Tire pressure ….do you care?

Life Cars & Motorcycles
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Tire pressure ? Do you check? How often? Do you care?

Now if you are anal retentive like me and actually really know your cars well tire pressure is crucial not only for safety but majorly affects the cars handling

I have a wealth of knowledge about my Acura and the tires and pressures associated with it but I don’t have that car now so I only concern myself with the two I have now

As a general rule I go with what the placard says the pressure should be but make minor adjustments as I feel relevant

The Acura rode rough and over time I also discovered that at the listed pressure the front tires wore in the middle more meaning they listed pressures were too high so I went 2 psi Lower and that seemed to be better both for riding and actual tire wear

My TT is the same at the listed pressure of 33 front and 30 rear after 25k miles there is slightly more wear in the center

But I had been running them at 34 front and 32 rear to give them a margin of safety

The TT is also a very rigid riding car like the RSX I guess because this makes them more agile and go through turns better But don’t drive them right after a meal !!

The Prius lists 35 front and 33 rear and I had been running them at 34 / 32 because at 35 front there seems more center wear and while the acceleration is way better the car seems unstable on the freeway and wants to hunt all the time

34 allows it to settle on to the road better

Now you may think that one psi doesn’t make a difference but if you know your cars real well you may be surprised

And apparently there is quite a difference in tire gauges too

On Sunday I used a simple gauge the one where the stick comes out with the pressure instead of my normal ten dollar one that seems to be more pro

I have a bike hand pump too and I noticed the bike pump gauge and the more pro steel gauge
Disagreed

There was more indicated reading in the bike pump

But the bike pump agrees more with the simple gauge

So I put both the cars pressure to the simple gauge

34/32 on the TT and 36/34 on the Prius per the simple gauge and both rode much much better

So I think I’d been using the wrong gauge?

I couldn’t believe where the car maker in the case of the Prius would choose a pressure too high for the car that made it hunt on the freeway (but acceleration was better esp important to the Prius)

On the TT the only diff I perceived was ride quality

What is your experience ?

Ps I check my pressures weekly more often than I check my blood pressure :smiley_cat:

Pps both cars have pressure sensors but the ones in the Prius are long inoperative and the ones on the TT are also ones that don’t read the actual pressure but only indicate if one of them is 4psi below what you had set

Useful but not that useful

A lot of nicer cars now give you instant actual readings on all four tires

Ppps. About bike tire pressure since you are pedaling or rather I am

I certainly know the diff tire pressure makes

I like to put as much pressure as possible
Makes riding s lot easier

But I blew out two inner tubes going 50psi even though the tires themselves list max 50psi the tubes couldn’t take it

Finally arrived at 38 front (for ride quality as I don’t have suspension) and 40 back for more support they say the back should have higher pressure due them supporting more weight

And so far that seems the best

No blowouts and sufficient air to ride on without making extra work

Now I ride mostly road and light gravel and my bike is a hybrid meaning jack of all trades and not a specialized mountain bike with front and even rear suspension for serious trails like my bro has

His is a 8k trek
Mine is just a 900 dollar hybrid but suits me fine

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TL/DR
always 40
oops sorry that’s bicycles

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Generally 35 psi on cold startup, no higher than 42-44 when running long under hot hot weather.
Hope you’re rotating tires every 5000 miles, as in theory the treads even out among the tires depending on placement.

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I rotate at 10k instead of 5k to save 20 bucks at the oil change at my local gas station on the prius

I find this works on that car

My local gas station charges me 40 bucks to change the oil and filter and another 20 to rotate the tires . I like to bring my own oil but I don’t get a reduction in price

Since the listed oil change interval is 10k I figure rotate at 10k ok

Even though I usually change the oil at 5k unless I’m lazy to do it

And actually 10k should be fine as the engine is only on about 2/3 of the time so 10k is really only 7k in the Prius

The TT has a 10k interval and I bought a 4 year service plan at the time of purchase for 1300 for the 4
It’s one time a year or 10k miles whichever comes first

This is less than half what the audi dealer will charge for the same services

Now I hear the 30k service alone is 1500 dollars as they change all the fluids at 30j instead of just the oil and inspection and tire rotation

But at the 10k my TT is 50/50 weight distri so a rotation was not needed

And on the 20k I can’t rotate now because one of my rear tires is mismatched due to my buying a diff brand on eBay to match the other three when I blew out one rear tire

On they can’t be rotated to the front due mismatch being more relevant on the front

I had actually been having the gas station do an additional oil change at 5k cuz I’m not sure engine oil should be replaced only after 10k miles

That’s 16k kilometers ??!!

I used to change the oil in my car in Taiwan every 3k kilometers so going 16k Minda worries me

He charges me 45 to change the oil on the TT because there is a plastic cover that has to be removed
It’s a bit of a pain with like many screws and fasteners

Why did audi do that?

I bring my own oil and filter in the case of the TT and just the oil for the Prius

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Are you doing 35 psi cold on front and rear?

Depends on the brand of car that should be a good approximation
For example BMW placard has very diff pressures depending on how many people riding the car ??!!

Audi just gives an over all recommend

Same as most makers

So one can do an approximate and that’s fine

Unless you are super anal like me

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That’s a cheap (payment wise) oil change.
Can visit a Les Schwab. They’ll rotate tires for free and give free batterry, brake, etc. checks, cuz want business later.

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But I think they charge 100? And won’t allow you to bring your own oil

Still I should look into it as my Prius has never had brakes checked so far

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Les Schwab only tires, no oil change.
Call them up.

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Ah tire specialists and brakes

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What margin of safety do you think you get running your pressure high?

Prius runs high pressures for better fuel economy.

Something’s wrong there - maybe a defect, maybe running wrong pressure (what the tire lists as max pressure may not be what you should be running at), but probably something on your rim or tire, . Tubes don’t have psi ratings themselves; the tire holds the tube in to provide the pressure, not the tube providing the pressure, and the cheapest tube should be able to easily do 100psi+ (the weakpoint is probably the stem itself and the area around it).

If you’re wheels are well aligned, rotating doesn’t really make that much difference if you’re not driving really sporty.

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I don’t really look out for it every time but I do pay attention.

Tire pressure is really important for safety. A few Psi can cause a car to pass or fail the moose test. A rollover vs staying stable for some control can be a life or death difference

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Low tire pressures are a common cause for blowouts. Sounds counterintuitive, but a lower pressure tyre generates a lot more heat. Additionally, it’s the tyre pressure that keeps the rubber on the rim primarily, it’s sealed with that white gloop but that’ll just tear right off if it’s proper flat.

Another thing to pay attention to is the quality of the tyres. About a decade ago I had a Ford Focus, front wheel drive, the front tyres and the rear right were michelins, the rear left was a Ling Long or an Achilles or whatever horrendous brand,(all with good pressure and tread on them) anyway making a right turn the backend would spin out something fierce.

It was really dangerous, great fun but really dodgy.

As for bicycles, yeah again, low tyre pressures cause pinch flats. When your front tyre at 85psi pinches on a bump and blows, oh jeez, you are lucky to avoid serious injury.

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I keep an eye in it and have a mechanic check if i visit for something else. With big weather changes when I notice a difference is about the only time I go out of my way to adjust. Motorcycle

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Re TT and Prius
Yes I like to go one psi higher to compensate
for the expected one psi loss per month that naturally occurs so in case I am lazy to check tire pressure I’m still at or slightly above recommended

I don’t know why my bike tire tubes blew at 50psi
I heard pinch flats can occur if they are under inflated but I was over inflated per SILCA professional tires pressure calculator for the tires in question factoring my weight and bike weight

Both happened after hitting slight bumps

Now that am running 38/40 fr/rear
I have not had that happen

Re Prius yes I understand they use skinny tires which then much run at higher pressure to carry the weight

And generally over inflate should give better mileage

I’m trying something diff today

Yesterday in ran two psi less that’s to say
33/31. And strangely over a 50 mile run from sf to half moon bay and back I felt less urge on acceleration but the ride was awesome and I averaged 55mpg going average 50mph

The car really dragged its heals getting up to 70 on the freeway though but was really compliant on the bad roads

Today I’m going 34/34 and the ride is not as compliant but the performance has really come up

(Much as Prius can perform that is ). I really had to hold back to 65 as it kept running to 70mph (ticket territory in a 55zone ).

And I’m doing same pressure back and front for a change although per the placard the fronts are supposed to he 2 psi higher due to more weight up front I guess

It’s supposed to be 35/33 but I felt at 35 the fronts hunt but seem more planted at 34

And perhaps going 34 on the back instead of 33 may lessen the drag and thus compensate for the front being one psi less?

Yes I know I have way too much time on my hands

:nerd_face::nerd_face::nerd_face:

My friend thinks I have some sort of princess syndrome where a princess can feel a pin under seven mattresses as he can’t even tell if he’s running 20 psi low !!

Now I’m no prince and even less a princess but I just have the feel of a computer scale

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What TF ???:scream_cat::scream_cat::nerd_face::eye::muscle::lion::speak_no_evil::pouting_cat::clown_face::metal::love_you_gesture::tiger::stuck_out_tongue_closed_eyes::stuck_out_tongue::heart_hands:

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I always inflated my bike tires to about 50 psi. Makes it so much better ride.

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And I blew out two of my tubes at 50
Maybe cuz I’m 207 pounds and you are not?

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I weight about the same. Must depend on the tube/tire. I just read that it could be inflated to somewhere between 40-50 psi.

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(This is not normal! - No…this is Super!!!")

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