YSS Fork Springs, progressive, 520mm length, 1 pair. SR400, SR500

Product Description

Application: SR400 77-18 Type 1J4, SR500 78-99 (fork oil: SAE 10, air chamber 210mm)

YSS Progressive Fork Springs

YSS Progressive Fork Springs are engineered to deliver a dynamic suspension response that adapts across the full range of fork travel. Manufactured from premium high-tensile spring steel, each spring is cold-wound, heat-treated, shot-peened, and polished to ensure exceptional durability and resistance to fatigue.

Unlike linear springs, YSS Progressive Springs feature a variable spring rate. The initial portion of travel is softer, providing improved comfort and compliance over small bumps, while the rate increases deeper into the stroke to resist bottoming and enhance stability under heavy braking or aggressive riding. This makes them the ideal choice for riders who demand both comfort and control in a wide variety of conditions—whether on road, touring, or spirited weekend riding.

Each set is precisely manufactured to tight tolerances, ensuring accurate fitment for your motorcycle model. Combined with the correct fork oil, YSS Progressive Springs transform front-end performance by reducing harshness over uneven surfaces, improving stability during cornering, and delivering a smoother, more confidence-inspiring ride.

Key Features:

• Progressive spring rate for comfort and control across full travel
• High-quality spring steel, heat-treated & shot-peened for long service life
• Manufactured to precision tolerances for consistent fitment
• Enhanced compliance over small bumps, improved resistance to bottoming
• Suitable for road, touring, and everyday riding applications
• Sold as a set/pair

YEAR  77-18 78-99
VIN 2J4/48T
MODEL SR400 SR500
OD 1 24.5
RATE 1 4.4
RATE 2 6.0
LENGTH 520
FORK FLUID 15W
OIL HEIGHT (MM) 150
CODE S2
CHECKED YES