Sunday, 17 February 2013

Tires and Wheels

The tires on a car are a critical factor in its performance. Having bad tires on a great car would be analogous to having crummy speakers hooked up to a fantastic sound system.

The wheels on the M5 are forged alloy and are either 19" (1) or 20" (2). This dimension refers to the diameter of the wheel itself, not the wheel+tire diameter. On my M5 I have 19" wheels for the winter tires, and 20" for the summer tires.


It is important that the wheels be as lightweight as possible, because they act like a gyroscope and resist turning if too heavy. Also, they are part of the so-called "unsprung" mass of the car, that part of the car which is isolated from the heavier chassis. Lighter unsprung mass means that the wheels will more readily conform to the road surface, promoting better traction.

The summer tires are Michelin Pilot Super Sports. The front tires are 265/35R20 at the front, and 295/30R20 at the rear. The "295" part is the width of the tire in millimetres, or 11.6" wide. The "30" part is the ratio of tire width to tire sidewall height. So the sidewalls are 295 * 30% = 88.5mm = 3.5". Therefore the diameter of the tire and wheel together is 27". The summer tires are rated for very high speed, and the tire has been customized by Michelin specifically for the F10 M5. The tires would be extremely poor for winter driving, as the grippy rubber compound becomes hard like a hockey puck when too cold.


The tire has two types of tread rubber. The outboard shoulder features a track-type compound to withstand the stresses of high performance cornering while the notched centre ribs and inboard shoulder feature a compound designed for superior performance at very high speeds and in wet conditions. The tire's internal structure has twin steel belts reinforced by a spirally wound Twaron cord. Twaron is a polyamide cord that offers a lightweight, high-strength reinforcement above the steel belts.

The winter tires are Pirelli Winter 240 Sottozer Series 2.


They are 255/40R19 all around. The narrower tire is better for traction in the snow. It concentrates the weight of the car onto a smaller patch to allow for better grip in the snow. However traction on dry pavement is less good due to the smaller contact patch with the road. The rubber, however, stays soft even in the cold. The tire is optimized for winter driving, high speeds, and great handling.

Unlike on most BMWs, the tires are not "run-flat" models.  The very stiff sidewall on a run-flat compromises grip and handling, and so is not deemed suitable for an "M" car. However, neither is there a spare tire in the trunk due to space and weight considerations. Instead we get a "kit" that attempts to seal and re-inflate a punctured tire.


Hmmmm....

21 comments:

  1. If you want your car to have a greater speed and performance, choose wheels that are lightweight and tires that has a higher performance and long tire life.

    Cepek Wheels

    ReplyDelete
  2. You need high performance tires that are also Multi-Mile tires.

    ReplyDelete
  3. I appreciate this a ton! I've been looking for some quality car tires in Omaha NE. Do you have any suggestions?

    ReplyDelete
  4. Truly said, and that is why I used to buy all types of tires and wheels from Dubs and Tires who are providing all types of tires, wheels and rims for various types of vehicles.
    DubsAndTires.com

    ReplyDelete
  5. Rims and wheels are can relatively enhance the appearance and the performance of your vehicle.
    Thanks! for sharing informative post for vehicle.
    Wheels Ottawa

    ReplyDelete
  6. Your excellent guidelines will be of great help to many unusually snowy winter is main cause of the cancellation of several longer driving trips . Nice post. I enjoyed reading it. Thanks!
    Ottawa Winter Tires

    ReplyDelete
  7. I've been trying to find some insights on what to look for in quality car tires. With so many different kinds it's hard to know what ones are good and what ones aren't. This helped a ton, and I feel confident that I'll be able to find some by this weekend.

    http://www.metrotyreservices.com.au/index.php/tyres-services/tyres

    ReplyDelete

  8. Excellent post. I was checking constantly this blog and I’m impressed! Extremely useful information specifically the last part :) I care for such information much. I was looking for this particular information for a long time. Thank you and good luck. Ottawa Rims

    ReplyDelete
  9. We know that very well how much tires are important for a wheels,if we have a good quality of tires than we can get the better performance by our wheels.That's why we should always care about our wheel's tires. This post is really awesome for making people alert about his wheel's tires.
    Thanks for lovely post! buy range rover tyres online

    ReplyDelete
  10. Yes I do agree this. Tires must be resistive so cars performance becomes better. I recently searched about latest tires. I would like to give you information about latest bridgestone dueler tires. Thats very high performance tires.

    ReplyDelete
  11. Very nice article sharing and provide a lovely information about buy tyres online and is really appreciable. Need more Post like this.

    ReplyDelete
  12. This is really informative. I want to know the prices to buy car tyres online for all four tyres of my Skoda car.

    ReplyDelete
  13. Great article but does anyone know the optimum tyre pressures for the following tyres;

    Front tires: Michelin Pilot Super Sports 265/35R20.
    Rear tires: Michelin Pilot Super Sports 295/30R20

    For some idiotic reason the previous owner decided to remove the door sticker.....

    ReplyDelete
  14. Great blog about tyres. If you want to buy tyres at discount in oakland or east liberty, please contact us from the links below

    Here is an article Oil Changes East Liberty that counts for all important aspects and issues related to car repairing as well as oil changes. The Engine Repair East Liberty article delivers every little thing about car repairing and Discount Tires Oakland necessary oil changes that are done to help get comfortable as well a smooth service. It is all about the good work and Collision Repair Oakland provided solutions delivered by expert car service centers.

    ReplyDelete
  15. Nice Website...
    Hey JOIN now fblikesbot.com and Increase Facebook Likes your profile and websites.
    Increase Facebook Likes and check your website worth worth my websites
    FB Likes and check your website worth Website Value Calculator
    Hot Wallpapers seo tools website
    its may be very beneficial for you also really

    ReplyDelete
  16. Thanks for the post. Michelin Tyre are one of the best brands of tyres in the market. If anyone searching for Michelin tyres Pune then go for Shree Tyres. For more detail contact 8055678063.

    ReplyDelete
  17. if you get the standard Mega World trim but get the range extender, you also get the wider wheels and tires on the rears. Cheap Tyres

    ReplyDelete
  18. very nice blog post. I also found a very good website who are working in Intercoolers Suppliers Australia.

    ReplyDelete
  19. Tyres & Wheel Dealers in Delhi, Noida, Gurgaon - Get best price quotes from Tyres & Wheels Dealers in Delhi, Tires & Wheels Dealers Delhi, Car & Truck Tyre & Wheel Sales Delhi furthermore download Delhi Tyres & Wheel Dealers waylay addresses and phone numbers to your mobile from tyresnmore.com

    Website: - www.tyresnmore.com

    ReplyDelete
  20. Car Tyres dealers in Delhi manufacturers, suppliers and exporters in Delhi along as soon as their entre details & domicile. Find her Car Tyres suppliers, manufacturers, wholesalers, traders next Car Tyres prices for buying.

    Car Tyres Dealers in Delhi - Tyresnmore.com

    Best Car Tyres Price in Delhi- Tyresnmore.com

    ReplyDelete
  21. Prime the unit before fitting it and check all components before replacing them - if they're old and worn, they too should be replaced. Don't grip the piston rod with pliers or place the unit itself in a vise, you'll damage it.
    Wheel alignment Balancing machine
    Car Wheel alignment Balancing machine in Delhi, India

    ReplyDelete