Hillclimb Suspension Development

Over the years the British Hillclimb scene has seen a huge amount of technical innovation, in particular (traditionally) in the area of suspension and steering.

Will Hall Force WH

Traditional, but highly effective pushrod/monoshock set-up on the Force WH

 

From the early days of the BHC when ERAs used clever radius arms in conjunction with leaf springs to generate immense traction, through the transverse leaf-springs of the early Coopers, to wishbones with the 1960s mid-engined cars we’ve seen it all… Or have we?

The current suspension trend of choice in professional motorsport is the pullrod. Red Bull Racing started the modern trend for this method of suspending the car with the rear geometry of it’s 2009 F1 car, and has since been followed by Ferrari in F1 (with pullrod front and rear) and by Audi (pullrod rear) on their R18 in ACO Rules racing (Le Mans, WEC, etc.).

Audi R18 E-Tron Quattro

Pullrod rear suspension on the Le Mans winning Audi R18 E-Tron Quattro

 

The main benefits of a pullrod system is that you can get all of the weight of the rockers, dampers, and springs mounted much lower in the car than with a pushrod system.

Pullrod suspension has been seen in hillclimbing of course, and was a favourite of suspension guru Mike Pilbeam with pullrods featuring front and rear on the all-conquering Pilbeam MP58, and it is even seen today on the front of the GWR Raptor by way of it’s very clever pullrod monoshock system.

Martyn Griffiths Pilbeam MP58

Pullrods all-round for Martyn Griffiths’ Pilbeam MP58 (thanks to Steve Wilkinson)

 

However, it is never seen on the rear of a modern Speed Event car. Why is this?

Is it because the damper, spring, rockers, etc would encroach too much on valuable venturi space in such a open-aero formula? Is it because of the complexity of such a system to develop and set up? Is it because everyone is following the leader at the moment and Gould haven’t done it (surely not!)?

Gould GR59

Pushrod front end on the Gould GR95

 

Is there anyone cleverer than me (don’t all jump at once!) out there that could shed some light on this?

Comments

  1. I know the limitation for the diffuser on my ADR is currently limited by the height of the lower wishbones and they’re always going to be lower than the pushrod. With a pullrod, then the rockers and dampers need to sit below, beside or behind the gearbox, which will always encroach on the diffuser unless they can be sited high enough to be above the lower wishbone. I’d suggest that working out these complexities vs the simplicity of placing the rockers above the gearbox are the reason why we don’t see it. In F1, they have the space because the diffuser size is limited by regulation.

  2. Phil says:

    My uneducated guess would be aerodynamics. If i remember correctly when Brawn used the double diffuser that helped Button to the title, Red Bull could not replicate it due to the pull rod rear suspension. As hill climb cars can still run full ground effect diffusers if they wish to, it makes me think that maybee a pull rod lay out would take up too much diffuser room, and a pull rod running through the diffuser would disturb airflow more than a push rod above it. Just my thoughts. Hopefully some of those clever techy guys will give a better answer.

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