We drive the new Chevrolet Trax

What's with all the little SUVs these days?

No idea, but you lot love ‘em. Unbelievably, the market's worth 41,000 cars a year in Blighty, and it seems like all the manufacturers want in. Skoda's got the brilliant Yeti, Nissan the Juke and Qashqai, there's a 208-based Peugeot 2008 coming next week, and a whole raft of others in the pipeline.

So what's under the Trax, then?

Before we get into all that, we should probably mention that companies are usually pretty happy to tell us what cars they share their underpinnings with. They volunteer it, even. But not this time. And we suspect that's because under the rugged styling fluff, there's something a bit limp. Like a...

...Vauxhall Mokka?

Chevy's engineers were only willing to tell us that the engines ­- a 1.4-litre turbocharged petrol, 1.6-litre non-turbo petrol, and 1.7-litre turbodiesel -­ were shared across both models. Which isn't terribly surprising, because we weren't that impressed with the Mokka.

Aha. Same story with the Trax?

Well, a bit. But before we tell you why, we should stress that the cars we drove were pre-production models, and improvements have been promised before they land in dealerships. Still though, there are some fairly big issues.

And they are?

The engines for a start. The 140hp 1.4-litre turbocharged petrol feels properly burdened, even on the flat. Then there's the 1.7-litre turbo diesel, which is a tad more powerful ­ 128bhp and 221lb ft ­ but it's incredibly noisy (though the engineers say it'll be quieter when it reaches showrooms).

Any pay-offs?

They're quite efficient. The 1.4-litre will do 44.1mpg and emits 149g/km of CO2, and that percussive diesel manages a decent 62.7mpg and 120g/km.

Fun to drive?

No. The firm ride makes a right old fuss over small lumps and ruffles in the road, and there's little in the way of steering feedback through the wheel (though that's another issue on GM's to-do list before it goes on sale). It's a nervous little thing through tight corners too, and manages the impressive combination of excessive body roll and jittery road holding (both of which are also on the list).

Then there's the noisiness. Above 50mph it's loud. Very loud. We actually checked to see if we'd left a window open. Hadn't... Again, this lot's all on GM's list so it's hard to say how accurate a reflection our impressions are. But the problems here seem fairly fundamental, and not the sort of thing that can be resolved with a minor tweak.

Lordy. Any good news?

Yeah, there's a bit. It's pretty spacious inside, and six-foot bepaunched types can easily fit in the back. And the interior materials may not be the most tactile, but they feel durable and properly glued on. There's all sorts of oddment stowage and cupholdery too, as well as a pretty tough-looking plastic covering on the bottom bit of the boot opening so you won't ruin the paint when you take your lawnmower to get repaired.

The MyLink touchscreen infotainment system (standard on the LT trim) is pretty good too. It basically works as an extension of your smartphone, so you can play your music, call and use it as a sat-nav if you download a special app. That said, the navigation app did have a nasty habit of falling over when we tried it, and at several points refused to turn left, sending us up the road slightly, right, right again, right, then straight on. Like an electronic Derek Zoolander.

So I shouldn't rush out to buy one?

We can't say categorically, because the car we drove wasn't actually the same as the one's available in British showrooms. But as we said earlier, the problems don't feel like they'll be fixed with a tune-up (though we've been wrong about that in the past).

Is it cheap, even?

Almost - £18,945 for the diesel, which is the only engine that won't make you a bit depressed. Thing is, an equivalent Skoda Yeti isn't much more expensive, but it is a lot better. And you can land a helicopter on the roof. If you like your cars to look like racing wasps, the Juke's very good too, again, not much pricier but quite a lot better. As we keep on saying, this isn't the finished article, and we're not in the business of beta testing cars, but based on what we've seen, nothing about this car will tighten any trousers.