Tire pressure for Queenie

As with any car or tire, I usually start with factory recommendation and depending on (personal) comfort, vehicle handling/performance, thread wear, type of driving (city/suburbia, highway), speeds, etc try different (higher and/or lower) settings until I find the one I prefer.
In some cases, it might take a few trials (perhaps 100-500 miles each ?) to find the ideal preference for you and your car.

 

Is a Ferrari that heavy?
And if so most cars like these have tires with larg reserves to the GAWR's.

Copied this from my post in other forumtopic, so I dont have to write it all over again.

Needed tire-pressure is to give tire a deflection, so heatproduction a cycle, that wont overheat any part of tire-material, when driving the speed constantly, for wich the pressure is determined.

Other things, like riding quality, comfort and gripp, and energy use, are also important, but for tiremakers this is main goal.

Maxload of tire is calculated for this goal, and for the reference-speed and - pressure.

That deflection is made by the relation pressure/load on tire.
So to laws of nature you can calculate your specific pressures if you know load on tire, and maximum speed used, wich you wont go over for even a minute.

To mother nature you must be hounest about your maximum speed, and determining the axleloads, or better axle-end loads 99% acurate, is the greatest chalence, and your responcibility.

I determined once that if 90% of loadcapacity used for the pressure for 160kmph /99mph, that then comfort and gripp is still acceptable.

You can use this reserve to cover inacuracies in pressure measure measurement, pressure loss in time, misyudged weight on tires, etc.

I can make a cold pressure /axleload-capacity list for your tires, with that build in reserve.
But if you want for higher speed, write it, and I make it for that speed.

Then you "ONLY" have to determine the axleloads 99% acurate and search them back in the list for the needed cold pressure.

To make that list, I need from tires.
1. Maximum load or loadindex
2. SL or XL to determine the referencepressure.
3. Speedcode, less important, Q and above have referencespeed of 160kmph/99mph.

 

Here is my super-low-budget version to determine tire pressure:
Wet the tires, roll down the dry driveway and check the "print".

Fear not, there is a super-high-budget version also:
Get on a track, go around a few laps with a comfortable pace (not racing) and use a tire pyrometer to evaluate outside, middle and inside of each tire. The one with a needle.If you want to race, same as above, but under racing pace (obviously).

Or call Roger Kraus Racing and ask them

On a side note, my 911RS required 1.8 Bar cold to get to 2.5 Bar hot (track). It had 205/50/17 and 255/40/17. Your truth is between 1.8 and 2.5 Bar.



Left Rear tire (example)

Inside, Center, Outside.


Center too hot - example: I 170° - C 180° - O 170°
Too high air pressure. This can be too high cold or "starting" pressure or excessive heat caused by sliding due to car setup or driving style.

Center too low - example: I 180° - C 160° - O 170°
Too low air pressure. This can be too low cold or "starting" pressure, car setup or driving

 

Start out with 35 psi COLD all around, drive the car and see how you like it. Make adjustments from there as you feel a need. 35psi all around works for most Ferraris from that era, except for Daytona's which seem to like 40 psi.

 

Manicotto: The higher pressures for the Daytona are to help "lighten" the steering effort. Generally, the higher the pressure, the more quickly the car will react to steering inputs, but the ride will become stiffer. You will find a good compromise.

 

Because of your recomended 27F/33R, i suspect motor in back, I dont know anything about yoyr car, so dont laugh now.
Mayby if 2 seater, persons also closer to rear axle. Gives higher axleload rear then front.

And I already googled your 215/70R15.
Found loadindex 95 in Standard load, and 98 in XL/reinforced / extraload..

But comfirm this or corect it

 

I don't see a "problem", per se, since I believe your 365 GT 2+2 has factory recommended (not mandated) tire pressure settings specified in your owner manual for the car.
Besides, like I & Dyke (DRW46) noted, you must start somewhere, whether it's the factory or tire manufacturer recommendation for the given car or tire or some close-by number (35 psi ?) and keep adjusting to your liking & driving style.
I change tire pressures in my vintage cars fairly frequently, depending type of driving, loads/passengers in them, road conditions, etc.
Not rocket science, just part of old school ownership practices that have worked for me since I started driving vintage cars nearly 45 years ago.

 

also it is important if you use "normal air" or nitrogen

 

Hi

You can contemplate going back to standard, because Pirelli have made them again. they are a bit taller so they will fill your wheel arches correctly, and lift the car a bit further above the speed bumps.

https://www.borrani.com/ferrari-wheels/365-gt-2-2.html

However the 215/70VR15 Michelin XWX are a great option as is the Pirelli 215/70R15 Cinturato.

I think a 215/70 has a very similar volume of air inside them to carry the weight of a Ferrari. If you are comcerned add a couple of psi. More pressure is safer than less.

 

Buying setd like this are the best value

https://www.borrani.com/205-r-15-pirelli-cinturato-cn72.html

 

always buy michelin tubes. the cheaper ones always need air added.

 

agreed

https://www.longstonetyres.co.uk/classic-tyre-inner-tubes.html

Always put inner tubes in wire wheels.

 

I prefer to use a gas mix of 78.08 percent nitrogen, 20.95 percent oxygen, and 0.93 percent argon, with just a trace of water and lubricating oil. aka "shop air"

 

sure, and in the summertime some ice to cool the tires

 

some tyre stations here in germany use up to 95% nitrogen. so the same as airplanes use in their tires and also racecars.