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Slacker Virtual Fender Mount for MTB – Precise 1:1 Rear Axle Sag Measurement Tool – Real-Time Millimeter & Percentage Readings – Universal Seatpost Mount – MTB Accessories for Suspension Tuning

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Availability: In Stock.
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Arrives Saturday, May 9
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Features

  • TRUE 1:1 AXLE SAG MEASUREMENT: Measure actual rear axle movement instead of shock stroke. Unlike a traditional sag tool, this system eliminates linkage ratio errors so your MTB suspension settings reflect real travel and accurate performance.
  • REAL-TIME PRECISION DISPLAY: Works with digital measuring tools & scales to show exact sag in millimeters or percentage in real time. Instantly see changes as you adjust, reducing guesswork and speeding up accurate suspension setup.
  • SET SAG WITHOUT ASSISTANCE: Integrates easily with common bike tools and mounts securely to the lower seatpost, allowing riders to set sag independently. No second person needed for precise suspension tuning at home or trailside.
  • UNIVERSAL MTB COMPATIBILITY: Designed as essential mtb tools for serious riders, it includes 5mm, 6mm, and 8mm hex inserts to fit multiple axle standards across trail, enduro, and all-mountain bike setups.
  • BUILT FOR SERIOUS RIDERS: A performance-focused addition to your mtb accessories, built from durable plastic and metal components to withstand repeated installation, adjustments, and suspension checks in workshop or race conditions.

Description

Accurate suspension setup requires measuring where it truly matters. Traditional shock-based sag tools estimate compression at the shock body, but due to linkage and leverage ratios, those readings can be off by several percent. This virtual fender mount is designed to deliver true 1:1 rear axle measurement, giving mountain bike riders precise data for confident suspension tuning. As a precision sag tool for MTB suspension, it measures actual axle movement instead of shock stroke. That means no more guesswork, no more inconsistent adjustments, and no more trial-and-error setup. Whether you ride trail, enduro, downhill, or all-mountain, accurate sag directly impacts traction, balance, geometry, and ride control. Designed to work alongside digital measuring tools & scales (sold separately), this system provides real- time sag readings in millimeters and percentage through a connected device. Instantly see changes as you adjust preload, air pressure, or damping settings. This level of accuracy transforms standard bike tools into professional-grade MTB tools for suspension diagnostics and setup. Installation is simple. The mount attaches to the lower seatpost and aligns directly above the rear axle for stable measurement. Included 5mm, 6mm, and 8mm hex inserts ensure compatibility with multiple axle standards, making it a versatile addition to your MTB accessories collection. Built from durable plastic and metal components, it withstands repeated tuning sessions in the garage or workshop. For home mechanics, suspension tuners, and performance- focused riders, this tool elevates mountain bike maintenance beyond basic bike tools & maintenance practices. If you want consistent ride quality, optimized suspension health, and maximum performance on technical terrain, measure at the axle — not the shock. Upgrade your MTB setup with precision and ride with confidence.

Item Package Dimensions L x W x H: ‎6.42 x 6.3 x 1.34 inches


Package Weight: ‎0.35 Kilograms


Item Weight: ‎11.5 Ounces


Brand Name: ‎Motool


Warranty Description: ‎1-Year warranty for manufacturing defects.


Model Name: ‎Slacker Virtual Fender Mount


Color: ‎Yellow


Material: ‎Plastic


Suggested Users: ‎Suspension Setup


Manufacturer: ‎Slacker


Style: ‎Virtual Fender Mount for Precise


Included Components: ‎5mm, 6mm, and 8mm hex key axle inserts., Adjustable swivel., Seat post clamp., Slaiding loop for retractable cable., Virtual fender rod assembly.


Size: ‎Standard


Date First Available: June 8, 2025


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, May 9

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Leasing options through Acima may also be available during checkout.

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Top Amazon Reviews


  • Excellent
Excellent accessory to go with my slacker so I can now use it on my mountain bike
Reviewed in the United States on February 2, 2026 by Matt N

  • Mountain bike ride booster
Works well for mountain bike. I set the slack and the ride was way, way better. If you have a slacker, get this for a mt bike performance boost.
Reviewed in the United States on October 14, 2025 by J or M Stein

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