Reading Slicks.

[JustenGT8]

Hmm hard to say...by the scrub marks on the slick sidewall the front compresses approx 50-60mm max?

[rms]

Quite soft.

Here are some settings from a certain 'works' taxi earlier this year on Dunlops.

Front
715lb/in, 1 1/8 x .156 bar, 6.2deg neg camber, 15mm droop, 1.5mm toe out.

Rear
290lb/in, 1 1/8 x .120 bar, 2.5 deg neg camber, droop ???, 2.0mm toe in

[JustenGT8]

Ok the mega spin at the end of the day hasn't done the diagnostics any good as pretty well cleaned the tyre faces

Left front still shows som,e signs of the tyre of wear though and that's the main tyre of concern.





so what psi were thry running Erol?

[Rodger]

empty, pushed button before finishing.

[Rodger]

Justen,

I was in Capital Steering checking on progress of work on my Konis and asked the question.

I know you have done a lot of work both front and rear and it is rear wheel drive, but I still reckon more castor is the go.

Anyway for the record, from the files, a Factory spec ST185R 4x4 Turbo, on 6.5Jx15 215/50R 15/88 wheels and tyres at 2.1bar:

Front axle
Total toe 0.00 degree

Half toe
LH +0.00 +- 0.16 degree
RH +0.00 +- 0.16 degree

Camber
LH -0.17 +- 0.75 degree
RH -0.17 +- 0.75 degree

Castor
LH +1.00 +- 0.75 degree
RH +1.00 +- 0.75 degree

King-pin Angle
LH +14.17 +- 0.50 degree
RH +14.17 +- 0.50 degree

Rear Axle

Total toe +0.40 degree

Half Toe
LH +0.20 +- 0.08 degree
RH +0.20 +- 0.08 degree

Camber
LH -0.75 +- 0.50 degree
RH -0.75 +- 0.50 degree

Maybe worth talking to Peter about the tyre issue and to see what can be changed.

It is a great thread as there is plenty of reference material to help all of us.

Regards

Rodger

[JustenGT8]

I guess i need to confirm what the tyre is showing 1st...Fish?

My specs are

Front:
Camber: -2.5 deg
Toe: zero
Caster: factory is assume?

Rear
camber: -1.5 deg
toe: 1.5mm toe in a side (dunno what the conversion to deg is?)

[OnAll-FOUR]

does + toe on the rear = toe out (the tyres are wider at the front edge and narrower at the rear)?

Interesting if that is how they come stock.

[Billzilla]

Nearly forgot to mention that old slicks are usually crap - That's why they're either given away or sold really cheaply. You might get some useful data off them, but if you really want to learn about how to make them work, you need new ones.
It's expensive, but once you throw some new rubber on you won't believe the difference.

[Rodger]

I am not sure 100% but +toe is toe out. I should have asked. Just the way the measurements are given in degrees and not mm for toe.

From those pics I'd say at some point in their life they were run at too high a pressure as they have no wear indicator dimples in the middle third of the tread but have worn evenly on each side as the dimples are around the same depth.

Regards

Rodger

[JustenGT8]

Nearly forgot to mention that old slicks are usually crap - That's why they're either given away or sold really cheaply. You might get some useful data off them, but if you really want to learn about how to make them work, you need new ones.
It's expensive, but once you throw some new rubber on you won't believe the difference.

I got these set from a decent source but yeah not a patch on a set of new tyres. new is a bit steep for what is really just a bit of fun....maybe once i'm consistent and reckon i have the car well sorted i'll lash out to see what it can do? I'd better have that 'real' race driver there that day too

[Fish]

looks good on the inner but the middle looks like it not even contacting the ground.

could be from the shoulder being worn away and then switched.

give it some more castor.

how does the wheel look goind around corners?

[Rodger]

Well there you go. Two complete opposite readings of the centre of the tread.

Are there any dimples under (if) any rubber build up in the centre of the tread?

Regards

Rodger

[Fish]

i reckon rodger we need more photo's

the light reflecting of the tyre is a bit of a pain...

i always thought toe out is postive measurements and toe in was negative.

some people tell me some toe out is good and i ahve never tried it but some also say some toe in on the rear helps - but i have never tried it.

[oldcorollas]

go-pro pointing at tyre next time you head out? (maybe with perspex shield?)

[JustenGT8]

Hmmm OK so inside looks alright then...surely not too much neg camber?

arrrgh, for the last time I CAN"T CHANGE CASTOR!!!!!

Centre tread has no wear indicators they are just in pairs on the outside 3rd of the tyre. Centre wear is fine, nothing weird there.

The 'clean' tyre face looks just like the pic of Ed's tyres.