Suspension Secrets BMW F20/21 M135i/M140i Front Offset Caster Bushes
Suspension Secrets offers a solution to transform the performance of the BMW F20 M135i/M140i front axle with their Suspension Secrets Front Offset Caster Bushes.
The standard front lower control arm bushes in the BMW F20 M135i/M140i are crafted from soft rubber. This pliable material flexes during cornering, leading to imprecise steering and understeer. The rubber’s inherent flexibility also compromises stability under hard braking.
Suspension Secrets Front Offset Caster Bushes directly address these issues while simultaneously refining suspension geometry. Unlike the original bushes, these solid caster bushes eliminate flex, ensuring the steering remains precise and communicative. This rigidity also significantly improves braking stability.
Enhanced Steering and Grip Through Optimized Caster
The offset design of these caster bushes incorporates rose joints that increase positive caster. This augmentation results in a noticeable improvement in steering feel and increased cornering grip. The enhanced grip is a direct benefit of the dynamic camber gain generated by the increased caster.
Compatibility with Caster-Adjustable Top Mounts
Suspension Secrets has also developed these bushes to assist BMW F20 M135i/M140i owners who have already installed caster-adjustable suspension top mounts. When running maximum caster, the front wheels can shift, potentially rubbing against the wheel arch liners during turns. These caster bushes can realign the front wheels within the center of the wheel arch, preventing rubbing without the need to reduce positive caster on the suspension top mount.
Key Benefits of Installing Suspension Secrets Front Offset Caster Bushes:
- Increased cornering grip and steering feel due to enhanced positive caster.
- Improved braking stability and steering accuracy.
- Enables complete control over the suspension caster angle.
- Allows the use of maximum camber on camber-adjustable top mounts without inner arch liner contact.
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TRACK READY SETUPS
Everything you need to dominate on-track. From suspension and geometry to braking solutions.
// DESIGNED & MANUFACTUERED IN THE UK
It's time to give your suspension some attention. We are delighted to be working alongside supercar alignment specialists Suspension Secrets to enhance the performance of all vehicles using the standard adjustment provided with the car. We tweak the settings to reduce understeer and “switch on” the handling capabilities of the car.
Also specialising in Porsche, Mclaren and BMW suspension systems, working extensively to develop all our setups that we apply to cars with many road and track miles testing the setups that we design.



