Pirelli tire selection

That's a wildly subjective question relative to the track you're riding, your pace, desired outcome and what compounds you're using (and a few other things). Best to check with the trackside vendor with all your specific details and get a proper recommendation with all your details.

As a very general rule, if your (properly recorded) hot track pressure is more than a 1.5 psi rise from the warmers, you did something wrong. But that "wrong thing" could vary from warmer thermostat setting to power supply to gauge inaccuracy to setup to compound selection and suspension setup, to name a few things.

 

Same.

Also account for your garage location at COTA. That hot pit lane can be long if you're pitted at the end of the building toward track entry.

 

I use a LongAcre Pyrometer to check the actual temp of the pavement, the temp of my tires while on the warmers and when I get off track. I also look at pressure differences based on tire temp. Obviously if the tire is hotter when I get off track, the pressure will be higher. But sometimes the temp can be slightly lower This was happening at Pitt a few weeks ago on the Friday before the ASRA weekend.. I was coming off the warmers at 180F but I was coming in at around 145-160F after 6-7 laps in the morning. Outside temp was low 50s and track temp was about 65F in direct sunlight. I was losing 1.5-2.5psi. So I upped the psi on the warmer and was good to go for the day. (it never got much warmer)

This has really helped me to get tires into an operating window much faster.

 

I dont get that deep into my tire temps. I use a simple infured laser temperature gauge, I plug my warmers and check the tire temp as they rise until they reach 80c, if it goes over I unplug the warmers until they reach the heat. Then set the tire psi!

The way the bike handles and the condition of the tires is what determines if I go up or down on the psi. If you think you can just leave the same tire psi pressure you are wrong and actually slowing yourself as a rider or destroying tires.

 

Uhhh... OK?

Why do you think I didn't list what tire pressure I run? Could it be because it's different for every track, track conditions, wear and how I like the tire to FEEL to ME?

I responded with a generalized summery on my process to get the tire where I want. As well as some objective factors that play variables on how that process is achieved. I did not list subjective factors such as "feel", because that's not the same for everyone, obviously.

 

You guys run 32 psi hot in an SC1 front?

 

That's in Pirelli's range:

 

My local tire guy told me this weekend Pirelli is going to stop making 160 Slick Rears. Anyone else got any info in regards to that?

 

I was told that they are no longer making the 160 SC3 DOT when I tried to buy some earlier this year. So it wouldn't surprise me that they are going to stop making the slick. I guess I need to look into a wider rim for my SV.

 

I believe that chart could be out of date. For example on the Rear 140/70 it says 24-26 PSI but if you go on Pirelli's website their recommendation is 26-29

 

Some good info on this page about slick compound selection. Might already be in the thread.

https://www.pirelli.com/global/en-ww/road/motorcycles/tyres/the-dream-compound-49540/

 

Here is a link for the current tires and recommended pressures;

https://www.ctracetires.com/pages/pressures-tech-info

 

The fun part of figuring out ideal tire pressures is that every process for it is indirect. Whether be it measuring temperatures with a probe before/after a session or pressures as soon as you roll in etc. I got tired of chasing all that, got annoyed and built a logging solution for it that's compatible with AIM dashes (Solo2 DL and up) https://github.com/torqu3e/aim-tpms

The kinda insights I've had from it has really helped me dial pressures to exactly what I want on the track. Its also highlighted how far off most pressure recommendations are and the effects of temperature or even half a lap taking it easy.

 

That's friggin cool. I know Aim sells a kit for cars, but I'm not sure how you'd retrofit those sensors on MC wheels and it's pretty $$$.

Could you share some squiggly lines with us?

 

Yeah I saw what they offer, balked at the price and started researching building one. From that point on it was a matter of getting the individual pieces together.
The squiggly lines aren't much but here's a screenshot of the first session of a cold late march morning at Thunderhill east where I sat in the hot pit too long and then someone in front of me wasn't willing to book it from the get go.

Temperatures are basically air temp as read by the sensor on the valve in Celsius. HR is heart rate which comes from a chest strap through the same system. You can see the front PSI dropped a bit in this particular lap. IIRC the session would've started with 31 or 32 PSI front, 24 PSI rear fresh off 80C/180F warmers.

 

An alternative to this is using a third party TPMS system that is available off the shelf.

An easy integration with AIM is the I2M TPMS is possible with a custom CAN configuration. I use it on my bike that has the AIM MXs dash on it, and I've got the I2M TPMS connected to the CAN2 interface.
Same could be done with the 2D TPMS, which is quite a bit more expensive, but has the added benefit of relative humidity sensing which is helpful for tracking pressure rise delta and ensuring you have a good nitrogen purge, if you use nitrogen in your tires.

Likewise for heart rate, I have a 2D ANT/ANT+ receiver that pairs with the Polar H10. We used it on our Superbike last year to measure our riders heart rate.
We later expanded into a Moxy sensor to measure our riders SmO2% while on track to tailor his training regiment, as well as integrating the Core skin/core temp sensor to try and prepare for COTA which was expectedly hot, and 3 races instead of the usual 2, which is absolutely brutal on the body.
Although those two had to be recorded using Garmin and later exported into CSV for import/sync with session data.

It would be fairly trivial to build a CAN configuration that has both the 2D ANT receiver, and TPMS from I2M/2D onto a single CAN, you'd just need to make the wiring adapter which is fairly easy as well if you made it this far.

 

No ETA for the 160 SC1 SBK. They need to get worked into production. Pirelli has a good supply of 160 SC2 in the states and until the 160 SC1 SBK situation gets sorted out, Pirelli has imported the 160 SC1 DOT. Should be making their way to the trackside vendors soon.

 

We'll have the 160 SC1 DOT available for the remainder of the season as well as the 160 SC2 SBK option. I'm getting my first shipment since they arrived stateside this week.