Tyres?

[cirvy]

I'm busy trying to spec my new tyres for the Cerbera, & i'm wanting to bias them towards track-days. You guys must spend a bit of time on track, what rubber do you use? Thanks in advance, (i'm finding this tyre thing quite bewildering!!!!!!!!)

[m12_nathan]

I use Yokohama 048R and have been very impressed with them, really good grip and very progressive break away, rubbish in standing water mind.

[DanH]

cirvy said:

I'm busy trying to spec my new tyres for the Cerbera, & i'm wanting to bias them towards track-days. You guys must spend a bit of time on track, what rubber do you use? Thanks in advance, (i'm finding this tyre thing quite bewildering!!!!!!!!)

Are you using stock dampers or nitrons etc? Makes a difference wrt to tyre choice.

[cirvy]

DanH said:

cirvy said: I'm busy trying to spec my new tyres for the Cerbera, & i'm wanting to bias them towards track-days. You guys must spend a bit of time on track, what rubber do you use? Thanks in advance, (i'm finding this tyre thing quite bewildering!!!!!!!!) Are you using stock dampers or nitrons etc? Makes a difference wrt to tyre choice.

I've got Ohlins all round.

Presently, my tyre options (from a bit of online research) seem to be the Pirelli P Zero Nero, or the Dunlop Super Sport Race. Any thoughts?

[paulcundy]

cirvy said:

I've got Ohlins all round.

Dear Cirvy,
How do you find the Ohlins?
Regards
Paul C
~

[cirvy]

paulcundy said:

cirvy said: I've got Ohlins all round. Dear Cirvy, How do you find the Ohlins? Regards Paul C ~

Ohlins very good, they DO make a difference, especially as wtih my car, the original equipment is quite poor!

They are a service item though & i think its getting harder to find service agents!

[m12_nathan]

Super sport race are supposed to be very good, even in the rain.

[DanH]

Noble recommend Pirelli P-Zero Rosso Corsas for track usage. They are stock fit on the M400. Not entirely sure how they compare to AO48s although I'm under the impression the factory prefer them.

You need a fairly stiff setup to take advantage of the grip given by either type. Especially since they could cause you to hit the bump stops on a soft setup which isn't going to be fun.

[m12_nathan]

And this is with 650lb springs:



We need to find a way of getting negative camber!

[DanH]

Nothing wrong with the springs mate, just a fat driver!

p.s. there is some negative camber already, just not enough.

Per wheel Across axle Deg’s across
axle
Front Toe (OUT) .078” .157” 0.50 (30 minutes)

Rear Toe (IN) .118” .236” 0.75 (45 minutes)

Degrees
Front Camber (Negative) -.50 + -.25 Non adjustable
Rear Camber (Negative) -.50 + -.25 Non adjustable

Degrees
Front Castor Angle Aprox. 10 Non adjustable


Of course you could just machine down some parts, or the race car had shims jammed in IIRC?

Or even buy the cundy style adjustable setup thats been fabricated up.

>> Edited by DanH on Wednesday 16th February 13:36

>> Edited by DanH on Wednesday 16th February 13:38

[jmg944t]

Is that correct, no camber adjustment? I am not suggesting that it isn't true just that it is amazing a performance car would be designed without it. My track tires require 2-2.5 degrees of camber and they only last about 90 minutes of track time at .5 degree's. If there is a kit out there where can we have a look?

[m12_nathan]

That is correct

[DanH]

jmg944t said:

Is that correct, no camber adjustment? I am not suggesting that it isn't true just that it is amazing a performance car would be designed without it. My track tires require 2-2.5 degrees of camber and they only last about 90 minutes of track time at .5 degree's. If there is a kit out there where can we have a look?

Yeah I think its a bit crap too. Paul C has had some adjustable bits made up I think, but dunno how well its all worked out nor the cost.

Apparently you can shim certain parts, but not quite sure where/how.

[V6GTO]

I think Lee thinks it is at the optimum angle and therefore doesn't need adjustments!

Martin.

[DanH]

V6GTO said:

I think Lee thinks it is at the optimum angle and therefore doesn't need adjustments! Martin.

It probably is until you start screwing around with tyres and dampers...

[m12_nathan]

Now now Martin

Daniel is probably correct

Spoke to the factory about this today, the later cars now have more neg camber at the rear. I can see where the inside 2" or so of my rear tyres isn't being used as well as verifying it with a pyrometer (outer 2/3 of tyre is much hotter than inside).

Interestingly the later cars also have their steering racks higher up as well, presumably some kind of bump steer change?

[DanH]

Interesting about the bump steer change as Glover was blobing about that on one of the North Weald corners. Wonder if its a trivial retrofit...

[V6GTO]

m12_nathan said:

Interestingly the later cars also have their steering racks higher up as well, presumably some kind of bump steer change?

Don't know about that,Nathan, but I've never had to do a 5 point turn

Martin.

[DanH]

V6GTO said:

m12_nathan said: Interestingly the later cars also have their steering racks higher up as well, presumably some kind of bump steer change? Don't know about that,Nathan, but I've never had to do a 5 point turn Martin.

Hmm only ever got to 4 I think. It turns ok when going backwards!

[turbocup]

I always thought that negative camber would result in more wear on the inside of the tyre.i.e bottom of tyre further out than top.Am I confused?