Lloyd, As someone who has driven both D9s and RMs, How would you compare them?
Interesting question. Although some describe the D9 as the 'Birmingham Routemaster', in fact they are like chalk and cheese.
London Transport put an almost unbelieveable amount of money into the Routemaster design and development, it was intended to replace the remaining pre-war stock (of which there was quite a lot) and most of the trolleybuses. It was going to be the standard double decker of the fleet and had to be right from the word go. Maintenance and overhaul proceedures for them had to be designed as well, and it paid off as the design was the capital's standard for 40 years (the first one was built in 1959 and there are a few still running in London, and plenty running all over the world. The drivers' viewpoint (as well as the conductors', the mechanics' and the passengers') was greatly taken into account - these were the people who were going to use it, after all.
Its handling on the road reflects this, and although underpowered by today's standards, it was extremely advanced for its day. Semi-automatic or fully-automatic gear changing (at the driver's discretion), power steering, high-pressure hydraulic brakes, effective heating and ventilation and good all-round visibility giving a comfortable and even easy time behind the wheel were definitely NOT the driver's norm for the day on any other vehicle.
Although Midland Red addressed many of the same design requirements, obviously they could not afford to spend anything like as much money on it, but within such limits they produced a vehicle well capable of doing its job. Midland Red vehicles are designed for what they have to do, no more - they are certainly NOt over-engineered in the same way the Routemaster was, and suffered (albeit only slightly) because of it.
The disc brakes used by BMMO since the S14 single decker of the mid-50s was not up to the weight of a double decker, and soon had to be replaced by 'normal' drum brakes. Brake fade with the discs was an early problem, as units overheated sometimes enough to weaken the mounting bolts, when the caliper would literally fall off causing complete loss of footbrake. The rubber suspension could cause uncomfortable 'bouncing' at speed on some road surfaces (particularly cast concrete) and one strange effect of the gearbox-driven brake and power steering pumps was that on approaching a sharp bend you could brake, or steer - but not both at the same time!
An hour or so behind the wheel, though, and you had learned the D9's idiosyncrasies, and with that knowledge they were a very nice bus to drive - certainly better than the D7 or LD8 models before them, which had clutch and gearbox transmission and no power steering.
How would I compare them? How would a car driver compare a (modern) Rover 75 and a Rolls-Royce?
Both do their job very well, but one does it a bit better than the other. But there again, it cost quite a lot more.