Bicycle Archive · Specification report

1999 GT Bump

Velopedia Archive ID 86541

Overview

Model year	1999
Brand	GT
Model	Bump
Bicycle type	Freestyle/jumping
Archive ID	86541
Original MSRP	$316.99
Colors	Atomic Blue, Khaki

Frameset

Frame construction	Welded
Frame material	Chromoly
Fork	GT
Fork material	Chromoly, oversize, unicrown crown
Rear shock	N/A

Drivetrain

Component group	N/A
Shifters	N/A
Front derailleur	N/A
Rear derailleur	N/A
Crankset	GT 1-piece chromoly, 44 teeth
Bottom bracket	One piece
Rear cogs	1-speed, 16 teeth
Chain	1/2 x 1/8"
Pedals	GT aluminum platform

Brakes

Brakes	Dia-Compe 990 rear brakes, Dia-Compe MX-97 rear levers

Cockpit & contact points

Headset	1 1/8" threadless Aheadset SX-1
Handlebar	GT
Handlebar extensions	N/A
Stem	GT Piston
Saddle	GT
Seatpost	GT chromoly micro-adjust, 31.8mm diameter

Wheels & tires

Hubs	GT Mohawk
Rims	Weinmann ZAC-X, 48-hole
Spokes	Steel, 2.0mm straight gauge
Spoke nipples	Brass nipples
Front tire	Front: 20 x 2.125" Powerlite Retro-Tread, Rear: 20 x 1.75" Powerlite Retro-Tread
Wheel size	20" wheels

Manufacturer-published archive data. Confirm exact standards and dimensions before ordering parts or performing service. Generated by Velopedia on September 28, 2026.