- Frame
- Chromoly main triangle
- Brakes
- Tektro 907A U-brake rear brakes, Tektro 274A rear levers
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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 2009 GT Bump and 2007 GT Bump.
- Data limitation
Only 2009 GT Bump has enough published drivetrain data for gearing calculations.
- Identity & price
2007 GT Bump had an original MSRP $130 lower than 2009 GT Bump.
Original MSRP is the published list price when new, not today’s used-bike value.
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
Rear tire: 20×2.1.
Gearing unavailable for this size.
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
2009 GT Bump
2007 GT Bump
Overview
Model Year
2009
2007
Brand
GT
GT
Model
Bump
Bump
Bicycle Type
BMX
Freestyle/jumping
Original MSRP
$399.99
$269.99
Colors
Light Green, Purple
Matte Navy Blue, Matte Brick
Sizes
21.1" TT
20" wheel
Weight
—
—
Frameset
Frame Construction
TIG-welded
TIG-welded
Frame Material
Chromoly main triangle
Chromoly
Fork
GT Dirt/Street
'05 GT dirt jump
Fork Material
Chromoly, unicrown crown
Chromoly, unicrown crown
Drivetrain
Component Group
BMX
BMX Mix
Crankset
GT Tubular Cr-Mo 3pc., 33 teeth
GT Tubular Cr-Mo 3pc.
Bottom Bracket
Mid BB
Ball type with 8 spline Cr-Mo axle
Cassette
Cassette cog
—
Rear Cogs
1-speed, 12 teeth
1-speed, 12 teeth
Chain
KMC Z510
KMC Z410
Pedals
GT Dirt/Street platform
'05 GT Dirt/Street platform design, aluminum body, cr-mo alxe
Brakes
Brakes
Tektro 907A U-brake rear brakes, Tektro 274A rear levers
Tektro, FX-330 rear brakes, Tektro 274A levers
Cockpit & Contact Points
Headset
1 1/8" Tange Seiki Fatty 22
1 1/8" threadless Tange Seiki FATTY 22
Handlebar
GT dirt/street Cr-mo
GT dirt/street Cr-mo
Handlebar Extensions
Not included
Not included
Stem
GT FS design
GT FS design
Saddle
GT Slim
Velo mini street
Seatpost
Aluminum micro-adjust double bolt
Alloy Micro adjust
Wheels & Tires
Hubs
Front: GT aluminum sealed, Rear: GT sealed cassette
Front: GT aluminum sealed, Rear: GT sealed cassette
Rims
Alienation PBR, 32-hole/36-hole
Alex G22, 36-hole
Spokes
Stainless, 14ga. (2.0mm)
14ga. (2.0mm) straight gauge
Spoke Nipples
Brass
Brass nipples
Front Tire
20 x 2.125" Kenda K-Rad
Front: 26 x 2.125" Front: Kenda K-Rad, Rear: 26 x 2.10" Kenda Konxsion
Rear Tire
20 x 2.10" Kenda Kiniption
—
Wheel Size
20" wheels
26" wheels
Historical specifications are presented as an archival reference. Components may have varied by market, size, or production run.