Tire Pressure

[Bob Bidonde]

What tire pressures do you run in stock size tires?
At the factory specification of 35 PSIG, my Model A
Victoria rides too harsh for my liking, so I reduce the tire pressures to 28 PSIG in the rear wheels, and 30 PSIG in the front wheels. I run the front wheel pressure higher to ease the steering effort. The tires on my car are 4.75-5.00x19 Universal brand, and the shock absorbers are rebuilt original Houdailles. At their best, the Houdailles are ineffective high maintenance decorations in my opinion.
I just received my modern shock absorber conversion kit from Bratton's that will go into my Victoria.

 

[JayJay]

I run 35 in my European Classic bias ply f&r and you’re right, the ride is a bit harsh. Not sure I’d go all the way to 28. I like to believe that the engineers specified 35 for a reason.

Side note - in California cars leaving a licensed repair facility are required to have their tires inflated to manufacturer spec (yes, that’s a law here) for enforced fuel economy. But most repair shops I’ve dealt with, including tire dealers, are too lazy to look up the mfg spec, so they routinely inflate to the 35 psi max pressure on the tire sidewall. So we have a bunch of cars running around with incorrect tire pressure. Stupid unintended consequence.

Incorrect tire pressures were a partial but significant contributor to the instability issues with the early Corvairs, which the engineers corrected. Still, these issues, coupled with the publication of “Unsafe at Any Speed”, led to the demise of a unique car that still has something of a cult following.

 

[WHN]

I disagree with your comments on Houdaille Model A shocks.

New good quality reproductions or properly restored/rebuilt originals make a big difference in your cars ride and handling.

The secret is “good quality “.

There is no way I would ever use tube shocks. Do it right or don’t do it. I understand that it most likely will cost more but there’s a reason for that.

 

[David in San Antonio]

Ineffective high maintenance decorations? Reminds me of my first wife.
Just kidding.
I didn’t realize Ford recommended 35 psi. Was that for the lighter roadster too? I always run 32 psi using the free nitrogen pump at Costco. Have had some great double takes from the other shoppers, too.

 

[JayJay]

Ineffective high maintenance decorations? Reminds me of my first wife.
Just kidding.
I didn’t realize Ford recommended 35 psi. Was that for the lighter roadster too? I always run 32 psi using the free nitrogen pump at Costco. Have had some great double takes from the other shoppers, too.

I believe the owners manual specifies 35 psi for all the light duty vehicles. If you are heavily loading a pickup it might be prudent to increase the rears a couple of psi. I’m not aware of any differences in recommendations for different body styles. I bring the tires back up when they’ve gone down to about 33, and I do notice a difference in steering when I inflate to the proper pressure.

As far as nitrogen vs air - air is 70% nitrogen anyhow. I think it’s a myth, or at least an expensive marketing hype, that normal passenger car driving benefits from nitro inflation. (I think some beers definitely benefit, though).

 

[David in San Antonio]

I also think nitrogen is marketing hype when a dealer charges $250 for unlimited lifetime refills. But for free at Costco it’s fine.

 

[Big hammer]

Tires act like springs, try 45 psi and see if your springs start working. By accident I pumped my tires up without a pressure gauge and the ride back home to the garage was better, checked the pressure and reduced down to 35 psi. I then serviced the springs which then worked as advertised.

 

[nkaminar]

For a softer ride try the radial tires.

 

[Herb Concord Ca]

Like JJ, I have European Classic and set them to 35 a day before a tour. They are on my Slant T/S with Speedway Frictions shocks. Am thinking about installing front VW shocks.

 

[Y-Blockhead]

I disagree with your comments on Houdaille Model A shocks.

New good quality reproductions or properly restored/rebuilt originals make a big difference in your cars ride and handling.

The secret is “good quality “.

There is no way I would ever use tube shocks. Do it right or don’t do it. I understand that it most likely will cost more but there’s a reason for that.

I was experimenting with my Stipe Shocks a while back and I can say for sure if they are adjusted too loose the front end will "pogo". When adjusted as Stipe suggest, they work fantastic.

I believe a combination of "Good Quality" shocks and springs that work properly are required for a good ride. Rusty springs will not help.

I run gaiters on my leaf springs to keep them clean and working as they should.

I have American Classic Radials set at 35psi.

 

[Mike1291]

I have original springs and shocks on my Coupe and the ride does benefit from lower tire pressure. However, my front springs/shocks are pretty stiff when I do the "bounce" test by putting my weight on a corner of the car to see what it's rebound is like. My springs are rusty which might be why it's pretty stiff.

I also have driven in a 31 SW 4 door with the aftermarket friction shocks. It went over the bumps very smoothly but they couldn't take the weight of the car around a corner.

 

[nkaminar]

60 years ago the shocks on most Model A's were rusty springs. The original hydraulic shocks were long gone.

 

[Bob Bidonde]

The Houdaille shocks I run were professionally rebuild originals by a highly respected restorer. I stick to my opinion that original Houdaille shocks are at best decorations. I am converting to tube shocks.

 

[Kurt in NJ]

Bob, have your shocks been adjusted to factory specifications?
Are you springs well lubricated?
Or is there red rust dust oozing from the edges?
It was amazing the difference that well lubricated springs and shocks working properly and adjusted to specifications made on my car the ride became smooth yet properly controlled.

A lot of complaints about tube shock making the ride harder— of course choosing a tube shock with the proper damping could take some experimenting because there is more involved than just fitting on the mounts .

 

[Oldgearz]

The Houdaille shocks I run were professionally rebuild originals by a highly respected restorer. I stick to my opinion that original Houdaille shocks are at best decorations. I am converting to tube shocks.

My 30 coupe came to me with gas filled tube shocks and boy were they stiff. I converted to oil filled VF dune buggy shocks which look like any other tube shock and now I float down the road.....what a difference. Car handles perfectly. Do a search on this site. Because of these shocks I run air pressure at 32 psi all the way around and rotate tires every 3,000 miles.

 

[The Master Cylinder]

The Houdaille shocks I run were professionally rebuild originals by a highly respected restorer. I stick to my opinion that original Houdaille shocks are at best decorations. I am converting to tube shocks.

That's kind of a broad statement, don't you think. Just because your shocks are junk doesn't mean all Houdaille shocks or shocks of that design are junk.

 

[nkaminar]

Oldgearz, Do you mean VW dune buggy shocks, not VF?

 

[German guy]

I run 32 psi on all four....that is what is on the sidewalls. 28 seems very low and probably reduces tire life due to the flexibility of the sidewalls at temp. LOL...also because if I am in an accident and the polizei do the typical on-scene investigation and tires are not at the sidewall prescribed pressure ...it can result in being held partially accountable for the accident even when it is clearly not my fault. 32 seems to give a decent ride now that I have greased by springs and replaced the shocks.

 

[Bob Bidonde]

My Houdaille shocks were adjusted & and adjusted again. I also filled them with ATF and other oils, but they do nothing to improve the ride of my Victoria or my Coupe. With tube shocks, I have the luxury of using adjustable pneumatic shocks if necessary.

 

[Kurt in NJ]

I had used ATF for a while before that hydraulic jack / shock oil and by “feel” thought I had proper damping.
Then I found a perfect shock with no wear and all internal clearances between.001-.002”.
I started with Kubota hydrostatic multi viscosity oil figuring it would have a more stable viscosity through temperature changes.
The test times were way too fast.
Then I bought the higher viscosity hydraulic oil (AW68) the test time was better but still way too fast. — even with the needle valve totally closed.

So I did some looking at relative viscosity of glycerin and other liquids and found that pure glycerin was quite thick.

Then the can of “Check Shock” oil was found and I made a viscosity test cup and found that a blend of 85-140 gear oil with 10% of my 600 gear oil ( Shell Omala 680) matched the Check Shock oil.

With that oil the shock performance with the needle valve at a range of 3/8-1/4 open matches the times in the service bulletins.

So I ask again— Bob what standards and testing were you using to adjust your shocks and what performance were you getting from the test procedures?

Restoration to original specifications eliminates the need for many modifications