Why the BMW 3 Series still rules after 50 years

Similar thinking unfolded when it came to tracking down an ancestor. BMW UK has a covetable E30 M3 on its books, and we nearly put in a call to score a few days with the homologation special that is widely regarded as the greatest 3 Series that has ever existed. But then, with a little internet digging, I came across this charmingly original E21 320 for sale, in right-hand drive, from 1975. Ground zero, in other words.

Never mind the UK market, this is one of the earliest 3 Series to exist, full stop. You can tell as such from the fact that it lacks the plastic panel between the tail-lights. But yes, it is an automatic, and no, this isn't ideal from a driving perspective. But it's a rare opportunity for direct comparison with our G20-generation car. The number of doors aside, we have the same model, same flavour, only a lifetime apart.

If there is any pathos here it stems from the thought that there may well be no 60th bash for the 3 Series. Next year the critical Neue Klasse i3 arrives as a de facto electric 3 Series. BMW will continue to offer a combustion-engined 3 Series for a while.

According to head of design Adrian van Hooydonk, that car - the G20’s replacement - will look very similar to the i3, with an appealing Italianate-ness in the silhouette and the kidney grille in its historical, upright form. But let's not pretend this arrangement will last. BMW has no fixed date for the termination of ICE sales, but if you want to buy a showroom-fresh Bavarian junior executive saloon in, say, 2035, you'll probably have one option: an i3 EV.

Let's not get ahead of ourselves. The first 3 Series was really just a pretty, shark-nosed shawl, designed by Paul Bracq and thrown over the original Neue Klasse - the saloon that was introduced in the 1960s and credited with saving BMW's independence after it was nearly bought by Daimler. The most famous car in that line-up was the 2002, the fizzing Tii and liveried Turbo versions of which were in essence proto-M cars that presaged the M3 and today are worth enormous money.

BMW spent a serious 35 million Deutschmarks developing the successor to the 02 (still an utter bargain by today's standards, though, at the equivalent of £19m), even though the resulting E21 was mechanically fairly similar. Maturity, quality and big-car feel in a small-car package were the primary goals. Sportiness was less critical at first, although rack-and-pinion steering was a noteworthy development for the 3 Series, even with its slower ratio.

All cars got a front anti-roll bar, too. The E21 soon gained power steering, fuel injection and smooth six-cylinder engines, plus optional shorter gearing and a limited-slip diff that made the 323i a delight on a damp road. Spring rates also rose over time as the car morphed into something more driver-centric.

That said, our early carburetted E21 still has the hallmarks of its type: fantastic ergonomics and an easy balance that has you pushing it harder than a 50-year-old deserves. It also feels absurd today that this magazine complained the A-pillars were too chunky compared with those of the 02 - by modern standards visibility out of our cream-headlined E21 is nothing short of liberating. And the instruments really are faultless; sadly, this is something BMW appears to have recently given up trying to achieve. In the main the E21 just feels well engineered, barring the awkward clunk as the automatic gearbox slots into the first of only three forward ratios.

It's also a sensationally diddy thing next to the whopper that is the G20, in a way the raw figures simply can't convey. And handsome. When we arrived at the lock-up the car was wearing Alpina-style multi-spoke wheels, but Williams and Phipps set to work swapping it back onto the original 13in steels. They're perfect - as is the little toolkit that presents itself when you open the boot. And the micro-check upholstery and the inspired, heavily angled centre console.

On the road, performance is laid-back. It doesn't quite live up even to the expectation of 109bhp pushing a little over a tonne, which sounds quite promising on paper. In fairness, a lot of this is down to the gearbox, which always seems in a hurry to hole up in its lofty third and final ratio, although the shift quality en route is actually very good. Near-seamless at times, in fact. BMW still turns to ZF today.

The handling is genuinely interesting, though. As we know, the mechanicals of the 3 Series would iterate rapidly in the years following 1975, but even this early car has traces of the good stuff. For one thing, while the suspension is soft, the cornering balance is neutral. What's more, while the trailing-arm rear axle doesn't always feel exceptionally well located, trimming the throttle mid-corner generates a controlled flicker of rotation that is primordial M3-type behaviour. It's an old softy, but one that is mischievous and oh so easy to run along with.

BMW would sell more than 1.3 million versions of the E21, the majority in four-cylinder form. However, it was the E30’s arrival in 1982 that marked the point at which the 3 Series started to take off. This era ushered in the option of four-door, convertible and touring bodies. It also introduced diesel to the gene pool, and in 1986 the first M3 wailed into showrooms. E30 production was vast at 2.2 million units, with outputs ranging from 86bhp to 238bhp in the case of the M3 Sport Evolution - a car that pushed pricing to breaking point.

At the time, Porsche charged less for a 3.0-litre S2 944. ABS and M styling kits were also newly available to buyers, as was four-wheel drive (BMW even built a handful of 325iX mules with an electrically driven front axle). Turbocharging technically first appeared on the 320i Turbo of 1981, but that was a Group 5 firebreather. The first blown road-going 3 Series was the six-pot E30 324td.

The E30 set the template for the 3 Series we know today. The only material changes to the recipe since then have been the brief adoption of a V8 engine for the E90-generation M3, dual-clutch gearboxes for the following M3 and PHEV technology. The E30 was also the generation that cemented the 3 Series’ appeal as a driving tool for anybody. If the M3 was out of reach, models such as the twin-cam 318iS were still phenomenally enjoyable while offering sophisticated road manners.

Group test wins became the norm. However, the best-selling 3 Series of all time was the E46 introduced in 1998, with around 3.3 million sold. On one hand, this was rather an unnecessary refinement of the aerodynamic E36 that had been introduced just six years earlier.

On the other, it was an evolution that resulted in the properties of the 3 Series aligning beautifully with the expectations of enthusiasts. You got an upmarket silhouette, a manual gearbox and a strong, soulful six-cylinder engine if you so desired, plus an elegant cockpit and real touring ability. For many, the E46 was the platonic ideal of the performance coupé. It also spawned the M3 CSL.

That car's S54 3.2 generated an intake wail that once heard can never be forgotten. It also had the ability to glamorise what amounted to a cardboard boot floor. Of course, you could also have your E46 as a svelte diesel estate, happy in the knowledge it could carry the dog and also skin its opposite number from Mercedes-Benz or Audi at any time.

After that point crossovers began to creep in, and as the market share of traditional bodystyles was diluted, E90 sales fell to 3.1 million. That car was introduced in 2005 and followed much the same template as its E46 predecessor, but without quite the reverence from fans.

Then came the F30, with which BMW generated consternation by turning what had always been the 3 Series coupé into the 4 Series. A decade later, it still doesn't sound quite right, although the car’s dynamic appeal undoubtedly took another step forward. This was also the last point at which you could buy a manual, six-cylinder 3 Series in rear-wheel-drive form, courtesy of the 340i. You could even have one on 18in wheels and with untinted glass. Try finding one now.