Powerflex Road Series PFF5-1901G Caster Adjustable Front Radius Arm to Chassis Polyurethane Bushes for BMW 1 Series F20 F21 (Front Control Arm/Wishbone Rear) Pair

Transform the front end of your BMW 1 Series F20 F21 with Powerflex PFF5-1901G caster-adjustable polybushes. This precision bush kit replaces the factory rubber in the rear position of the front lower arm, delivering crisper turn-in, rock-steady braking and more confident high-speed tracking. We run these in-house at MJ Modifications and the feedback from owners is outstanding for fast road and track-day use while remaining daily-drive friendly.

What you get

• Part number: PFF5-1901G
• Position: Front lower arm rear pivot - often called tension strut bush, radius rod bush, wishbone rear bush, control arm rear bush
• Adjustment: On-car caster correction up to ±0.75 degree for precise geometry
• Material: Powerflex Road Series polyurethane - around 60 percent stiffer than OE rubber for durability without harshness
• Quantity: Supplied as a pair
• Diagram reference: 1
• Warranty: Lifetime Warranty
• Fitment: BMW 1 Series F20, F21

Why upgrade

Ageing OEM bushes allow unwanted compliance that dulls steering and upsets stability. PFF5-1901G uses a stiffer, resilient polyurethane with an offset sleeve so you can dial in extra caster. The result is stronger self-centring, improved straight-line stability, enhanced camber gain on turn and a more consistent contact patch under braking and cornering.

Real-world benefits

• Faster steering response and cleaner feedback through the wheel
• Added front-end bite from increased dynamic camber on turn-in
• Reduced tramlining and better stability under heavy braking
• More even tyre wear and improved road holding
• Long-lasting performance compared with soft rubber bushings

Common issues this kit addresses

• Vague steering and wander
• Uneven or rapid front tyre wear
• Brake shimmy and instability

Prefer a fixed-geometry option with no caster adjustment? Choose PFF5-1901.

Cross-references

OE numbers for search and comparison: 31126855743 / 31126855741 / 31126855742

Installation and alignment

Professional fitting and a proper alignment are strongly recommended to set caster accurately. Book expert installation with MJ Modifications in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Trusted by enthusiasts

We have installed this kit on multiple F20 and F21 cars and owners consistently report sharper handling with minimal change in NVH. Backed by Powerflex’s Lifetime Warranty for peace of mind.

Search-friendly terms

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