The Sirris R46 2SC MX Tune shock brings more adjustability and control to the Surron Ultra Bee. Updated with Two Stage Compression (2SC), revised rebound tuning and clicker settings, a revised bottom-out bumper, and new graphics, it delivers a race-focused feel for aggressive motocross riding.
The MX tune is built for riders who spend their time on the track and need more support and bottoming resistance for big jumps, whoops, and fast corners.
MX Tune is purpose-built for motocross performance. Its race-focused setup delivers the balance, control, and bottoming resistance needed to charge through big jumps, hammer whoops, and attack fast corners at race pace. High-flow internals and fully tunable compression and rebound circuits help maintain consistent damping through repeated hits, while independent high-speed and low-speed compression adjustments let you dial in support and impact absorption separately.
Designed specifically for the Ultra Bee and developed to pair with the Sirris F43 fork, the R46 installs as a direct replacement for the stock shock.
Note: This listing is for the Motocross (MX) Tune. If you are a Trail Rider, please see the Sirris R46 Trail Tune Shock here.
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Key Features
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Independent compression adjustment: The 2SC system provides separate high-speed and low-speed compression adjustments for greater control over suspension feel.
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Updated MX Tune: Race-focused damping designed for motocross, with the support and bottoming resistance needed for big jumps, whoops, and fast corners.
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High-flow damping: A high-flow base valve cavity and 46 mm main piston provide a broad tuning range, responsive damping, and consistent performance.
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Rider-matched spring options: Five spring rates let you select the setup for your weight.
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Durable construction: A Type 3 hard anodized aluminum body and 16 mm induction-hardened, chrome-plated hollow steel shaft are built for demanding riding.
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Large floating piston reservoir: Designed to manage the oil displacement of the 16 mm shaft and maintain consistent damping through repeated hard hits and high heat loads.
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Fully serviceable: Rebuildable construction with compression and rebound valving that can be custom tuned.
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Direct fit: Stock replacement dimensions of 320 mm length and 85 mm stroke, with no additional parts or modifications required.
Rider Weight and Spring Selection
Select your spring based on rider weight without riding gear. Sirris already accounts for 15 lbs of riding gear in the ranges below.
| Rider Weight Without Gear |
Spring Option |
Spring Rate |
| Under 160 lbs |
Light |
85 N/mm |
| 160–200 lbs |
Medium |
95 N/mm |
| 200–240 lbs |
Heavy |
105 N/mm |
| 240–280 lbs |
X Heavy |
115 N/mm |
| Over 280 lbs |
XX Heavy |
125 N/mm |
External Adjustments
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Low-speed compression: 18 clicks
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High-speed compression: 24 clicks, adjusted with a 20 mm hex
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Rebound: 24 clicks
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Spring preload: Manually adjustable threaded retainer with locking feature
Specs
R46 2SC MX Tune Specifications
| Specification |
Details |
| Fitment |
Surron Ultra Bee |
| Tune |
MX Tune |
| Architecture |
Piggyback shock with steel coil spring |
| Length |
320 mm |
| Stroke |
85 mm |
| Weight Without Spring |
3.9 lbs / 1.76 kg |
| Compression Adjustment |
2SC with independent high-speed and low-speed adjustment |
| Damping |
High-flow internals with fully tunable compression and rebound circuits |
| Main Piston |
High-flow 46 mm CNC-machined 6061 billet aluminum, Type 3 hard anodized |
| Piston Band |
Hard band |
| Shaft |
16 mm OD induction-hardened, chrome-plated hollow steel; 5.5 mm ID |
| Shock Body |
Seamless 6061 aluminum, Type 3 hard anodized, ACME thread |
| Spring Retainer |
Seamless 6061 aluminum, Type 3 hard anodized, ACME thread, manually adjustable with locking feature |
| Reservoir |
Pressurized internal floating piston system |
| Bottom-Out Bumper |
Updated MCU bumper |
| Top-Out Bumper |
Rubber bumper |
| Seals |
NBR |
Pair It with the Sirris F43 Fork
Complete your Ultra Bee suspension setup with the Sirris F43 fork. With 260 mm of travel and purpose-tuned damping, the F43 is designed to work alongside the R46 for balanced handling, traction, and control.
Fitment
(Direct replacement for the stock shock with no modifications or additional parts required.)
