Thumpstar Dual-Sport 12" Rear Wheel Assembly - 3905 Silver Alloy Rim w/ Stainless Spokes & 20mm Axle - 6-Bolt/4-Bolt Hub - Fits TSK110/TSB110/TSB125E/TSX125/TSR140

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

• Gravity-Cast A356 Aluminum Construction

  • T6 heat-treated for maximum strength-to-weight ratio

  • CNC-machined bead seats (0.02mm tolerance)

  • Electro-polished silver finish with clear coat protection

  • 20% lighter than equivalent steel rims

Premium Spoke System

• Marine-Grade 316 Stainless Steel Spokes

  • 8-gauge thickness (4.0mm diameter)

  • 4-cross lacing pattern for optimal load distribution

  • Pre-tensioned to 110kgf with locking nipples

  • Saltwater corrosion tested for 3000+ hours

Dual-Function Hub Assembly

• Billet 6061-T6 Aluminum Hub

  • Hard-anodized (Type III) surface treatment

  • 20mm hardened 4140 chromoly axle (HRC 40-45)

  • Dual ceramic hybrid bearings (6004-2RS)

  • 6-bolt sprocket mounting (standard 65mm BCD)

  • 4-bolt disc brake mounting (standard 56mm BCD)

  • Laser-etched timing marks for precise alignment

Technical Specifications

• Wheel Diameter: 12 inches (304.8mm)

• Rim Width: 1.85 inches (47mm)

• Overall Width: 5.25 inches (133mm)

• Hub Width: 110mm (center-to-center)

• Axle Diameter: 20mm (included)

• Spoke Count: 36 (9-gauge)

• Weight: 4.1 kg (complete assembly)

• Max Load Rating: 140kg (308lbs)

• Max Speed Rating: 130km/h (80mph)

Performance Advantages

• Dual-Sport Versatility: Compatible with both chain drive and disc brake systems

• Unsprung Weight Reduction: Alloy construction improves suspension response

• Enhanced Power Transfer: Stiffer wheel construction minimizes energy loss

• Superior Corrosion Resistance: Marine-grade materials withstand harsh conditions

• Precision Balancing: Factory-balanced to <3g at all speeds

Precision Fitment

Engineered specifically for:

• Thumpstar TSK110 (All variants)

• Thumpstar TSB110 (2016+ models)

• Thumpstar TSB125E (Electric version)

• Thumpstar TSX125 (Pro and Race editions)

• Thumpstar TSR140 (All versions)

Track-Ready Features

• Pre-Installed Ceramic Bearings: 25% less rolling resistance

• Dynamic Balancing: Computer-matched to 0.005mm radial tolerance

• Tool-Free Sprocket Alignment: Includes laser-etched reference marks

• Universal Brake Compatibility: Works with 160mm-220mm rotors

Complete Package Contents

• 1 x Fully assembled rear wheel

• 20mm chromoly axle with spacers

• 316 stainless steel spoke set

• High-tensile mounting hardware

• Technical installation guide

Ideal Applications

• Supermoto conversions

• Adult pit bike racing

• Electric pit bike upgrades

• Professional training bikes

• Heavy rider applications