There is less effort required because there is less of the tyre in contact with the road. Perhaps it doesn’t matter on a bike but if you have less rubber on the road there is less grip – and on a bus that might be important.
If you have only just purchased the bus you should check the tyres have adequate load rating – what is the full tyre size on the sidewall including the numbers and letters? For pressure on another forum a few years ago @snotty wrote: Peer through the steering wheel at the large sticker attached to the top of the steering column... But if it is missing this is the page from the handbook.
It's a case of compromise, if tyres are too soft the sidewalls will roll around if they're too hard they'll leave the ground on every bump, cornering will exaggerate both of these.
If the modern tyres are the correct size, type and load rating they are exactly as VW originally intended for the vehicle.
Also worthy of note is that most garage gauges are inaccurate. This is a bit of a nightmare for us at work because all new cars have to have tyre pressure monitors as standard.
In my Westy the original sticker on the steering column says 30psi front and 40psi on rear when fully loaded which is what I use on the c rated tyres and standard steelies all times
Apart from handling, having the wrong pressures can seriously affect the wearing of tyres. Too high and they will quickly wear down in the centre whilst hardly touched at the edges and vice versa.
The tyre profile and intended design goals are completely different. The bus tyres are essentially a "U" shape profile, designed to offer significant traction and load carrying ability. Over inflate them and you deform the side walls, reduce the contact patch and bugger up the load tranference through the side walls. Road bike tyres are designed to carry skinny blokes with a unhealthy Lycra fettish at warp speed with the absolute minimum of friction loss with the road surface......... I suspect they are also secretly designed to offer the minimum amount of grip possible as natural population control of those with the Lycra issue
Mountain biker - a proper one too.....never ride on the road.....prefer honking great hills and the great outdoors
Checked, they are correct commercial tyres ! Now set at 30 psi front and 42 psi rear. (providing the gauge is accurate !)