM = pedal turns per minute.

1999 GT Bump44T · 16T · 1-speed
Ratio2.75:1
Estimated speed at 90 RPMGear14.4 mph

Rear tire: 20×1.75.

2003 GT Bump39T · 14T · 1-speed
Ratio2.79:1
Estimated speed at 90 RPMGear15.1 mph

Uses front tire 20×2.1; 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

Complete specification tableShows different published values and gaps where a bicycle lacks data. Different wording reflects source language, not necessarily different components. Swipe for more columns.
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Specification
1999 GT Bump
2003 GT Bump
Overview
Model Year
1999
2003
Brand
GT
GT
Model
Bump
Bump
Bicycle Type
Freestyle/jumping
Freestyle/jumping
Original MSRP
$316.99
$249.99
Colors
Atomic Blue, Khaki
Blue, Yellow
Sizes
—
One
Weight
—
—
Frameset
Frame Construction
Welded
TIG-welded
Frame Material
Chromoly
Chromoly main triangle/hi-tensile steel rear stays
Fork
GT
GT
Fork Material
Chromoly, oversize, unicrown crown
Chromoly, unicrown crown
Drivetrain
Crankset
GT 1-piece chromoly, 44 teeth
GT 3-piece chromoly, 39 teeth
Bottom Bracket
One piece
—
BB Shell Width
—
American
Rear Cogs
1-speed, 16 teeth
1-speed, 14 teeth
Chain
1/2 x 1/8"
KMC 410, 1/2 x 3/16"
Pedals
GT aluminum platform
GT Johnson design
Brakes
Brakes
Dia-Compe 990 rear brakes, Dia-Compe MX-97 rear levers
Tektro 907A U-brake rear brakes, Tektro 274A rear levers
Cockpit & Contact Points
Headset
1 1/8" threadless Aheadset SX-1
1 1/8" threadless Victor VP-A74F
Handlebar
GT
GT BMX
Stem
GT Piston
GT Piston
Saddle
GT
GT Jr Jump, 9mm rails
Seatpost
GT chromoly micro-adjust, 31.8mm diameter
Steel micro-adjust
Wheels & Tires
Hubs
GT Mohawk
Aluminum, 14mm axle
Rims
Weinmann ZAC-X, 48-hole
Alex G22, 36-hole
Spokes
Steel, 2.0mm straight gauge
Stainless steel, 14ga. (2.0mm) straight gauge
Spoke Nipples
Brass nipples
Brass nipples
Front Tire
20 x 2.125" Powerlite Retro-Tread
20 x 2.10" GT LP-4
Rear Tire
20 x 1.75" Powerlite Retro-Tread
—
Wheel Size
20" wheels
20" wheels

Historical specifications are presented as an archival reference. Components may have varied by market, size, or production run.

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