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Discussion Starter #1
some say every 8500 miles others after 7 or 8k...as a practice how often do u replace the tires?(Pzero rosso):eek:
 

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6 years thats great...how many miles we talikn'? I put about 100 miles each weekend...in the past 5 months 2k....i drive it normal, dont race it never track it...once or twice brought her up to 110mph but other than that keep her 80 or under with 50% city driving....(not abused at all) guess i'll be getting new tires once every year and a half...oh well...i was prepared for the annual brake fluid flush and oil change but not this...its not the $$ its the inconvenience:mad:
 

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assuming normal wear and tear your supposed to max out on milage with a set of Pzero's around 15,000. Or rather i've never heard of anyone getting more than that out of a set. This includes people running them on Porsche/Audi/Ferarri/Lamborghini.

obviously the more hard you run the car, the faster you burn through the tires.
 

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Discussion Starter #6
i was at a lambo dealer recently(I know i cant believe they still exist either) and the service guy said every 5500 miles or every 2 years the pzero rosso's gotta go...i'm at 7k and down to the wear bars
 

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All depends on how you drive, and with that said you need to keep an eye on the wear... and stick with the Pirellis, other brands have caused issues on the Gallardos!
 

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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.
 

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> [viscous coupler ... signal from CAN ... circumference]

The shaft from the rear is driven by the engine.
The shaft from the front is driven by the front wheels.

Both shafts end in a bunch of disks with hole patterns.
Those disks are placed closely, but they don't touch.

The whole thing is enclosed in a case, filled with liquid.
That liquid is sensitive to heat, stemming from friction.

The more heat it "sees", the more "goo-ey" it behaves.

Normally the front and rear wheels spin at the same rate.
Hence the shafts and disks do too.
Hence there is little flow of the liquid through the holes.
Hence there is low friction.
Hence there is low heat.
Hence the liquid isn't "goo-ey".

Now consider the case of a front vs rear difference.
The shafts and disks will spin at a different rate.
The liquid will be dragged around more.
The friction will result in heat.
The liquid will behave "goo-ey".
To the point where it hardens in those holes.
Voila, the rear shaft will end up driving the front shaft.
And so power goes to the front wheels.

The normal front vs rear difference in rolling circumference
is tuned so that a certain amount of power always goes to
the front -- AWD. The brand of tire doesn't matter -- only
the front/rear ratio does.

At the same time the viscous coupler -- disks with holes +
fluid -- is tuned so that it kicks in at a desired point (i.e. X
friction = X temperature = fluid starts to behave differently)
as well as a desired rate (i.e. X temperature change / time
results in slow/fast fluid change). While it is possible to tune
for a specific brand of tire, the Gallardo comes with various
different Pirellis, and Pirelli has manufacturing variation -- so
Pirelli vs Pirelli is not much different from Pirelli vs non-Pirelli.
On top of that, the viscous coupler is a mass product, and
as such it has variation too. Toss in different temperatures,
different road conditions, different driving styles, plus what
not, and that whole "only Pirellis are guaranteed to not f***
up your viscous coupler" gets rather weak.

In a modern E-diff you can control the fluid's behavior with
and electro-magnetic field -- magnetorheological fluids, just
like in some shock absorbers.

To the best of my knowledge the Gallardo's viscous coupler
predates that, i.e. no wire goes to the unit.

But yes, the car does have a notion of how circumference.
It needs that for the ABS (which detects slip via difference
and then applies brakes).

There.

No go out drive! :)
 

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LAUTLOS - thanks for the nice laymans explanation. My conversation with this guys lasted at least 90 minutes and I asked how it worked. He said the same thing - it's a liquid that increases in viscosity when subject to heat (hence the name) and as it becomes closer to a solid it acts almost as a wet clutch.

Much of what he said is what you said.

He didn't say the MPSS would screw it up. He said they didn't know what effect they'd have because Lambo hasn't tested them.

I worked for a manufacturing company for 25+ years. Our products were used in conjunction with other products. We could only test systems comprised of our products and would never endorse using other products due to liability.

The MPSS may work perfectly well with the car. He acknowledged there are tons of variables that can change over time with wear, and can be difficult to measure. For sure it's a range. What he didn't know was how the MPSS would work with the car cause they've never been tested.

I understand his position. Our decision to keep or change the MPSS will be based on research and as much data as we can muster.

I did get a great education from a guy with the patience to answer all my questions and explains things in terms I could understand since I don't have a lot of technical knowledge.

To some extent his concern is the corporate line and some CYA - but I also think he's a guy that has seen some problems caused by different tires and his thinking is to keep it simple and stay with the tried & true tested Pirelli.

If the MPSS weren't such a spectacular tire this decision wouldn't be nearly so difficult. I usually like to stay OEM and go along with a manufacturer recommendation. In this case I want to find a way to make the MPSS work because I like them THAT much better than the Pirelli's.

Thanks so much for your detailed post!
 

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To the best of my knowledge the Gallardo's viscous coupler predates that, i.e. no wire goes to the unit.
Exactly - same as all VT lambos.

The only other point I would make is the sequence. The fluid is subjected to "shear" force which given the close spacing of of the plates causes it to heat quickly which in turn causes the fluid to act like a solid.

-mick
 

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> Thanks so much for your detailed post!

You're welcome!

And yeah, I'm of the same "we know what X does because we tested it, but
we don't know what Y might do, simply because we didn't test it" school. :)

I am not looking forward to the day when they stop making PZero Corsas.

And I am wondering how long the G viscous couplers will last -- so far I have
not yet seen any replacements due to age... but they won't last forever.
 

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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.
I'm confused...


There are NO electronics whatsoever involved in the AWD system. Aventador, si. Gallardo, no. :confused::confused:

Again, the variance between manufacturers is often less than the normal variance from wear over the tyres' life (front or rears wearing out faster, pressure differences, etc.)é



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