some say every 8500 miles others after 7 or 8k...as a practice how often do u replace the tires?(Pzero rosso)
Exactly - same as all VT lambos.To the best of my knowledge the Gallardo's viscous coupler predates that, i.e. no wire goes to the unit.
I'm confused...Just posted this in another place. Andrew already replied that I should change back to Pirellis. I've gotten mixed reviews from others but they don't claim any special technical knowledge - so far just opinions.
Here's my original post which is relevant here:
This past week at GIRO I met a Lambo corporate guy who trains the Lambo techs. We got into a lengthy, detailed discussion on tires because last week we mounted Michelin Pilot Super Sports on the Callistos. The PZeros were past 50% life but more important were getting old. We wanted good tread for our trip where we correctly anticipated some wet conditions. We love the MPSS that we have on the Z06 - they are fantastic as DD, track, and in wet, and have worn like iron.
The tech said this is a bad move. He explained in detail the viscous coupler (essentially like a wet clutch) works on a signal from the computer (CAN) to put more torque to the front wheels. Lambo goes to great lengths to homologate the system with approved tires (Pirelli PZero & PZeroCorsa) on OEM wheels. The rolling circumference on tires can vary even if they are the same size and spec. It further varies depending on the rim to which it's mounted. And it varies even more under dynamic measure (which they don't really do). Plenty of things can change the rolling circumference including air pressure, rims, ambient temp not to mention distortion at highway speeds due to different compounds and maybe other factors not known or catalogued.
It may not be off much - but even a small difference in rolling circumference measurement will be multiplied exponentially at highway speeds and dramatically increase the signals received by the viscous coupler.
His point: if the CAN sends a signal to put torque to the front wheels at "X" times at "X" mph - if the rolling circumference is off (or out of measured tolerance for how the system was homologated) - it may send many more signals and prematurely burn out the viscous coupler. They have documented cases of problems that disappeared when tires were changed and they think it points to differences in rolling circumference.
This guy is passionate and extremely knowledgeable about Italian cars and has an obvious love for all thing automotive. He is hands on and learns by taking stuff apart (he is not just book smart but has tons or real world tech experience on lambos especially but other italian brands too). He has nothing to sell and could care less about the Pirelli brand. His main concern seemed to be for us not to screw up our car - and he recommended we ditch the MPSS and go back to Pirelli.
Maybe a car that won't rack up miles won't see a problem. As you guys know - we DRIVE our car - and I don't plan to stop. It's been relatively trouble free with only minor annoyances - all fixed under warranty (which has since expired). It seems pretty bullet proof - and I respect this guy's opinion. I know many who go with after market rims and different tires and I'm not reading about lots of problems - but maybe it's because most of those cars are very low usage (low miles).
I love the MPSS but don't want to create a mechanical problem. For those who don't know - it's a 2009 LP560. I bought it new in 2011 and it currently has 14,000 miles. It's stock.
Thought I'd put this question out here for the "devil's advocate" point of view and to see if anyone else with a "driven" car on "unapproved" tires has experienced issues with their viscous coupler or shifting or AWD issues.