tire pressure question

The flow rate you want to use those quarter inch quick connectors that are marked high flow put them on your compressor and get a compressor that has a real pump attached to it it doesn't make that funny vibrating noise sounds like a piston going up and down that way there if you want you could run air tools not big air hogs but you know a ratchet a body gun a few things like that

 

The 51 on the tires is the maximum pressure they are built to safely handle. The 35 on the door jamb is the pressure Toyota recommends for adequate load capacity and a good ride.

You can choose to go above the 35 for whatever reasons of your own, as long as you don't exceed the 51.

I've settled on slightly above, like 36 and 38 instead of 33 and 35.

When I first bought my Gen 1, back in 2008, it was an amazing car, 126,000 miles and still quiet like a vault. I followed some of the higher tire pressure recommendations I saw here, like 42/44, and before I knew it the cabin was full of squeaks and rattles and sounded like an old jalopy. Also, the ride was not comfortable for me at those pressures.

I backed the pressures down to 36 and 38, and it was more comfortable for me, but there was no "undo" for the cabin squeaks and rattles; they were with me for as long as I had the car, reminding me what I had done.

 

Somewhere between 35 & 51 is the correct answer... The higher the pressure the better the MPG but the rougher the ride and eventually it gets so rough you lose traction. Down at 35psi really crappy drivers will be safer and MPGs will be awful but ride will be nice and soft. Try adding a few PSI at a time and once you start losing traction on the main road you drive everyday back off on the PSI a little and you'll be good to go.

 

OP, YMMV, but I run 35 PSI on the front tire, 33 PSI on the rear tires and I get great MPG. There is more than tire pressure involved in the whole MPG equation and in my experience higher tire pressures make a very minimal contribution to higher MPG. I also did not enjoy replacing my tires prematurely because they wore down to the tread wear indicators in the center of the tires.

As I say, your mileage may vary.

 

The pressure indicated on the tire is from the tire manufacturer, at max load.

The sticker is from Toyota; I’d follow that one.

 

Probably none of both!!!
The 51 psi is the maximum allowed cold pressure of a personscartire, and the 35 psi is not coincidentially the reference pressure of a P-tire.

If carmaker calculates recomended pressure, they do it nowadays for GAWR's and maximum technical carspeed.
But often they yust recomend reference-pressure for reason of liability.

The maxload for upto 99mph/160kmph is calculated by the tiremakers for referencepressure of that 35 psi most likely.
And there is a officiall formula and system to calculate pressure for lower load on tire and higher speed then 99mph.

End 2007 I got hold of that formula and system, and went running with it.

Now use an even safer formula that leads to higher pressure, and use a simpler but better system for higher speed.

Its possible that my calculation comes to even 25 psi, but have to calculate it.

But if you give tire specifications, I can make a pressure/axleload list for it, in wich I give 90% of the calculated loadcapacity for the reference-speed of that 99mph. Determined this to give maximum reserve, with still acceptable comfort and gripp.

Then you " ONLY" have to detetmine the axleloads in your use acurately, and look them back in the list.
Succes with that, the most tricky part in it all.

Need from tires next, and can be read from sidewall.
1.Maximum load or loadindex.
2. Kind of tire to determine the reference pressure.
3 speedcode would be nice.

2. Standard load AT 35 or 36 psi.
XL/reinforced /extraload AT 41 or 42 psi.
C-Load LT tire AT 50 psi.
6Plyrated C(omercial)-Tyre ( Eur) AT 55psi.
And so on, but I think you dont have them.

 

Be sure to get a "good" quality handheld pressure gauge (I prefer dial type gauges). I have often found the gauge that's built in to a compressor to be very inaccurate.

Posted via the PriusChat mobile app.

 

If you’ve got several gauges , check the same tire with all of them, see how close they are, note the outliers.

still, it could be like “Twelve Angry Men”; only the outlier got it right.

 

Is this for portable use......carrying around with you in the car........or for stationary use at home ?
If using at home, one with a TANK on it is much better.
But then the cost is about double.

 

For small and portable, Go with the SLIME brand. Lots of options and the build quality is pretty good. I tried to make do with Chinese imports from no-name companies as well as a "Husky" from Home Depot and they were all junk and all failed quickly.

The Slime I bought a few years ago is dead-on accurate (according to my other gauges), works quickly and their customer service is supposedly great -- don't know, never had a need to contact them.
kris

 

In this post, I'm noticing that all of your flow rates are given as numbers with no units (30 whats? 300 whats?)

In the US, compressor ratings have most often been given in cubic feet per minute (CFM), but that's a unit very open to manipulation because air is, umm, compressible, so the same amount of air is a lot more cubic feet at one pressure than at some other pressure. To do real comparisons, you need a standardized version, like SCFM, which talks about the volume of air at a specific temperature and pressure. It wasn't easy to get the whole industry to publish SCFM ratings, because oddly enough, those weren't always as rosy as the CFM ratings a maker might have advertised before.

For a while that gave you one useful way to judge whether the compressor you were looking at was from a serious outfit: if it was labeled for so many "SCFM", they were at least looking to be taken seriously, and if it was labeled for so many "CFM" , you could pass. (Or give them a call and ask "what temperature and pressure was that rating for again?".)

But these numbers you're showing must not be CFM or SCFM, because numbers like 30 (let alone 300!) would be pure fantasy for a portable compressor. The one I hardwired in provides 2 (and it needs about 23 amps to run, which is why it had to be hardwired). Actual portables are likely to be less than that.



I see in your first post there was an L, so maybe your figures are liters? As a flow rate, they'd still have to be liters per something, maybe per minute. And just like CFM vs. SCFM, to make fair comparison possible, the label would have to specify liters per minute at some standardized temperature and pressure. The term nl/min (normalized liters per minute, in this context, not nanoliters per minute!) seems to be what's used.

This could be another area where compressor marketers can play the same sort of games they used to with CFM before SCFM became common. If something is advertising a rosy liters per minute number that isn't normalized liters per minute, some skepticism may be in order.

A pump for moving a lot of air quickly into a lower-pressure space like an air mattress can probably be built around the same price as a pump for moving air more slowly into a higher pressure, because one isn't "better" than the other, it's just a choice of which job it's designed for.

The compressor I used for the hardwired installation is a Viair, and they seem to make decent stuff. They have some portable models too.

 

For small job site compressor I like my CaliforniaAirTools. Unbelievable quiet.

My understanding is that tire burst pressure is 4x the recommended max. I haven't tried it, don't plan to, and suggest you don't either.

 

Again, if they're not saying "normalized liters per minute" or nl/min, this may be a way of playing the same games they used to play when they'd list CFM but not SCFM.

 

I got this floor-standing BV bicycle pump about 2 years back, easy pushing onto valve stems, raises car tires about 1 psi per 10 strokes.

In case the link craps out, screen-grab from US Amazon site:

 

Yes, I'm a big fan of these types of pumps... Great exercise... And I've been procrastinating on my air compressor rebuild project. :-(

Usually when I'm done working on a car I do 30-40 pumps per tire (5-7psi) because humans suck at checking & maintaining tire pressure and they are always low on air.