Incorrect Information re: Tire Pressure in Efficiency Mods

[j12piprius]

Originally Posted by PaleMelanesian

At higher inflation levels, the tires tend to heat up less. There's less flexing in the sidewall to generate heat.

What tire pressures would you put in the following tires?
I would love to be able to put at least 50 psi in them. If so, should I work up to this gradually?

99 honda civic ex - 175/70 R14 84T
altimax RT general tire / max inflation 44 / max load 1102

89 chevy celebrity - 185/75 R14 89S M+S
front: douglas xtra-trac II / max inflation 44 / max load 1102
back: michelin X radial / max inflation 35 / max load 1290

89 chevy celebrity x - 185/75 R14 89S M+S
3: dayton quadra SE / max inflation 35 / max load 1290
1: douglas XTRA Trac A/W / max inflation 35 / max load 1290

[Frank Lee]

Perhaps your mechanic can help.

[j12piprius]

Originally Posted by Frank Lee

Perhaps your mechanic can help.

He'd say 35 pounds.

I also went to costco and that was their maximum.

[Frank Lee]

There ya go.

[j12piprius]

There I go what.

[CapriRacer]

Originally Posted by Frank Lee

Yeah, I didn't feel like googling all night when the asker could do the same.

I spent some time googling and came up empty. I can find folks "saying" what the burst pressure of a passenger car tire is, but I didn't find anyone who actual tested one or even a "got it from a guy who got it from a guy ....".

It's almost like one of those urban myths.

[Frank Lee]

If a dinky featherweight bicycle tire can hold well over 100 psi I don't see why a car tire in good shape couldn't. That said, I don't like running car tires over 50 psi just cuzza ride harshness.

[CapriRacer]

Originally Posted by Frank Lee

If a dinky featherweight bicycle tire can hold well over 100 psi I don't see why a car tire in good shape couldn't. That said, I don't like running car tires over 50 psi just cuzza ride harshness.

That assumes they are constructed the same - and clearly they aren't.

Bicycle tires are specified to run at much higher pressures than passenger car tires - as are medium duty truck tires (over 100 psi). This has to do with the strength of the materials in the sidewall.

Heck, the tires on the space shuttle are inflated to over 300 psi.

[PaleMelanesian]

Originally Posted by johnlvs2run

What tire pressures would you put in the following tires?
I would love to be able to put at least 50 psi in them. If so, should I work up to this gradually?

All I'll say is I have mine into the "margin of safety" range.
I backed down a little when the back end started skittering sideways on speed bumps.

[PaleMelanesian]

Here you go:
I heard it from a guy* who heard from a tire engineer. He quoted 200 psi burst. The engineer requested anonymity, of course.

* who runs another fuel-economy site.