The Problem

• When a weight stack is lowered or released, the impact between weight plates is transmitted directly through the machine frame and mounting feet into the floor structure
• This short-duration, high-amplitude impulse is particularly effective at exciting building structure resonances — it is perceived as a loud thud in rooms above, below, and beside the gym
• Isolating the machine feet addresses the transmission path but not the source — impact energy still enters the frame from the weight stack itself
• The most effective solution combines weight stack isolation (MPR washers) with machine foot isolation (Akustik-fit or g-fit)

How MPR Washers Work

• Sylomer® washers are fitted between consecutive weight plates in the stack
• When a weight is released, the Sylomer® element deflects and absorbs the impact energy — extending the contact duration and reducing peak force transmitted to the frame
• The colour-coded density grades ensure the correct stiffness is selected for the stack weight at each position
• Available in 12mm and 25mm thickness — thicker variants provide greater deflection and lower natural frequency for more demanding isolation requirements

Typical Applications

• Selectorised weight stack machines — lat pulldown, cable rows, leg press, chest press
• Plate-loaded machines where weight plates are stacked on a guide rod
• Any weight training machine generating impact complaints in adjacent or below-grade spaces

Specification

• Sylomer® density grade: SR 110
• Colour: Brown — for visual identification of grade in the stack
• Maximum load: 30 kg per washer
• Thickness options: 12mm (code 712386) · 25mm (code 712321)
• 3D BIM model available for each thickness variant

Suitable For

• Light weight stacks on smaller selectorised machines
• Upper positions in a weight stack where individual plate weight is lower
• Cable machines and pulley systems with lighter weight increments

Specification

• Sylomer® density grade: SR 220
• Colour: Red — for visual identification of grade in the stack
• Maximum load: 50 kg per washer
• Thickness options: 12mm (code 712387) · 25mm (code 712322)
• 3D BIM model available for each thickness variant

Suitable For

• Standard commercial gym selectorised machines (50–100 kg stack range)
• Mid-stack positions where cumulative weight reaches medium levels
• Leg press and compound movement machines with higher weight stacks

Specification

• Sylomer® density grade: SR 450
• Colour: Grey — for visual identification of grade in the stack
• Maximum load: 100 kg per washer
• Thickness options: 12mm (code 712388) · 25mm (code 712323)
• 3D BIM model available for each thickness variant

Suitable For

• High-capacity commercial gym machines with full weight stacks exceeding 80 kg
• Base position of a weight stack where the total stack weight bears on a single washer
• Plate-loaded guide rods with heavy plate totals

Grade Selection

• The load at each washer position equals the total weight of plates above it — not the full stack weight
• Bottom washer carries the full stack load → MPR 450 (grey)
• Mid-stack washer carries a partial load → MPR 220 (red) or MPR 110 (brown) depending on weight at that position
• Colour coding allows quick visual verification of correct installation

Thickness Selection

• 25mm: greater deflection under impact → lower transmitted force → higher isolation performance. Preferred where the guide rod length and machine geometry allow
• 12mm: reduced height gain per washer → suits machines where total stack travel is limited or the guide rod has minimal clearance above the top plate

Combining with Machine Foot Isolation

• MPR washers address impact at the weight stack — the highest-energy source in a weight training machine
• For complete isolation, combine with Akustik-fit or g-fit Gear mounts under the machine feet — these handle residual vibration from the frame and motor