Dial In Preload on Large Bore Coilovers
The Fox Spanner Preload Wrench – Large Bore, part number 398-00-370, is a service tool built to adjust the threaded spring collar on Fox 2.0 diameter coilover shocks. Made from zinc-plated steel, it gives you the leverage needed to turn the collar for setting spring preload or acting as a backup jam nut wrench, without relying on makeshift tools that can slip and damage the collar’s notches.
Key Features
- Purpose-built to engage the collar notches on Fox 2.0 diameter coilover shocks
- Zinc-plated steel construction resists corrosion in shop and trail use
- Provides leverage for preload adjustment or use as a backup spanner
- Compact size for storage in a tool bag or trail kit
Fitment
| Year Range | Make | Model | Notes |
|---|---|---|---|
| Universal | Universal | Fox 2.0 diameter coilover shocks | Does not fit Fox 2.0 OEM-fit coilovers |
Specifications
| Detail | Value |
|---|---|
| MPN | 398-00-370 |
| Tool Type | Spanner preload wrench |
| Compatible Shock Diameter | 2.0 in (large bore) |
| Material | Zinc-plated steel |
What’s Included
- 1 spanner preload wrench
About FOX
Fox Factory designs and manufactures performance suspension products and the service tools that support them, supplying coilover shocks and related setup tools used across off-road, overland, and racing applications.
FAQ
What is the 398-00-370?
It is the manufacturer part number for the Fox Spanner Preload Wrench built for large bore 2.0 diameter coilover shocks.
Which shocks does this wrench fit?
It is sized for Fox 2.0 diameter coilover shocks and is not intended for a specific vehicle application.
Will this fit Fox 2.0 OEM-fit coilovers?
No. This wrench does not work on Fox 2.0 inch OEM-fit coilovers.
What is this tool used for?
It is used to turn the threaded spring collar on a coilover shock to set spring preload, and it can also serve as a backup jam nut wrench.
What material is the wrench made from?
It is made from zinc-plated steel for corrosion resistance.
Do I need this tool for every coilover install?
Any time you need to adjust spring preload or lock a jam nut on a compatible 2.0 diameter coilover, a spanner wrench like this makes the job easier and reduces the risk of slipping and damaging the collar.
Can this wrench be used on other brands of coilovers?
It is designed and sold as a Fox-branded tool for Fox 2.0 diameter coilovers; compatibility with other brands’ collars is not confirmed by Fox.
Does this product carry a California Prop 65 warning?
Yes, see the Prop 65 notice below.
Install Instructions
- Confirm the coilover shock uses a 2.0 diameter threaded spring collar compatible with this wrench.
- Engage the wrench’s tabs into the notches on the spring collar.
- Turn the wrench to raise or lower the collar and set the desired spring preload.
- If using as a backup wrench, hold the lower collar steady with this tool while tightening the upper jam nut against it.
Prop 65 Warning
This product can expose you to chemicals known to the State of California to cause cancer or reproductive harm. For more information, visit P65Warnings.ca.gov.
