tire pressure myth?

[UncleBob]

I don't care what motor engineering you got, no oil = siezed motor. You might "survive" the abuse of running it down to 1/2 a quart of badly burnt oil that has gone so far that it lost all its viscosity and then regained it due to all the soot, but damage was done and will be back to haunt you.

Eventually....

[GreyGoose006]

oh sure, but when you are trying to kill an engine...

[corning_d3]

I witnessed an '84 4-banger mustang go 20 miles with no oil, plug or filter. Then it snapped the cam in two....

[KiwiBacon]

Originally Posted by GreyGoose006

which is why i inflate to the pressure on the sidewall.
that pressure was calculated to be safe on the average car driving down the road. why would you inflate to a lower pressure to increase the contact patch for regular driving?

The point is, when your "normal driving" limits are exceeded, it's too late to get out and air down your tyres.

Your grip is reduced, the chances of impact are so much higher.

Tyre air pressure is one of the first things an accident investigator will check.
Of course by the time an accident investigator is checking over your car, it's usually involved in an accident that killed someone.

[UncleBob]

hey! No hijacking our hijacked thread!

I think talking about dumb car owners and blown up engines is way more entertaining....The stories I got....alas....

[GreyGoose006]

the tire issue is gone.
lets agree that i'm right and the rest of you are wrong...
LOL.

okay just kidding.

seriously though, some engines can take all kinds of abuse that they were never meant to take.

Originally Posted by cornering_d3

Then it snapped the cam in two....

holy shiznits thats cool.
what kind of forces are required to snap a cam?
a LOT.

[GreyGoose006]

Originally Posted by KiwiBacon

The point is, when your "normal driving" limits are exceeded, it's too late to get out and air down your tyres.

Your grip is reduced, the chances of impact are so much higher.

Tyre air pressure is one of the first things an accident investigator will check.
Of course by the time an accident investigator is checking over your car, it's usually involved in an accident that killed someone.

oh, and to get back on topic, yes, but how often do you find yourself skidding out of control for no apparent reason...
with a little caution and level headed vehicle control, you can manage just fine in any emergency.
many times i have been driving around and somebody pulls out from behind a bus and stops right in front of me. i dont SLAM on the brakes and slide into him because my wheels ae locked up (no abs)
its more of an ever increasing pressure on the pedal to prevent front wheel lockup... that way you can still steer and avoid the situation entirely.
i'll be driving 45 on the bypass and some jerk hauling 5 horses pulls right out.
again, if you dont panic, and know a little bit about car control, accidents can be avoided, and you will never have to exceed the limits of your cars control

[2.2 Straight six]

Originally Posted by GreyGoose006

what kind of forces are required to snap a cam?
a LOT.

varies, when removing them it doesn't take a lot. if you loosen the cam retainers wrong (like removing the ones on the left completely without touching those on the right) they can snap under the force of the valve springs. you need to loosen the retainers slowly and equally.

[Knap]

The correct pressures for conditions and circumstances should be used. Low pressures are more dangerous (accident reports) despite the "ultimate" grip re race use. Higher pressures give better steering response. Although max pressure on sidewall is more likely to give higher wear, to a certain extent radials do not balloon and the burst pressure is say 100psi. In view of additional pressure for high speed use and potential drop in pressure if not monitored, keeping them marginally higher than recommended for the conditions, which could include wet roads, is not a great sin, although this is unlikely to be max pressure on sidewall.

[2.2 Straight six]

Originally Posted by Knap

the burst pressure is say 100psi.

if you're running 50psi and hit a big enough bump at a high enough speed the pressure will surge and can blow your tyres out. i've seen it happen on tyres running 32psi. i was in the car when it hit a speed bump at ~120mph.

[KiwiBacon]

Originally Posted by GreyGoose006

oh, and to get back on topic, yes, but how often do you find yourself skidding out of control for no apparent reason...
with a little caution and level headed vehicle control, you can manage just fine in any emergency.
many times i have been driving around and somebody pulls out from behind a bus and stops right in front of me. i dont SLAM on the brakes and slide into him because my wheels ae locked up (no abs)
its more of an ever increasing pressure on the pedal to prevent front wheel lockup... that way you can still steer and avoid the situation entirely.
i'll be driving 45 on the bypass and some jerk hauling 5 horses pulls right out.
again, if you dont panic, and know a little bit about car control, accidents can be avoided, and you will never have to exceed the limits of your cars control

You're obviously invincible, far be it from us to convince you otherwise.

Have you tried a temp check to see how even your wear is going to be?


The max pressure for the BFG's on my truck is 65psi.
40psi is the correct pressure for the 600kg I have on each wheel to get even wear.
Lighter trucks run them around 30psi to get even wear.

You may notice a trend here.

[GreyGoose006]

every time i get off the highway at a rest stop or something i check my tires by holding my hand on them and visually glancing to see that they are at the correct pressure.
usually, unless the wether is exceedingly hot, the tires are no warmer than what i'd say is 85-90* in the summer, and 80-85 in the winter.

dont worry, i'm not invincible, just levelheaded.
just last week i broke my wrist when i flew over the handlebars of my bycicle.
the bike was/is ~10 years old, and the bolt that holds the angle block inside the head tube snapped from fatigue. the front wheel turned 90* to my direction of travel and i flew off. my flying skills are a little rusty, so i hit the ground pretty hard.
dont worry tho, i'm freshening up on those 31337 flying skillz.

[534BC]

I have yet posted my opinion on this matter, I do have one. Just haven't been able to articulate it yet. I do see that it seems everyone is complicationg the matter quite a bit. Here's a question though before I do.

To all who religiously use the setting on the door panel:

Do you ever reduce your pressure when your 3 fat friends get out of the car?

sorry, I couldn't resist, lol.

[534BC]

I'll exgerate it a bit more using truck tires and weight and pressure. Must say that it is true that a higher than recommended inflation/weight may reduce traction and it may even be due to a reduced contact patch.

Speaking of rest-stops; When the truck driver unloaded his trailer , I always wonder why he let out a lot of air pressure,.? NOT

A tire is not like a air bag, nor is it like a balloon. It does not get it's shape from weight / pressure relationships that we are talking about.

[UncleBob]

Originally Posted by 534BC

Do you ever reduce your pressure when your 3 fat friends get out of the car?

sorry, I couldn't resist, lol.

that is a note worthy point, and I agree with the general issue: there is some room to play

But running tires that the door panel says should be 25psi at 44psi is a lot more extreme than what you're discribing