DDK - Die Deutschen Klassiker

Hi all,

I'm just mulling over some options for 2014 race outings, and the HSCC Guards Trophy series looks interesting. I'm only able to get out a couple of times each year so the longer format of the races are attractive, simply to get as much track time as possible when I do get the chance.

That series has the Dunlop CR range as it's control tyres (which are Cross Ply). I'm wondering if there are any general rules or guidelines to follow when chopping and changing between the different tyre structures, to get them to work optimally?

The Dunlop CR's are "for competition only' so I would plan to carry on running my current Avon radials on the road.

I would be most interested to hear your thoughts and experiences.

Cheers
Rob.

Me to! no expert on crossply myself, but I belive thy`r not that sensitive to camber as the sidevals flex more than on a radial.
Most intrested in other racers experience!

I have a limited experience in tyre choices, so take this as you will:

Geometry:

Radial road or racing tyres can take a far greater level of negative camber, I ran my Impreza and 911 on hillclimbs for 13 years with max neg camber, -3.5 deg on the Impreza.

For crossply slicks i had to deduce the neg camber to -1 deg rear and -1.5 on the front on the Impreza.
Both cars ran max castor.
I left toe the same.
Crossply construction will not tolerate high camber levels.Side walls are very stiff.

I noticed no difference to the driving of the car except it was much faster track times (about 3 sec on a 50 second hill).
The Impreza was a road registered car on Kumho V70 radials and it drove well on the road, changed to slick at the hill then back to go home.

Driving:

The radial Kumho had remarkable grip in wet or dry (soft compound) but would get sketchy closing to the grip limit.
The crossply slicks (Avons) had far greater grip as you would expect, and very progressive behaviour at the limit and beyond.

Braking was unaffected.

I now hillclimb a real racing car, a Lola, and this is on Avon crossply, recommended because of their progressive characteristics by the supplier, BMTR.

HTH

Graham.

911 on Kumho V70 radials, car set-up by Bob Watson

I know you're not mixing them but is just reminded me of this public safety film
http://www.youtube.com/watch?v=c23MFIKiVdE

we're running the Dunlop Racing L and M on the 356 (check out the race car thread on the 356 forum). wet weather grip is severely reduced and the slip angle greatly increased in both wet and dry conditions (i.e. the car will adopt a drift if you even think about changing direction!). Tyres generate grip only when warmed up. having said all this, they are a lovely tyre, producing a lovely predictability to the handling. we're running 3 degrees negative camber at the rear, fairly neutral at the front. toe is set to zero I think. handling of the car is more affected by damper and roll bar set ups than anything. they take some getting used to if you've been used to a radial road tyre with a low profile, but they are a whole lot of fun once you realise that the slip angle just starts early and provides a great opportunity for drifting hope that helps.