The Alpha Four Mk III is a versatile, 24″ geared bike crafted for confident riders ages 7 to 11. Designed to handle paved routes, paths, and light trails, it blends trail-ready performance with youth-friendly ergonomics.
Key features:
- 8‑speed Microshift Acolyte drivetrain with wide 11–38 T cassette and clutched derailleur
- Promax hydraulic disc brakes for smooth, consistent stopping
- Tubeless-ready double‑wall 24″ rims paired with Kenda Small Block Eight tires
- Rider Supply Pod mounts for easy access to snacks and tools
- Kid‑optimized HEIR crankset and narrow Q‑factor for efficient pedaling
Mk III upgrades over Mk II:
- Hydraulic disc brakes
- Clutched Microshift derailleur for better chain security on rough terrain
- Tubeless capable double wall rims
- Rider Supply pod mounts for strap-free gear carrying
At just ~19.2 lb, the Alpha Four Mk III delivers nimble agility, climbing ability, and range—without outgrowing your kid any time soon.
Use
Paved, dirt paths
Wheel Size
24 in
Age
~ 7 to 11 years
Type
All-purpose Bike
Weight
19.2 lbs
Inseam
23" to 28"
Components
| Frame | Lightweight Triple Butted 6061 Aluminum. Low Center of Gravity, Kid Specific Geometry. Internally routed Cables. 3D Forged Dropouts. Dropper Post Compatible. |
|---|---|
| Fork | Bladed Aluminum Legs with 1 1/8" Aluminum Steer tube |
| Seat Clamp | Aluminum Quick Release |
| Brakes | Promax Hydraulic Disc Brakes |
| Derailleur | Microshift Acolyte Super Short with Springlock chain retention system |
| Shifter | 8 speed Microshift Acolyte Quick Trigger w/ Indicator |
| Freewheel / Cassette | 8 speed 11-38t Microshift H083 |
| Crank | HEIR Lightweight Aluminum 3 piece. Narrow Width, 130mm length |
| Chainring | 28T Narrow Wide with aluminum chain ring guard |
| Bottom Bracket | 68x113 Hollow Square Taper with Sealed Cartridge Bearings |
| Headset | 1⅛" Integrated Threadless Sealed Cartridge |
| Rims | Doublewall Aluminum, tubeless compatible |
| Front Hub | 28h Aluminum Sealed Cartridge with Quick Release Skewer |
| Rear Hub | 28h Aluminum Sealed Cartridge with Hex Key Skewer |
| Tires | Kenda Small Block Eight 24x1.95 Folding Bead 60 TPI |
| Saddle | Prevelo 1pc Junior |
| Seat Post | ⌀31.6mm alloy 1 piece |
| Handlebar | HEIR Riser Lightweight Aluminum 31.8 clamp, 19mm grip 580mm wide, 25mm rise |
| Stem | Lightweight Aluminum 31.8, 35mm Extension |
| Grips | 110mm Black Rubber 19mm diameter Lock-On |
| Pedals | Composite Big Kid, 9/16 LONG Crmo Spindle |
| Version | MK III |
Measurements
| Weight | 19.2 lbs |
|---|---|
| Recommended Inseam | 23" to 28" |
| Minimum Saddle Height | 26.1 in / 665mm |
| Maximum Saddle Height | 31.5 in / 800mm |
| Gain Ratio | 1.79 - 6.18 |
| Max Tire Width | 2.2 in |
Geometry
| Wheel Diameter | 24 in |
|---|---|
| Wheelbase | 38.38 in / 975 mm |
| Chain Stay Length | 15.94in / 405 mm |
| Head Angle | 68° |
| Seat Tube Angle | 73° |
| Seat Tube Length | 12.59 in / 320 mm |
| Effective Top Tube | 19.88 in / 505 mm |
| Bottom Bracket Height | 9.9 in / 252 mm |
| Bottom Bracket Drop | 1.7 in / 43 mm |
| Stack | 18.7 in / 475 mm |
| Standover | 20.07 in / 510 mm |
| Q Factor | 140mm |
| Reach | 14.13 in / 359 mm |
Shipping Weights & Dimensions
| Box Dimensions | 51.0 in x 8.3 in x 26.9 in |
|---|---|
| Shipping Weight | 27.8 lb |
Specifications and components are subject to variations and change without notice.
Promax Hydraulic Disc Brakes
Hill Conquering Gear Range
Tubeless Capable Double Wall Rims
Confidence Inspiring Geometry
Protected Flat Mount Rear Caliper
Kid Sized Control Center
Kid Friendly Shifting
Rider Supply Pod Ready






