GT Mach One Junior

Name: GT Mach One Junior
Brand: GT

2026 YouthGeneral youth Manufacturer page

Last known price: $360

Prices shown first for United States
Suspension: Rigid
Wheels: 20″
Drivetrain: 1 × 1 40t / 16t
Gear range: 100%
Frame: Aluminum
Brakes: Rim brake

Sizes

Size guide

The manufacturer did not publish rider heights for these sizes.

Components

9 of 20 identified

Parts found in a manufacturer catalog show their brand, model and key numbers, and the steps show how precisely they are identified: brand, series, model, or the exact product. The info button has every detail and the text the manufacturer published.

Frame and fork

1 part

Frame

GT Mach One Race MK2, 6061 Alloy, Euro BB, Reverse Dropouts, V-Brakes, 1-1/8" Integrated H/T Not identified

Suspension

1 part

Fork
- GT

Drivetrain

4 parts

Bottom bracket

Threaded Square Type Not identified
Cassette

16T Freewheel Not identified
Chain
- KMC S1 1 speed
Crankset
- GT 40t

Brakes

2 parts

Brake levers

Alloy V-type Not identified
Brakes

Alloy V-type Not identified

Wheels and tires

5 parts

Front hub

Steel Body, 28h, 3/8" Axle Not identified
Rear hub

Steel Flip Flop Thread-on Body, Freewheel, 28h, 3/8" Axle Not identified
Rims

Alloy Double Wall, 28h Not identified
Spokes

Stainless Steel, 14g Not identified
Tires
- Kenda

Cockpit and contact points

7 parts

Grips
- GT
Handlebar
- GT
Headset

1-1/8" Sealed Integrated (41.8 x 45) Not identified
Pedals
- GT
Saddle
- GT
Seatpost

Combo Alloy 22.2 Integrated Not identified
Stem
- GT

Sizes and geometry

1 size Open in the geometry plotter

Complete rider-height ranges are not published for these sizes. You can still explore the geometry below.

Size SM

Table

Geometry diagram unavailable

The drawing needs wheelbase, reach, stack, head tube length, seat tube length and chainstay length, which the manufacturer did not publish. Available facts remain in the table.

Size

Complete manufacturer geometry table 1 published size

Complete manufacturer geometry by size
Measurement
Head tube angle	73°
Seat tube angle	72°
Bottom bracket dropmm	10.75
Fork rakemm	1.3

Not published by the manufacturer: Reach, Stack, Top tube length, Seat tube length, Head tube length, Chainstay length, Wheelbase, Front center, Bottom bracket height, Standover height, Trail, Stack/reach ratio, Front travel, Rear travel, Crank length, Handlebar width, Stem length, Stem angle, Seatpost length and Dropper post travel.

Specifications

Frame and fork

Intended fit: Unisex
Frame material: Aluminum
Fork material: Steel

Suspension

Suspension configuration: Rigid

Drivetrain

Derived by Bikelake

Front chainrings: 1
Smallest chainring: 40
Largest chainring: 40
Rear sprockets: 1
Smallest sprocket: 16
Largest sprocket: 16
Lowest gear: 50.0 in
Highest gear: 50.0 in

Wheels and brakes

Wheel configuration: Same size
Brake type: Rim brake

Fit and controls

Seatpost: Rigid seatpost
Shifting: No shifting

Additional specifications

Bottom bracket standard: BSA
Wheel material: Aluminum
Wheel size: 20″

Gearing

Estimated speeds at 80 rpm

Lowest gear: 19.2 km/h
Highest gear: 19.2 km/h

Total gear range 100%

Technical details and class reference

These speeds describe the gearing at the selected cadence, not how fast you can ride.
Calculated from published gear-inch values and their wheel-size assumptions.
These gearing values describe the bicycle, not a selected frame size.
A 100% range means one ratio; 500% means the highest ratio is five times the lowest.
For e-bikes, motor assistance cutoff is not represented.

Gear-inch range

Lower gear-inch values travel less distance per pedal revolution; higher values travel farther.

This bicycle: 50.0–50.0 gear inches

Lineup changes

The published facts that differ across this family's builds and from the same model a year earlier. Missing information never counts as zero.

Differences across 2026 builds
Specification	This bicycle GT Mach One Junior	GT Mach One 16	GT Mach One Expert	GT Mach One Mini	GT Mach One Pro	GT Mach One Pro 24
Drivetrain
Smallest chainring	40	36	42	38	44	42
Largest chainring	40	36	42	38	44	42
Smallest sprocket	16	16	16	16	16	18
Largest sprocket	16	16	16	16	16	18
Lowest gear	50.0 in	36.0 in	52.5 in	47.5 in	55.0 in	56.0 in
Highest gear	50.0 in	36.0 in	52.5 in	47.5 in	55.0 in	56.0 in
Other specifications
Bottom bracket standard	BSA	Not informed	BSA	BSA	Not informed	Not informed
Wheel size	20″	16″	20″	20″	20″	24″
Tire width	Not informed	1.75″	Not informed	Not informed	1.75″	2.1″