Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Tyres > Tyre Pressures

[John W]

Thanks for the replies.

The following is taken from the pirelli web site:
"Tyre Pressure
It is important to always inflate the tyre to the correct pressure. Be sure to check cold inflation pressure frequently (i.e. once a week). Although most motorcyclists love to work on their bikes, they seldom remember to check tyre pressures. Correct tyre pressure, however, is critical for safe handling. Over-inflation or extreme tyre pressure will impair your riding comfort and decrease the contact of the tyre with the road. Under-inflation or too little air pressure will result in poor handling and the bike will be inclined to "wander." Improper and insufficient tyre pressure will also cause rapid tyre wear, an increase in fuel consumption, lower top speed, and provide less control. Remember to check the inflation pressure of your tyres weekly.

You will find the correct pressure in the operating manual of the motorcycle. The manufacturer's information is the minimum values only. With luggage or with a second rider the rear tyre needs an extra 0.2 bar, and for high speed riding the pressure of the front tyre should also be increased by 0.2 bar.
Attention: When the recommended pressure has been changed for use off-road (race track, off-road), it must be reset to the correct value before riding on the street."

The tyre fitment chart for the ST4S recommends 2.2 bar front, 2.5 bar rear for each type of tyre in the list presented.
I run with 2.5 & 2.9 due to the 2 up with luggage loading, rather thsn the 32/36 above, and that matchs the pressures in the bike manual.

Its interesting to see the same Pirelli tyres fitted to an 08 R1 (my other bike) are quoted as 2.5 & 2.9 for normal use. In fact Ducatis are the only bike I can see that gets quoted with a lower pressure...

Thanks again for the comments, I'll drop the pressures for at least the start of our next trip and see how we get on.

Cheers,
John.

[Cobbett]

Certainly the case that specified pressures seem to be notably higher for Jap bikes, never really understood that either.

[PS meant to say 'Diablo Rossos' rather than 'Diablo Rossis' - wishful thinking!...]

[skidlids]

from what I recall all the majority of tyre manufacturers recomend high pressure for road use.
These aren't necessarily the optimum pressure for each type of bike, road condition or riding style. But they know there will be know tyre issues under normal use even when encountering pot holes etc. and therefore you can't hold them liable for say a damaged wheel rim when encountering said pot hole or the resulting accident.

As Chris says on the DD bikes and other race bikes we drop the pressures to below 30psi whem measured cold as these are specific conditions, with the softer tyre caused by the lower pressure it flexis more, the radial belts move over each other more, causing friction and hence heat which in turn raises the pressure.

Many track tyres use compounds that rely on running hot to allow them to grip as designed and lowering the pressures allow them to get to these temperatures quicker, either that or use tyre warmers. Now you may put the warmer onto a cold tyre at 28psi but when its properly warmed you will probably find the pressure has rissen to around 34psi.
On the roads its hard to keep the heat in these sort of tyres and once they have cooled and the pressure dropped you wouldn't really want to encounter a pot hole especially if your using Mag wheels as i do on my 998 hence me usually running road tyre pressure when cold of 32 psi

[Monty]

John, I always ran my ST4S at 32F/36R unless on track when I dropped to 30 F/R. I always found the ST4S would feel a bit 'vague' on the steering with higher pressures.
When we were racing the TZ250 that ran at 36psi F/R-HOT-straight out of the warmers. Those pressures are on slicks and with a bike weighing 103kg don't forget.

John

[skidlids]

Originally Posted by Monty

When we were racing the TZ250 that ran at 36psi F/R-HOT-straight out of the warmers.
John

I recall a Pembrey meet where they were a fair bit higher than that John

Poor WJB found out the hard way

[John W]

Thanks guys.

Hopefully the ST won't be doing any more trips if the new MS1200 turns up in time. If I do still use it I'll try your pressures John.

I'll run the MS at the pressures specified in its manual and see how I get on.

Thanks again.

[Monty]

Originally Posted by skidlids

I recall a Pembrey meet where they were a fair bit higher than that John

Poor WJB found out the hard way

True-but then he was the one who set the pressures-or rather didn't check them.....................3 times he chucked it down the road that weekend-first race meeting-talk about a baptism of fire.

John

[WeeJohnyB]

Originally Posted by Monty

True-but then he was the one who set the pressures-or rather didn't check them.....................3 times he chucked it down the road that weekend-first race meeting-talk about a baptism of fire.

John

That has to have been one of the worst meetings ever. Sleeping in a puddle in a tent. Strong winds throwing peoples gazebo's down the paddock. Rain and dry in the same race. Slicks or inters or wets. You working half the night to fix the bike. Holbeach changing to the inters tyres and as I now know, he always over-inflates to get the tyre to seal properly, but some idiot (me) tried to make a change 30 seconds before the race and didn't check and after falling off at the fast right hander checked to find the tyres at 45psi. To be fair the other off was on oil and I was not the only one to go down on it. Can't recall the third off, maybe that's a good thing. That was a long drive home eh

Happy days

WeeJohnyB