ROCKBROS Gravis 20"Folding Bike 9-Speed Hydraulic Disc Brake 4130 Steel Frame
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About this product
The ROCKBROS Gravis 20" Folding Bike is designed for unisex adults, featuring a durable 4130 Cr-Mo steel frame with LUG construction and a 9-speed MicroSHIFT ADVENT drivetrain with a trigger shifter. This model includes dual-piston CNC machined aluminum hydraulic disc brakes with 160mm front and 140mm rear rotors. It rolls on 20-inch tubeless tires and features an aluminum folding stem, adjustable seat, and quick-release seatpost clamp. The bike comes with a 3-year manufacturer warranty.
Our take
This ROCKBROS Gravis folding bike appears to be a well-specced option for a portable ride. The 4130 Cr-Mo steel frame gives it a sturdy, classic feel, and the LUG construction is a nice touch for frame integrity. I particularly like the 9-speed MicroSHIFT ADVENT drivetrain, which offers a good range of gears, and the trigger shifter for precise changes. The hydraulic disc brakes are a definite plus for reliable all-weather stopping power. While the 20-inch wheels contribute to its compact folding size, they inherently offer a slightly less smooth ride than larger wheels. However, the tubeless tires are a great addition for reducing flats, and the 3-year warranty is very generous.
Pros & Cons
Pros
- Strong 4130 Cr-Mo steel frame
- Precise 9-speed MicroSHIFT drivetrain
- Powerful hydraulic disc brakes
- Compact folding design
- Tubeless tires for reliability
Cons
- 20-inch wheel size limits ride comfort
- No suspension system
Specifications
- Handlebar Type Flat Bar
- Wheel Size 20 in
- Frame 4130 Cr-Mo Steel Frame with LUG Construction
- Item Length 150cm
- Number of Speeds 9 Speed
- Vintage No
Show all 35 specifications
- Department
- Unisex Adults
- Model Year
- 2026
- Cassette
- Lightweight 9-Speed 11-34T Cassette
- Unit Type
- Unit
- Manufacturer Warranty
- 3 Years
- Features
- Adjustable Seat, Lightweight, Quick-release seatpost clamp
- Shifter
- MicroShift Advent 1 X 9S
- Brakes
- Dual-Piston CNC Machined Aluminum Hydraulic Disc Brakes
- Folding Stem
- One-Piece Forged Aluminum Folding Stem
- Cable Housing
- LUG Housing
- Bike Type
- Folding Bike
- Tire Type
- Tubeless Tires
- Crankset
- Forged Aluminum Lightweight 44T Single Chainring
- Wheelset
- Aluminum Hub + Double-Wall Sleeve-Joint Aluminum Rim, 24 Spokes
- Brand
- ROCKBROS
- Custom-Built
- No
- Frame & Fork
- 4130 High-Strength Steel
- Brake System
- 160mm Front / 140mm Rear
- Brake Type
- Disc Brake - Hydraulic
- Suspension Type
- No Suspension
- Cockpit
- 6061-T6 Forged Handlebar & Seatpost
- Model
- ROCKBROS Gravis
- Shifter Style
- Trigger Shifter
- Drivetrain
- MicroSHIFT ADVENT 9-Speed
- Tires
- 406 x 1.95 inch CST Mountain Bike Tires
- Gear Change Mechanism
- Derailleur Gears
- Item Weight
- 11.8 kg
- Country of Origin
- China
- Frame Size
- 20 in
