Riaction TPU Coilovers for 1999-2005 BMW 3-Series AWD Non-M (E46)

Product Details

These Riaction TPU coilovers fit the 1999-2005 BMW 3-Series AWD Non-M (E46).

The Riaction TPU Coilovers for the 1999-2005 BMW 3-Series AWD Non-M E46 bring Riaction's digressive damper technology to the BMW 3-Series AWD Non-M, engineered for drivers who prioritize high-speed control, flatter cornering, and sharper response than a linear coilover can deliver. Each TPU set is built-to-order so valving and spring selection are matched to your exact BMW 3-Series AWD Non-M application, with the same 32-level damping adjustment and full-length ride-height range you'd expect from the Riaction platform. For E46 owners chasing a track-focused setup without giving up street composure, this E46 coilover kit bridges the gap between daily driver and weekend warrior.

Digressive pistons give the TPU a higher initial damping rate at low shaft speeds (body roll, weight transfer) and relax over big inputs (potholes, curb strikes), so you get better control without the harshness of a stiffer linear tune. Riaction coilovers for the 1999-2005 BMW 3-Series AWD Non-M ship fully rebuildable and backed by a 2-year warranty, making the TPU a long-term investment for enthusiasts serious about their 3-Series AWD Non-M setup.

TPU Series Technology

• Digressive piston design — high control at low shaft speeds, compliant over big hits
• 32-level damping adjustment (1-Way)
• Monotube damper with seamless 52mm electroplated carbon steel body
• 44mm CNC-machined 6061 aluminum piston
• Built-to-order valving matched to vehicle and spring rate
• SAE9254 cold-wound linear main springs
• Multi-thickness valving shims for precise damper tuning
• Polyurethane oil seals and 7.5W suspension fluid
• Fully rebuildable — built to be serviced, not replaced

Features

• Full-length ride-height adjustment (preload-independent)
• 32 levels of damping adjustment
• Digressive valving for better control under load
• Front camber adjustment via pillowball top mounts
• Optional Swift Springs upgrade (sold separately)
• Built-to-order — 2-4 week lead time typical
• 2-year limited warranty

TPU vs GT1 — Which Is Right for You?

Both kits share the same 52mm monotube damper body, 32 levels of damping, full-length ride-height adjustment, and spring rates. The difference is in how the damper reacts:

The GT1 uses a linear piston — good low-speed control for body roll, turn-in, and weight transfer, with damping that follows a predictable curve through bumps. That balance makes it the right call for street, canyon, and occasional track days. The TPU runs a digressive piston that sharpens low-speed response with higher initial resistance for flatter cornering, then softens at higher shaft velocities — a blow-off behavior that relieves harshness over potholes, curbs, and expansion joints. The TPU is built for track-focused driving, autocross, and aggressive street use where you want the extra bite under load.

Short version: choose GT1 if you want the best daily-street-track balance — typically in stock and ship-ready. Choose TPU if you want tighter response under load and don't mind the lead time on a built-to-order digressive tune.

Specifications