Keep tires deflated or not?

Dignini, with due respect, I really don't see the point of deflating the tires. I know that keeping the tires off the ground is often recommended, but, with some cars with bonded rubber suspension bushes, droop distorts the bushes. Accordingly, for these cars, the suspension should be kept at ride hide, even when the car is jacked up. Because I have a few old cars, including a sports racer, they tend to get laid up a lot. I don't keep them on stands. Sometimes the tires flat spot, and I notice this more on the Dunlop vintage race rubber, but they do recover quite quickly. For a lay-up of a couple of months, I don't think you need to do that. I do try to control humidity in the garage - I live in the tropics. Cheers, Andres.

 

If you deflate the tire it may effect the seating of the bead on the rim. If you keep it inflated it would keep the correct pressure on the sidewalls.

If you don't want flats spots from sitting I may suggest raising the car and supporting it on the frame at all four corners. Raise the wheels the same amount but support them by the suspension. This will give you the same ride height but the wheels will be off the ground.

 

You do have to be careful as I have heard of older Konis "freezing" up at extended positions....kind of embaressing I'd think..

There are cradles to resist flat spotting...how long are we talking about????

 

There are many things you can do to prevent/protect against them, cradles, foam insulation, rubber mats, etc.

My cars sit for 6-7 months/year. When I pull them out in the spring and go for the first drive, usually I don't feel any sort of flat spots/vibration. One time I did on my 66 corvette with repo redlines... first mile or so I could feel some vibration and then it was gone.

My $.02 is that it's not much of an issue.

 

Letting the suspension sag would reasonably cause premature failure of the bushings, which are expensive to replace. This is because the rubber is bonded to the metal of the inner and outer sleeves, so there is no actual rotation during compression movement--it is the rubber stretching that allows that.

If the rubber is under the tremendous stress of being distorted constantly from its rest shape / position it will probably crack sooner.

If you want to prevent tire flat spotting you could roll the car back or forward a little every month or two, or raise it and rotate the tires, so it rests in a new position.

 

That's all I have ever down with my 308 during the long damp winters here in the UK.
I simply roll the car forward so the tyres are sitting on a fresh area.
The car does resist the movement and tries to roll back to the original position, so some very temporary flat-spotting does take place.
I have never had a problem (with tyres...)

 

Dignini,
One other consideration about annually introducing a fresh charge of air (and moisture) into your wheel/tire assemblies . . . magnesium oxide. Very bad stuff for your stock Dino Cromodora mag alloy wheels. This is a nasty black oxide that can severely damage your wheels from the inside out. I just put a new set of XWXs on my '74 Dino and, during the process, I carely inspected for this problem. Sure enough 3 of the 5 wheels showed surface MgO2 in a few spots on the bead area. I used emory cloth to clean the areas and sprayed the effected areas with gray primer. That was probably not the ideal solution but I didn't have time to do the proper research.

Using nitrogen rather than regular air would probably help prevent this problem.

I think the Compagnola wheels that come with the Daytona option are aluminum, so this wouldn't apply.

Anybody have additional knowledge/thoughts/experience with this problem?

Bill

 

Keeping the Tire off the Surface is a great Idea , Deflating the air is not harmful nor really necessary as tires naturally leak air

 

That was quite an experiment, Dignini. Now we know. Many thanks! Andres