Velopedia Bicycle Archive

2005 GT Power Series Ultra Box

Original specifications: 20" wheels.

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At a glance

Archive #92978
Model year
2005
Category
BMX
Original MSRP
$699.99
Sizes
Pro
Colors
Factory Blue
In this record
22 specifications · archived image · original MSRP
Model history 5 other years

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Identification clues

2005 archived details

Published colors
Factory Blue
Frame
6061 T6 aluminum
Original equipment
N/A

Clues, not proof of model year. Colors vary and components may have been replaced.

Campaign
Original build6061 T6 aluminum · 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

Pro

Published colors

Factory Blue

Frameset

Frame ConstructionTIG-welded
Frame Material6061 T6 aluminum
ForkGT BMX Stiletto
Fork MaterialChromoly, unicrown crown

Drivetrain

CranksetTruVativ Racing Team, 44 teeth
Bottom BracketTruVativ GIGA pipe DH
Rear Cogs1-speed, 16 teeth
ChainKMC Z610HX, 1/2 X 1/8"
PedalsAluminum platform

Brakes

BrakesTektro BX-25 rear brakes, Tektro BX-2 Sabre rear levers

Cockpit & Contact Points

Headset1 1/8" integrated FSA Orbit Z
HandlebarChromoly 2-piece
StemAluminum
SaddleSDG I-Fly
SeatpostSDG I-Fly

Wheels & Tires

HubsGT aluminum
RimsSun Rims Rhyno Lite XL
Spokes14ga. (2.0mm) straight gauge
Spoke NipplesBrass nipples
Front Tire20 x 2.125" IRC Siren
Rear Tire20 x 1.75" IRC Siren
Wheel Size20" wheels

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 Gear14.4 mph

Rear tire: 20×1.75.

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" IRC Siren
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Saddle · Original
SDG I-Fly
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Seatpost · Original
SDG I-Fly
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More parts (1)Fewer parts
Headset · Original
1 1/8" integrated FSA Orbit Z
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Based on the original build. Check fit and installed parts before ordering. Affiliate links may earn Velopedia a commission. As an Amazon Associate I earn from qualifying purchases.

Parts and service referenceQuick reference before buying parts

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

Front tire
Front: 20 x 2.125" IRC Siren, Rear: 20 x 1.75" IRC Siren
Drivetrain
1-speed
Bottom bracket / shell
TruVativ GIGA pipe DH
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: GT BMX Stiletto · Chromoly, unicrown crown

Drivetrain

Check drivetrain wear →

Archived: Crankset: TruVativ Racing Team, 44 teeth · Bottom bracket: TruVativ GIGA pipe DH · Rear cogs: 1-speed, 16 teeth · Chain: KMC Z610HX, 1/2 x 1/8"

Brakes

Inspect the brakes →

Archived: Brakes: Tektro BX-25 rear brakes, Tektro BX-2 Sabre rear levers

Wheels and tires

Check wheels and tires →

Archived: Wheel size: 20" wheels · Rims: Sun Rims Rhyno Lite XL · Hubs: GT aluminum · Front tire: Front: 20 x 2.125" IRC Siren, Rear: 20 x 1.75" IRC Siren

Controls and contact points

Archived: Headset: 1 1/8" integrated FSA Orbit Z · Handlebar: Chromoly 2-piece · Stem: Aluminum · Seatpost: SDG I-Fly · Saddle: SDG I-Fly · Pedals: Aluminum platform

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Market Snapshot

Checked Nov 6, 2026

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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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