Published 1 November 2026 · OFM4x4.co.uk

A steel bumper, winch or drawer system changes the vehicle every day. Weekend camping equipment does not. That difference matters more to spring choice than the desired lift height alone.

The quick answer

Choose the spring application for the measured, regularly carried load and the exact vehicle. A heavy-duty spring fitted to a normally empty vehicle can produce a harsh ride; a comfort spring cannot be expected to support a permanent build.


Separate fixed from occasional weight

List the bumper, winch, battery, drawers and other fixed parts by axle. Add passengers, water and luggage separately because they change between journeys. A gross vehicle weight figure alone hides how the two axles share the load.


Compare the manufacturer's applications

Ironman 4x4 describes comfort and constant-load spring options for different uses. Check the part number, vehicle generation and front or rear rating in the current application guide. Do not substitute a visually similar spring from another model.


Check the complete suspension

Spring selection changes ride height and working position. Confirm the matching damper, bump stop, brake hose and alignment requirements for the kit. A lift is not an increase in the vehicle's permitted gross or axle weights.


Review the vehicle after fitting

Measure from a fixed point on each side with tyres correctly inflated and the intended normal load aboard. Record the baseline and ask the installer to check alignment and fasteners to the kit instructions. Reassess if permanent equipment is added later.


Specification checklist

Before ordering or booking work, have these details ready: Vehicle year, exact variant, axle loads when practical, existing kit part numbers, and a list of fixed and occasional accessories.


Frequently asked questions

Will a heavy-load spring increase legal payload?

No. Spring support does not by itself change the manufacturer's permitted vehicle or axle weight limits.

For an application check, contact OFM4x4.co.uk with the vehicle and component details above. Confirm the current fitting instructions for the exact product before work starts.

Technical reference: www.ironman4x4.com. The relevant product manual takes priority over general guidance.