Velopedia Bicycle Archive
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Compare published geometry, gearing and specifications for up to three bicycles.
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1 of 2 bicycles
At a glance
Key differences
Supported differences are shown below. Data limitations are labeled separately.
- Identity & price
These bicycles are categorized differently: 2002 Diamondback RM20 is BMX; 2010 Diamondback RM20 is Kids.
- Data limitation
No geometry is recorded for 2010 Diamondback RM20.
- Gearing
2010 Diamondback RM20 has a 27% lower climbing ratio than 2002 Diamondback RM20.
A lower ratio gives more mechanical advantage; rear-wheel rollout determines distance per crank turn.
Gearing comparison
Lower gears help on climbs. Higher gears suit higher speeds.
RPM
RPM = pedal turns per minute.
Ratio2.75:1
Estimated speed at 90 RPMGear
Rear tire: 20×1.75.
Ratio2.00:1
Estimated speed at 90 RPMGear
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.
Complete specification tableShows different published values and gaps where a bicycle lacks data. Different wording reflects source language, not necessarily different components. Swipe for more columns.
Specification
2002 Diamondback RM20
2010 Diamondback RM20
Overview
Model Year
2002
2010
Brand
Diamondback
Diamondback
Model
RM20
RM20
Bicycle Type
BMX
Juvenile
Original MSRP
$500.00
Not documented
Colors
Red/White
Gloss Blue
Sizes
Pro
One Size
Weight
—
—
Frameset
Frame Construction
TIG-welded
TIG-welded
Frame Material
7005 aluminum
Hi-Ten Remington Steel
Fork Material
Chromoly, unicrown crown
Hi-Ten Remington steel, unicrown crown
Drivetrain
Component Group
—
Juvenile Mix
Crankset
AC Race 16 3pc, 44 teeth
1-piece steel 140mm, 36 teeth
Bottom Bracket
AC Euro Sealed Bearing
Loose ball
BB Shell Width
68mm English
—
Cassette
—
Cog
Rear Cogs
1-speed, 16 teeth
1-speed, 18 teeth
Chain
KMC HP20NP, 1/2 X 3/32"
—
Pedals
Aluminum
Resin platform
Brakes
Brakes
Tektro BX-20 linear-pull rear brakes, Tektro Sabre rear levers
Alloy Linear Pull/Coaster Brake rear brakes, Alloy linear rear levers
Cockpit & Contact Points
Headset
1 1/8" threadless aluminum
1" Threaded
Handlebar
Chromoly BMX
Hi-Ten 2-piece 24" wide x 6" rise
Handlebar Extensions
—
Not included
Stem
Aluminum
Steel quill
Saddle
Diamondback BMX
DB BMX padded
Seatpost
Aluminum, 27.0mm diameter
Steel pillar, 25.4mm diameter
Wheels & Tires
Hubs
Aluminum
Front: Nutted, Rear: Nutted Coaster
Rims
Alex Supra B Pro, 36-hole
Alex R-1000, 36-hole
Spokes
Stainless steel, 14ga. (2.0mm) straight gauge
14ga. (2.0mm)
Spoke Nipples
Brass nipples
—
Front Tire
20 x 2.125" Tioga Comp III
20 x 2.125" Comp III style
Rear Tire
20 x 1.75" Tioga Comp III
—
Wheel Size
20" wheels
20" wheels
Geometry · choose a size for each bicycle
Geometry size
—
Head-tube angle
73.5°
—
Seat-tube angle
71°
—
Chainstay / rear center
393.7 mm
—
Wheelbase
985.5 mm
—
Fork offset / rake
30.5 mm
—
Historical specifications are presented as an archival reference. Components may have varied by market, size, or production run. Legacy reference geometry is model-level historical data whose corresponding frame size is not identified; compare those dimensions as reference values rather than size-normalized fit data.