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The Bilstein 33-225487 is a B8 8125 Series 46mm monotube coilover shock absorber with a remote reservoir, built for competition-level custom off-road applications. The 33-225487 measures 19 inches extended and 13 inches collapsed for 6 inches of travel, with eyelet-to-eyelet mounting and 1/2-inch inner diameter with 5/8-inch bearing inserts on both ends. The threaded body accepts dual-rate coilover hardware for quick spring changes and preload adjustments, and the 22mm hard-chromed, case-hardened piston rod provides exceptional tensile strength with resistance to sand blasting and rock chipping in the harshest off-road environments.
The 33-225487 features a high-temperature remote reservoir connected via a size-8 high-temperature hose, filled with Bilstein's nitrogen-charged monotube design for fade-free, consistent damping performance under sustained off-road abuse. All hardware on the B8 8125 is billet machined with no cast parts. The 33-225487 is fully owner rebuildable and revalvable in the field, an important feature for serious off-road competitors who need to adjust damping characteristics between events. Spring seats are sold separately and must be selected for the specific coilover spring application.
33-225487 Key Features
- B8 8125 Series competition-level 46mm monotube coilover with remote reservoir
- 19-inch extended length, 13-inch collapsed length, 6-inch travel
- Threaded body with dual-rate coilover hardware for spring and preload adjustments
- 22mm hard-chromed, case-hardened piston rod for maximum tensile strength
- Remote reservoir via high-temperature size-8 hose for increased heat dissipation
- All billet machined components, no cast parts
- Industry-standard 5/8-inch bearing, 1/2-inch ID eyelets both ends
- Owner rebuildable and revalvable
- Nitrogen charged monotube design for fade-free performance
- Zinc-plated for corrosion resistance
- Competition 3-stage seal pack for harsh off-road environments
Product Specifications
| Specification | Detail |
|---|---|
| Part Number | 33-225487 |
| Brand | Bilstein |
| Series | B8 8125 |
| Body Type | Threaded Body Coilover |
| Body Diameter | 46mm (1.811 in) |
| Piston Rod Diameter | 22mm (0.866 in) |
| Extended Length | 19.00 in (482.6mm) |
| Collapsed Length | 13.00 in (330.2mm), without bump stop |
| Travel | 6.00 in |
| Valving | Compression 1000 at 0.52 m/s, Rebound 2550 at 0.52 m/s |
| Nitrogen Charge | 200 PSIG |
| Mount Type | Eyelet to Eyelet |
| Upper Mount | Eyelet 1/2 in ID x 1.5 in with 5/8 in bearing |
| Lower Mount | Eyelet 1/2 in ID x 1.5 in with 5/8 in bearing |
| Internal Design | Monotube |
| Reservoir | Yes, Remote, Steel |
| Reservoir Hose | Size-8 High-Temperature Hose |
| Finish | Zinc Plated, Silver |
| Rebuildable | Yes, Owner Rebuildable and Revalvable |
| Fitment | Universal, Custom Coilover Application |
| Warranty | Bilstein 90-Day Limited Warranty |
| UPC | 651860755748 |
What's Included
- 1x Bilstein 33-225487 B8 8125 coilover shock absorber with remote reservoir
- Bilstein sticker
Installation Notes
The 33-225487 is a universal application coilover shock for custom off-road suspension builds. Spring seats and bump stops are sold separately and must be selected for the specific coilover spring diameter and rate being used. The 1/2-inch ID eyelet inserts accept up to a 5/8-inch bolt when the included reducer is removed, though Bilstein notes this may reduce flex in certain configurations. Builders should verify shock stroke and mounting dimensions match the suspension geometry of the specific application before purchase. Professional installation is recommended for custom competition suspensions.
Frequently Asked Questions
What is the Bilstein 33-225487 designed for?
The 33-225487 is a competition-level B8 8125 Series coilover shock designed for custom off-road suspension applications. It is not a vehicle-specific replacement but a universal coilover shock chosen by stroke length and valving for custom builds including rock crawlers, prerunners, sand cars, and purpose-built off-road competition vehicles.
What is the travel on the 33-225487?
The 33-225487 provides 6 inches of travel with a 19-inch extended length and 13-inch collapsed length without a bump stop installed.
Is the 33-225487 rebuildable?
Yes. The B8 8125 Series is fully owner rebuildable and revalvable. All components are billet machined with no cast parts, and the shock can be disassembled, rebuilt, and revalved in the field. This is a key advantage for serious off-road competitors who need to service or retune damping between events.
Does the 33-225487 come with spring seats?
Spring seats are not included with the 33-225487. They must be purchased separately and matched to the specific coilover spring diameter and rate being used. The optional Bilstein reservoir clamp (B4-KT1-Z315A00) is also available separately for a cleaner reservoir installation.
What bolt size does the 33-225487 use?
The 33-225487 uses 1/2-inch ID eyelet inserts with 5/8-inch bearings on both ends. The 1/2-inch insert can be removed to accept up to a 5/8-inch bolt, though Bilstein notes this may reduce flex in the joint.
How does the dual-rate coilover hardware work?
The threaded body with dual-rate coilover hardware allows the use of two springs in series on the coilover. The softer primary spring engages first for a compliant ride over small obstacles, while the stiffer secondary spring engages once the primary is fully compressed, providing progressive resistance during large suspension events. Preload and transition point can be adjusted by repositioning the threaded spring seats.
What is the warranty on the Bilstein 33-225487?
The 33-225487 is covered by a Bilstein 90-day limited warranty. Note this is a shorter warranty period than Bilstein's street shock absorbers, as the 8125 Series is designed for competition use. As a suspension component, the Magnuson-Moss Warranty Act provides federal consumer protections regarding warranty coverage on other vehicle components.
WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information visit www.P65Warnings.ca.gov.
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