Piken, the tires you mentioned are spec'd by their manufacturers to run 26-30 lbs.
They're designed for track day use on lighter bikes (like your zx-10)
Tough to make a comparison to street bikes with Sport Touring tires.

yes, that is the only reason why I mentioned the zx10 because lighter bikes can run even lower pressures.

Then again the zx10 manual states F 36/ R 42 so shouldn't that be where I should set the pressure?

The Front tire on the zx10, Pirelli Diablo Supercorsa SP states
the same as the M5 on the zx14 ( max load 520lbs / 42psi )

It's just that some people take the manual at 42 / 42 as the
best psi to run on the 14 (max load / max psi for tire)

I guess I'm trying to point out that 42 / 42 and weight is the point to consider.

I think 42 / 42 is taking in consideration of having 2 people and perhaps
a little extra cargo, max load / max psi, covering their butts.

Drop to 1 person and no cargo you would be taking off 150-200lbs, should you not
drop the psi to compensate or.... are you overloading the tires when riding with two people at 42/42

I don't know, I'm currently running the M5's and I cannot seem to get any heat in the tires until I'm
at F 36 / R 34, which is only, Front -6 psi and Rear -8 psi from max tire pressure. I started at 42/42
when I got the bike and the tires scared the hell out of me. I kept dropping psi and even posted that
I couldn't wait to trash the M5's. Finally I got down to 36/34 and they are much, much better.

Everyone will be different, I guess.

Summer 38lbs cold pressure, winter 40lbs cold pressure front and rear for me. Anything less and my tires wear funny.

I set my tire pressure 36 front and rear works perfect for the hot pavement here in Albuquerque, the tires grip way better at that pressure. maybe places were it's cooler you would want the pressure to be higher.

Here are some tips I have picked up over the years from people who make a living by preparing race bikes.

A bike setup rule (from experts) is that tire pressure should NOT do the work of the suspension and you should NOT reduce tire pressure to improve ride comfort.
If you find that you need to reduce tire pressure to improve ride comfort then the suspension setup is incorrect for the rider / bike combination, if this can't be dialled in by adjusting the suspension then spring rate and valving must be changed to suit.

Track and road tires are designed for different purposes and tire pressures should not be compared as on the track the tire needs to perform for one club or race event at optimum level, normally 50 to 100 km's, on the road we use the same tire for a few 1000 km's. Race tire carcasses are designed to meet a different set of criteria than is required for road tires.

Lower tire pressure results in more flex in the tire wall and will result in higher temperatures,some riders see this as better tire grip but this grip is usually short lived and will destroy a tyre very quickly.
Therefore, once the suspension is sorted, what tire pressure is used depends on tire type, rider / bike weight, air / road temperature, road surface condition (abrasive or smooth) and ride style.

As HanksZX rightly posted that Michelin recommends tire pressure after a ride should be 10% higher than the cold tire pressure you start of with.

So for optimum grip and tire life we should check / set the pressure, using a good known pressure gauge (not use the service station pressure gauge), as conditions and riding style changes.

nkd.... So out of all that you forgot to tell us what pressures you
are running on your zx14?

Tires and tire pressures are a part of a bikes suspension or
else why not just have solid foam filled tires?

Lower tire pressure results in more flex in the tire wall and will result in higher temperatures,some riders see this as better tire grip but this grip is usually short lived and will destroy a tyre very quickly.

Motorcycle tires "flex" differently than cars. The flexing is not in the tires side walls,
They flex along the diameter of the tires, forward to back. Which is why swerving left to
right to warm up a cars tires work but not on a motorcycle. The way to warm up bike tires
is by hard accelerating and hard stopping.

Not only lower tire pressures cause flex and heating, but you forgot to
mention overall "weight load" on the tire as well.

Which really has been my point in the thread. The bike calls for 44 psi and some
think that is golden, that is the pressure to use all the time.

I say "BIG" difference in psi setting from a single rider to 2 riders.

2 riders and gear, 44psi (max psi) and prob max load for tire (? 590lbs)

1 rider and no gear, a lot less that 44psi. Riding single, I'm at 36~38 front and 34~36 rear.
and if I want a little more heat I'll even drop to 34f / 32r for a frisky run.

Yes, higher heat in a tire can lead to a shorter tire life, that's the price you pay
for added grip. Increasing the temp of a tire helps to peel away the outer rubber
to keep fresh rubber exposed.

* Last updated by: piken on 12/26/2015 @ 3:17 PM *