21st Century Tyre Heating System
The Franc System
A Unique Concept In Tyre Temperature Management

There it was, behind the RML pit garage at Paul Ricard on the morning of March 25 – glowing brightly, even against the early morning sun.

The RML MG Lola’s O.Z. wheels and Michelin tyres were loaded into the aluminium framework – “fronts on top because they’re lighter” – the front cover was dropped down, a button was pushed, the rollers started rotating, and the whole set was left for about 15 minutes to gently ‘cook’.

“Unlike tyre blankets, our system provides a deep, even heat,” explains Stuart Hepworth, of Tyre Technology Limited.

After five minutes on the rollers, the surface of the tyre has reached 90 degrees Celsius, while a prick test of the rubber reveals 82 to 83 degrees. After the full 15 minutes, “the whole wheel-tyre combination has reached 90 degrees throughout. It’s a deep, even heat.”

If the timing of a pit stop is precisely known, the four wheels and tyres can be taken straight from the heating system and through the team’s garage, straight onto the car. Alternatively, the four can be transferred to a conventional warming system (below) to keep them hot, then transferred to pit lane when needed.

So who’s paying for all this electricity, Stuart Hepworth?

“We’re connected to the circuit’s supply, but actually we’re using less energy than would an F1 team (this system has been banned from F1 now - allegedly on the grounds of cost). When an F1 team is testing, it’s not unusual for them to have 36 wheels and tyres covered in blankets, and left on all day – and then they’ll be switched off at the end of testing that day, then all switched on again next morning. This system is much less wasteful.”

Part of the reason for that is the very high temperature of the four elements: 1250 degrees C. The tyres rotate with a gap of approx. five centimetres between the rubber and the element behind, helping to transfer heat quickly.

TTL’s system draws 10kW to heat four wheels and tyres, whereas a conventional four-blanket system uses 3kW.

“It’s an optimum temperature strategy,” explains Stuart Hepworth. “Heat the whole wheel-tyre combination to 90+ degrees and it’s a very even 80+ degrees by the time they’re on the car.”

“You can feel the heat in the tyres,” says Tommy Erdos, “but the great thing is that it heats the tyres so quickly. Say you had to pit with a puncture straight after a refuelling stop: the next set of tyres would already have a lot of heat in them.”

Besides using the system at Paul Ricard and in this year’s Le Mans Series (and at Le Mans) RML is also handling the sales and marketing of this unique product.

Speaking of Le Mans, a little known fact is that this system played a significant role at Le Mans in 2004. The only car using it was… the Goh Audi. The Audi Sport UK Team Veloqx R8s may have had a fabulous weather forecasting system, but Kazumichi Goh’s team had Stuart Hepworth’s tyre and wheel heating system.

In Business F1, Jo Hausner (engineering the winning car) is quoted as saying that "I had to have a soft tyre very quickly prepared because of tyre damage. Within six minutes, I had the tyres heated up. If I had had to do that with tyre blankets, the tyres would not have been heated up prroperly."

But TTL isn’t drawing the line at systems set up behind the garages.

“We’re working with MIRA to see if a system fitted to a car could withstand use on the track,” says Stuart Hepworth. “We tried a simple system on a Lotus 7 at MIRA – and it worked. We’d had it running on a test rig beforehand though, to make sure it is up to the job.

“In time, RML will fit it on the MG Lola and we’ll see how it performs.”

So where will all the energy come from, on the car?

“A special alternator, which carries a 20 kilo weight penalty. We need 4 kW of power.

“Because of the safety angle, we’re working very closely with the FIA on this. Ayrton Senna’s accident is generally accepted to be related to the period under the safety car, when the tyre pressures (and the ground clearance) would have dropped.

“The emitters (they use a black carbon element, in a high tensile, quartz tube) would be fitted with a safety grid in the wheelarches, and water on them is no problem at all. During the safety car, the driver would switch them on, and he’d have hot tyres ready to go as soon as the field went racing again.”

Stuart Hepworth hasn’t completely walked away from F1 though, and seriously suggested the fitment of four pods on the single-seaters, which would rotate through 90 degrees and heat the tyres, behind the safety car, then would be moved out of the way when racing resumed.

By mid-morning on Monday at Paul Ricard, RML had used 11 new sets of Michelins, on their way to covering over 450 laps of the High Tech Test Track. Each set was heated before it went on the car, and each set was used more than once. Just like the MG Lola, the tyre heating system worked faultlessly.

“We’re off to Japan next week,“ says Stuart Hepworth. “For motorbikes, this system is absolutely the dog’s doo-dahs. Tyre temperature is absolutely critical for them, and we’ve got an agent there already. The unit for motorbikes is much smaller than this one, but otherwise very similar.”

It will be very interesting to see how this system performs in Istanbul in a few days’ time – and how it is developed in the months to come.



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