Rear Suspension

Again, the lever arm dampers are replaced with a telescopic kit, half the price of a new one on eBay. This was an early conversion and looking back, I could have built it from scratch as well. Some people swear by the lever arms, but I found that the telescopic rears gave the single biggest improvement to the handling of the car. 10 years on, that’s probably still true!

The dampers are not mounted vertically, and a future job is to try some vertical ones to see if they are different. The dampers also seem to help with the rear axle location, and have eliminated the rear axle ‘skippyness’ that was present before. Axle tramp is only an issue if driven really hard in the wet, but a Panhard rod/ location device is also in the pipeline.

Since going K series, the dampers are still on.  The harder it gets driven, the more tyre movement appears.  This got to a point where the tyres were contacting on the leaf spring clamps – quite surprising seeing as there’s about 1/2 an inch between the tyre and the spring! Due to the front end improvements with the negative camber wishbones, the cornering speed went up rather, meaning that this became more of an issue. With the change to 14 inch wheels and 185 tyres, this became more of an issue on the first road based blast in the dry.  Further investigation revealed that it was a combination of tyre flex and the axle moving relative to the body.  There are a couple of options to combat this, a Panhard rod, a Watt linkage, a Mumford link, or driving slower.  Seeing as the last option’s not going to happen, I picked up a second hand Mumford link (which Frontline retail as their RTL) from someone who was having the ultimate in rear ends built – a 6 link coil over Ford based rear from Will Corry in Ireland.

Once the RTL was fitted (this took quite a bit of fettling, the boot floor is not all that strong, and I needed to mess about with the handbrake rods quite a lot to get them to miss the arms, I don’t have any tyre catching any more and the axle stays in the same place (not in the middle, because none of these cars have the axle in the middle!).  Under normal driving you can’t tell the RTL is there.  When the road gets rough and rapid cornering arrives though, you can feel it keeping everything in line. It’s not intrusive, and it has stopped squirming under full bore upshifts; previously it was possible to change lanes on a flat out 2nd to 3rd gearchange without any steering input as the springs wound up. A definite recommendation, but it’s an expensive one if buying full price.  A Panhard does the same job for a fraction of the price, but introduces some sideways movement into the rear by it’s design.

Check out the rear axle page for more details, but there’s an LSD and harder half shafts in there now, meaning I can set off more smartly without risking breaking things quite so much any more. This has introduced a bucketload of axle tramp as the springs wind up, so I’ve built some radius arms that are copied from the Frogeye locations.  I couldn’t find a satisfactory geometry mounting the tramp bars under the axle as bought ones do – they fight the springs to some extent, and really reduce the ground clearance under the springs.  these have to be in the right place or they will bind up – there’s one point where they don’t.

They have to have a crank in the arm to clear the axle on full bump; they also pick up on the RTL mount which I had issues with: it kept coming loose as the only way it joins to the car is by an unsatisfactory clamp on the bump stop – the rear mount of my radius arm picks up the RTL mount and anchors it very securely.  The front mount joins to the old leaver arm damper mounting point.

These arms have massively reduced axle tramp.  There is no appreciable difference in the way that the car drives except on flat out acceleration, which is much improved.  There’s a rose joint on one end of the arm to allow axle roll, the other end uses a set of original Midget rear spring shackle rubber bushes.  Instead of tramp, I get a small chatter from the LSD and an instant launch to very fast very quickly.  There also seems to be a reduction in squat, looking at the design of these arms I appear to have built quite a bit of anti-squat into the rear suspension too.  Though it might just be the fact that the springs don’t wind up any more keeping the back higher than it used to be.