I was taken all the time for a fool

"Spanfeller is a twat" (theaspiringengineer) 08/30/2018 at 18:35 • Filed to: None

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And now I know why.

Tech: Yup, here’s the tire

Me: Fantastic! Finally!

*Tech installs*

Tech: Mkay’ It’s done, let me fill it up, 40PSI ok?

Me: What?!?

Tech: You see, Normally these go to 32PSI, but given our streets are pieces of shit, we always put em up to 40.

Me: Seriously?

Tech: Yeah, but if you want to break another tire fine by me, guero!”

Me: Okay, do your thing.

*Sometime later*

Me: Seriously?

Friend that owns a shop in Monterey: Yes, seriously.... my god, you’re such a noob.

Me: Seriously?

Second Uncle (Mechanical engineer): Yes, dude, I mean, they have some issues but for what you need them to do, put the pressure up.

Every I spoke with told me that it was better to go higher because apparently that makes the tire harder to break

themanwithsauce - has as many vehicles as job titles > Spanfeller is a twat 08/30/2018 at 18:43

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I don’t know if it’s necessarily harder to *break* but I have heard that “overinflating” by a PSI or two above the usual is good practice and modern tires can take a bit more pressure than they used to. So yeah, you fill to 36-38PSI when you used to do 32-34 so that you keep pressure in the tire. 40 PSI seems high unless you have a strong tire but if the pic is of your tire, it is XL load rated so yes, you can do 40. I run 40 up front and 38 on the rear in my FoST. Good, crisp feeling on the highway and on side roads .

Rusty Vandura - www.tinyurl.com/keepoppo > Spanfeller is a twat 08/30/2018 at 18:43

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I don’t know about donk rubber band tires, but I always inflate my tires to 90% of their max pressure.

Future Heap Owner > Spanfeller is a twat 08/30/2018 at 18:45

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Wait, really? I’m just as fool as you. I’d expect that higher pressure would increase stress when you go over a big bump or hole, making failure more likely. But that’s assuming the failure mode is pressure-induced rupture.

Thinking back to my last bicycle flat, which happened when I went over pothole at ~15 mph on less-than-optimally-inflated tires, perhaps the pressures are still well within Lolita and the important thing is minimizing tire deformation?  But now I’m just making up theories to fit the data.

Spanfeller is a twat > Future Heap Owner 08/30/2018 at 18:50

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A higher pressure allows for less deformation, which means, that the contact patch that absorbs the bump is effectively larger, so there’s less load on the sidewalls?

It seems hard to grasp, but pressure spreads across the whole chamber, so the added stress is dampened by the entire chamber rather than just that one small section of sidewall on the verge of rupture. 

Spanfeller is a twat > themanwithsauce - has as many vehicles as job titles 08/30/2018 at 18:52

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Apparently I should have all of them up to 40, I used to have the rears at 35 and the fronts at 32. 

Spanfeller is a twat > Rusty Vandura - www.tinyurl.com/keepoppo 08/30/2018 at 18:52

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donk rubber band?

OH, you mean the profile?

I hate it, I miss my huge profile tires on the jeep. My GC didn’t rock crawl, but it sure as hell sidewalk-crawled when necessary! 

facw > Future Heap Owner 08/30/2018 at 19:02

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Higher pressure should better protect the tire, but it will mean a slightly rougher ride as well (probably also improved gas mileage, decreased wear, and decreased grip) .

On bicycles, high tire pressure is important to avoid pinch flats, the condition where the tire and tube get pinched against the edges of the wheel enough to puncture the tube. Beyond that the advantages and disadvantages are about the same, high-pressure leads to lower rolling resistance, but also means the tires aren’t as good at absorbing impacts. Cars don’t have tubes so there’s no worry about pinching them, but the same sort of compression can damage the sidewall.

TheRealBicycleBuck > Spanfeller is a twat 08/30/2018 at 19:05

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Suggested tire pressures by your car’s  manufacturer are intended to keep your tire cross-section flat given the weight of the car. While over-inflation may help resist pinch flats, it comes at a cost. The first is excessive tread wear at the center of the tire. The second is poorer handling. 

Spanfeller is a twat > TheRealBicycleBuck 08/30/2018 at 19:08

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I can live with that! I’m not exactly canyon carving in this 2 ton kia

(I appreciate the insight) 

LOREM IPSUM > Spanfeller is a twat 08/30/2018 at 19:10

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I spe culate that m ore pressure means more force required to squish the tire, which means less likely you’ll run out of air pocket before the wheel contacts the ground. Probably more likely to blow the th e itself, however.

Wrong Wheel Drive (41%) > Spanfeller is a twat 08/30/2018 at 19:10

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Depends on the tire and the car and the application it is being used for. On my Miata, I run 30 PSI cold when street driving and 30 PSI HOT when track driving. The difference there is that pressure is going to increase significantly when you heat up the tire so I am realistically seeing 34-36 on the street after driving a bit. And that 30 PSI hot on the track would turn into like 24 PSI cold after sitting for a bit. 30 PSI cold is Mazda’s recommendation on the door sill/owners manual for both front/rear.

STi is a bit higher PSI but again I just basically follow what the door sill/owners manual says. I believe it is offset with 36 front/33 rear. However, I think it is stupid to set things this way since the car has a tendency to understeer. So I run it the other way around with 33 front/36 rear to help get the rear end to rotate better and get more grip out of the front. It helped a little bit and feels more balanced, although I think a rear sway bar and better alignment are in order to really dial out the understeer.

If I cared about gas mileage instead of performance, I would run both at higher pressures. Probably 33-35 (F/R) in the Miata and 36-38 (F/R) in the Subaru. 

Wrong Wheel Drive (41%) > Spanfeller is a twat 08/30/2018 at 19:13

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A 225/40 is not a donk rubber band lol. 

Spanfeller is a twat > Wrong Wheel Drive (41%) 08/30/2018 at 19:15

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Everything is a donk rubber band compared to my geep’s tires

Spanfeller is a twat > Wrong Wheel Drive (41%) 08/30/2018 at 19:19

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Seems like my m ileage is bound to increase

Rusty Vandura - www.tinyurl.com/keepoppo > Wrong Wheel Drive (41%) 08/30/2018 at 19:22

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benjrblant > Spanfeller is a twat 08/30/2018 at 19:25

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Sounds like you need one of these.

Spanfeller is a twat > benjrblant 08/30/2018 at 19:28

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We were actually on the verge of getting a defender, but here they sold something like twice as much as they do in England

shop-teacher > Spanfeller is a twat 08/30/2018 at 19:37

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A friend of mine is an auto shop Teacher. He's ASE certified, and is always going to professional development conferences to stay up on the latest techniques and research. Every tire session he's been to, the tire guys say to run sidewall pressure. The tire pressure on the vehicle is tuned for a cushier ride. Because of his insistence, I've been running sidewall pressure in all my cars and trucks for like a decade. I've seen no abnormal wear from it.

Spanfeller is a twat > shop-teacher 08/30/2018 at 19:42

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Sidewall pressure? Pardon my ignorance, but I do not know what that means.

The Crazy Kanuck; RIP Oppositelock > Spanfeller is a twat 08/30/2018 at 19:55

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Depends what I’m doing. Daily driving I run 40psi F, & 40psi R. For auto-x & track I do 42psi F, & 37psi R. Helps the rear end grip more, & the high front pressure helps lots with sidewall roll & turn in. I only know that when an experienced fwd auto-x guy asked about my tire pressures, then he suggested run the front about 5 psi higher then the rear.

Spamfeller Loves Nazi Clicks > Spanfeller is a twat 08/30/2018 at 19:57

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Sometimes true, sometimes not. It depends on the tire, sidewall height, etcetera. e.g. rubber bands? ALL THE FUCKING PRESSURE. P185/65R13? Yeah, you’ll be fine at 30 ish .

Spanfeller is a twat > Spamfeller Loves Nazi Clicks 08/30/2018 at 19:58

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I suppose 225/40r19 is inbetween rubber band and hi-pro

Chuckles > Spanfeller is a twat 08/30/2018 at 20:00

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I think they just mean the pressure written on the sidewall of the tire.

Berang > Spanfeller is a twat 08/30/2018 at 20:02

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A tire guy would say that, if you wear out your tires faster he can sell more.

Also, have no idea what “break” means in the context of your post.

Spanfeller is a twat > Chuckles 08/30/2018 at 20:02

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So... the max pressure?

Spanfeller is a twat > Berang 08/30/2018 at 20:04

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Which is why I sought out second opinions.... I mean, if the dude was telling me to run 50 I’d decline, but both my Uncle and my shop friend recommended I ran 40PSI, even if the factory rating is lower. 

shop-teacher > Spanfeller is a twat 08/30/2018 at 20:06

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Yes. The max cold pressure.

Spanfeller is a twat > shop-teacher 08/30/2018 at 20:09

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It probably makes sense, you’d have to be a very shoddy tire manufacturer to make a product that bursts if it’s out of speck pressure, plus, if manufacturers carry out their fuel economy tests with 45 PSI tires, why shouldn’t I daily my car like that!

shop-teacher > Spanfeller is a twat 08/30/2018 at 20:15

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When we hit potholes, the tire pressure spikes into the hundreds of psi. So I laugh when people think their tires are going to burst at 40-50 psi. My trucks tires say 44psi, so that's what I run. Bonus, if you loose a few pounds of air and don't catch it right away, you haven't been driving around under inflated.

Honeybunchesofgoats > Spanfeller is a twat 08/30/2018 at 20:24

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This explains why every goddamn time I check my mom’s tire pressure, it’s at least 8 PSI over spec. 

Spanfeller is a twat > Honeybunchesofgoats 08/30/2018 at 20:39

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Why is the pressure so high? 

Berang > Spanfeller is a twat 08/30/2018 at 20:40

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Raising the pressure won’t save the tire, but it may save your rim.

If your wheel well could handle it, and you do kill tires or rims regularly, I’d upgrade to 225/4 5 R19. The only thing that can really save the tire is more tire. More sidewall + more air capacity = more resilient tires.

Spanfeller is a twat > Berang 08/30/2018 at 20:54

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My sidewall had a big slit (10 -13 mm) down the middle and I lost all pressure in matter of seconds , the rim did get a small bruise. Rear tire got a small buldge on the sidewall but no damage to the rim, I can tell its time is nigh.

It’s the first flat I’ve ever gotten on any car , normally I am very mindful   of potholes, but this was a small manhole without a cover that had been flooded (a puddle covered it)

It’s common during the rainy season for man hole covers to dissapear, I do not know why this happens, all I know is that drainage is so bad water sometimes shoots out of the manhole.

Aparently I’m not the only victim of this, several cars at the uni parking lot had space savers on, I used to feel superior than them, but now I’m just like them...a poor idiot that destroyed a tire.

On the issue of tire size itself, I do want taller tire, I know my wheel well can take it, and I don’t care about speed error anyway. Originally I wanted to go up to 245/40 (max recomended width for 8J rims ) and maybe go 255/40 at back (currently 255/35 with a 8.5J) , however, a set of tires like that would cost me upwards of 1600 dollars, tires here are ludicrously expensive, it is absolutely insane. It’s also worth mentioning that these tires are really hard to find here, not a single store had them in stock! 

merged-5876237249235911857-hrw8uc > Spanfeller is a twat 08/30/2018 at 20:55

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I run mine a couple psi over the door sticker and a few psi less than the sidewall cold max, and I’m running 35 series in Detroit, so you should be fine wherever you’re at.  It gives a better ride than running at the cold max psi.  Also you should check the wear over time too, you may end up running the center thinner than the shoulders over time.  It really comes down to preference too.  Running mine at 44psi makes for a rough ride, every bump is more severe into the cabin.  38psi is just about right.  Even tire wear and softer ride.  But not winter tire soft, just enough to take the edge off.  Experiment a bit.

Berang > Spanfeller is a twat 08/30/2018 at 21:01

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You’d get more sidewall going to 225/45 than going to 245/40, but you would have more air volume in the 245. I’d still take as much sidewall as I could fit for any vehicle that needs to be driven on actual streets.

Spanfeller is a twat > merged-5876237249235911857-hrw8uc 08/30/2018 at 21:02

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Detroit, motor city, has bad streets? Thats quite the irony....

yeah, I’m pushing the pressure up to 40 on the remaining tires

I was also reading in a Kia forum that their Tire pressure sensors don’t work under 35PSI? Which is wierd considering recomended pressure is 32/35 

Spanfeller is a twat > Berang 08/30/2018 at 21:03

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In reality I want to buy the smaller 2.0 rims in order to go even taller , and then just run 235/45 on all four tires. But I don’t even want to think how much that’d cost!

facw > Spanfeller is a twat 08/30/2018 at 22:26

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Detroit (like many cities in the US midwest) has seen its population decline dramatically:

They can’t really afford to keep up all the infrastructure that was built when the city was much larger. Many of the suburbs outside Detroit have gotten bigger, but not much of their tax money goes to Detroit.

bhtooefr > shop-teacher 08/30/2018 at 23:03

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The problem, really, with running max sidewall is that it can severely affect handling behavior, especially over bumps. I’ve definitely heard of some cars where they just do not handle right pushed up to max sidewall...

There’s a balance of factors in selecting the right tire pressure for the car - vehicle weight (and weight distribution), handling, fuel efficiency, and yes, comfort.

I personally run a bit higher than specified - I tend to corner aggressively, and increasing the pressure a bit helps ensure that the tire doesn’t roll over onto the sidewall, and it does help fuel efficiency. But, that means I’m running 39 front, 36 rear (the Prius Eco spec) instead of 36 front, 35 rear (the spec for most other 15" wheel Gen 4 Prii), on 195/65R15s.

(And yes, I went for a trim with 15s on purpose. Better fuel economy, better ride comfort, and shockingly, no real loss in handling (some reviews even noted better handling from the 15s).)

DipodomysDeserti > Spanfeller is a twat 08/30/2018 at 23:19

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Overinflating tires not only wears then out faster, but makes them more susceptible to pothole damage. Inflating to the vehicle specs ensures proper sidewall deformation. From Michelin’s website:

DipodomysDeserti > Future Heap Owner 08/30/2018 at 23:21

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You’re not a fool. Tire manufacturers as well as places like AAA warn against overinflating tires as it’ll make them more susceptible to pothole damage.

Tire shops always overinflate tires as it causes excessive tread wear without risking a blowout at speed.

Spanfeller is a twat > DipodomysDeserti 08/30/2018 at 23:25

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I’m getting mixed messages from all oppos on this...

shop-teacher > bhtooefr 08/30/2018 at 23:49

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I don’t blame you on the 15 s. I much prefer the 17 s on my truck several very the available 18 s and 20s.

for Michigan > Spanfeller is a twat 08/31/2018 at 05:32

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Detroit has some of the worst roads in the country.

merged-5876237249235911857-hrw8uc > Spanfeller is a twat 08/31/2018 at 07:29

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Yeah there’s some pretty bad spots. Funny thing this past winter was that the normally decent suburb streets were actually worse than the Detroit streets. The difference being, those same suburb streets are all being repaired right now, whereas Detroit’s aren’t.

It’s got a huge footprint for a city and they chopped it up so much when they made the expressways for all of us suburbanites to commute in and out of the city, that it’s left good chunks of neighborhoods split up. So that’s just made it even harder for city services to keep up as now they have to drive out of their way to services homes that might be the only one on a half mile block.

People have been moving back into the downtown areas, but it’s still got a ways to go.  

Spanfeller is a twat > merged-5876237249235911857-hrw8uc 08/31/2018 at 07:57

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In that sense Mexico City rarely improves, last year they repaved an avenue close to my house, it’s already full of small indentations that will turn into potholes in a few months; they just don’t build with reliability in mind. The suburbs are somehow worse and also filled with speed humps (many times made illegally by the homeowners) 

DipodomysDeserti > Spanfeller is a twat 08/31/2018 at 09:25

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I think Michelin might know what they’re talking about when it comes to tire pressure. AAA also says overinfkation can cause pothole damage. It’s also pretty common knowledge that overinflated tires are more likely to suffer damage when offroad as well. Not sure where this pothole myth came from.

Spanfeller is a twat > DipodomysDeserti 08/31/2018 at 10:22

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I did keep on reaserching it and I ended up in a stump;tire manufactuers don’t want any nuance, they recomend factory pressure and say either are dangerous. Forums say that techs either want to screw you over or that they do it because they have more practical knowledge. For instance, overfilling so that people that don’t check their pressure regulary never end up driving on underinflated tires. Underinflated tires are much more dangerous. it’s also another safeguard since, if you don’t check pressure often, the slow loss of air eventually balances out the inside and outside wear.

On the one hand, my car is some 150-200kg heavier than factory, so I do need to up the pressure a little to avoid excessive wear on the outsides. maybe 40 is too much, but 38 cold might be good enough , compared to 32/35 oem spec .

also, Kia’s tpms doesn’t seem to work under 35 psi according to forums, after a practical test, I concluded it is true. How exact can a PSI requirement be if the door jam and factory TPSM have different specs in mind ?

On the other hand, out of spec inflation should be bad (why else would manufacturers recomend a specific pressure?) but given pressure varies in many ways and due to many circumstances, being even 5psi off can’t be that bad.

DipodomysDeserti > Spanfeller is a twat 08/31/2018 at 11:50

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I think you’re right about tires places over inflating in order to avoid people driving around on under inflated tires. If your car is a bit over the factory weight, then it’ll probably help you to over inflate by a few PSI. 

Longtime Lurker > Spanfeller is a twat 09/01/2018 at 11:27

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Your car is armored, correct? Si nce it weighs more then factory you should be using higher then factory tire pressure anyways.

Spanfeller is a twat > Longtime Lurker 09/01/2018 at 11:55

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Oh, that is true! All of them are at 38 now. But the debate that sprung up here was intense over whether a tire should or shouldn’t be overinflated