The epitome of racing feeling in everyday traffic starts a new round. 35 years after the debut of the first BMW M3, BMW M GmbH presents the latest generation of its high-performance automobiles in the premium mid-size segment. Time to introduce the two new vehicles. In the #M3M4explained series, the developers have the floor.
In episode three, Frank, who is responsible for BMW M3 and M4 tyre development, explains the possible tyre combinations for the new BMW M high-performance vehicles and provides an insight into the complex tyre development work. In addition, Frank shares his insider knowledge with the M community. We publish an excerpt from the questions and answers.
BMW M ENTHUSIASTS ASK, BMW M EXPERTS ANSWER.
Will it be possible to get the racetrack tyres for the normal BMW M3 or M4?
Frank: Sure, they are available for all models.
How many inches are the racetrack tyres?
Track tyres are the same dimension and mounted on the identical rims as the standard tyres. I.e. 9,5Jx19" at the front, and 10,5Jx20" at the rea
What is the pressure difference between the street and the race track tyres?
For road legal use, the pressure for street and race track tyres is the same as they have the same load index. For racetrack use, the tyre pressure needs to be adjusted to track, temperature and driver requirements accordingly.
Can we put 295/30 tyres at the rear?
With the standard rear rims this is not suitable. However, the M Performance accessory wheels, styling 1000M, with 295/25-R21 tires will be available.
Due to the increased width of the tyre did you encounter any problems? If so what is the fix?
There were a lot of changes to the entire frontend to integrate wider tyres for improved performance. Everything was optimized around that idea.
What if you are doing a track run in the wet? Are the road tyres more suitable to use?
It completely depends on the friction level of the track, temperature and amount of water on the track. Generally speaking, in the wet and at cold temperatures the grip of the track tires will be below the standard tyres.
How do you measure tire grip-level?
Longitudinal and lateral accelarations are quite good indicators … and of course the smoke that you see in your mirrors ;)
Do you advise to change summer and winter tyres, or an extra set with winter rims and tyres?
I recommend a specific set of winter wheels. For the new BMW M3 and M4, winter tyre dimensions are different to the summer tyre dimensions. Generally speaking, I would not advise to mount and unmount tyres several times.
Do we have to use run flat tyres? Is the suspension setting made for run flats?
For the new BMW M3 and M4, all tyres are non-runflat tyres and the entire chassis setup is optimized with that type of tyre.
Is it necessary to use star marked tyres to get the whole BMW guarantee?
No. But only star rated tyres guarantee the M handling experience.
If the tyres are bespoke to BMW what is the difference between the Cup 2s?
The star-rated Michelin Cup2 tyres are exclusively developed and fine-tuned for the new BMW M3 and M4 and its staggered wheel setup.
What's the recommended pressure in bar and psi for urban driving?
2.2 bar front and rear for both, standard 18"/19" and optional 19"/20" combinations.
Which winter tyres have been homologated by M?
These will be 275/35-19" all around. Using the 19" dimension on the rear wheels enables the use of snow chains.
How do you find the best balance for the tyre size? Isn't more usually better for performance?
The tyres and wheels portfolio is the result of extensive testing and enables a significant step forward in terms of dynamics for the new generation BMW M3 and M4. Based on the experience with former generations, i.e. BMW M4 GTS and M3 or M4 CS (F8x), the staggered wheels sizes represent the optimum solution for comfort and dynamic on any type of road.
How do you maintain the balance between grip and the possibility to drift?
With your right foot!
Can the track tyre be used on both hot and wet track? The track tyres can be used in both situations. However, performance depends on friction level of the track, temperature and amount of water on the track.
What tyre pressure should we use for track-like driving scenarios?
On a track, I would warm up the tyres and adjust the pressure according to track and driver demands but not below the recommended cold pressure level. Experienced drivers balance understeer and oversteer tendencies by adjusting tire pressures accordingly.
Are tires developed in conjunction with the alloy development or afterwards?
Tire development and its adjustment to the desired vehicle characteristics is a very complex process. Therefore, it starts quite early with rims that are identical to the upcoming series rims dimension-wise. During development, the performance of tires and rims are optimized in parallel.
Which wheel/tire size combo is the best to appreciate all the effort that went into development?
For handling and track performance, I would recommend the 19"/20" combinations.
Does the 18/19 inch combo also come with 275 width from tyres?
Yes, standard tyres are 275/40-R18 (front) and 285/35-R19 (rear).
Why do race cars have more tyre sidewall around the rim that street sports cars?
The book of requirements for a street legal sports car is quite different compared to a pure race car - think of brake dimensions, cooling and passive safety, just to name a few.
What is your favorite M Car?
The all-new BMW M3 with track tyres.
What do you drive and what tyres are you running?
A BMW M2 CS with Michelin Cup2s.
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