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.
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
Rear tire: 20×2.1.
Ratio2.79:1
Estimated speed at 90 RPMGear
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.
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
2004 GT Bump
2003 GT Bump
Overview
Model Year
2004
2003
Brand
GT
GT
Model
Bump
Bump
Bicycle Type
Freestyle/jumping
Freestyle/jumping
Original MSRP
$249.99
$249.99
Colors
Red, Silver
Blue, Yellow
Sizes
One
One
Weight
—
—
Frameset
Frame Construction
TIG-welded
TIG-welded
Frame Material
Chromoly main triangle/hi-tensile steel rear stays
Chromoly main triangle/hi-tensile steel rear stays
Fork
GT
GT
Fork Material
Chromoly, unicrown crown
Chromoly, unicrown crown
Drivetrain
Crankset
GT 3-piece chromoly, 39 teeth
GT 3-piece chromoly, 39 teeth
BB Shell Width
American
American
Rear Cogs
1-speed, 14 teeth
1-speed, 14 teeth
Chain
KMC 410, 1/2 x 3/16"
KMC 410, 1/2 x 3/16"
Pedals
GT Johnson design
GT Johnson design
Brakes
Brakes
Tektro 907A U-brake rear brakes, Tektro 274A rear levers
Tektro 907A U-brake rear brakes, Tektro 274A rear levers
Cockpit & Contact Points
Headset
1 1/8" threadless Victor VP-A74F
1 1/8" threadless Victor VP-A74F
Handlebar
GT BMX
GT BMX
Stem
GT Piston
GT Piston
Saddle
GT Jr Jump, 9mm rails
GT Jr Jump, 9mm rails
Seatpost
Steel micro-adjust
Steel micro-adjust
Wheels & Tires
Hubs
Aluminum, 14mm axle
Aluminum, 14mm axle
Rims
Alex G22, 36-hole
Alex G22, 36-hole
Spokes
Stainless steel, 14ga. (2.0mm) straight gauge
Stainless steel, 14ga. (2.0mm) straight gauge
Spoke Nipples
Brass nipples
Brass nipples
Front Tire
20 x 2.20" GT 1453
20 x 2.10" GT LP-4
Rear Tire
20 x 2.10" GT LP-4
—
Wheel Size
20" wheels
20" wheels
Geometry · choose a size for each bicycle
Geometry size
—
Head-tube angle
74.5°
—
Seat-tube angle
71°
—
Chainstay / rear center
355.6 mm
—
Historical specifications are presented as an archival reference. Components may have varied by market, size, or production run. Legacy reference geometry is model-level historical data whose corresponding frame size is not identified; compare those dimensions as reference values rather than size-normalized fit data.