After I began searching into this subject I believed it was gonna take me ten minutes to locate a definitive answer. Four hrs later I’m neck deep in graphs, formulas, research papers, etcAnd appears like lots of cycling nut PhD students did their thesis’ on researching the optimum tire pressure for any bike. Glad to determine a number of them do something helpful.
There has been a couple of common styles throughout all of the research I’ve been digging using that I’ll explain:
Tests have proven that moving resistance is high at really low tire demands. As demands increase, tires roll faster, however the performance levels off in a certain pressure. Beyond this time, greater inflation offers minimal performance enhancements; A correctly inflated road tire (700x23C) at ~85 psi has nearly exactly the same moving resistance because the same tire at ~115 psi. This is just a marginal difference – with respect to the weight from the rider. But in the greater pressure, the rider surrenders a few of the cornering traction and luxury essential to cycling.
There’s a notion that running tires at high demands of 115-140 psi in some way helps make the bike roll faster. The thinking behind this is it reduces moving resistance because less surface part of the tread is touching the street. However, at greater demands, internal deficits because of flexing from the casing decrease, but suspension deficits because of vibration and bouncing from the bike increase. The resulting vertical movement is taking forward momentum. This cancels out the majority of the gains the elevated pressure tried to provide. What individuals high demands do is accelerate put on, compromise handling and provide an very harsh and nervous ride.
Everyone knows what pressure their tires are ranked for – it’s printed around the sidewall. However, very few people understand what their rims are ranked at. Rims change with time too. As the brake surface wears, high tire demands will progressively cause your rim flanges to flare outwardly. Eventually, there is a time the forces attempting to blow your tire from the rim will exceed ale your tire and rim to face up to them. It always happens in the center of a turn and you’ll be on the floor before very long. Also, heavy braking on descents will heat the edges while increasing tire demands beyond their tolerances.
Optimum tire pressure is really about moving resistance. This can be a whole other subject that is dependent on casing, durometer (hardness from the rubber), rim width, air temperature, load along with other variables. This debate inevitably adopts clinchers versus tubulars. This really is like talking about capitalism versus communism, Jesus versus Allah, Cheesy versus Shimano, Mac versus PC, Coke versus Pepsi. You’ll hit exactly the same brick wall everytime.
What can I suggest for optimal tire pressure for the clinchers? If only I may offer you a chart and a simple answer. Things I will say is you can’t fail if you’re somewhere in-between your suggested pressure printed around the sidewalls of the tires. My Michelin Open Pro 3’s say 87-116psi. Perform the low side of the tire’s tolerances if it’s wet out. For those who have a tire such as the Vittoria EVO that’s ranked for 115-140psi, make damn certain your rim is ranked with this too.
Optimal tire pressure for tubulars (known as singles within Aus) is really a different subject since both tire and rim are created in a different way and could be run at greater demands.