SAVE
$6.28
Representative image of an RCScrewZ metal-shielded bearing kit for HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840); exact bearing sizes and quantities vary by RC model.
Upgrade Your RC Car with Metal Shielded Bearings for HPI Savage 21 1/8 4WD | hpi003b - High Performance Upgrade | Durable & Reliable - by J-M SUPPLIES
Infographic: 'Choose Wisely for Your Need for Speed' – Highlights Metal Shielded Bearings as the top choice for unbeatable on-road RC car performance -
Infographic: 'Choose Wisely for Off-Road Adventuring' – Recommends Rubber Sealed Bearings for maximum protection and enhanced off-road performance in RC vehicles -
Infographic: 'Choose Wisely for Off-Road Adventuring' – Recommends Rubber Sealed Bearings for maximum protection and enhanced off-road performance in RC vehicles -
Infographic: 'Choose Wisely for Your Need for Speed' – Highlights Metal Shielded Bearings as the top choice for unbeatable on-road RC car performance - hpi003b
Infographic: 'Choose Wisely for Off-Road Adventuring' – Recommends Rubber Sealed Bearings for maximum protection and enhanced off-road performance in RC vehicles - hpi003b
Infographic: 'What Matters Most to You? Performance on the Streets or Durability in the Dirt?' – Guides on selecting bearings to match your RC lifestyle, highlighting the importance of choosing based on whether your focus is speed on paved roads or resilience in off-road conditions - hpi003b
Infographic: 'Need Bearings? How to Check Your RC's Bearings for Replacement' – Instructions to remove, clean, and inspect bearings for gritty texture or improper movement, indicating the need for replacement - hpi003b
Step-by-Step Guide: Checking RC Bearings. 2. Assess if bearings feel gritty or aren't spinning freely. 3. Non-free spinning bearings impair RC performance. 4. Bearings not spinning freely may need replacement - hpi003b
RCScrewZ and J-M SUPPLIES offer high-quality RC bearing kits, available as metal shielded or rubber sealed options, suitable for diverse RC needs - hpi003b
Elevate Your RC Adventure! Image introducing Stainless Screw Kits as the Ultimate Upgrade. Offers enhanced durability, superior corrosion resistance, and a sleek look, making them a top choice for complementing high-quality bearing selections. Trusted by RC enthusiasts worldwide - hpi003b
Infographic on RCScrewZ Bearing Kits: Highlights features of both metal and rubber shielded bearing kits, detailing high-quality components suitable for various RC models. Covers standard, flanged, one-way, and thrust bearings included in kits, with extra spares. Explains the shielding and performance benefits of each type, tailored for specific RC model needs - hpi003b
Infographic reminder: Refer to the item description for more detailed information about the product - hpi003b
Infographic reminder: Refer to the item description for more detailed information about the product - hpi003b
Notice: Check the product description for detailed information on the specific bearing sizes included in this bearing kit - hpi003b
J-M SUPPLIES - RCScrewZ Metal Shielded Bearings hpi003b for HPI Savage 21 RTR 1/8 Nitro Monster Truck (#831) | SET -
J-M SUPPLIES - RCScrewZ Metal Shielded Bearings hpi003b for HPI Savage 21 RTR 1/8 Nitro Monster Truck (#831) | RCX -

Why Choose This Kit

Key features and intended use for this kit.

Shield type

Metal-Shielded (On-Road)

Performance focus

Low-drag, not sealed

Best suited for

Cleaner on-road / prepared surfaces

Metal-Shielded Bearings

RCScrewZ Metal Shielded Bearing Kit hpi003b for HPI Racing Savage 21 RTR / Kit 1/8 Nitro 4WD Monster Truck (#831, #12840) | SET

RCScrewZSKU: hpi003b

Model-specific metal-shielded bearings for smooth, low-drag operation on cleaner on-road or prepared surfaces.

Fits: HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840)
OEM / model: 831, 12840

US
Regular price
$53.67
Sale price
$53.67
Regular price
$59.95

In stock

View Cart

Confirm this kit fits your RCMatch the RC model and OEM/model number shown above to your vehicle.

Exact model check

Confirm This Fits Your RC

Match the RC model and OEM/model number below before ordering.

RC model
HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840)
OEM / model number
831, 12840
Kit type
Metal-Shielded Bearing Kit — Low-Drag for Cleaner Running
Scale
1:8
Power
Nitro & Glow Fuel
View all verified kits for this model →
More compatibility details
RC brand
HPI Racing
Vehicle class
Land
Kit SKU
hpi003b
Model series
Savage
Product information

Everything You Need Before Ordering

Review what is included, installation notes, shipping details, and complete kit information.

Kit Contents & Installation

What’s Included Model-specific bearing set with one spare of each included size.
  • All bearing sizes listed below for this model-specific kit
  • One spare of each included size
  • Bearing styles vary by RC model and may include standard, flanged, one-way, or thrust bearings

Included bearing sizes for this kit:

  • 5x10x4mm bearings
  • 5x11x4mm bearings
  • 6x10x3mm bearings
  • 6x13x5mm bearings
  • 8x16x5mm bearings
  • 10x16x5mm bearings
Installation & Model NotesImportant instructions and model-specific guidance.

Seat bearings fully and squarely. Do not force them into the housing or overtighten the hardware that retains them.

Keep metal-shielded bearings clean and dry.

After cleaning and drying, apply a small amount of light bearing oil.

Details & Support

Kit Details Lower-drag metal shields for clean, dry running conditions.
Shield Type
Metal-Shielded Bearings
Performance Priority
Lower drag
Protection
Not sealed; best kept clean and dry
Best For
Cleaner on-road or prepared surfaces when lower drag is the priority
Not Ideal For
Dust, dirt, sand, mud, water, or frequent wet-condition use
Prefer Rubber-Sealed?
Choose Rubber-Sealed bearings for off-road use, dust, dirt, sand, mud, water exposure, or lower-maintenance protection.
Shipping & Returns Handling time, current delivery estimate, and return policy.
Free shipping on all U.S. orders (USPS Priority Mail).
Ships within 1–2 business days (Mon–Fri); some Saturday shipments by 12:00 PM ET.
Most orders ship from Canton, MI 48187. APO/FPO/DPO & PO Boxes welcome.
Priority Mail typically delivers in 2–3 business days (estimates; not guaranteed).
Easy 30-day returns with prepaid USPS label; refunds issued within 3 business days after the return is received.

Over 99% positive over ~14,000 orders on eBay (last 12 months) — as of October 2025. View on eBay

Full Product Description Read the complete product specifications and details.

Exact RC Model Fitment

Confirm the exact RC model and RC vehicle OEM/model number below before ordering.

Compatible RC Model
HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840)
Compatible RC Brand
HPI Racing
RC Vehicle OEM / Model Number(s)
12840, 831
RCScrewZ Kit Part Number
hpi003b

Vehicle Compatibility Details

Review these vehicle details to help confirm compatibility with your RC model.

RC Vehicle OEM / Model Number(s)
12840, 831
RC Chassis Compatibility
Savage 21 monster truck
Compatible Vehicle Type
Monster Truck
Terrain Compatibility
Compatible Scale
1:8
Compatible Fuel Type
Nitro & Glow Fuel

What Is Included

Included bearing sizes for this Metal-Shielded Bearing Kit:

  • 5x10x4mm bearings
  • 5x11x4mm bearings
  • 6x10x3mm bearings
  • 6x13x5mm bearings
  • 8x16x5mm bearings
  • 10x16x5mm bearings

What Is Not Included

Only the bearings identified in the included-bearing-size list are part of this kit. 

The RC vehicle and separately sold parts are not included unless specifically listed.

Installation & Model Notes

Compatibility Title: HPI Racing Savage 21 RTR / Kit 1/8 Nitro Monster Truck Compatibility

Quick Fit Summary:

  • Compatible Brand: HPI Racing

  • Fit: Model-specific for the listed RC model/platform: Savage 21 RTR / Kit

  • Compatible RC Model/OEM Numbers: 831, 12840

  • Scale: 1/8

  • Power Source / Fuel Type: Nitro

  • Battery / Cell Count: Not currently verified.

  • Drive Type: 4WD

  • Vehicle Type: Monster Truck

  • Chassis: Savage 21 monster truck

  • Era: Not currently verified.

  • OEM / Models: 831, 12840

  • RC Model Terrain: Off-Road

This Kit Details:

  • SKU: hpi003b

  • MPN: hpi003b

  • Bearing Type: Metal-Shielded Bearings (On-Road / Low-Drag)

  • Sealed Bearings: No

  • Water/Dust Protection: Low-drag, not sealed

  • Product Material: Carbon Chrome Steel Bearings

  • Product Color: Silver

  • Bearing Sizes Included: 5x10x4mm bearings; 5x11x4mm bearings; 6x10x3mm bearings; 6x13x5mm bearings; 8x16x5mm bearings; 10x16x5mm bearings

Release / Catalog Date: Not currently verified.

Product Benefits: This HPI bearings kit uses metal shielded, low-drag bearings for Savage 21 RTR / Kit maintenance and clean, dry, low-debris running. The bearings help reduce friction in drivetrain and rolling assemblies while the metal shields maintain reduced friction, low-drag performance for clean running conditions.

Fitment Note: Match each included bearing size to the removed factory bearing and confirm smooth rotation before final assembly.

OEM Alias Coverage: 831, 12840

Terrain Compatibility: Off-Road

Metal-Shielded Bearing Kit Details

Review the bearing-kit details below before ordering.

RCScrewZ Kit Part Number
hpi003b
Product Brand
RCScrewZ
Shielding Type
Metal-Shielded (On-Road)
Sealed Bearing Status
No
Bearing Material
Carbon Chrome Bearings
Approximate Piece Count
Color
Silver

Before Ordering

  • Confirm your exact RC model, RC brand, and OEM/model number whenever possible.
  • Review the included-bearing-size list before purchase.
  • Read the installation and model notes before disassembly or installation.

Vehicle versions, chassis revisions, and model-year configurations can differ. 

Confirm fitment before purchase when your RC vehicle differs from the details shown above.

Share This Kit

Know another RC owner who could use this kit? Send them this exact product page.

More ways to share:

Customer Reviews

Same-model kit options

More Verified Kits for This RC Model

These kits are verified for the same exact RC model and OEM/model number.

Stainless Screw Kit

For HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840) OEM/model: 831, 12840
Current price: $38.94 Compare-at price: $43.95 Save $5.01 In stock View Stainless Screw Kit

Rubber-Sealed Bearing Kit

For HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840) OEM/model: 831, 12840
Current price: $53.67 Compare-at price: $59.95 Save $6.28 In stock View Rubber-Sealed Kit
Next step

Continue Shopping by RC Model

Shop More Parts for This RC Model View all verified kits for this exact model Find Parts for a Different RC Model Search by brand and model in the Compatibility Hub
Fits: HPI Racing Savage 21 1/8 Nitro 4WD Monster Truck (831, 12840)
$53.67