A testing time at Mondello Park for Bridgestone's Run Flat tyres leaves Justin Hynes impressed by their usefulness and reliability
It's lashing at Mondello Park. The rain is coming down in stiff grey sheets, angled by a cantankerous north wind, into cold pointed reminders of just how thankful you'd be for the Bridgestone Run Flat tyres that I'm desperately trying to listen to as I barrel into Mondello's Shell corner.
I'm not having much luck though. The sound of dispersing standing water is all I can hear and anyway this BMW 520 is so bloody quiet that when I climbed into it I had to press the throttle a couple of time to check it was on.
Hard to know what they're doing really. Half the battle with these old run flats is convincing people that they're not noisy: I said, "HALF THE BATTLE . . ."
An earlier tour around a demonstration course comparing Bridgestone's latest RFT tyres against regular Potenza RE050s and the difference (taking into account rain and the BMW's snoozy comfort zone of an interior) didn't appear all that noisier.
Indeed, they didn't seem to be more uncomfortable either.
Afterwards former Formula One driver and Bridgestone tyre tester Stefano Modena goes to great lengths to impress upon me that yes, the company has been aware of concerns that because of the extra stiffening in the sidewall of the RFT tyres that ride and noise could be impaired.
But the inscrutable types at Bridgestone have thought of that, by getting Stefano to pilot a car around the company's Rome test track with a passenger.
"He's a dummy," says Stefano. "Well half a dummy. He has receivers in his ears and all the noise is analysed by a computer and they can then adjust the tyre to make sure that any unwanted elements are removed.
"He's not a great conversationalist," he smiles, "But he's a very good listener."
All well and good, but I'm still not convinced. Sure, on this cocooned BMW everything's hunky-dory, but I'd really like to hear what it's like in the rattly cage of some microcar made from baking foil and recycled coke tins.
Again Bridgestone insists that factory-fit tyres (as on the BMW 6 and Z4 series) can be tuned to complement a vehicle, and anyway, no manufacturer in its right mind would accept tyres from Bridgestone that didn't give their cars the feel and comfort they felt necessary.
Fair point. But what about the cost? Another frequent complaint is that RFTs are much more expensive than their regular counterparts. "Yes," admits a Bridgestone spokesman. "About 20 per cent. But for that you're getting increased safety - there's no danger of a sudden, extreme loss of air, and you're not going have to change a tyre on the side of the M50 in the dark, late at night - and you're getting peace of mind.
"And remember that with run flats, you don't need a spare, so you don't need to buy five tyres. The cost differential is not much."
Another argument shot down. And another bonus for manufacturers and drivers is that the loss of a spare tyre, reduces weight and creates more available space. On a car like the Z4 that's a major consideration.
But how do they perform when put to the test? The answer is incredibly well.
Everyone is aware of how compromised drivability is with a flat, a massive pull in the direction of the flat, impossible cornering, unpleasant shocks on meeting any obstacle, and the wincing knowledge that with every extra kilometre you're destroying not only the tyre, but also possibly damaging the rim.
With the run flat, the comfort zone is restored. Unladen, you can pilot one of these for 230 km without any major problems. That means you could have your puncture outside Galway and arrive home in Dublin and happily forget about replacing the tyre until the following morning.
And it feels fine. There is still a small amount of judder and sideways movement on a medium-paced corner, but even approaching 80 kph - Bridgestone's estimated speed limit for the tyres - the awareness of one tyre being punctured is limited. And shocks? None.
In all, they get top marks. Personally, the slight increase in road noise and whatever compromises are made on ride, and I couldn't find any, are of negligible impact. The ride was fine, the noise level fine. The peace of mind, though, is a major incentive. I think I've had just one puncture in the last three years, but I do recall being exceptionally annoyed at having to spend 20 minutes changing the tyre in the pouring rain on a country road.
With RFTs I could have driven to a garage and got them to change it, in the dry, in comfort. That's about as good a recommendation as can be offered.
Just one question though? What effect will garda road spikes have on these? I think I've just found the perfect getaway car.