Product Description
The 3905 12" Rear Wheel Assembly is engineered for riders who demand maximum performance and versatility from their Thumpstar pit bikes. This high-spec alloy wheel combines a lightweight silver alloy rim with military-grade stainless spokes and a dual-purpose hub featuring both 6-bolt sprocket and 4-bolt disc brake mountings, making it ideal for both dirt and supermoto applications.
Aerospace-Grade Construction & Components
High-Performance Alloy Rim
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Gravity-Cast A356 Aluminum Construction
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T6 heat-treated for maximum strength-to-weight ratio
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CNC-machined bead seats (0.02mm tolerance)
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Electro-polished silver finish with clear coat protection
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20% lighter than equivalent steel rims
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Premium Spoke System
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Marine-Grade 316 Stainless Steel Spokes
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8-gauge thickness (4.0mm diameter)
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4-cross lacing pattern for optimal load distribution
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Pre-tensioned to 110kgf with locking nipples
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Saltwater corrosion tested for 3000+ hours
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Dual-Function Hub Assembly
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Billet 6061-T6 Aluminum Hub
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Hard-anodized (Type III) surface treatment
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20mm hardened 4140 chromoly axle (HRC 40-45)
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Dual ceramic hybrid bearings (6004-2RS)
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6-bolt sprocket mounting (standard 65mm BCD)
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4-bolt disc brake mounting (standard 56mm BCD)
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Laser-etched timing marks for precise alignment
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Technical Specifications
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Wheel Diameter: 12 inches (304.8mm)
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Rim Width: 1.85 inches (47mm)
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Overall Width: 5.25 inches (133mm)
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Hub Width: 110mm (center-to-center)
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Axle Diameter: 20mm (included)
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Spoke Count: 36 (9-gauge)
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Weight: 4.1 kg (complete assembly)
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Max Load Rating: 140kg (308lbs)
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Max Speed Rating: 130km/h (80mph)
Performance Advantages
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Dual-Sport Versatility: Compatible with both chain drive and disc brake systems
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Unsprung Weight Reduction: Alloy construction improves suspension response
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Enhanced Power Transfer: Stiffer wheel construction minimizes energy loss
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Superior Corrosion Resistance: Marine-grade materials withstand harsh conditions
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Precision Balancing: Factory-balanced to <3g at all speeds
Precision Fitment
Engineered specifically for:
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Thumpstar TSK110 (All variants)
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Thumpstar TSB110 (2016+ models)
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Thumpstar TSB125E (Electric version)
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Thumpstar TSX125 (Pro and Race editions)
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Thumpstar TSR140 (All versions)
Track-Ready Features
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Pre-Installed Ceramic Bearings: 25% less rolling resistance
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Dynamic Balancing: Computer-matched to 0.005mm radial tolerance
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Tool-Free Sprocket Alignment: Includes laser-etched reference marks
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Universal Brake Compatibility: Works with 160mm-220mm rotors
Complete Package Contents
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1 x Fully assembled rear wheel
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20mm chromoly axle with spacers
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316 stainless steel spoke set
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High-tensile mounting hardware
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Technical installation guide
Ideal Applications
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Supermoto conversions
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Adult pit bike racing
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Electric pit bike upgrades
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Professional training bikes
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Heavy rider applications
