Velopedia Bicycle Archive
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Compare published geometry, gearing and specifications for up to three bicycles.
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1 of 2 bicycles
At a glance
Key differences
Supported differences are shown below. Data limitations are labeled separately.
- Data limitation
No geometry is recorded for 2003 GT Bump and 2005 GT Bump.
Gearing comparison
Lower gears help on climbs. Higher gears suit higher speeds.
RPM
RPM = pedal turns per minute.
Ratio2.79:1
Estimated speed at 90 RPMGear
Uses front tire 20×2.1; rear size isn’t listed.
Ratio2.79:1
Estimated speed at 90 RPMGear
Rear tire: 20×2.1.
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.
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.
Specification
2003 GT Bump
2005 GT Bump
Overview
Model Year
2003
2005
Brand
GT
GT
Model
Bump
Bump
Bicycle Type
Freestyle/jumping
Freestyle/jumping
Original MSRP
$249.99
$269.99
Colors
Blue, Yellow
Deep Artic Blue, Madness Pewter
Sizes
One
—
Weight
—
—
Frameset
Frame Construction
TIG-welded
TIG-welded
Frame Material
Chromoly main triangle/hi-tensile steel rear stays
Chromoly
Fork
GT
GT
Fork Material
Chromoly, unicrown crown
Chromoly, unicrown crown
Drivetrain
Crankset
GT 3-piece chromoly, 39 teeth
GT tubular chromoly, 39 teeth
BB Shell Width
American
—
Rear Cogs
1-speed, 14 teeth
1-speed, 14 teeth
Chain
KMC 410, 1/2 x 3/16"
KMC Z410, 1/2 x 1/8"
Pedals
GT Johnson design
GT Dirt/Street
Brakes
Brakes
Tektro 907A U-brake rear brakes, Tektro 274A rear levers
Tektro 907AD rear brakes, Tektro 274A rear levers
Cockpit & Contact Points
Headset
1 1/8" threadless Victor VP-A74F
1 1/8" threadless Tange Seiki Fatty 22
Handlebar
GT BMX
Chromoly 2-piece
Stem
GT Piston
GT Johnson III
Saddle
GT Jr Jump, 9mm rails
GT-6 Original
Seatpost
Steel micro-adjust
Aluminum micro-adjust
Wheels & Tires
Hubs
Aluminum, 14mm axle
Aluminum, 3/8" axle
Rims
Alex G22, 36-hole
Alex G22
Spokes
Stainless steel, 14ga. (2.0mm) straight gauge
14ga. (2.0mm) straight gauge
Spoke Nipples
Brass nipples
Brass nipples
Front Tire
20 x 2.10" GT LP-4
20 x 2.20" GT 1453
Rear Tire
—
20 X 2.10" GT LP-IV
Wheel Size
20" wheels
20" wheels
Historical specifications are presented as an archival reference. Components may have varied by market, size, or production run.