JAVA Fit 20inch 451 18 Speed Disc Folding Bike
$2,980.00
Color Options
Black Blue
Black Wite
Titanium OrangeSize Options
The Java Fit 20 inch 451 is an 18-speed aluminium folding bike with disc brakes, built on larger-diameter 451 wheels with a DECAF 2 x 9 drivetrain (52/42T hollow crankset, 11–32T cassette) and C STAR disc brakes, weighing about 10.5 kg. The double chainring gives a folding bike a wider gear range, for riders who want to cover longer distances and still handle hills.
Key Facts
- Category: 20-inch (ETRTO 451) aluminium folding bike, 2 x 9 for 18 speeds, disc brakes
- Brand: Java (Shenzhen ChuangXinWei Bicycle Co., mainland China)
- Standout feature: 451 wheels with a 52/42T double chainset, a wider gear range than single-ring folders
- Key numbers: about 10.5 kg; DECAF shifters and front/rear derailleurs; 11–32T 9-speed cassette; 540 mm handlebar; C STAR disc brakes; bearing hubs with quick release
- Best for: riders about 150–180 cm tall who want a folding bike for longer rides or hilly routes
The Problem It Solves
Many folding bikes have a single chainring, so you run out of gears when you want more speed on the flat or an easier gear on a climb. The Java Fit pairs a 52/42T double with an 11–32T 9-speed cassette: use the 52T ring on the flat, and the 42T ring with the 32T cog on climbs. Its 451 wheels are slightly larger than standard 20-inch 406 wheels, and Jollymap's review notes that 451 rolls better and reaches higher top speeds while keeping the bike compact.
Who It Suits
- Good fit: riders about 150–180 cm tall who like a flat-bar position; anyone who wants a foldable bike for cycle tracks or longer rides; riders who want double-chainring gearing for hills.
- Maybe not: if the smallest possible fold for daily MTR trips matters most, a 16-inch bike suits better, such as the Java NEO 9S 16 inch 349 9 Speeds Folding Bike; for a carbon frame and electronic shifting on the same 451 wheel size, see the Java NEO Carbon 20 inch 451 105 Di2 Folding Road Bike.
Key Features
451 wheels that roll better
The aluminium rims are 451 size. Both 451 and 406 are called 20-inch, but 451 is slightly larger in diameter, rolls better and reaches higher top speeds. Replacement tyres must be 451; they are not interchangeable with 406 tyres.
2 x 9 for 18 speeds
DECAF shifters and front and rear derailleurs work with a DECAF 52/42T hollow crankset and an 11–32T 9-speed cassette. The double gives suitable gears for both flat cruising and climbing, the biggest difference from a typical single-ring folder.
Aluminium frame and disc brakes
The dedicated JAVA-FIT aluminium frame comes with aluminium brake levers and C STAR disc brakes; front and rear hubs run on sealed bearings with quick-release skewers.
540 mm flat bar and 550 mm seatpost
The handlebar is 540 mm wide (25.4 mm clamp), and the seatpost is 33.9 mm in diameter and 550 mm long, with a laser-engraved finish.
Java 451-Wheel Models Compared
The table compares three Java bikes on 451 wheels:
| Model | Type | Frame | Gearing | Chainrings | Brakes | Weight (approx.) |
|---|---|---|---|---|---|---|
| JAVA Fit 20inch 451 18 Speed Disc Folding Bike (this page) | Folding bike, flat bar | Aluminium | 2 x 9, 18 speeds (DECAF, 11–32T) | 52/42T | C STAR disc | 10.5 kg |
| JAVA CL Carbon 20inch 451 18 Speed Disc Mini Velo Bike | Mini velo, flat bar | Carbon | 2 x 9, 18 speeds (Shimano Sora, 12–28T) | 34/50T | Shimano MT-200 hydraulic disc | — |
| Java NEO Carbon 20 inch 451 105 Di2 Folding Road Bike | Folding bike, drop bar | Carbon | 2 x 12 electronic (Shimano 105 Di2, 11–34T) | 52/36T | Shimano 105 hydraulic disc | 9.4 kg (with pedals and drop bar, Jollymap measured) |
Comparison sources: each model's Jollymap product page and Jollymap review articles. "—" means no reliable figure is available.
Jollymap Recommends
This bike comes in one size, and Jollymap's spec sheet lists a suitable rider height of 150–180 cm. If you are near either end of that range, or unsure whether the 540 mm bar and seatpost length suit you, chat with us or message our Jollymap Facebook page before ordering, with your height and inseam. When you buy replacement tyres, remember to choose 451 size.
Specifications
| Brand | Java |
|---|---|
| Frame | JAVA-FIT 18-speed aluminium frame |
| Brake levers | Aluminium |
| Shifters | DECAF |
| Front derailleur | DECAF |
| Rear derailleur | DECAF |
| Crankset | DECAF hollow 52T/42T |
| Cassette | 11-32T 9S |
| Handlebar | 25.4 x 540 mm |
| Seatpost | 33.9 x 550 mm, laser engraved |
| Brakes | C STAR disc brakes |
| Rims | Aluminium 451 |
| Tyres | CST 20-inch (451) |
| Hubs | Bearing hubs with quick release |
| Weight | 10.5 kg |
| Rider height | 150–180 cm |
| Colours | Titanium Orange, Black White, Black Blue |
Specification source: Jollymap product data, matching the Java Fit 18S specification published by a Hong Kong bike shop (Java's official website no longer lists this model).
*Components and parts may vary between production batches. Enquiries are welcome.
FAQ
How much does the Java Fit weigh?
About 10.5 kg. That is the figure in Jollymap's product data and in a Hong Kong bike shop's Java Fit 18S listing; parts may vary slightly between production batches.
Does the Java Fit use 451 or 406 wheels, and what is the difference?
This Java Fit uses 451 wheels. Both 451 and 406 are called 20-inch, but 451 is slightly larger in diameter, rolls better and reaches higher top speeds; the tyres are not interchangeable, so buy 451 tyres when replacing them.
What rider height does the Java Fit suit?
Jollymap's spec sheet lists 150–180 cm. The bike comes in one size, so if you are near either end of the range, contact us before ordering to check the seatpost and handlebar height.
What is the difference between the Java Fit and the Fit Pro?
They are different versions with different drivetrains. The Fit on this page uses DECAF shifters and derailleurs with a 52/42T crankset and 11–32T cassette; a Hong Kong bike shop's Fit Pro (18S-Pro) listing shows a Shimano Altus shifter, Shimano Sora front and rear derailleurs, a 46/56T crankset and an 11–28T cassette. If you are interested in the Fit Pro, please contact us first.
How does the Java Fit differ from the Java NEO 20-inch?
Mainly in wheels and gearing. The Java Fit runs 451 wheels with a 2 x 9, 18-speed drivetrain; the Java NEO 20 inch 9 Speed Carbon Fork Folding Bike uses 406 wheels, a single 50T chainring with Shimano CUES 9-speed (11–40T) and a carbon fork, as part of the Java NEO tri-fold range, listed at about 10.5 kg. Choose the Fit for a double chainring and 451 wheels, or the NEO 20-inch for a tri-fold design and carbon fork.
Can I take a 20-inch folding bike on the MTR or a bus?
It depends on the folded size. The MTR limits luggage to 170 cm in total length, width and height, with no side over 130 cm, so check the actual folded size (including pedal width) before travelling; we have not been able to verify an official folded size for the Java Fit, so contact us before ordering. On franchised buses, the Public Bus Services Regulations (Cap. 230A) section 14 only allows free carriage of items within 5 kg and 0.1 m³, which a whole bike exceeds, so it is up to the bus company and driver; minibuses make no guarantee either.
Where can I buy the Java Fit in Hong Kong?
It is available from the Jollymap online shop and store. To check colours or specification, chat with us or message our Jollymap Facebook page before ordering.
Specifications and components follow the manufacturer's latest release and may change without notice. If in doubt, please contact us to confirm before ordering.
Last updated: October 2026
