Tyre pressure Diablo SC

[zxr4000]

Guy's,

How much perssure do you set your tyres for racing conditions and which compound, specially for the rear. i've got a unconfirmed Pirelli document but I don;t know if those values still count for our bikes. The document only mentions 180/190 rears.

Here's the document: http://zxr409racing.nl/media/download_g ... blo_SC.pdf

[-GQ-]

These work for me:
SC1 front - about 29/30 cold; 35 hot
SC2 rear - about 27/28 cold; 33 hot

Cold means first thing in the morning.
Hot means either in decent warmers for an hour+, or straight back from a race/track session.

[zxr4000]

You're measuring PSI? My reason for asking is my tyres are showing heavy wear on the right hand side. Looks like a cold tear so I was thinking about lowering the pressure to get more heat in it..

[-GQ-]

Yes, it is psi. Some conversions:
28psi = 1.93bar; 30=2.07 ; 33=2.27 ; 35=2.41

Not sure about what causes cold tear, how to correctly identify it and how to prevent it. Will leave that to the experts.

[lucky77]

more likely to be a badly set up rear shock than the tyre pressures - unless you are wildly off what has been posted.
I have had cold tear from the michelin power ones, but Pirelli super corsa's always wear great on my 4. Saying that I use SC1 front and SC2 rear. Were you using SC 1 front and rear??
Cold I use 30 front, 29 rear. anywhere around that mark and you doing what the majority of the paddock do.

[Fatspanner #44]

I run 27 front and rear on track on the supercorsa

[zxr4000]

I'm running SC2's at the front and rear.

At first I thought it was the suspension setup as well untill someone mentioned my tire temp. could be too low on the track. So to get more heat into it I was thinking about lowering the pressure a bit or try harder .

Next practice I'll be more acurate measuring tack temp. tyre temp and suspension travel to see what's going on.

[zxr4000]

I run 27 front and rear on track on the supercorsa

Would that be measured hot (straight from the track) or cold?

[sinap]

We went on a Pirelli test day last year and were given advice by there test riders, set the tyre pressures hot in the warmers after about 1hr 30-32psi front, 27-30psi rear.
Measure the tyre pressure after the race the last lap should be done at racing speed imediatly as you come off track not after going back to your pit, both front and rear should be 34.5psi-36psi, as lucky says a big factor in cold tearing is the suspension settings.
We have a base setup for each track we go to, then fine tune this setting after each session if required, if we spot signs of cold tearing we would increase compresion damping by two or three clicks which normally does the trick, this works for my bike with my base suspension settings and my lap times and may not work for anybody else.
The other bit of advise we were given was that it was the heat cycles that kill the tyres, keep your tyre warmers on at all times ( off track ) minimise your time in the holding area as much as possible, use the warmup lap to get heat into the tyres by going as close to race pace as you can, the slower you go the more heat you lose.
Hope this helps

Si
#91

[zxr4000]

Thanks I'll keep your advices in mind. What is interesting though is that I was thinking about lowering the compression damping to make life a bit easier on the tyre. So maybe I thinking the wrong way. Got a picture on my web site so maybe you recognise it http://zxr409racing.nl/pages/gallery/cold-tear160.php

[zxr4000]

Hi Guys,

Did ome testing during qualifying practise. That temp was 19 degrees. Ambient was about 22 n the moring. Tire temp was 44 degrees. I've lowered the compression setting a bit and lower the tire pressure to 1.7 bar. Now all is OK. In the afternoon when the track temp went up the tire temp went to 55 degrees so still a bit low. Next time I'll try a softer compound..

Roy