BMW 320d Executive Touring 2010 review

An American study has revealed potholes cost motorists about $335 a year in suspension repairs.  But what about all those speed bumps in suburban streets and shopping centres? I'm sure they must wear out your car's suspension.

In fact, someone should start a class action against local councils claiming back suspension repairs for the damage done by these insidious bits of Super Nanny nonsense.  If I lived on a busy street, the last thing I would want in front of my house would be a speed hump.

Think of it: Cars and trucks slowing down, going down the gears, screeching to a halt, some scraping as they go over the bump and then accelerating loudly away up through the gears.  And then there are the hoons that like to use them to launch their cars and the drunk drivers who hit them too hard and leave behind their bumper bars and some sump oil.  I'd never get any sleep if I lived near one.

Yet there are still people out there who want them - although "not in front of my house". It's a derivation of that much-hated NIMBY syndrome.  Apart from the noise speed bumps cause residents and the damage they no doubt do to your suspension, what about the extra wear and tear on brakes and the extra fuel you burn up?

Then there is the indisputable fact that speed bumps are the biggest cause of the proliferation of large four-wheel-drive vehicles in suburbia that are used solely for picking up the kids from school and never get their tyres dirty.  Motorists have worked out that big SUVs are great for suburbia because their long-travel suspension and high clearance means they can hit speed bumps at a generous speed without having to slow down.

That alone should be enough to have the greenies and therefore the politicians clammering to ban the omnipresent obstacles.  Which brings me neatly to the BMW 320d Executive Touring I have been testing on our suburban obstacle course.

This streamlined wagon is actually the perfect remedy for speed bumps and a better option for soccer mums than a big fuel-burning SUV.  Runflat tyres aside, BMW has created the perfect ride for our potholed and speed-bumped streets. 

Their brilliant suspension engineers have perfectly tuned this car to be able to hit these obstacles at a reasonable speed without jolting the hot coffee out of the precariously dashboard-mounted cup holders.  The secret is to hit them while accelerating. Too many people jam on the brakes, compressing the suspension and dropping the nose of the car. This lowers the clearance and inhibits the ability of the suspension to soak up the bump.

The 320d rides beautifully over these obstacles if you get all your braking out of the way first, then actually accelerate over the bump. This slightly lifts the nose and extends the suspension to full unsagged height for maximum impact absorption.  Shame the runflat tyres can't handle the smaller and sharper hits on the road such as small stones, squashed Coke cans and road joins.

While the brilliant double-joint spring-strut front axle and five-link rear suspension absorbs the big hits and helps the car hold the road like a much slimmer sportscar, it can't negate the runflat tyre's inability to deal with the smaller surface irregularities.  And then there's that cup holder problem.

There is no cup holder in the centre console, so the driver has to store his or her burning-hot latte in the spring-out holder that sits just above the right knee of the front-seat passenger.  At least if an obstacle does cause some hot coffee to spill, it won't burn the driver and cause an accident.

But that's it for the criticism of this ideal small suburban family wagon.  The 320d is the only diesel in the 3 series wagon range and it's a pearler.

It goes, stops, steers and handles almost like a sportscar, it has generous room in front and back for five adults, a reasonable cargo area with a flat floor and it's frugal on fuel.  And despite being a wagon, it is actually very sleek and sexy.  Just watch your coffee on those speed bumps.

BMW 320d Executive Touring

Price: $61,500
Body: 5-seater wagon
Engine: 1995cc, 4-cylinder turbo diesel
Power: 130kW @ 4000rpm
Torque: 350Nm from 1750-3000rpm
Economy: 5.9L/100km (tested)
CO2: 146g/km
Transmission: 6-speed auto
Kerb weight: 1520kg
Tyres: 205/55 R 16 (runflats)