Velopedia Bicycle Archive

2025 Marin Donky JR 20" 1SP

Original specifications: 20" wheels.

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At a glance

Archive #900000823

Model year: 2025
Category: Kids
Original MSRP: $449.00
Sizes: One Size
Colors: Aqua Blue, Metallic Lime, Black Purple
In this record: 21 specifications · 3 archived images · original MSRP

Original buildAluminum · 20"

Manufacturer catalog

Published sizes and colors

1 size · 3 colors

Manufacturer-published sizes and colors; availability and exact size/color pairings may vary by market or production run.

Published sizes

One Size

Published colors

Aqua BlueMetallic LimeBlack Purple

Frameset

Frame Construction	Series 1 Aluminum, 20” Wheels, Single Speed, Rim Brake
Frame Material	Aluminum
Fork	Steel Fork, Rim Brake
Fork Material	Steel

Drivetrain

Crankset	Forged Alloy, 32T, 140mm, Ring Guard
Bottom Bracket	Sealed Cartridge Bearings, Square Taper
Cassette	Single Speed Freewheel, 16T
Chain	KMC 1-Speed
Pedals	Kids Specific Nylon Pedal

Brakes

Brakes	(F) Linear Pull, Alloy / (R) Linear Pull, Alloy; Levers: Kid's Specific Short Reach Alloy Lever

Cockpit & Contact Points

Headset	Threadless
Handlebar	Riser Bar, 127mm Rise, 580mm Width
Stem	Alloy, 48mm
Saddle	Integrated Saddle/Post
Seatpost	25.4mm, Integrated Saddle/Post

Wheels & Tires

Hubs	(F) Forged Aluminum Alloy, 16H / (R) Forged Aluminum Alloy, 16H
Rims	Aluminum, CNC Brake Surface
Spokes	14g Stainless Steel
Front Tire	Marin X Vee Tire Co. Speedster, 20x2.0”
Rear Tire	Marin X Vee Tire Co. Speedster, 20x2.0”
Wheel Size	20"

Gearing

Lower gears help on climbs. Higher gears suit higher speeds.

Pedal cadence

RPM

Speed units

RPM = pedal turns per minute.

All published sizes32T · 16T · 1-speed

Ratio2.00:1

Estimated speed At 90 RPM Gear10.7 mph

Rear tire: 20×2.

How it works

Ratio = front teeth ÷ rear teeth. Hub gears also include the hub’s internal ratio. A 400% range means the highest ratio is four times the lowest.

Speeds are estimates from tire size and pedal cadence. Actual speeds vary.

Try other gearing

Try your current gearingChanged tires or gears? Calculate your setup.

Your changes apply to this calculation. The archived build stays unchanged.

Gears Drivetrain

Front teeth Smallest rear teeth Largest rear teeth

Use up to three front tooth counts, separated by /. For one rear sprocket, enter the same count twice.

Rear tire

Rear tire marking

Apply the marking on your rear tire or edit its dimensions below. Older or fractional inch sizes need the ISO marking (e.g. 37-590).

Rim diameter (BSD, mm) Tire width (mm)

For 32-622, width is 32 mm and rim diameter is 622 mm. Use the rear tire on mixed-wheel bikes. Leave both fields empty to compare ratios only.

Cadence (RPM) Speed units

Gear, dimension and cadence changes update results automatically.

Gearing comparison
Measure	Original	Your setup
Lowest ratio	—	—
Highest ratio	—	—
Total range	—	—
Lowest-gear speed	—	—
Highest-gear speed	—	—

Speeds are estimates. These calculations do not establish component compatibility or available tire clearance.

Parts & serviceability

Find replacement parts

Original specifications

Front tire · Original

Marin X Vee Tire Co. Speedster

20x2.0”

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Parts and service referenceQuick reference before buying parts

Archived specifications for reference. Check the fitted parts before ordering.

Front tire: Marin X Vee Tire Co. Speedster, 20x2.0”
Rear tire: Marin X Vee Tire Co. Speedster, 20x2.0”
Drivetrain: 1-speed
Bottom bracket / shell: Sealed Cartridge Bearings, Square Taper

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Gallery3 images

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Specifications are presented as a reference. Components may vary by market, size, production run, or later manufacturer revisions.

2025 Marin Donky JR 20" 1SP