When a vehicle is "homologated" or "type approved" or whatever they want to call it nowadays, the vehicle manufacturer tests the vehicle over a range of pressures and will use the best pressures for a compromise of comfort and handling, tyre life generally does not feature. These pressure ranges are offered up by the tyre manufacturer based on the vehicle axle weights, driver only, part loaded and fully loaded.....
Motorcycle tyres are running much closer to the casings weight tolerances than car tyres, again, generally speaking.
A classic example over here of a WIDE range of tyre pressures was those recommended for the Ford Granada Scorpio, the driver only pressures were something like 28F 36R (these are not accurate just a guess from memory) but the loaded/high speed pressure was 38F 46R.......
If you set the higher pressures then forgot to lower them the car handled like a breeze block on castors in the wet...... and the tyres wore out real quick.
If you did not set the higher pressures for the high speed and load, the car was positively dangerous and risked catastrophic tyre failure at high speed, the tyre pressures would go high as the temperature built up to very, very high levels.....
Does this mean we should put more air in our tyres when we load our bikes right up?
No, what we should do is stay within the tyres rated load and ride at a more "respectable" pace.
We should listen to what the tyre engineers VIA the vehicle manufacturers plate.
OF course, there are occasions when as a tyre company technical sales representative I would recommend a higher pressure for a vehilce, but it had to be based on vehicle axle weights, vehicle loading and duty cycle (how long the vehicle ran loaded).
Over time and with experience of a very large number of vehicle inspections and pressure recommendations, one was able to make "educated" guesses at the approximate recommendation, subject to monitoring tyre performance over days, weeks or even months.
I did this on a daily basis for a great many customer fleets and never saw anything but good results when fine tuning took place. This was necessary as every vehicle is different, even two vehicles of the same size, power and loading with the same driver on a regular or even permanent basis.
I had some smaller van fleets where we achieved over 100,000 miles on rear tyres.
I had a leased people mover with Michelin fitted which had over 97,000 miles on the rear tyres, with plenty of tread remaining and had regularly achieved over 25,000 miles on the driven front wheels.... conversley another people mover I had achieved around 23,000 maximum on the fronts but only 60,000 on the rears.... it had Continental tyres fitted... which had nowhere near the grip levels of the Michelin and did not inspire confidence at all, no matter what you did with the pressures....
Bike wise, I run Avon these days, mainly because I can't afford the UK price for Michelin, or Bridgestone, when compared to Avon. I run a minimum of 36 lbs/psi in the front, but normally run 38 lbs/psi..... in the rear I run 42 lbs/psi but will not panic if I am only riding locally and the tyre is at 38 lbs/psi... if I am going further afield and intend to run highway speeds, then the rear is set to 42.
Maximum pressures for casings moulded into sidewalls are there for a reason, the casing, like your bike, has design limits.
Would you ride your bike to maximum revs in every gear and at maximum speed ALL day?
No, that demonstrates no mechanical sympathy or sense...... then why do people do it with tyres when they are all that separates them from the tarmac and potential disaster?
Discuss.
