Bicycle Archive · Specification report

1999 DirtMaster Jump

Velopedia Archive ID 87727

Overview

Model year	1999
Brand	DirtMaster
Model	Jump
Bicycle type	Freestyle/jumping
Archive ID	87727
Original MSRP	$339.99
Colors	Chrome-Plated, Green
Sizes	Pro
Weight	31 lb

Frameset

Frame construction	TIG-welded
Frame material	4130 chromoly
Fork	Dirtmaster Dirt Fork
Fork material	4130 chromoly, unicrown crown
Rear shock	N/A

Drivetrain

Component group	N/A
Shifters	N/A
Front derailleur	N/A
Rear derailleur	N/A
Crankset	1-piece chromoly 180mm, 44 teeth
Bottom bracket	YST BB 621
BB shell width	American 24tpi
Rear cogs	1-speed, 16 teeth
Chain	KMC 410, 1/2 x 1/8"
Pedals	Wellgo LU-313

Brakes

Brakes	Tektro 910A rear brakes, Tektro RBP-341A rear levers

Cockpit & contact points

Headset	1 1/8" threadless Tioga TG
Handlebar	SE Racing Rollbar
Handlebar extensions	N/A
Stem	Kalloy MX-817
Saddle	Team Products embroidered
Seatpost	Steel micro-adjust, 25.4mm diameter

Wheels & tires

Hubs	Formula OV 31
Rims	Alex X-303, 48-hole
Spokes	Da-Sen steel, 2.0mm straight gauge
Spoke nipples	Brass nipples
Front tire	20 x 2.25" Cheng Shin M-110
Wheel size	20" wheels

Geometry · Legacy reference

Top tube	527 mm
Head-tube angle	75°
Seat-tube angle	72°
Chainstay / rear center	406.4 mm
Wheelbase	952.5 mm
Fork offset / rake	38.1 mm

Manufacturer-published archive data. Confirm exact standards and dimensions before ordering parts or performing service. Generated by Velopedia on September 30, 2026.