Velopedia Bicycle Archive

2001 Marin MBX-125

Original specifications: 20" wheels · legacy reference geometry.

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At a glance

Archive #35962
Model year
2001
Category
BMX
Original MSRP
$275.99
Sizes
Junior
Colors
Tuning Fork Blue/Metallic
Geometry
Legacy reference
In this record
21 specifications · archived image · original MSRP · geometry
Campaign
Original build4130 chromoly · 20" wheels

Manufacturer catalog

Published sizes and colors

1 size · 1 color

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

Published sizes

Junior

Published colors

Tuning Fork Blue/Metallic

Frameset

Frame ConstructionTIG-welded
Frame Material4130 chromoly
ForkMarin
Fork Material4130 chromoly, unicrown crown

Drivetrain

Crankset1-piece chromoly 175mm, 44 teeth
Bottom BracketLoose ball
Rear Cogs1-speed, 16 teeth
ChainKMC, 1/2 x 3/32"
PedalsPlatform

Brakes

BrakesProMax linear-pull rear brakes, Unspecified front/ProMax linear-pull rear levers

Cockpit & Contact Points

Headset1 1/8" threadless Tange Aheadset
HandlebarChromoly BMX
Handlebar ExtensionsNot included
StemAluminum, forged
SaddleBMX
SeatpostAluminum micro-adjust

Wheels & Tires

HubsAluminum
RimsAlex aluminum, 36-hole
SpokesStainless steel, 2.0mm
Front Tire20 x 2.125" knobby
Wheel Size20" wheels

Geometry

Legacy reference · 4 measurements

Historical measurements. Frame size unknown.

All geometry measurementsLegacy reference · 4 measurements
MeasurementLegacy reference
Top tube457.2 mm
Head-tube angle72.5°
Seat-tube angle68.5°
Chainstay / rear center393.7 mm

Frame size not recorded.

Gearing

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

RPM

RPM = pedal turns per minute.

Published build44T · 16T · 1-speed
Ratio2.75:1
Estimated speed At 90 RPM Gear14.9 mph

Uses front tire 20×2.125; rear size isn’t listed.

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.

Your gearing setup
Gears

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

Rear tire

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).

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.

Gear, dimension and cadence changes update results automatically.

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

Parts & serviceability

Find replacement parts

Original specifications
Front tire · Original
20 x 2.125" knobby Replacement search: 20x2.125 bicycle tire Before ordering: Check rim type and tire clearance.
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Brake pads · Original
ProMax linear-pull rear brakes

Unspecified front/ProMax linear-pull rear levers

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Parts and service referenceQuick reference before buying parts

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

Front tire
20 x 2.125" knobby
Drivetrain
1-speed
Bottom bracket / shell
Loose ball
Campaign
Equipment inspection checks 10 checks based on 5 archived component groups Open equipment checksClose equipment checks
0 of 10 checked Progress stays in this browser for this record.

Checks selected from the archived equipment. Confirm what is fitted today. This is not a complete safety inspection; use the full inspection guide before test riding.

Full used-bike inspection guide →

Frame and fork

Inspect the frame and fork →

Archived: Frame: TIG-welded · Fork: Marin · 4130 chromoly, unicrown crown

Drivetrain

Check drivetrain wear →

Archived: Crankset: 1-piece chromoly 175mm, 44 teeth · Bottom bracket: Loose ball · Rear cogs: 1-speed, 16 teeth · Chain: KMC, 1/2 x 3/32"

Brakes

Inspect the brakes →

Archived: Brakes: ProMax linear-pull rear brakes, Unspecified front/ProMax linear-pull rear levers

Wheels and tires

Check wheels and tires →

Archived: Wheel size: 20" wheels · Rims: Alex aluminum, 36-hole · Hubs: Aluminum · Front tire: 20 x 2.125" knobby

Controls and contact points

Archived: Headset: 1 1/8" threadless Tange Aheadset · Handlebar: Chromoly BMX · Stem: Aluminum, forged · Seatpost: Aluminum micro-adjust · Saddle: BMX · Pedals: Platform

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

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