Tire Pressure

[BigLou]

My 1969 Pagoda was completed in July 1969. The trunk sticker calls for these cold pressures: front, 26 psi; rear, 32 psi. The original tires were 185 HR 14, with tubes. The current tires are Coker Phoenix 185 R 14, tubeless. I've read just about everything I can find in Forum about tire pressures and I'm left a bit confused. I drive the car once or twice a month, mostly on the Interstate, where I sometimes go pretty fast. I'm currently at 30 psi front, 32 rear. At what cold pressures should I be? Thanks.

[teahead]

what does the max PSI specified on the tires that are on there?

I usually go by that minus a few psi.

[BigLou]

Thanks Rob. I’ll check that.

[zak]

I like a softer ride so I go 30 front and 32 rear

[Garry]

After driving some of the US roads, i can see why you would want a softer ride.  Boy they are rough a lot of the time even on the interstates.   

[zak]

Garry, yes. A lot of rough road surfaces over here. Road and infrastructure improvements here are the last on the politicians lists and seem to only be done on an emergency basis.
Even so I enjoy the softer ride on those fat 70 series tires. I had an oil change done at a new place a few years back. When I drove out the car rode so stiffly my teeth were rattling.
I figured what it was and turned around and back to the shop. Turns out they put 40 lbs psi in all tires " just like modern cars" he said.

jz

[Tyler S]

Here is a standardized list of tire sizes vs weight vs pressures. You can go to your tire manufacturer for exact call-outs. It all has to do with the weight the tire is supporting. Take the total (gross) weight of the Pagoda and divide it by 4. Then go to the chart to find the recommended pressure. 

[wwheeler]

On my daily drivers, I simply monitor the wear on the tread. I want it to be even straight across. It doesn’t take long to see if you are over or under inflated. Normally, I am a bit over what the factory recommends and under the max psi for the tire. As long as you are in that range, you are fine. I think it is a matter of preference with comfort vs. handling.

[neelyrc]

I add two pound to the trunk sticker values both front and rear.

[russelljones48]

here's a pointer to a Tirerack tech page that provides some useful info.  https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=8

The manufacturers (car) recommendations are based on a number of factors - most importantly vehicle corner loads (dividing total vehicle weight by 4 is only a very rough estimate).  But driver/passenger "comfort" is often a major consideration.  Hence, the factory recommendations often tend to be a little "soft" for my tastes and I, like others here, typically run a couple more PSI that the factory settings.  The only other thing I recommend is to use the best gauge you can afford.  I use a big face Intercomp.  I've found them to be quite reliable and accurate.   

[MikeSimon]

what does the max PSI specified on the tires that are on there?

I usually go by that minus a few psi.

The max PSI cold that is indicated on a tire is a max load pressure and really is too high for most driving. 

[Shvegel]

I usually Inflate to 30 then do a bit of spirited driving around my neighborhood then us a surface pyrometer to measure the tread temperature at three or four places across the tread and based on that data I adjust the tire pressure accordingly... Just kidding 32 psi all around.

[RAY]

That......was funny. At first i was thinking 'really, oh my god'

[MikeSimon]

When I started reading this, knowing Pat, I actually bought it. Only when I came to the "just kidding" I knew he was pulling our collective leg...

[stickandrudderman]

I usually Inflate to 30 then do a bit of spirited driving around my neighborhood then us a surface pyrometer to measure the tread temperature at three or four places across the tread and based on that data I adjust the tire pressure accordingly...

If you were setting up a race car that is exactly what you do!