Flatout Rally Suspension Buyer’s Guide

Sep 4th 2025

Flatout Rally Suspension Buyer’s Guide – GR40 vs. GR40R vs. GR40-PRO vs. GR50 vs. GR50-PRO

When it comes to rally, rallycross, and motorsport suspension, one size doesn’t fit all. That’s why Flatout Suspension offers a complete lineup of coilover systems designed to meet the demands of grassroots racers, weekend warriors, and professional teams alike.

This guide will walk you through the differences between our GR40, GR40R, GR40-PRO, GR50, and GR50-PRO coilovers, so you can choose the right suspension for your build.

A Note on Ride Height & Applications

Most of our rally-focused coilovers are designed for 0–2 inches of ride height adjustability. While the systems can go higher, we strongly recommend setting your suspension to around +1 inch over stock. This provides the best balance of clearance and handling stability for rally and mixed-surface racing.

Also, while you may only see limited listings for certain applications, don’t hesitate to reach out through our [Contact Page] — we may be able to build a suspension for your specific vehicle.

GR40 – Proven Rally Coilovers

What It Is: The base rally coilover, designed with inverted shocks and bypass piston valving for reliable rally and rallycross performance.
Adjustability: 1-way rebound.
Ride Height: 0–2” adjustable (recommended +1”).
Best For: Grassroots rallycross, stage rally beginners, and budget-minded competitors who still need real rally suspension strength.

Great entry point into Flatout’s rally lineup.

GR40R – GR40 with External Reservoirs

What It Adds: External reservoirs on all four shocks for greater oil capacity, cooler temps, and fade-free performance.
Adjustability: 1-way rebound.
Ride Height: 0–2” adjustable (recommended +1”).
Best For: Racers running longer events or rougher conditions where damper fade is a concern.

Step up from GR40 when endurance is a priority.

GR40-PRO – Professional Rally Upgrade

What It Adds: Reservoirs with high & low speed compression adjustments, reinforced components, and pro-level tuning options for serious competition.
Adjustability: More advanced than GR40/GR40R with rebound and compression tuning.
Ride Height: 0–2” adjustable (recommended +1”).
Best For: Competitors looking for a professional-grade suspension at a lighter package and lower cost than the flagship GR50.

Perfect balance of performance and value for serious rally drivers.

GR50 – Flagship Heavy-Duty Rally Coilovers

What It Adds: 50mm inverted dampers inside 62mm threaded housings for unmatched strength and rigidity. External reservoirs included.
Adjustability: 1-way rebound damping adjustment.
Ride Height: 0–2” adjustable (recommended +1”).
Best For: Stage rally competitors and heavy builds that demand nearly indestructible coilovers.

Built for the harshest rally conditions and aggressive competition use.

GR50-PRO – The Ultimate Rally Suspension

What It Adds: Everything the GR50 offers plus expanded external reservoir capacity and pro-level multi-way damping refinement.
Adjustability: Fully independent rebound and high & low speed compression adjustments.
Ride Height: 0–2” adjustable (recommended +1”).
Best For: Professional rally, rallycross, and motorsport teams looking for flagship-level durability, precision, and tunability.

The strongest, most tunable rally suspension Flatout offers.

Which Suspension Is Right for You?

Grassroots/Weekend Rallycross: GR40
Endurance Rallycross/Stage Rally: GR40R
Advanced Competition: GR40-PRO
Heavy Builds & Harsh Conditions: GR50
Professional Teams & Extreme Performance: GR50-PRO

Final Thoughts

The Flatout Suspension rally lineup is designed to meet drivers where they are — whether you’re starting out in grassroots rallycross or building a professional-level rally machine.

Remember: most kits are designed for 0–2” of lift, and we recommend setting them to +1 inch for ideal handling.
If you don’t see your exact application listed, don’t hesitate to reach out through our [Contact Page] — we may be able to build it for you.