F1 To Abandon Old Tire Standards? By Flood1

 

With the news that Bridgestone is going to abandon their Formula 1 involvement after the 2010 season, I look forward with anticipation that the basic tire construction will be changed by whoever will replace them. Am I talking about slicks, grooves, compounds or the two tire rule?

 

No, I am talking about aspect ratio. I hope the new supplier abandons the current tire for a low profile version.

 

What? I know, you are thinking that Flood is off again pursuing a niche tech area that only a few people understand or care about, but you are wrong. This subject is directly related to your road car tires and is considered every time you buy a set of tires.

 

First, let’s consider the current F1 tire size standards. Using the measurements supplied by Bridgestone, the tires are currently 270/55 R13 (front) and 325/45 R13 (rear). What do these numbers mean?

 

Let’s use the front tire dimensions. The first number, 270, is measured in millametres and refers to the width of the tire.

 

The second number, 55, is the sidewall dimension represented as a percentage of the width. So, the sidewalls are = to 55% of the width. In this case, the sidewalls are 145.75mm.

 

The R means radial, and all that signifies is that the “weave” of the tire is transverse to the direction of travel as opposed to diagonal. Almost all road car tires are radial.

 

The last number, 13, refers to the size of the hole (in inches not mm for some damn reason), i.e. the size of the wheel.

 

F1 tires have been stuck on this aspect ratio for about 15 years with very little change. The technical rules do not refer to anything but overall dimensions. No mention of wheel size or aspect ratio, only overall size. The manufacturers determine the exact details, and for years the tires have been fitted to tiny 13” rims. Only the most economical road cars adhere to this standard.

 

For example, my BMW 135 has tires that are 215/40 R18 on the front and 245/35 R18 on the rears. They are low profile but not extreme. This is a good handling tire because the sidewalls do not flex as much during cornering. No racing series in the world uses a tire that has such a large sidewall relative to its width as F1. It is an antiquated tire construction.

 

I suspect that the reason manufacturers choose to continue with this tire size is because it affords a larger palette for their logo or name to be displayed, and they already have all the moulds and equipment to make tires this size.

 

So, why do I prefer a lower profile tire? I prefer it for the same reasons that racers all over the planet do. It is a better tire for racing.

 

There are two issues. One: the tires with the current ratio have a lot of compression under load. This softens the load, but it compromises suspension settings. When compressing or flexing, the tires change ride height, suspension geometry, etc. If the tires did not do this then the suspension settings could be more precisely dialed in. But the biggest advantage to low profile tires is brake rotor sizing.

 

F1 must use carbon fibre rotors today because the small wheels result in small brake rotors. Carbon rotors are time consuming to produce and expensive. Large wheels allow one to use conventional steel brake rotors and get the same force because of the larger contact area for the brake pads.

 

Larger wheels would allow cheaper steel rotors, the same braking force, and road car relevance. How many of you have carbon rotors on your road cars?

 

The last issue is who will be the next F1 tire supplier? Not Bridgestone, not Michelin, not Goodyear, not Pirrelli. Who? I think Khumo or Hankook, the Korean manufacturers.

 

There will be a Korean race next year (probably/maybe), and these guys do not have any moulds that fit the old F1 sizes. They will start anew and produce a tire from scratch. And they will negotiate their preferred sizes as part of the deal. And, they will demand a small space on each car for their logo. A logo that will replace the advert no longer possible on the sidewalls of the low profile tires.

 

Welcome to the 21^st century.

Comments

[sportsman]

It's a very good point.I cannot understand why F1 or more correctly the FIA technical regulations specify a 13inch bead.
Current FIA wheel specification from stable technical regulations 2010.

12.4 Wheel dimensions :
12.4.1 Complete wheel width must lie between 305mm and 355mm when fitted to the front of the car and
between 365mm and 380mm when fitted to the rear.
12.4.2 Complete wheel diameter must not exceed 660mm when fitted with dry-weather tyres or 670mm when
fitted with wet weather tyres.
12.4.3 Complete wheel width and diameter will be measured horizontally at axle height, with the wheel held in a
vertical position and when fitted with new tyres inflated to 1.4 bar.
12.4.4 Wheel bead diameter must lie between 328mm and 332mm.
This is clearly very old and out of date with todays requirements.
So although I haven't done the maths, there is clearly room to change to a 17 or even 18 inch wheel and by usinga low profile tyre maintaining present ride heights, will not require a complete redesign of the chassis.
Who will be the supplier. I agree thatit is more likely to be one of the far eastern manufacturers.
Companies like Handkook and Kumho no longer make tyres only suitable for donkey carts.
Here in Eastern Europe they have very strong market presence and they compare well with the known names.
I would guess thatit would be one of these companies that will win the tender

[GordonB]

Excellent analysis!

I hope this happens. Give the suspension travel back to the suspension guys!

[sportsman]

Kumho already have a rather impressive pedigree in race tyres

http://www.kumhotyre.co.uk/Motorsports/KH_brochure01.html

[KM-TV]

Hmm... I suspect that as likely as the korean names liable to re-enter, I think that the contract will go to a more established brand. Pirelli are looking likely to leave the WRC and may be interested in a new world motorsport contract, Michelin will probably tender, and don't discount Goodyear - Dunlop.

I rather hope that Dunlop do get it as unlikely as it is, as this will be a poke in Bernie and Gillett's Eye after they'd got rid of the Dunlop Bridge!

[flood1]

Bridgestone – Gone

Michelin – not interested in a one tire series with dumbed down specs and no competition. They want to develop the ultimate tire, and they want to use racing to further their understanding.

Goodyear – currently suffering from the global economic conditions per their own reports. And, they are sole supplier to Nascar.

Pirelli – leaving WRC but not until the end of 2010. They will not be able to develop and implement an F1 tire program parallel to their WRC contract.

Dunlop - They are Goodyear, see above.

Avon – Too small

Continental – German outfit that has never been a big time racing constructor

Hankook –

•Japan Super GT
Sponsored Team: Hankook Porsche Team ? GT300
•German Endurance Championship Nuerburgring (VLN) and 24 Hour Race Sponsored Team: Hankook-H&R Spezialfedern-Team Alzen Motorsport
•American Le Mans Series (ALMS)
Sponsored Team: Primetime Race Group Team
•China Circuit Championship (CCC)
Sponsored Team: Hankook Tire Lufang Racing Team (2000cc)
•German Rallye Championship (DRM)
Sponsored Team: Wallenwein Rallyesport
•China Rally Championship (CRC)
Sponsored Team: Wanyu Rally Team (2007 Series Champion)
•Formula D (Drift)
Sponsored Team: Hankook JIC Motorsports Team
•IMSA Lites (Official Tire)
•Japanese Formula 3 Series (Official Tire)
•Hankook DDGT Championship (Title Sponsor & Official Tire)
•CJ Super Race (Korea - Official Tire Supplier)
•Hankook R1 (Korea - Title Sponsor & Official Tire)

[Paulo]

I, for one, totally disagree.

The point you make about brakes is wrong. Having done research into brakes as part of my degree, steel brakes would just not work on an F1 car. The temperatures generated by the brakes when under full load reaches well over 1000 degrees! In these conditions, steel discs would warp within one or two corners. And there is also the weight issue to consider. A 12" carbon rotor compared to a 15" or 16" steel one... Go figure! Not only do you have the added mass of the steel and then the extra dimensions of it, but you increase the unsprung mass, which then makes life harder for the suspension guys!! And then there is the problem of more rotating mass, and also if you have bigger steel brakes you'll need bigger calipers too, again meaning more unsprung mass...

Certainly as far as brakes go, what is currently being used is the much better option don't you think?!

[flood1]

Hi Paulo, it’s nice to have you here. Let’s look at a comparison.

Indy Cars use 15” wheels and steel rotors on the road courses. They use carbon rotors on the ovals and 6 pot calipers everywhere. The cars have a minimum weight of 740 kg as compared to a weight of 605 kg for an F1 car: about 22% heavier. The IRL cars travel at top speeds comparable to F1 cars, although their lap times are not as fast. Because of their weight they do not accelerate, corner, or stop as fast. They also have less sophisticated aero. But, they do not have any routine problems with the brakes. We seldom see a brake failure.

Carbon brakes do not work unless they are very hot. Used moderately they will glaze over and will not grip. Steel brakes work well at all temps and therefore don’t need the high temps of carbon to be effective. That’s why you don’t see them on many road cars. Plus they are very expensive.

Lenny Peake is the head mechanic at Ferrari of Silicon Valley, in Redwood City, California. He provides this information about replacing the carbon ceramic brakes of an F430 Road Car. Here are the costs: $7,000 per disc, $14,000 per axle or a mere $28,000 for the front and rear. But, steel rotors are only $350 per rotor, $700 per axle or a paltry $1,400 for front and rear when compared to $28,000 for carbon ceramic disc replacement.

http://sportscars.clubsportiva.com/labels/Lenny%20Peake.html

[Craig F]

Unless you allow the F1 cars to use carbon rotors (or similar) at whatever size, you will decrease performance.

The MAIN reason that F1 cars are still on 13" rims is to keep the braking forces sane.

Braking is the PRIMARY performance difference between F1 and the other formulae listed above. The other advantages (accel in every dimension) are largely due to the very small unsprung masses.

Bigger wheels (heavier), plus steel rotors (much heavier)=major performance loss.

Put those nice looking 18's or 20's you like so much on your sports car (you could put 27's and big mean 12 piston calipers on and you will still have 1/4 the braking power of an F1 car) on an F1 car AND allow state of the art brake materials and watch your favorite racing drivers cut into sixths by their harnesses.

Other fish to fry folks.

[flood1]

So explain to me why LeMans cars have big wheels and low profiles. Do they have trouble stopping and put their drivers at risk due to their brakes.

Also, Champ cars and Indy cars are much heavier than F1 cars and still they use steel rotors and do not threaten their drivers with injuries due to brake failures.

Please explain yourself further.