Bike Comparison
    MSRP
    $159
    $179
    $199
    Where to Buy
    $1

    At

    $1

    At

    $1

    At

    Category
    General YouthGeneral YouthGeneral Youth
    SteelAluminumAluminum
    Fork
    SteelSteelSteel
    Wheels
    AluminumAluminumAluminum
    Wheel Size
    12″16″20″
    Drivetrain
    Single-speedSingle-speedSingle-speed
    Brand Site

    gtbicycles.com

    gtbicycles.com

    gtbicycles.com

    Summary
    The GT Grunge Boy's 12", GT Grunge Coaster 16", and GT Grunge Coaster 20" are all general youth bikes. The Grunge Boy's 12" has a steel frame and 12″ aluminum wheels, the Grunge Coaster 16" has 16″ aluminum wheels, and the Grunge Coaster 20" has 20″ aluminum wheels and higher gearing.
    Similar Bikes
    Accessories
    Gear Range

    A bike with lower gearing will be easier to ride up steep hills, while a higher top end means it will pedal faster down hills.

    Lowest gear

    (climbing)

    5 mph

    Grunge Boy's 12"

    8 mph

    Grunge Coaster 16"

    12 mph

    Grunge Coaster 20"

    Highest gear

    (descending)

    Geometry
    Specs
    Frame

    12" GT LegitFit Design, Hi-Ten Steel

    16" GT LegitFit Design, Alloy

    20" GT LegitFit Design, Alloy

    Fork

    GT Hi-Ten Steel, 1" Threaded Steerer

    GT Hi-Ten Steel, 1" Threaded Steerer

    GT Hi-Ten Steel, 1" Threaded Steerer

    Bottom Bracket

    Steel, Ball type

    Steel, Ball type

    Steel, Ball type

    Headset

    Steel, 1"

    Steel, 1"

    Steel, 1"

    Stem

    2-Bolt Alloy Top, Steel Quill

    2-Bolt Alloy Top, Steel Quill, 30mm

    2-Bolt Alloy Top, Steel Quill

    Handlebar

    Steel 480mm width x 130mm rise

    Steel 500mm width x 130mm rise

    Steel 580mm width x 176mm rise

    Saddle

    GT 1-piece

    GT 1-piece

    GT 1-piece

    Seatpost

    Alloy

    Alloy

    Alloy

    Pedals

    Jr. BMX design, resin

    Jr. BMX design, resin

    Jr. BMX design, resin

    Grips

    95mm closed end

    95mm closed end

    120mm closed end

    Groupset
    Crank

    Forged One-Piece Type, 89mm, Steel, 24T

    Forged One-Piece Type, 89mm, Steel, 28T

    Forged One-Piece Type, 127mm, 32T

    Cassette

    16T Coaster

    16T Coaster

    16T Coaster

    Chain

    KMC HV410 1/2" x 1/8"

    KMC HV410 1/2" x 1/8"

    KMC Z410A, 1/2" x 1/8"

    Brakes

    (F) N/A, (R) Coaster

    (F) N/A, (R) Coaster

    (F) N/A, (R) Coaster

    Wheels
    Rims

    Alloy, 16 hole

    Alloy, 20 hole

    Alloy, 28 Hole

    Front Hub

    (F) Steel, 16 Hole, 3/8" Axle, (R) Steel, 16 Hole,Coaster

    (F) Steel, 20 Hole, 3/8" Axle, (R) Steel, 20 Hole, Coaster

    (F) Steel, 28 Hole, 3/8" Axle, (R) Steel, 28 Hole, Coaster

    Tires

    GT 12 x 2.25" (F/R)

    GT 16 x 1.95" (F/R)

    GT 20 x 1.95" (F/R)

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