WHEN a thicker-rimmed steering wheel and a new badge on the radiator grille are talked about features of a newly updated car you might expect nothing very fundamental has changed on the vehicle they're attached to.

And you'd be right. But in the case of Nissan's X-Trail, at least, there are very sound reasons for not tampering with what you've got already.

This larger of Nissan's SUV offerings (bigger than the British-built Qashqai), the X-Trail is the world's best selling SUV. More than 766,000 of them went to owners around the globe is the last financial year.

You meddle with a success like that at your peril, but it's in the DNA of car companies that mid-way through a model's life cycle it comes in for a bit of a refresh. That gives them (and the motoring press) something to talk about and the car dealer a reason to talk to customers too.

So say hello to the refreshed X-Trail, complete with new lights and bumpers, added flashes of chrome and a touch of gloss black - all intended, we're told, to add a bit of aggression to the looks of a car that is now 50mm longer than before.

Inside, there's a flat bottomed steering wheel with a thicker rim, jointly adding - Nissan hopes - a sporty feel and safer grip. Slimming down the wheel's centre and spokes has made the already clear instruments even easier to read - a precise 17 per cent better, says Nissan.

Heated seats front and rear are now standard on the top Tekna grade and there's the option of tan leather (a rather smart orangey look) to relieve the blackness of the standard X-Trail cabin.

Subtle changes to boot design have released another 15 litres of space (now 565 litres) on cars fitted with two rows of seats. As ever, there is a £1,000 option (£660 on Tekna) of a pair of third row seats, with space for larger children or smaller adults.

Tekna owners now enjoy an eight speaker Bose sound system (on five-seat versions) while every X-Trail has DAB radio as standard for the first time.

Talking of Tekna, this high end trim level is comfortably the most popular, with 47 per cent of sales going to the grade that now starts at £32,810 for a car with two-wheel drive, manual gearbox and 130 horsepower 1.6 litre diesel engine.

The range tops out at £37,410 for a Tekna with more powerful 177 horsepower 2.0 litre diesel and a CVT Xtronic automatic gearbox and all-wheel drive.

Fuel consumption and emissions across the new X-Trail ranges from 45.6mpg/145g/km for the petrol engine to 57.6mpg/129g/km for the 1.6 diesel - expected to be the most popular power unit in the range.

Showing how customers are happy to spend on the aspirational X-Trail is the mere one per cent who choose the cheapest model, a £24,845 Visia trim with front-wheel drive, manual gearbox and 163 horsepower 1.6 litre petrol engine.

Second best selling version (39 per cent) is also the second most expensive N-Connecta, with the Acenta below it claiming 13 per cent of sales.

Sometime next year buyers will be able to order their X-Trail with ProPILOT, Nissan's approach to a car that drives itself. Not quite there yet, but with the system engaged the car will steer, accelerate and brake itself on roads with well defined edges and in traffic jams too.

That system wasn't fitted to the cars on the press launch in deepest Wales but there was plenty of time to assess the modest upgrades to a car that was already high on the potential purchase list of many SUV buyers.

A commanding driving position in a cabin obviously built with precision are abiding first impressions, along with a sense of space and clarity to instruments and minor controls.

The petrol powered X-Trail needed more gear changing than its diesel sibling - not a criticism, simply a characteristic common to all petrol/diesel comparisons - but was quieter and smoother than the diesel.

But a bigger contrast was the way a diesel with manual gears felt so much more lively and responsive than a car with the same engine but a CVT automatic gearbox. Chalk and cheese, almost.

All the cars rode some indifferent Welsh roads with firmly controlled aplomb and a brief and moderately demanding bit of off-roading a 4WD version showed the X-Trail would go places no owner was ever likely to venture.