Austin A105

Introduction

The A105 model of the Austin was a livelier version of stock A95. It was more powerful and, in deluxe version, was fitted with an automatic transmission. The increase in output over the A95 amounted to 17 horsepower, thanks to a higher engine compression combined with twin S.U. carburettors (instead of the single Zenith used on the A95).

The aforementioned deluxe model used a Borg-Warner three-speed transmission, coupled to a torque converter which gave a maximum torque multiplication of 2.2 to 1. The result was an energetic and versatile car, which held the road very well, and was particularly pleasant to drive on country tours, or in the city. This was indeed a time when Austin not only meant quality, but roadability and comfort.

A time before the muscle cars of the 1960’s, and where performance equated to compromise, with sports cars being open, noisy, hard to tune and more often than not very unreliable. And that was the beauty of the 105. Austin’s from this era were exceptionally well built – and in the 105, while we may laugh at the performance on offer by today’s standards, it represented for the time a reliable, sound and well sorted driving experience.

If we could travel back in time, all of us would have been looking very seriously at the Austin brochure. And no doubt, had our soul possessed a driver inside, we would have been looking at the 105. It was an inevitable performance comparison that we assume many did at the time. No doubt only those who could not justify the extra cost would have gone for the A95 with its manual transmission.

It was a characteristic of the very smooth Borg-Warner transmission that top gear was a direct drive, thereby avoiding any power loss in that gear. The deluxe Austin A105, with the auto tranny, weighed some 2cwt more than the standard car. Further, an engine with twin carburettors was obviously not as economical as the single carburettor version, but this was generally offset if a higher compression ratio was used, and on the A105 this was the cast.

A broad comparison of the A105 in relation to the standard version showed that it was about 5 mph faster in top gear and that it climbed and accelerated much better than the A95 if the auto-transmission was allowed to operate in a normal way. These pronounced gains in performance were at the expense of only two miles-per-gallon in fuel consumption, with the two cars driven at the same average speed over the same test route. The operation of the torque-converter type of automatic transmission was, by the mid 1950s, becoming fairly well-known. The Borg-Warner transmission was very sensitive to load conditions, and it changed gear up and down in a fashion which always protected the engine from any suggestion of heavy slugging.

On the Road

Numerous road testers and motoring journalists claimed that it changed down to a lower gear too readily, but since that change was silent and smooth, and gave better acceleration, we are at a loss to understand the criticism. To this day, and thanks to computers that monitor what you do, we all appreciate an auto that interprets the style in which you are driving. Obviously the A105 transmission was nothing approaching the sophistication found today, but there was an innate sense of purpose that only those that had driven an A105 could describe. For example, if you started from rest in a leisurely manner, the A105 gearbox would change from low to intermediate gear at 12 mph, and to top gear at 27 mph.

Drive with more aggression and the resultant fully-opened throttle would delay the change to intermediate until the speed was 41 mph, and the change to top was not effected until a speed of 77 mph. Thus the transmission took full advantage of the lower gears to give the best possible take off. There were some other useful and interesting aspects of the Borg-Warner auto-transmission. In circumstances requiring a lower gear urgently, you only needed to "kick" the throttle pedal to the floor. Engine braking was available in top gear, but not in intermediate. If you wanted more powerful engine braking on a steep hill, the change of the selector lever to low (which could be done at any speed below 35 mph) supplied a powerful deterrent.

A free-wheel was provided in intermediate and low gears, with D range selected. Should the car be bogged – which was far more common on Australian road of the time, it could be rocked back and forth until firm ground was reached, simply by moving the selector gear between low and reverse. The car could be locked in the stationary position by moving the selector to park. This gave additional safety when standing on a hill. A lock prevents the inadvertent selection of reverse or park with the car moving forward at speeds above 4 mph – we mention this because, back then, some autos did not have this wallet saving device. The engine could be started by pushing or towing the car at about 25 mph., and then selecting low gear.

Austin A105 Performance

The extreme readiness of the transmission to select intermediate gear as soon as the throttle was opened on a climb ensured that most climbs were made in that gear, in place of top. It was only when you eased off the throttle in approaching a slow corner on the climb that the transmission changed up to top. Down it would go again to intermediate as you accelerated through the corner.

Intermediate would be automatically selected for most ascents, and was about the equivalent of third gear on the Austin’s conventional gearbox at speeds above the torque multiplication range. On full torque multiplication, however, intermediate ratio dropped down to a figure slightly lower than conventional second gear. That meant the intermediate gear was sufficiently versatile to deal with most climbs and road circumstances. Rarely would low gear have been necessary or desirable, other than for starting.

The power (laden) weight ratio of the A105 was good at 67 brake horsepower per ton, with the standard load of 3cwt (A95, 59.6 bhp. per laden ton). The action of the auto-transmission (when correctly adjusted) always ensured the best gear for rapid acceleration thereby relieving the driver of any concern as to gear selection. As the transmission would always move down to intermediate gear depending on the throttle opening all hard acceleration at driving speeds was done in that gear.

The times for the various acceleration ranges (D selected) were: 20-40 mph: 6.1 seconds. (compared to the A95 third gear at 6.3 seconds), 30-50 mph.: 7.2 seconds compared to the A95 at 9.6 seconds), 40-60 mph: 8.4 seconds (compared to the A95 at 11.3 seconds. The maximum pulling power was 142 lb-ft developed at a road speed of 40 mph. in top gear. The corresponding torque for the A95 was 30 lb-ft, developed at the same speed. All those figures were representative of the fact that the additional power of the A105 over the A95 would always result in a higher overall speed, be it around town or on the highway. Cruising along the highway between 70 and 80 mph was easy in the A105.

Structurally the A105 was the same as the A95, albeit with the additional 2cwt. And you don’t need us to tell you that meant it handled pretty much identically to the A95. But there was a little more weight over the rear, which resulted in better adhesion – the actual front to rear dead-weight distribution was 58:42. And, much the same as the A95, the A105 had pleasant steering that was just quick enough, combined with a moderate turning circle of 40ft.

Allowing for the better performance, Austin increased the brake lining area to 198 sq. ins. The brakes were good, with just a trace of fade after heavy braking, and they were able to dissipate the built up heat fairly quickly so that performance was not compromised unless you were really pushing hard. At an average speed of 46 mph the A105 would put in fuel consumption figures of around 22 mpg. Twin fog lights, a heater and wheeltrims were standard although a radio was still an option. Two-tone paint and white-wall tyres were introduced for visual effect, eveb though very few short boot versions of the A105 were produced. Today these are very rare, thus our 3 star collectability rating.