Misc Thread VI: Return of the Threadi

[Jastreb]

Cow's post and some of the others on tire pressure should probably be moved to it's own thread. The information is too good to be lost in the MIsc Thread.

[theholycow]

What should I really be looking out for in terms of differences in attributes?

Look for these immediate advantages: Increased cornering grip. More crisp/less sloppy.
Beware of these potential immediate disadvantages if you go too far (I'd guess north of 60psi): Stiff or bouncy ride. Wet pavement launch traction loss.

Long term: Increased total tread life no matter what. If you overdo it (again, probably somewhere over 60psi in this context) you will see increased center wear -- though tread life will still be increased, pattern will be center wear...anyway if that happens then you've probably found the limit of how much increase is useful.

Also, I've heard of people going above the recommended spec of range for inflation. How dangerous or unsafe can this be viewed as? Are the increases in performance and efficiency worth the risk? I'm actually studying and reading your tirerack post and such... interesting.

Beyond the maximum molded into the sidewall? Note that it may be lowered from the tire's actual engineered rating by unclear regulations. See the section halfway down this page...
http://www.barrystiretech.com/loadtables.html
...with the paragraph ending in "the regulation is unclear which of those values it is supposed to be." Lots of great stuff on that site, BTW. Dude is no expert in web design (looks like he did it approximately the way I was doing utilitarian pages in 1998) but he sure knows his tires, isn't afraid to tell what the manufacturers don't want to tell, and is great at putting all the data into one place.

If you are considering exceeding the maximum rating of the tire molded into its sidewall, I've found it to be harmless but I avoid it for one reason: Paranoia about legal liability. After a crash I'd hate to be assigned legal blame by default if some overzealous investigator decides that excess pressure means I'm a good scapegoat. I generally obey the maximum. Usually the maximum is reached before I reach diminishing returns on handling improvements/other advantages, so it usually ends up being my number.

Similarly I would not advise someone to exceed the maximum.

Exceeding the car manufacturer's number, however...that's another story. Free performance increase that also increases tire life and fuel economy. Hell yeah!

Also, don't forget that you can stagger your pressures to adjust balance to your preference. Your GTI probably has excellent balance, but if you want a little understeer (which I think you might) then adjust pressure for slightly better rear traction than front.

[potownrob]

honda has us putting more air in the front tires than the rears. the car practically oversteers and feels RWD at times. probably the chassis and not so much the staggered air pressures. i also usually add 1-2 psi more than recommended for better performance and driving confidence.

[Teamwork]

Swerve

Doing some more investigating on my door jamb it states that the recommended PSI for the stock tires are 36-37 PSI. I did a double take around with an analog pressure gauge and they were all rated between 31-32 psi. Not too sure what happened but I guess I left it up to "assumption". I'm glad I brought this up though now. Problem is I couldn't do anything about it because it's raining outside and I even did the pressure readings quick in the rain. I also have to reset the TPS sensors when I make the proper adjustment and should read up about doing that properly.

I'll be on the look out for the differences and characteristics. I plan on turning it up to 37 psi just to see it out. I'm wondering how my fuel economy will be from this point forward... I was pretty satisfied by 29-30 mpg before hand on 31-32 psi.

Also, don't forget that you can stagger your pressures to adjust balance to your preference. Your GTI probably has excellent balance, but if you want a little understeer (which I think you might) then adjust pressure for slightly better rear traction than front.

I'll probably keep it consistent for now but how much psi would qualify the difference in "staggering". Like 1-2 psi- or even more significant bias? Not the first time I've ever heard of this but never really understood the point or if the results were noticeable to be worth while.

Side Story
My last car was a 2013 KIA on a lease. Towards the last month of the lease I was planning on going on a vacation to Atlantic City with my girlfriend and as I was washing the car the day before the trip I noticed I had a nail sticking out of my front passenger tire. The tread on the car was pretty suspicious (not like really worn but definitely close to the lease 'exception') so I decided to get new tires. I was at the mercy of the tire place because I literally had 3 hours to get it done so I just got "whatever" was available and departed on the trip. I was shocked at how it transformed the car... The worst part of all of that though was I literally only had a few weeks to use them before returning the car. Some kid probably got a pretty sweet deal on that car... I stayed way below the mileage for the 3 year lease, I always maintain my vehicles well cosmetically, and pretty much brand new tires on the car. I should check up on the vin report...

[tankinbeans]

Guessing you had those godawful Nexens on your Kia. I had a 2011 Forte with those tires. They were worn down to the wear bars at 15k miles. That was just one of the issues that led me to drop it like a cheap date.

[Teamwork]

Guessing you had those godawful Nexens on your Kia. I had a 2011 Forte with those tires. They were worn down to the wear bars at 15k miles. That was just one of the issues that led me to drop it like a cheap date.

Dodged that bullet because I had the SX trim so I had the Eagle LS tires which weren't much better though they seemed to actually be pretty decent in the snow. That was actually the best attribute I could remember about those tires. I remember when I got the tires to go on my trip that it increased my speed rating and it felt like it was more controlled and stable at a higher speed. In some other posts I have around this forum taking the Garden State Parkway- I was getting passed spiritedly when I was doing 75-80 mph in the right lane. Live and you learn though... I daily drove a 95 Corolla before all of this and that basically had no name bicycle tires on it throughout its tenure. I couldn't even take a spiraling exit ramp at 30 mph without them screaming at me.

This was my last day with my KIA. Returned back to stock.

[LHOswald]

I can't believe how many familiar faces are still here...what's going on everyone!?

[tankinbeans]

Teamwork, that is a gorgeous car. I thought mine had nice lines and a clean design; not writing Kia off as a brand. My clutch and transmission really killed anyenjoyment for me. I guess for $15k what should I have expected? Alas, there are reasons I got my first Focus, Clifford.

[theholycow]

recommended PSI for the stock tires are 36-37 PSI. I did a double take around with an analog pressure gauge and they were all rated between 31-32 psi.

I'm wondering how my fuel economy will be from this point forward... I was pretty satisfied by 29-30 mpg before hand on 31-32 psi.

You should see a minor improvement, but you might not.

How good are your fuel economy tracking habits? Are you just using the DIC? Do you track exact miles driven and gallons pumped, using the same pump with the car facing the same direction etc? No matter what, look for long-term trends...short term numbers are not dependable even when you do everything as perfectly as possible.

how much psi would qualify the difference in "staggering". Like 1-2 psi- or even more significant bias? Not the first time I've ever heard of this but never really understood the point or if the results were noticeable to be worth while.

I don't pussyfoot around with pressures, I generally start with large increments and refine if necessary, but you can certainly try just a few psi at a time...though I doubt you'll feel 5psi, let alone 1-2. Chances are you don't even have a gauge that can consistently give you good readings without a 2psi margin of error.

The point is to change balance. I like a loose rear end (:lol:). Based on an earlier post I think you may like some understeer. As I said, your GTI probably has excellent balance. You could produce some of the understeer that you desire with staggered pressures.

I was shocked at how it transformed the car... The worst part of all of that though was I literally only had a few weeks to use them before returning the car.

I too have had experiences like that...and I too have put nice tires on a lease that I was returning.

When I had my 2008 VW lease I kept wearing the OEM rubber down and eventually bought an excellent set of like-new tires for $100, but I decided to wait to put them on. Just before turning it in I put them on, then realized I should have driven on them all that time and put the OEM tires back on at the end, or at least I could have discarded one set with a reasonable level of wear and driven the other set and turned it in within lease requirements but not so like-new.

Then, shortly after I turned in the VW, we bought my wife a 2005 Pontiac Sunfire (there's another GM that has treated me well). It used the exact same tire size AND the exact same wheels. I watched Craigslist for winter tires and wheels for her car and ended up scoring 9 excellent tires on wheels for a song and a dance. Considering how readily available they were I could have bought deals like that for the VW, driven the OEM tires down to just barely acceptable for lease turn-in, driven other tires without having to get them mounted to wheels, turned in the VW with its OEM stuff and kept the other tires for the Sunfire...oh well.

[Teamwork]

Teamwork, that is a gorgeous car. I thought mine had nice lines and a clean design; not writing Kia off as a brand. My clutch and transmission really killed any enjoyment for me. I guess for $15k what should I have expected? Alas, there are reasons I got my first Focus, Clifford.

My lease terms were seriously ridiculous... I miss it, honestly. I put down only 3k had a trade in for 1k value and paid only 165 a month for the highest trim level with every option checked off except for leather. In some ways I went backwards in terms of content levels from that car to my GTI and I got spoiled; little things such as, power folding mirrors, automatic head light controls, and a really decent stock stereo. Most importantly, everything worked reliably as it should've.

The bad things about that car were pretty much anything in terms of sportyness and dynamics. It was a good looking, "sporty looking" car but it never even came close to living up to the way it looked. The engine was old architecture which I didn't even mind... it wasn't D.I. and no party tricks. The 6 speed automatic was actually really good IMO- responsive and yielded decent fuel economy. The live rear axle was a nightmare though and the tuning overall for the springs and suspension was an absolute mess. The chassis never instilled much confidence that you could corner these things. Tires did help its cause but the root of the problem was way deeper then that. At the time that I got the car I was going through uncertain times and transitions so I didn't want to go crazy. Perfect car in that regard.
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Yeah Cow,

I filled up to 37 psi- used a digital pressure gauge to get it as exact as I could and reset my tps sensors. Not really too sure if it's placebo but I am very keen in noticing differences but I feel like my ride height is higher. Not significantly but it certainly feels more SUV like to me now (exaggeration). I took a fairly aggressive run on an entrance ramp and I felt more grip then usual. I think I even squeel'ed a tad. Definitely haven't put enough seat time to notice other things but could a difference of 5-6 psi really change the ride height noticeably?

How good are your fuel economy tracking habits?

I use fuelly so I track the actual odometer, the range, the price per gallon, and the amount of days that have gone by. I like it but the thing is I very rarely totally empty my tank out between fill ups. If I did that I've probably fill up once every 1.5 weeks- I've been a consistent week 6 days to a week basis. My mileage since my first oil change at 5k has been around 28-29 mpg- and this has been only on winterized blend of fuel and longer idling periods to warm up. If there's even a marginal increase I'd be pretty happy but I am completely satisfied as is. I'm not really beating on this car but I'm not babying it either.

On a side note the sidewall of the tire itself says not to exceed 40 psi. The door jamb recommends 37 psi... I'm assuming 38 psi would be fair game in essence.

I don't pussyfoot around with pressures, I generally start with large increments and refine if necessary, but you can certainly try just a few psi at a time...though I doubt you'll feel 5psi, let alone 1-2. Chances are you don't even have a gauge that can consistently give you good readings without a 2psi margin of error.

I have the old fashioned tire gauge but I also use a craftsman digital one that gives a more "exact" reading. I'm seeing how this goes consistent across the board but I wouldn't rule out doing something like this. I'd say I'm biased to predictable understeer but I really don't have experience with oversteer characteristics to know better or otherwise. The car does have decent balance, the chassis is willing, and body roll is present but it's MINIMAL. I sense body roll at limits that I would gasp at in other cars or I would've already flipped over the vehicle.

[tankinbeans]

Your experience mirrors mine. The car felt unsettled much of the time. The issue was probably compounded for you because of the bigger, more powerful engine. I was pulling an easy 33ish with the 2.0, but I couldn't believe it ate a set of tires in 15k miles, but stranger things have happened. I drove that thing for 18 months and never went more than a week between stalling events.

[Teamwork]

Your experience mirrors mine. The car felt unsettled much of the time. The issue was probably compounded for you because of the bigger, more powerful engine. I was pulling an easy 33ish with the 2.0, but I couldn't believe it ate a set of tires in 15k miles, but stranger things have happened. I drove that thing for 18 months and never went more than a week between stalling events.

That was originally supposed to be my "first" manual car but I got talked out of it by my father and the sales guy. I did some internal investigating and a lot of people said the manual transmission units in these were really bad overall. I don't know if you can attest but other people said their clutches acted really funny in sub 32 temperatures also.. so it was easy for me to steer clear. I never test drove the 2.0L it was SX 2.4L or nothing for me. The rear torsion beams in Korean cars seem to be really unrefined. I test drove the new one with the 1.6L and the Veloster Turbo and both suspension set ups really mirrored how I felt with my 2013 in a bad way. The ride always felt unsettled, stiff, and harsh and all of these attributes without much pay off to sportiness. Ironic because I'm riding on larger rim and even more low profile rubber in my GTI and this is one of the best ride "compromises" I've ever been in. If anything it's still a bit soft for my taste but ride compliance and bump compliance is NY friendly.

And it's ashame because I highly regard Hyundai and KIA at this point. I think they are seriously one Prius and half "handling by Lotus" away from trumping the Japanese. That's the only weak part I could think of aside from the jokingly bad resale value. (Sorry Potown) Honda and Toyota just don't do it for me anymore and they totally abandoned the enthusiast market in the US but we still continue to give them money for "me-too cars".

[tankinbeans]

Yup. There were times when I couldn't get into 4th gear if I tried. Brought to dealer was told, "you must be applying slight pressure toward the driver's side." Friend drove ot and the same thing happened. Cow and Rope can attest that I was getting a bit perturbed after awhile. On a whim, after buying a Blazer for my mom to drive, I asked the sales guy if a Focus SE would work and 5 hours later I drove off the lot. Took a bath a depreciation, but got a car that was infinitely more enjoyable.

[Teamwork]

Yup. There were times when I couldn't get into 4th gear if I tried. Brought to dealer was told, "you must be applying slight pressure toward the driver's side." Friend drove ot and the same thing happened. Cow and Rope can attest that I was getting a bit perturbed after awhile. On a whim, after buying a Blazer for my mom to drive, I asked the sales guy if a Focus SE would work and 5 hours later I drove off the lot. Took a bath a depreciation, but got a car that was infinitely more enjoyable.

God, I could only imagine if I didn't dodge this bullet. My initial impressions of manual might've turned me into a cvt lover... the sales guy who was a real nice guy and a straight shooter hinted to me that there were "cases" of problematic histories with the manual transmission unit and that it wasn't really ideal for a newbie in general. I again really had no qualms about the 6 speed automatic... it was responsive if you put your foot into it and it went straight to 6 as quickly as possible if you didn't. The paddles and manual shifting aspect of it was jokingly bad- it was unusable or... usable with 0 benefit. It didn't rev match down shifts so you felt like you were breaking the car, any type of shift response there was a noticeable 1 second of lag before it actually responded to what you were inputting, and it auto up shifted once you got to the red line. I probably used it a total of 2 times in 3 years of daily driving.

Pretty cool that we essentially went from the same car to a similar class car. It's going to be hard for me to ever turn away from forced induction at this point.

[watkins]

It's going to be hard for me to ever turn away from forced induction at this point.

Fortunately for you (and me), everything seems to be getting boosted these days.

Not that I really like even a single new car on the market...