Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Overheating tyres???

[spinoli1]

Hi Folks,

Now this may be a bit of an opinion biased question, but are track/road tyres inclined to overheat when pressing-on a bit at the track?

I first encountered this using Metzler Sportecs and have now got it with Diablo Corsas.

Scenario: Hot day at the track - 28 to 30 degC. (In France)

1 lap = 2.4 to 2.7 miles (different tracks - doh!)

5 or 6 laps into a session the tyre starts to slide occasionally powering out of corners in 2nd and 3rd gears.

I'm just trying to find out whether the sliding indicates that the tyre is overheating and traction is severely compromised. At the moment I tend to wick it down a bit if I get a slide, but this kind of ruins the session.

Or can I rely on the tyre to continue to give good levels of grip for anything up to 15 laps (after this it's me that overheats).

Don't misunderstand me - I am not a track god and there are plenty of peeps faster than me. I do like to go for it, and I generally ride in the fast group, or intermediate if I've not been to the particular track before.

FYI: I run 32psi in the rear Diablo Corsa at the track

Let the derision begin............

Spinoli

[Edited on 10-5-2005 by spinoli1]

[dickieducati]

from my experience yes. i had the same with supercorsa's (road compound) at brands last year and changed to sc1 and sc2's afterwards and they seem a whole lot better.

got some cold tearing on them though at the weekend, sunday run with cold road temperatures funnily enough.

guess you cant have it both ways.

[Shazaam!]

I suggest that you experiment with tyre pressure. Also, do a search on "Pirelli Diablo Corsa Review". Here's one rider's experience:

Pirelli Diablo Corsa Review - PART II

Now that we CR's have had some time on the Diablo Corsa tire, I thought I would pass on some of what we have learned. First and foremost, when you set the bike up right, these tires seem able to deliver nearly the SAME level of traction as both the Super Corsa and Dunlop race tire, and over a longer period of time. In fact, they inspired enough confidence that the faster CRs found themselves setting some pretty hard to follow lap times at Barber. For instance, Blandford, Garth, Peanut and some of the others, on both 600cc and 1000cc machines were dabbling in the 1:36 range with good results! To put this in perspective, many of the riders in the Advanced class were running 1:50s to 1:41s. Needless to say, these tires can turn out some very fast times!

I looked at Blandford's rear tire (he's on an R1 now, the *******) all through out the day and it was exhibiting very little wear. Conversely, I totally shagged a set by noon as I had used these at VIR the prior track weekend - AT A TOTALLY INCORRECT tire pressure. This is important if you are going to use these tires.

First. TRUST THEM. They are that good.

Second. Believe Pirelli when they tell you to use 36 pounds in the rear. Ignoring this cost me a tire.

Tire Pressure

We have found that trying to run Race Tire pressures in the Diablo Corsa will only hasten their demise.

Pirelli so much as told us this but being racers and knuckleheads many of us went our own path and used pressures far too low (and unnecessary) for the design. Going from running 30psi in the Super Corsa to 34psi or higher in the Diablo Corsa just seemed to alien too us so we stuck with what we knew - which in this case was WRONG. While traction was excellent, it soon fell off due to the abuse we were giving the rear tire, which is constructed differently than the Super Corsa and is meant to be run at much higher pressures. Street tire pressures in fact -- which in hindsight makes sense since this tire can be used with complete faith on both the street and track, unlike a race tire. Being a little inexperienced with this, many of us chased suspension problems that did not really exist. Once the light bulb went off and we started FOLLOWING Pirelli's recommendation for tire pressure, amazing things happened.

Example: At VIR I ran 31-31 (psi) and shagged a rear tire in 1.5 days. At Barber, I replaced the rear tire and used Pirelli's recommended pressure on the new rear. By the end of the weekend the tire still looked brand new or darn close to it. Unlike the tire I cooked at 31psi, the one set at 35psi or so just gripped like mad and never let up at the pace I was running.

I would not say the rear tire is "sensitive" to pressure settings. No more so than a race tire. Like any tire you have to be close to the recommended pressure for good wear. Pirelli often recommends 30 to 31psi for the rear Super Corsa as did Dunlop for the D208. You could go up or down a pound depending on conditions. Outside of those regions, the tires would cold tear or ****.

The Diablo Corsa is no different for track use. I experimented with 31 in the rear and shagged a tire. No surprise. I was FIVE POUNDS below the recommended psi!!! I then tried 34 psi and the result was drastically better. In the end I think we can recommend fully using 35 to 36 psi in the rear tire and you can except very good traction and life at this setting. Scott Powers

[Jools]

I was going to say that 31 psi seems low to me for a rear tyre, but Shazaam's post says it so much better.

It might also have something to do with your riding style? Are you hard on the gas while the bike is still cranked right over? If so, you might be trying to hard for the smaller contact patch you get when leant over.

Two choices. Use less throttle out of the turn (not want you want I'm sure), or....Stay hung off the bike on the exit, and pick the bike up before you get back on it. Then you can gas it harder on the exit and use less lean angle, so the bike will be on a fat bit of tyre.

[Edited on 10-5-2005 by Jools]

[spinoli1]

Thanks folks,

I had read the Diablo Corsa review and have run the rear at 36, 34 and 32 psi without significant change in feel or performance (bit of rear chatter under hard braking at 36 - possibly not related).

The wear pattern on the tyre seems best at 32 (nice and orange peely), and whilst the reviewer undoubtably knows what he is talking about, all of the other sources of advice that I respect favour lower pressures, especially at the track temperatures in the South of France (last July I was on track for 2 days at 39 degC!).

So, anyone got a clear answer to my main question - is the tyre overheating and losing grip and should I back off?

Or is a little slide every now and then to be expected and should I just suck it up? (Troy Corser's opinion not required).

Thanks for your input Jools, but if I wait to get upright before I gas it, I'm giving away my main advantage over the I4s, and I'm dealing with some pretty long straights here, so I need all the get up and go I can find.

BTW - I'm still running a 190 - could this be the problem? I have a 180 Diablo Corsa and a set of Supercorsas with a 180 rear ready for the next bash, so maybe I've already got a fix.

Bike is a 998 with an S upgrade kit.

Spinoli

[weeian]

im no master at this but alot go on about the 180 being far quicker for flicking about and turning faster.

/ian

[chris.p]

The wear pattern on the tyre seems best at 32 (nice and orange peely), and whilst the reviewer undoubtably knows what he is talking about, all of the other sources of advice that I respect favour lower pressures, especially at the track temperatures in the South of France (last July I was on track for 2 days at 39 degC!).


The higher the track & air temperature the the higher your tyre pressure needs to be, ie running at 34 - 36 psi in the rear will run the tyre cooler on a hot day than 31-32 psi in the rear.

Chris.

[spinoli1]

Thanks Chris-P,

I must say I've not heard that advice before, tho' when you think about it, it starts to make sense (I think). I will give your comments (and all the others) serious consideration, and I expect to end up on the 180 DC at 34-36psi.

However, I don't really want to get into a tyre pressure debate, I can listen to those for hours at any track day - and they never get fully resolved.

Noone has addressed the basic question - when the tyre starts to slide a bit after a few laps, does it mean that the grip is seriously deteriorating and that I should back-off before I bin it, or can the tyre be relied on to continue to provide good grip for the rest of the session.

I'm trying to establish whether the slides will get worse due to heat build up, or whether they will remain reasonably constant. After a high speed low-side (guess what - spun-up the rear on a corner exit) a couple of years back I would like to get some clues without another expensive destruction testing session.

All thoughts and comments gratefully received.

Additional info: The current set of DCs have now done 6 days on track plus about 1K road miles. The front looks good for plenty more abuse, the rear may get another 1 track day or 500 road miles before it is fully goosed.

Similar wear performance to Sportecs, but lots more grip (not so good in the wet).

Spinoli

[Old Yella]

Last year I had a similar problem with BT012SS's.

Pulled an instructor round for a few laps at the end of the next session and he told me I was getting on the gas before standing it up so the contact patch was the edge of the tyre which is not best to try and get the power on.

Made a concious effort to stand it up sooner coming out of corners in the next session and never had the problem again.

It was v warm and dry and the tyres were too hot to touch for more than a few seconds at the end of a session and was running 30psi.

Riding round the problem or good advice?
Worked for me

[spinoli1]

thanks Guys for all of your input,

I guess I'm going to need to experiment a bit with pressures, sizes, tyre types, style and suspension - should keep me busy.

Fortunately I've already got a 180 DC rear and a set of SCs with SC2 180 rear, so I'm fully set up to chop and change.

I'll let you know if I find a definitive answer.

Spinoli1

BTW - I've done a couple of hundred road miles since Nogaro, so the wear pattern on the rear has reverted to normal road type wear except for the very edges, and there's not much point in a piccie. Thanks anyway.

[Edited on 12-5-2005 by spinoli1]