One of the things I’ve long believed is that recommended tyre pressures should only be seen as a place to start, and not something that a rider has to rigidly stick to, yet an awful lot of riders make a big thing about checking their tyres and pumping them up precisely as the handbook says.
The obvious facts that get ignored are that no two riders are the same weight, which will clearly affect the way the tyre deforms and responds to machine input, few riders will use the original equipment tyre after it wears out, but will put an alternative fitment on which won’t have the same characteristics, and those replacement tyres are available for wide range of machines of different size, weights and performance characteristics.
In fact, look closely and many models come with different tyres from new!
The XJ6 Diversion I test rode last year didn’t handle particularly well on the Bridgestone BT021s that it was fitted with, and it was something of a revelation to find that the Dunlop Roadsmarts fitted to another, identical, model actually suited it far better.
So I was interested to see in a recent BIKE (the one with the free pressure gauge on the front, as it happens) that they’d tested a bunch of tyres at recommended pressure, then progressively let them down, whilst sending the riders out to see how they felt.
What particularly caught my eye was that many of the bike and tyre combinations felt best to the riders when the pressures were 5 psi down on recommended.
That’s interesting because I’ve been running non-recommended pressures for years.
The rear I’ve usually left at the recommended pressure as that seems to keep the bike straight line stable at speed.
But I’ve found that front radial tyres often give me a far better ‘feel’ with around 4-5 psi let out, offering more progressive roll from the vertical, and better feedback and a far more “planted” feel once leant over in corners.
Specifically many of the front radials I’ve ridden on since the mid-90s don’t seem to want to roll progressively from the vertical but have a “tippy” feel as if they want to head straight to maximum lean. They also have a tendency to feel as though they are bit vague about where they are going, giving the impression of running wide at full lean, which isn’t particularly reassuring on the road.
Given how gradual changes to the way a machine handles are often something that a rider is unaware of, because they are constantly compensating for the changes caused by wear to the tyres, suspension, bearings and all the other bits and pieces that keep a bike stable, it was also quite informative to see that some of the riders reported they could feel little real difference to the machine’s behaviour with as much as 10 psi suddenly missing from the tyres.
None of this is to say you shouldn’t bother to check tyre pressures for months on end, but it does suggest that it’s worth experimenting to see if you can fine tune them to advantage.