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2000 GT Speed Series UltraBox XL

2000 GT Speed Series UltraBox XL

With an initial price tag of $699.99, the 2000 GT UltraBox was by far the most expensive frame you could purchase in December 1999 - and it never sold for less than $599.99 at Dan's Comp.


When I first saw a picture of the 2000 GT Speed Series UltraBox frame in the September 1999 BMX Plus! magazine, I was beside myself.  Sure, Powerlite had its Coqpit, Haro had its Monocoque and SR-71, and Mountain Cycle had its AfterShock, but the UltraBox was different.  And I wanted one!


With an initial price tag of $699.99 USD, the 2000 GT UltraBox was by far the most expensive frame you could purchase back in December 1999 (Source: Dec. '99 BMX Plus!, p. 24).  It featured custom Easton butted 6061-T6 aluminum tubes, an oversized 1-3/4" outer diameter (O.D.) computer numerical control (CNC) machined head tube, a new formed top tube with a full-length internal cable guide, sleeker and lighter chain stays, a new monostay back end, and completely redesigned dropouts.  And to top it off, this lightweight, responsive, precision engineered frame was made in the USA at GT's factory in Santa Ana, California.  Here are some highlights of the 2000 GT Speed Series UltraBox frame (Source: Sept. 1999 BMX Plus!, p. 8):

  • Rather than using a standard 1-5/8" O.D. head tube, for the UltraBox, GT choose to use a beefier head tube in order to resist flaring and reinforce the headset cup area.  The extra material also provided a larger welding surface which made manufacturing the frame easier.  The head tube was then machined out from the inside so that the frame could run a standard 1-1/8" fork/headset.  The outside of the head tube was also machined to reduce weight.

  • New for 2000, the GT UltraBox frame featured a top tube that was not a monocoque - instead a single sheet of aluminum was cut to the specified dimensions, folded over a precise form, and then welded on the bottom, rather that welding two formed pieces together down the middle (like the Haro Monocoque).  This design produced a very stiff, yet very light top tube.

  • GT's unique top tube housed an aluminum full-length internal cable guide tube.  This eliminated the rattle that was prevalent with the Haro Monocoque.

  • The UltraBox took the Box Stays that had been designed in 1997 and refined in 1998 to the next level!  The UltraBox's new chainstays were a little sleeker and lighter that those that came on the previous model-year Speed Series frames.  The new chainstays were redesigned for more control, which they in fact provided.

  • When compared to the Speed Series frames, the Y2K UltraBox had new state-of-the-art dropouts that actually help increase chain clearance at the seat stays. 

  • The new monostay back end was also new for GT in 2000, and it helped to increase brake stiffness on the frame

The UltraBox frame weighed 3 lb. 8 oz. and was sold in 2000 as a frameset that included a black GT Stiletto fork and an anodized black 31.6mm GT micro-adjust seat post.  The frame was available in six different sizes (Expert, Junior, Cruiser, Pro, XL, and XXL) that all sported new race proven geometry - the new super-aggressive geometry featured steeper head tube angles, shorter rear ends, and lower bottom brackets (Source: 2000 GT BMX Catalog, p. 4).  And actually, when GT AA Pro Thomas Allier raced his 2000 GT UltraBox frame for the first time, he won three out of four pro heats in Santa Clara, CA (Source: Sept. 1999 BMX Plus!, p. 8).  Not too shabby :) .



Complete Frame Geometry - see image below (Source2000 GT BMX Catalog):

  • HA (Head Tube Angle): 74.0 deg.

  • SA (Seat Tube Angle): 70.0 deg.

  • TT (Top Tube Length): 21.0 in.

  • CS (Chain Stay Length): 14.9 in.

  • BB (Bottom Bracket Height): 11.88 in.

  • FC (Front Center Distance): 23.16 in.

  • WB (Wheel Base Length): 37.86 in.

  • SP (Seat Post Size): 31.6 mm



Advertisements for the 2000 GT Speed Series UltraBox frame:


The First Released Information about the 2000 GT UltraBox Frame (Source: Sept. 1999 BMX Plus!, p. 8):



Catalog Picture - 2000 GT Speed Series UltraBox Frame (Source: 2000 GT BMX Catalog):



The First 2000 GT UltraBox Advertisement (Source: Dec. 1999 BMX Plus!, pp. 6-7):


This bike started out as a pretty nice $400.00 USD eBay purchase.  However, since I had been looking for a Y2K UltraBox frame or bike for at least the last year, I had already begun finding the perfect parts for one of these bikes (e.g., CK hubs and headset, Answer Carbo forks, Technique double-pinch cranks, HED rims).  This bike is by no means complete yet, but it's comming along.  Here is my proposed parts list so far:


Proposed Parts List (when I finish building this bike):


Frame: 2000 GT Speed Series UltraBox XL (21.0" top tube, 1-1/8" head tube, American bottom bracket, V-brake mounts, designed for 3/8" thick axles, custom 6061-T6 butted/tapered aluminum tubes made in the U.S.A. by Easton, new Box chainstays and dropouts, oversized head tube, internally and externally CNC-machined head tube and bottom bracket shell, internal full-length aluminum cable guide tube, original 2000 GT Speed Series UltraBox XL decals, ball burnished/black two tone) 3 lb. 8 oz. - $699.99 Dec. '99

Fork: Answer Carbon Fiber w/ GT decals (carbon fiber legs, anodized black aluminum crown, polished aluminum dropouts and collars, 1-1/4" diameter 1/16" thick polished aluminum fork leg caps, decals from a stock 1999 GT Speed Series Team's GT Stiletto fork) 22.1 oz. - $199.99 Jan. '98

Handlebars: S&M Race XLT (butted 4130 chromoly tubes, 8" tall, originally 28" wide - but cut down to 27", 1.6 lb. (0.73 kg), 12 deg. back sweep, 1 deg. upsweep, 0.625" dia. cross bar, 4Q baked post-weld heat treatment, same geometry as S&M Slam bars and S&M Challenger bars, chrome plated) 25.7 oz. - $74.99

Stem: GT U.S.A.-made Piston XL (CNC precision machined, about 53mm reach, black chromoly bolts, anodized red aluminum body) 13.4 oz. - $34.99 '98

Headset: Chris King NoThreadSet (1-1/8", threadless, 110 g, aluminum cups, sealed cartridge-style bearings, USA-made, anodized black with silver logo) 3.8 oz. - $99.99 '99

Headset Cap: Profile Pro (aluminum, 1-1/8", comes with the Profile Pro stem lock, anodized black)

Stem Lock: Profile Pro (aluminum bottom cap, replaces a star nut, adjusts from 8" to 9", 200mm to 225mm) 2.1 oz. - $27.99

Grips: ATI Pistol (durable Newtron rubber, positive control thin profile design, extra long for 'controlled jumps and faster gate starts', designed by "Pistol Pete", made in the USA, black) $8.99 '99

Bar Ends: ATI (plastic, tough expandable end plug for extended grip life, black)

Seat: Profile Racing Saddle (embroidered "P" logo, titanium rails, released in 2006) '06

Seat Post: GT Aluminum Micro Adjust (6061 aluminum, 31.6mm dia., "GT Racing" logo, black anodized)

Seat Post Clamp: integrated into frame (19mm Cr-Mo binder bolt)

Crank Arms: Profile Racing (tubular chromoly, 177mm long, U.S.A.-made, chrome plated)

Crank Spindle: Profile GDH Titanium (6Al-4V titanium (Ti), hollow, 5-5/8" long, 153g, 19mm (3/4") dia., 48 splines) 5.4 oz. - $145.99

Crank Spindle Bolts: Profile GDH (12x1.25mm thread pattern, gun drilled hollow (GDH) flush-mounted chromoly allen bolts, polished aluminum washers) 1.5 oz. - $19.99

Crank Bearings: Profile (American, sealed) - $34.99

Spider: Profile (110mm bolt pattern, aircraft grade aluminum, silver)

Chain Ring: Profile BMX Billet (41T, CNC machined from aircraft quality billet aluminum plate, "fanned" design, fits 110mm bolt pattern spider, painted black and then clear coated - was originally anodized blue)

Chain Ring Bolts: Shimano (silver)

Chain: Shimano HG-91 Hyperglide  (1/2 x 3/32", silver/gray) 11 oz. - $19.99 '01

Chain Tensioners: Profile (CNC machined from a solid block of aluminum, 2 adjusting screws, designed for 3/8" axles, U.S.A.-made, anodized red) 1.7 oz. pr. - $32.99

Pedals: GT Power Series (solid 9/16" heat-treated Cr-Mo axle, sealed bearings, CNC precision-machined 6061-T6 alloy body and cages, lower profile to help prevent rolling, also known as 'Elite II' and 'Big Man' pedals,  black anodized body with polished cages)

Front Hub: Chris King (36H, 100mm OLD, premium quality sealed needle bearings, 19.5mm steel axle, steel axle nuts, anodized black aluminum shell)

Rear Hub: Chris King Cassette  (36H, 110mm OLD, RingDrive engagement mechanism, 72 points of engagement, premium quality sealed needle bearings, 16.5mm super-heavy duty steel rear axle, steel axle nuts, anodized black aluminum shell)

Cog: Chris King (15T, stainless steel, CNC machined in the U.S.A., bead-blasted following heat-treating) 28 g - $18.99 '99

Rims: Araya Super 7X (36H drilling, welded joint, double wall construction, aluminum, chrome plated) $34.99 ea. '99

Front Spokes: Sapim Stainless Double Butted (butted stainless steel, 14g on ends, 15g in center, 188mm long) 5.1 oz. pr. 36H wheel  (185mm w/o nipples)- $0.40 ea.

Rear Spokes: Sapim Stainless Double Butted (184mm long on drive side, 186mm long on non-drive side) 5.1 oz. pr. 36H wheel  (185mm w/o nipples)- $0.40 ea.

Nipples: DT Swiss Alloy (2.0mm diameter, 12mm long, aluminum construction, compatible with 14g spokes and the black Park Tool SW-0 spoke wrench, polished) 0.5 oz. pr. 36H wheel - $0.25 ea.

Front Tire: IRC Siren (20 x 2.125", 65 psi, 2.17" (55mm) inflated width, 20.6" (523.2mm) inflated dia.) 15.3 oz. - $16.99 ea. '01

Rear Tire: IRC Siren (20 x 1.75", 65 psi, 1.71" (43.5mm) inflated width, 19.59" (497.5mm) inflated dia.) 12.9 oz. - $16.99 ea. '01

Front Tube: Dan's Ultra Lite (Schrader valve, 20" x 1.95-2.20", 0.6mm thick) 3.0 oz. - $4.99 ea. '03

Rear Tube: Dan's Ultra Lite (Schrader valve, 20" x 1.50-1.85", 0.6mm thick) 3.0 oz. - $4.99 ea. '03

Brake Arch: Shimano DX V-Brake Arch (Model BR-M600-MX,  "awesome V-brake power" and "more vertical pad adjustability" made in Japan, red) 6.7 oz.

Brake Lever: Shimano DX V-Brake Lever (Model BL-M601-MX, "matched Servo-Wave brake lever" with "3-position power selection", made in Japan, red body w/ black blade) 3.0 oz.

Brake Cable: Shimano (1.6mm thick stainless steel cable, black 5mm thick housing)

Padset: 2000 GT UltraBox handlebar pad (black w/ yellow/blue/red) $17.99 '00



Other parts that I'd like to buy or might put on this bike include:

  • Chain Tensioners: 2000 GT UltraBox chain tensioners (CNCd aluminum, U.S.A.-made, anodized black)
  • Decals: 2000 GT UltraBox (complete NOS decal set, or reproduction decals if available)
  • Cranks: Technique (176 mm, U.S.A.-made aluminum arms and spindle, sealed bearings)
  • Spider: Technique (110 mm, aluminum)
  • Pedals: FPD StingRay (9/16" chromoly axle, aluminum body, double-cage design, replaceable pins, loose ball bearings, black/silver)
  • Hub Parts: hex-shaped titanium axle nuts
  • Front Rim: Mavic Xx (36H drilling, 406mm x 21mm wide (20" rim), SUP welded joint, UB Control machined brake surface, double eyelets, weight per rim: 390g, "Mavic black" color) $49.99
  • Rear Rim: HED. (36H, Sun CR18 aluminum rim with HED carbon fiber fairing, drilled for 2x both sides) $139.99


And much more to come later, like:

  • Detailed pictures of the frame (and parts when I get them),
  • More advertisements of the frame and the parts that will be on it, and
  • Pictures of this bike being ridden by factory GT riders.


Some Older Pictures of the Bike (differences being the seat, pedals, spindle bolts, and valve caps)


I hope you enjoyed!  Lastly, feel free to check out my other bikes too (




Submitted by pharv85

  • Race
  • Company: GT Bicycles
  • Model: Speed Series UltraBox
  • Wheel Size: 20"
  • Headtube angle: 74.0 deg.
  • Seattube angle: 69.0 deg.
  • Toptube length: 21.0 in.
  • Headtube size: 1-1/8"
  • Details