Suspension Development Update

Last week we posted an article about suspension development in modern hillclimb cars.

Dallara F301

Traditional front push-rod suspension on Dallara F301

 

This post seems to have generated a bit of interest, and a couple of my questions have been answered by some guys who really ought to know what they are talking about!!

Empire Racing Cars boss Bill Chaplin dropped me a line to remind me that:

“Simon Fidoe’s Empire has pull-rod rear suspension and so does my Empire Force DS600.”

 

Then we received word from former double British Hillclimb Champion and the builder of the stunning GWR Predator and GWR Raptor:

“Pull-rods can be tricky to get good rising rate compared to push-rods, we went to push-rods at the rear for the Raptor so as help maximise space for the floor.”

Graeme also sent over this fantastic shot of the lovely front pull-rod monoshock installation on the Raptor.

GWR Raptor

 

Driver of the hairy Westfield-Hayabusa turbo, McLaren F1 team employee and (of more interest in this context) ex. Xtrac Transmissions Engineer Piers Thynne added:

“Pull rod rears are unlikely to be seen on a ‘big hillclimb car’ as the rockers and dampers would essentially be required to be packaged very tightly into a bellhousing/gearbox.

I believe it is simply not viable on cost grounds to develop such a transmission and to package it.

The performance benefits you would get from this as you stated may increase the length of the transmission from engine mounting face to where it kicks up to the Final drive and output which would effect the aero performance.

Interesting thoughts.

One thing to add !

Its good we now see composite suspension members (GR 59) in the paddock.

Who else will follow suit?”

Gould GR59

Carbon rear push-rods on the Gould GR59

 

ADR-Suzuki Sports Car sprint driver Andy Laurence explained some of his experiences with the circuit-based sports racer:

“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.”

 

Thanks so much for these comments, they are much appreciated and certainly help to complete the tale…

Comments

  1. Andy Barton says:

    All Other Things Being Equal,
    In Favour of Pull-Rods:
    They can be of lesser cross-sectional area [Viz the Raptor Pic.] because they do not have to resist bending moments which can result from eccentric loading imposed on push-rods.
    In Theory, Theory and Practice are the Same, In Practice they Seldom Are.

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