C51 245 front/R888 275 rear - awesome combination

[Master Apex]

I have been tracking Z4M for the past 7months and been tweaking the car to make it turn-in sharper (Lotus Exige is my benchmark).

The car has:
- KW CS Coilover with front camber set at -3.5
- More rake, lowering the front more than the rear and use 245/35/18 front tire to allow more clearance (no rub at 23.3" ride height)
- 275/35/18 in the rear

From tires wear, I can see that the front tires are working harder than the rears. A week ago, as my Star Spec is worn out (after 8 track days), I decided to try out R888 on the rear and Hankook C51 on the front. I know the C51 compound is much softer than the R888 so curios to know how it would handle.

Well, happy to report that it was great.
The car turns like Lotus Exige S.
In fact, on a tight course (7 turns) where a season driver (instructor) was running 38.xx seconds laptime in his Lotus Exige S with R888 tires...that was considered benchmark, my Z4M broke the record as it was clocking 37.xx seconds.

The only trade off is obvious, the front tires wear much faster....so this is an expensive deal for HPDE but for competition, this is an absolute best combo that I have tried.

Just want to share my findings.

PS: I know with the same tire model, there is more grip in the back than the front , so my thought is to add grip in the front instead of taking grip away from the back (e.g. using narrower tires).
I also know that the front tires work harder ; I have been thinking about a way to shift the load, making the rear work harder. I think stiffer rear swaybar just change the steady state balance of the car toward oversteer and will not improve the turn-in response. I think that the Z4M platform is already compromised as engine/weight is in the front.

[esqu1re]

Thanks for the write up. It seems that the front is almost always going to work harder as there's just so much weight up there---especially noticeable on a tight course or auto-x.

[krnnerdboy]

thanks for the info...I'm running 235 in front and 265 in the rear on r888's ad I could definitely feel the rear being stickier.