Sorry i forgot to look at the values and get back to you. I just had a quick look at the C172 and it seems the only points with friction are points 0, 1 & 2. I have not changed them to be entirely sure but the 8th value of 0.424 looks to be the friction of the nose wheel, then for both the other wheels they have a co-efficient of friction to be 0.132. If it is not right then the 6th value given as 0.5 for all is the one to change. The others dont seem to fall into values i would associate to a friction co-efficient.
So the order of values after the contact points seems to be:
Point.No. = y, x, z, Design mass, Wheel No., Spring rate?, Steering angle, Friction but after that it gets confusing. So i cant guess what the rest of the values are for.