First time Testa owner, question about air pressure

Hi Everyone. My Dad (Glenn Wickstrom) passed away last year and I am trying to maintain his 85 Testarossa Euro. My Dad knew everything about cars, and I am a car person myself, but this Testa is a beast. I know I need to have it serviced about every 5 years. I just had brand new tires put on it extra Z rated. So my first question for right now is what pressure should these tires be at? I left the place with 25 psi in the fronts and 35 psi in the back. Is this right? The tires will go up to 50 psi but I know that is definitely not what to do.

Thanks in advance.

 

25 psi in the fronts is too low. I've been running 35 psi in both the front and rear (but if you want to go triple digits they should be even higher).

 

Ferrari recommended pressures for the TR is 38psi front 38psi rear.

Brian Brown
Patrick Ottis Co.

 

Ahhhh, OK, thank you! This is "TubiTubi" but I decided to change my member name to TubiStyleTesta instead.

No 3 digits around here. The car is in Oregon in it's own garage. So I'll have to get some air in the fronts. I spoke to a couple of people in town, and they recommended 25 psi in the front because the car is so light in the front. If you have remarks about that I'd appreciate it.

Thanks,
TubiStyleTesta

 

Ferrari arrives at correct tire pressures by track testing with engineers from both Ferrari and the tire companies, not by guessing. I would suggest you use their well researched and tested data.

 

Agreed!

Since it is unlikely that you will have put on tires in 2010 that were known to Ferrari in 1985, you will likely have to experiment a little to find the correct tire pressures. The right instrument to do this is a probe tipped Pyrometer.

With this device, you will measure the tire contact patch in three locations across the tread. You are going to be looking for an even temperature gradient from the ouside of the contact patch to the inside of the contact patch. Inflate the tires to a normally safe range 32-35 PSI all around, and go drive briskly but not dangerously down a nice long (10 mile) country road. At the end of the road, and with no cool down period, Get out and immediately measure 3 temperatures on all 4 tires and write them down.

A) if the tire temperature in the middoe is higher than the average of the inside and outside temperatures, the air pressure is too high. If the middle temp is lower than the average the air pressure is too low.

Once you get the tire temperature profile linear, you can then use the temperature measurement to adjust camber.

B) if the inside temperature is more than 20dF greater than the outside temperature, less camber is indicated. If the inside temperature is less than 10dF hotter than the outside temperature, more camber is indicated.

Once you get the tire pressures and tire temperature profiles in the right ball park, if the front temperatures are less then the rear temperatures by more than 20dF then you should add some Toe. If the reverse is true, you should subtract some toe.

After you get the tires working correctly. Let the car sit in the garage overnight and then in the morning measure the tire pressures. Write these down, and these are the tire pressures you should continue to inflate this set of tires to.

This probe tipped pyrometer cost just over $100 and will save thousands of dollars in tires over the life of one Ferrari.

 

Read and follow Mitch's post...good stuff but overkill for the casual owner.

To start, Ferrari's original recommendation was not for the tires you are now using.
When I got my Goodyear Eagle F1's which were rated for 45psi I put in 45psi. A further conversation with the tire dealer, he said start at 35psi and go up or down as needed. (read Mitch's post) With the car not being tracked or driven hard, 35psi it has stayed.

 

You're kidding right?

I think he was looking for recommended pressures to do a little street driving. No need to do a bunch of research for that. Just read the numbers out of the owners manual.

 

The car isn't that light in the front, it isn't a vintage VW beetle. Unless you are going to be racing this car at it's limits the owners manual is the place to go. Less air pressure in the front tires will also put more wear on your front steering/suspension in low speed driving.

 

Condolences for your loss, I'm happy you're keepping the TR in the family

 

C'mon, give the guy a break. What, ya think he has a Formula car?

+1, it's amazing how someone can make something easy so difficult!

Sparky

P.S. I say 35 at all 4 corners; that's what I use.

 

No, he does not need a forumula car all he needs is operating transportation.
But this short list is applicable to any new tires on older car--what should the air pressure be: So,
If you put larger tire footprint on the road, the above is applicble,
If the rubber compound is significantly different, the above is applicable,
If the tire construction is significantly different, the above is applicable,
If you alter the ratio of contact patch front to rear, the above is applicable
If you raise or lower the car significantly, the above is applicable,
If you start using the car differently, the above is applicable,
If you start using the car in different weather, the above is applicable,
Do this and you save money over the period of timeyou own and use the car.

So, basically, if you put on anything but an exact replica of the factory chosen tire, the above is applicable.

 

amazing that Ferrari doesn't certify new tires on their cars.

Porsche (still) does, even for cars that are waaay out of production (e.g., 356s).

 

Granted, but if you're not tracking the car is the above applicable. Your criteria is applicable to any car/tyre.

Tyre wear is a non-issue. They wear out and you replace them when you need too.

I know your post is meant to be helpful and useful and I'm not trying to be antagonistic, but it even confuses me.

Sparky

 

Hey guys, thanks for all your help. I really appreciate it, even the very complicated post. It helps just to know how technical you can be about these things. However, I do only want the short term solution for right now. I need baby steps. I got so much on my plate with my dad's passing, going though his things, etc. This July 18 will be one year and I feel like I'm barely treading water with my loss. I am an only child and he was not married.

And, I am his daughter. I relied heavily on my Dad to do things right. I wish he was around so I could take better notes. Times flies faster than that Testarossa.

The car is in it's own garage and I have my dad's best friend taking it out for a drive every 6 weeks since I live in another state (I don't have room for this car in California right now). First and foremost, I'm glad to know that the tire pressure it all wrong so that needs to be fixed at the next pit stop.

I'll be on this board quite a bit as I get my bearings. Thanks again everyone.

Cynthia

 

Ok, Cynthia, we need a pic of you so we know how much help to give you. I can't believe there are 16 posts and no requests for a pic or two. You guys are slacken! Oh yeah, 32PSI (cold) for the fronts and 35 for the rears is a good starting point. You can use nitrogen but don't pay for it. If it's offered free then go ahead. (Regular air is 71% nitrogen already.)

 

Great, let's represent the F-Chat community as a bunch of perverts. Make sure to ask for nude pics next time so we can scare off ALL the female F-chatters...

 

Why is 32 front and 35 rear a good starting point? It is incorrect! Have you read your owners manual?
Ferrari recommends 38 front and 38 rear as the correct tire pressures for a Testarossa.
Unless you are running different wheels/tires than the stock configuration, that is what the tire pressures should be set to.

 

My TR OM actually specifies 37 psi for front and rear on the 16" tires (for speeds less than 160 mph), but I found that this tends to wear out the center tread area prematurely -- 35 psi gives me more even treadwear (for my driving behavior/speeds which are rarely over 75 mph) although the slow-speed steering effort is increased (which might be a reason people would prefer a higher value regardless). The written spec itself indicates that there should be some sort of gradual increase in pressure with speed -- i.e., the spec states that 37 psi is fine at 159 mph, but at 161 mph the pressure needs to be 43 psi? If my average speed was higher, I'd be more worried about running a lower pressure and increasing the tire heating, but I prefer extending usable tire life -- JMO.

Are you still running Champion spark plugs in all TR?

 

Ha! Well as my Dad used to say.... "If it has wheels or testicles, it means TROUBLE."

 

You are one sick dude!

For regular driving I go with 35psi at all 4 corners. You'll get good even wear and a decent ride.

 

What he said.

Sometimes I don't understand why threads continue after Rifledriver has chimed in on a topic, but this one could have ended after Motob's post, unless there was some cause to dispute the accuracy of it.

 

I wonder if Ferrari has drivven a TR around Fiorano with Pirreli PS2s?

But I do know that when they do test, they pull out the probe tipped pyrometer and ...

 

...and I know that factory tire pressures are the result of numerous tradeoffs, not just limit handling performance.

OP isn't looking to set up a racecar. It doesn't make sense to go hammer it hard to determine tire pressures, then go tool around on the streets for the rest of the tire lifespan. You're bound to wind up with excess pressure. Worried about emergency handling? Go to an autocross & see how it handles at your selected tire pressures.

 

Read the post after yours.

If she was looking to put the car on the grid somewhere she would probably either know how to arrive at the perfect pressure or have a good source to do so. She would not be asking a bunch of strangers on the internet.

Making a mountain out of a molehill achieves nothing.

And BTW PS2's are a Michelin product.