This is ARC A10-25 Car Kit (Aluminum Chassis).
When the A10-23 was launched in 2023, detailed changes were made to boost its performance over the A10. Striving to further improve the A10 platform, ARC has been busy testing and developing new parts over the past 18 months to further increase performance. We have incorporated all these learning to deliver the new A10-25.
Performance
Despite looking similar to the A10-23, the A10-25 features key design changes to suspension geometry, lower arms, top & bottom bulkheads and motor mount.
The sum of these design changes maximizes corner speed of the A10-25 over a wider range of conditions while significantly increasing drivability.
The upper arms are now fully adjustable on the A10-25. This means both camber and caster are fully adjustable. This means that dive and squat settings on the lower arms can now be set without interfering with caster settings – something that was not possible on the R12.
The upper arms base features 2 different length bushings to allow adjustment of the upper arm in 3 different lengths. Generally, a longer upper arm will give more traction at the expense of some steering response.
The all-new suspension arm design allows even more roll center adjustments on both the inside and outside linkages.
New Suspension
For the A10-25, we have removed the traditional carbon shock towers with aluminum shock towers that connect directly to the chassis and sides of the bulkhead. This allows the shock absorber geometry to be precisely fine-tuned in smaller increments.
This design means the shock angle is no longer limited by the holes on the shock towers, with shock angle adjusted by adding or removing shims.
The new rear active shock mount allows suspension behavior to be further fine-tuned. For example, when traction is too high and rear rotation is insufficient, engaging the active suspension can increase off-power steering.
Durability
The steering block of the A10-25 is now made from 7075-T6 Aluminum. The new steering block together with the zero-play design allows all play to be removed between the steering, bearing and wheel hex adaptor.
Lastly the A10-25 features a new 5.8mm titanium lower pivot ball design for use below the steering block. The specially designed pivot ball allows an M3x4 round head screw to be installed onto the bottom of the pivot ball. This design significantly reduces the likelihood of the ball pulling out of the arm socket during accidental impact.
Low Profile Anti-Roll Bar
The anti-roll bars are located below the drive axle to further lower the CG of the car.
Adjustment of anti-roll bar tweak remains unaffected and can be performed by screwing/unscrewing the anti-roll bar ball stud.
Kevlar Transmission Pulley
Like all A10 series cars, the previously optional Kevlar transmission pulleys and diff case are standard on the A10-23. They help to reduce friction resulting in greater transmission efficiency.
New X-Low 17mm Springs
The new X-Low shock spring range offers 8 different spring rates-five linear springs from C2.5 to C2.9, along with three progressive springs C2.4-C2.7, C2.5-C2.8 and C2.6-C2.9.
All springs are color-coded for easy identification.
Easy Access Spur
The spur adaptor on the A10 is mounted on one side of the motor bulkhead, allowing easy access to the spur and belts. This allows for simple maintenance and spur replacement without removing upper deck and motor bulkhead.