Rock 'n' Rollers: Suspense Again

The Roller Mount as installed. Picture: J.J.Hildreth

Silentblocs™ and rubber are, as I remarked earlier in this little series, an effective solution to many production and geometrical problems. And they are cheap. Rubber can be extremely effective as a suspension medium as in the original Mini, but in other places it is not quite so good.

One of rubber’s properties is hysteresis, but in our optimised suspension we would like to see unrestricted movement so that the road wheels, springs and dampers can all work effectively together without winding and unwinding pieces of rubber.

This brings me to the famous connection between the upper wishbones and the front spring. I have already drawn your attention to the rather nasty goings-on that must occur when the suspension is working. It was of course the works that originally attacked this problem. They used a roller (actually a lower suspension pin) mounted in a simple steel fixture that was bolted to the upper wishbone. There is plenty of pre-load in the Fulvia’s set-up so the spring is always in contact with the roller and with the freedom of movement (i.e. without the interference of the rubber) the suspension works much more effectively.

I never liked the rubber installation, and had been studying the transverse spring installation on a FIAT 130TC as a possible solution. It was at that time that I read somewhere that the works used a roller arrangement, but I was unable to find a picture of it. At the very next Surrey meeting of the Lancia Motor Club, I mentioned the idea to Doug Ellis (who owns a magnificent SI 1.3S) and we discussed the likely improvements that might result. The following month Doug turned up as usual and placed in my hands an exquisite piece of machining: a superbly finished aluminium mount fitted with a Nylatron roller running on a stainless steel pin. “Something you were talking about” he said. Neither Doug’s nor my car were running at the time so it was Justin (he has the Kugelfischer car I have written about here) who was the guinea pig. He reported a distinct improvement in handling, notably turn-in.

Unfortunately, the Nylatron roller soon wore out, the load from the spring being too much. Doug of course came up with the solution: a pair of ball races together with hardened steel pads that bolt to the spring. The system has been totally reliable: I have covered over 40,000 miles on mine and I still have the original ball races fitted. Doug wrote up the story in Viva Lancia (the LMC magazine not the web site) in 2006.

Justin has made drawings of the units, which I reproduce here. I have to say that I should think that they would be expensive to make. The Factory version would be much cheaper to fabricate – there is a photograph in Carlo Stella’s Zagato book for those who would prefer to take this route. A nice feature of the works design is that with rallying in mind, the mounts were designed to provide two height settings.

À bientôt