ROCKBROS Gravis 20" Folding Bike 9-Speed 4130 Steel LUG Hydraulic Disc Brakes
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About this product
The ROCKBROS Gravis 20" Folding Bike features a robust 4130 Cr-Mo steel frame with LUG construction and a 9-speed MicroShift Advent drivetrain. Equipped with dual-piston CNC machined aluminum hydraulic disc brakes (160mm front / 140mm rear) and 20-inch tubeless tires, this unisex adult bike emphasizes performance and portability. It includes an aluminum folding stem, adjustable seat, and offers a 3-year manufacturer warranty, with an item length of 150cm.
Our take
The ROCKBROS Gravis folding bike presents a compelling package for riders seeking both performance and convenience. The 4130 Cr-Mo steel frame with LUG construction suggests durability and a classic aesthetic often associated with quality. The 9-speed MicroShift Advent drivetrain is a strong choice for varied terrain, and the dual-piston hydraulic disc brakes provide excellent stopping power, which is reassuring on a compact bike. I appreciate the inclusion of tubeless tires for puncture resistance. While 20-inch wheels are standard for folding bikes, some might find them less efficient than larger wheels on longer rides. The 3-year warranty adds good peace of mind.
Pros & Cons
Pros
- Durable 4130 Cr-Mo steel frame
- Reliable 9-speed drivetrain
- Powerful hydraulic disc brakes
- Convenient folding design
- Tubeless tires included
Cons
- 20-inch wheel size for folding bikes
- 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 33 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 Style
- 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
- Drivetrain
- MicroSHIFT ADVENT 9-Speed
- Gear Change Mechanism
- Derailleur Gears
- Item Weight
- 11.8 kg
- Country of Origin
- China
- Frame Size
- 20 in
