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Discussion Starter #1
I have been busy so haven't posted for a while and noticed that some people had asked some questions about slicks so here goes:

Firstly very few road cars are designed to take the cornering forces that slicks generate and most of them will break wheel bearings very quickly if slicks are used on the track. The GTR however has beefed up wheel bearings which in my experience have held up well - conversely I had 309 goodwood years ago which I put slicks on at Silverstone and did in all 4 wheel bearings in half a day.

Compound - I would reccomend a relatively hard compound for the GTR as it will generate alot of energy through the tyres in understeer and braking which can make the tyres go off quite quickly if they are a soft compound. To go "off" means the rubber melts and slides across the surface, this seriously changes the handling charatristics of the car and if pushing hard is one of the main contributing factors to spinning. Also, most slicks are designed for lighter racing cars so a hard compound is nessassary to compensate.

Warming up! In the GTR this can be alot of fun. Effectively, what happens is that the front tyres warm up much much quicker than the rears due to the weight distribution of the GTR, front brake heat, and turning. As I have found out from experience if you push to hard to early the car will "snap oversteer" this is when the back end slides out without being asked and with no warning!
Drive at 10 to 2 and leave the power where it is and gently push in about 1 quarter turn of opposite lock, if slide persists put in more opposite and more power. Ironically this warms the backs up but can be difficult for the inexperienced. The best way to warm the tyres is to drive at 75% for 4 laps and where room allows weave on the straits adding full throttle for every turn. This transfers the weight over the rear wheels helping them warm evenly all round.

Bring enough fuel for the whole day as to change to road tyres just to go to the petrol station is a pain in the ass!!

Slicks will allow you to go quicker on an overall lap as they will raise your average speed at all points, a road car will roll more on them and may lift a rear wheel. Depending how you balance your car you will notice that understeer seems to be dialled out, this is not actually the case you are just driving at the same speed you would have on road tyres, go quicker and all the same stuff will start to happen as you reach the limit.

To give an example, Ford at Goodwood in my old 33 with road tyres could be taken at an indicated 138mph, 4 wheel drifting with 3 quarter throttle. With slicks I could take it absolutely flat, in a 4 wheel drift at an indicated 157mph, The slicks are generating enough mechanical grip to allow this great speed, however, at this speed things happen a lot faster so if the car breaks away I have to be 25% more decisive with my corrective action and get it right first time, therefore the commitment needed is far greater because of the greater speed which = less time to think= barrier's are coming!!

Also you can brake later as more speed can be carried through the bend.

As a way of saving road tyres I strongly reccomend them, oh and 4 will fit across the back seat of a Skyline with the rear seat belts draped across them.


Jamie.
 

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Nice one.

Informative explanation mate .

BTW I haven't forgotten to make you a copy of you at Donnington doing 4 wheel drifts in the wet in front of me at 80/90 mph . I was wondering whether it might be possible to put it on the site . Joss ? (It's currently on Hi 8mm )
 

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Discussion Starter #3
I forgot about that peice of video. It would be nice to see it.

By the way, it was not a 4 wheel drift! It was what I call Bail out oversteer.... full opposite lock, full throttle, full boost 90 mph and hope you placed the car right on the track so as you don't kiss the green death:D

Jamie.
 
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