Harry I do have to say I am not completely sold on the RCA/bump spacers and may well pull them back off the car. As for skinning cats, I've said it before but I always marvel at how drivers from amateurs to pros can use polar opposite set ups in the same car and end up with near identical lap times.

Dave on the Avon ACB 9s (bias ply) I can turn them purple in three sessions; the rears get this look like they've been trimmed on a wood lathe, basically the rubber is sloughed of inside to outside, they are not blistered but as they are for Formula Fords and Spridgets my car at 1800lbs may be a bridge to far. Also the side walls are a bit tall 21.6 versus the 20.6 of the Hoosiers, the backend of the car hangs out much more with the Avons, adding to the rear tire peeling, it may impress the spectators and be fun but in the end I decided to bite the bullet and buy the Hoosiers. Background; I was using Hoosier take offs but they were getting hard to get used so I tried the Avons. The Avons run me $330 mounted versus $810 for brand new Hoosiers. For track days it's a who care if the tires go off a second or two but for vintages races the car is capable of top 5 so keeping fresh used tires on the car would mean 2-3 sets a year versus 1 set of Hoosiers every 10 months........so my point of bringing all this up is ditch the Dunlops and go to what works for your set up.

As for spring rates, I prefer a touch soft (sort of like me brain) as I pound over the curbs and just feel the extra compliance is part of how I manage to get more corner speed out of the car than most drivers.

Back to the moving steering knuckle; any chance the pad knock back is related?? I have never encountered that unless the rotors had an issue. Keep us posted.

Tom

pad knock-off can be caused by warped discs, hub run-out, bad wheelbearing or stub axle flex. The tie-rod to wheel interference is probably a combination of play in the tie-rod, ball joint and wheelbearing and stub axle and streering arm flex...

Hi Harry,
You are right on the money.My "eyeometer" was slightly out and on closer inspection the gap between the steering ball joints and the edge of the mag lip is around 3/5mm.
So I suspect some stub axle flex, amplified by the time it is extended out to the outer rim and possibly some play in the ball joints of the steering are to blame.
This also probably explains why my brakes are experiencing knock off- the small amount of stub axle flex, again amplified as it extends further out towards the edge of the rim and with the Wilwoods taking a fair amount of fluid relative to the single acting Toyota caliper that I used to use, the master cylinder simply cannot move enough fluid in 1 pedal movement to completely refill them.
Tom- what are your reservations on the rca's?
Looking closely at the Dunlops- I am even more convinced they are simply not up to the job- heat cracks inside all the treads on all 4 wheels. Something I have never seen before.
Anyway I've got some 275lb springs to try and I'll go visit my springmaker next week to sort out how many ( or what sort of ) leaf/s in the rear will be required to balance the increased front rate.
Cheers
Dave

Dave on the RCAs I don't have anything really tangible; mostly I'm not crazy about how the bolt together i.e. you have two mating surfaces versus one. As for the actual function the ones I have don't seem to make a huge difference in the position of the control arm, granted it changes the geometry.

Tom

Hi Tom,
Thanks for your reply.
Do you know how thick your rca's are?
I have a feeling mine are 35mm. The option is always there to shave enough off them to get that steering ball joint away from the edge of the wheel.
Cheers
Dave

I checked mine and they are 35mm.

Tom

Thanks Tom, and you are obviously having no issues with the steering ball joints hitting the inner edge of the wheel. Back to the drawing board....
Cheers
Dave