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 2001 GT Bump and 1999 GT Bump.
Gearing comparison
Lower gears help on climbs. Higher gears suit higher speeds.
RPM
RPM = pedal turns per minute.
Ratio2.75:1
Estimated speed at 90 RPMGear
Uses front tire 20×2.1; rear size isn’t listed.
Ratio2.75:1
Estimated speed at 90 RPMGear
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.
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
2001 GT Bump
1999 GT Bump
Overview
Model Year
2001
1999
Brand
GT
GT
Model
Bump
Bump
Bicycle Type
Freestyle/jumping
Freestyle/jumping
Original MSRP
$409.99
$316.99
Colors
Galaxie Silver, Raven Black
Atomic Blue, Khaki
Sizes
Pro
—
Weight
—
—
Frameset
Frame Construction
TIG-welded
Welded
Frame Material
Chromoly
Chromoly
Fork
GT
GT
Fork Material
Chromoly, unicrown crown
Chromoly, oversize, unicrown crown
Drivetrain
Crankset
GT 3-piece chromoly, 44 teeth
GT 1-piece chromoly, 44 teeth
Bottom Bracket
One piece
One piece
Rear Cogs
1-speed, 16 teeth
1-speed, 16 teeth
Chain
KMC, 1/2 x 1/8"
1/2 x 1/8"
Pedals
GT aluminum platform
GT aluminum platform
Brakes
Brakes
Tektro FX-10 rear brakes, Tektro 217A rear levers
Dia-Compe 990 rear brakes, Dia-Compe MX-97 rear levers
Cockpit & Contact Points
Headset
1 1/8" threadless Tange Seiki STE
1 1/8" threadless Aheadset SX-1
Handlebar
GT Freestyle
GT
Handlebar Extensions
Not included
—
Stem
GT Johnson
GT Piston
Saddle
GT
GT
Seatpost
GT aluminum micro-adjust
GT chromoly micro-adjust, 31.8mm diameter
Wheels & Tires
Hubs
GT Mohawk
GT Mohawk
Rims
Alex AL-MX22, 48-hole
Weinmann ZAC-X, 48-hole
Spokes
14g
Steel, 2.0mm straight gauge
Spoke Nipples
Brass nipples
Brass nipples
Front Tire
20 X 2.10" GT LP-III
20 x 2.125" Powerlite Retro-Tread
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.