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-   -   44 psi vs. 32 psi and costs (https://ecomodder.com/forum/showthread.php/44-psi-vs-32-psi-costs-28759.html)

Joggernot 04-19-2014 02:11 PM

44 psi vs. 32 psi and costs
 
I did a spreadsheet on the cost of running 44 psi vs. running the recommended 32 psi. I have found that 44 psi wears my tires in the center and I need to replace tires sooner than the stated lifetime of my tires. The spreadsheet shows that even with an extra set of tires I come out ahead using the 44 psi tire pressure.

I had to drop the miles per set of tires down to 1/3 the stated lifetime of my tires before it was almost a break even. Has anyone else done this evaluation? What are your results?

user removed 04-19-2014 02:19 PM

Never had my tires wear out in the center from 44 PSI. Several cars and probably 100k miles, many different tires. Measured them on my VX after 25k and no measureable difference. Tires last longer as well.

I'm not trying to tell you your observations are wrong, mine are just different.

regards
Mech

UltArc 04-19-2014 02:20 PM

One could run their tires at, for this situation, 44 psi, then start lowering it to let the tires wear more evenly and extend the mileage from them.

ksa8907 04-19-2014 03:37 PM

quick question, what are your tire dimensions and brand? I run 45psi cold and don't see center wear, in fact i still get shoulder wear.

2000mc 04-19-2014 03:37 PM

Would this happen to be noticed on the back of the Tacoma? More wear at the center seems to be normal from what I've seen, on solid axles. On my own vehicles I tend to see even wear at max sidewall, and the edges seem to wear out first at the pressures recommended on the door

mcrews 04-19-2014 03:54 PM

Ran 4 sets of kuhmos on my 2002Q45 at 40+psi. I got 40-45k miles on each set. They were summer high performance and this was acceptable wear. I never experienced center wear.

Joggernot 04-19-2014 04:13 PM

Quote:

Originally Posted by ksa8907 (Post 420870)
quick question, what are your tire dimensions and brand? I run 45psi cold and don't see center wear, in fact i still get shoulder wear.

My last set of Walmart specials 205/65 -15. The wear was on the front tires of the 2000 Accord. I haven't noticed the center wear on this set of tires (also Walmart specials), but I wanted to know if it was hurting me financially to do the 44 psi. Learned that it wasn't hurting me. I regularly check them and put them at 44 psi. Mileage increase was noticeable, but no A-B-A testing done. Scangage II only.

The Tacoma is doing just fine, front and rear. No difference at 50 psi, but the wife hauls things like bricks and landscape rocks quite often.

mcrews 04-19-2014 04:19 PM

There have been several threads concerning "center wear". You do realize you are suggesting thAt a steel belt can be made to expand with just 11 extra psi?

redpoint5 04-19-2014 04:59 PM

The tires in all of my vehicles are inflated to ~42 psi, and the outside edge always wears out before the center. Then again, I drive without brakes, so that means I enter corners and make turns at a much higher rate of speed than most people.

If the roads in TX are anything like OK, then they are all straight compared to the winding roads of the PNW. I once visited a friend in Enid, and he let me ride his motorcycle. The center was worn flat and I asked him if he ever uses the sides of the tire. His response, "the roads are all straight here". So, the discrepancy of your tire wear vs the experience of others might be attributed to straight vs winding roads.

My question is, how much faster do suspension components wear, given a 10 psi increase over manufacturers recommended pressure? I wonder how much extra force is transmitted to the suspension components due to the higher inflation pressure?

user removed 04-19-2014 06:16 PM

1 Attachment(s)
Here is a pic of my Fiesta's tires, factory Kuhmo Solus, close to 27k miles. They have been at 44 PSI since I got the car with 3770 miles and it was totalled in the front end.
I had the opportunity to get the toe set at minimum spec (closest to 0 within specs), when the shop that fixed it did the alignment.

regards
Mech

mcrews 04-19-2014 06:31 PM

Quote:

Originally Posted by redpoint5 (Post 420885)
s.

My question is, how much faster do suspension components wear, given a 10 psi increase over manufacturers recommended pressure? I wonder how much extra force is transmitted to the suspension components due to the higher inflation pressure?

This is a GREAT question! The Infiniti Q45 had electronic suspension so I never noticed the rougher ride. Sold it with 270k. I had replaced the shocks and struts twice...at 100k and 200k. But as a note I am a big believer in replacing them at regular intervals, regardless of psi.

mcrews 04-19-2014 06:33 PM

Quote:

Originally Posted by Old Mechanic (Post 420902)
Here is a pic of my Fiesta's tires, factory Kuhmo Solus, close to 27k miles. They have been at 44 PSI since I got the car with 3770 miles and it was totalled in the front end.
I had the opportunity to get the toe set at minimum spec (closest to 0 within specs), when the shop that fixed it did the alignment.

regards
Mech

I love kuhmos !!!

PressEnter[] 04-20-2014 02:06 PM

The centers are wearing slightly faster on my Bridgestone Turanzas at 45 psi, but they are still at 7/32 after 18,500 miles, so it doesn't seem like it will decrease the life that much.

Piwoslaw 04-25-2014 01:55 AM

I run my tires at the rated 51psi and noticed that the summer tires are a bit more worn in the middle. It's not wearing down as fast as I'd like it to though (I'm waiting for an excuse to purchase a set of low RRs);) The winter tires look OK, but they less milage.

Quote:

Originally Posted by Joggernot (Post 420851)
The spreadsheet shows that even with an extra set of tires I come out ahead using the 44 psi tire pressure.

To sum up this discussion:
  • If your tires do not wear in the middle when run at max sidewall - it's worth it.
  • If they do - it's still worth it.
  • As fuel gets more expensive - it's even more worth it (fuel cost will rise faster than tire price).

Xist 04-25-2014 05:31 AM

I ran the tires in my Forester at 44 PSI until I noticed center wear, but I really do not think that it should have happened that quickly, I had the car for a while before I found this site and I only drove 9,300 miles my first year.

However, the tires were only rated for 32 PSI!

Joggernot 04-25-2014 07:45 AM

Quote:

Originally Posted by Xist (Post 421473)
However, the tires were only rated for 32 PSI!

That could be the problem. I've never seen tires rated that low.

Fat Charlie 04-25-2014 11:54 AM

Quote:

Originally Posted by mcrews (Post 420877)
There have been several threads concerning "center wear". You do realize you are suggesting thAt a steel belt can be made to expand with just 11 extra psi?

They are Walmart specials. I'll suggest just that! ;)

PaleMelanesian 04-25-2014 12:10 PM

I've only seen even wear with mine at pressures *above* those mentioned here. I still see the edges wear down faster on the front if I don't rotate them. The worn edges sit high in the back until the middle is worn to match, then they wear evenly from there.

Three vehicles, 6 sets of tires, ~200k miles between them all. (2 sets were used when purchasing used vehicles). Tread wear I can't comment on since our "chip & seal" roads chew up everyone's tires prematurely regardless of pressure.

I do buy quality tires - Michelin, Goodyear, Yokohama.

Saskwatchian 04-25-2014 02:38 PM

It's so subjective to the vehicle you drive and the roads you drive on.

My Explorer used to chew through tires seemingly faster than it would go through gas. The worst was when I was experimenting with higher pressures. The increase in fuel economy was NOT worth the uneven wear and more importantly not worth the degradation in comfort, control, and safety. Bouncy tires were more than likely also a factor in blowing my shocks *again*, and blown shocks would have definitely been a factor in worn tires. It's a vicious cycle.

Now that I am driving a car the tires cost half as much and are seeming to last 4x as long, and I am able to bump up my pressure a bit past the vehicles recommended pressure without noticeably affecting the ride. In the time I would have killed a set on my Explorer the tires on the Versa look to be in 70-80% condition with nice even wear.

cowmeat 04-25-2014 02:38 PM

I got a set of cheap 12" tires on-line for 33 bucks a piece and had them put on the rims for 6 bucks each, I didn't even bother getting them balanced because they didn't have equipment to balance 12" tires. I run them at 50 psi, which is about 5 psi over max rating on the sidewall, and I've ran them that way since I got them last June, and I don't really notice any wear at all yet, much less any center wear. Might bump them up a couple of more pounds since I pretty much just creep around anyway

KrautBurner 04-25-2014 03:13 PM

I've noticed that most cars running "factory" pressure have tires that indicate underinflation (heavy wear on both the inside and outside shoulder)
but 44psi (when the car calls for 32) seems high

my GTi got great wear at 36 front 38 rear
my GTO is doing well at 36/36

Fat Charlie 04-25-2014 03:42 PM

The car can call for anything it wants. 44 psi is only high if the sidewall number is below it.

Saskwatchian 04-25-2014 05:52 PM

Quote:

Originally Posted by Fat Charlie (Post 421529)
The car can call for anything it wants. 44 psi is only high if the sidewall number is below it.

No, 44 psi is high if tires don't have enough load on them and/or your suspension relies on some tire deformation. 35 psi worked better than 45 psi for me, that's on tires rated for 65 PSI. At 50 psi they were getting so bouncy it was dangerous so I backed them off.

ecomodded 04-25-2014 07:20 PM

for me 35lbs in the tires is like having a parachute on, i have been using 50psi in my 44psi tires for 25000km and my tires are worn perfectly - even without tire rotations.

I suspect the added agility and coasting abilities of a 50psi tire is to much of a change for some people after slugging around at 35 psi for years and years.
When I first moved my tires to 50psi it felt like the car had way too much sensitivity, now that I'm used to it(it does take 1 or 2 weeks) I feel secure and nimble on the road.

I credit my great fuel economy to 50psi in the tires and my low rpm driving technique.

SoobieOut 04-25-2014 07:37 PM

I wonder about the safety of old tires with these 80K+ mile warrantees. Remember the actor killed in a Porsche accident, they are now blaming the crash on 9 year old tires (and driving too fast).

So replacing the tires every 4 or 5 years is a good thing for safety.

euromodder 04-25-2014 08:34 PM

I'm running 43.5 psi on a 2050 lbs car - over that and it gets bouncy.

The 32 psi recommended by VW felt like driving around with a supertanker's anchor dragging on 5 miles of chain.

Even wear so far.

Xist 04-26-2014 03:22 PM

Quote:

Originally Posted by MorphDaCivic (Post 421562)
I wonder about the safety of old tires with these 80K+ mile warrantees. Remember the actor killed in a Porsche accident, they are now blaming the crash on 9 year old tires (and driving too fast).

So replacing the tires every 4 or 5 years is a good thing for safety.

That and not driving too fast.

serialk11r 04-26-2014 03:43 PM

I think it depends on the car. My MR2 doesn't seem to coast much better from adding more psi, so I keep it about 8 psi higher than the door sticker (26/32 front/rear I'm at 35/40 ish), which is about the worst ride comfort I'll tolerate. I don't think it really saves much gas but the psychological effect that makes me think I'm saving gas is good enough that I will tolerate the bumpier ride.

My parent's Honda Pilot calls for something stupidly low like 26psi, and one time I secretly pumped them up to 35. Coasting distance was way better, but ride quality did suffer a little, not much though.

Xist 04-27-2014 03:33 AM

My problem is that whenever I take my car somewhere, they "fix" my tire pressure.

Joggernot 04-27-2014 09:18 AM

Quote:

Originally Posted by Xist (Post 421761)
My problem is that whenever I take my car somewhere, they "fix" my tire pressure.

=
+1
I've gotten the checking and filling of my tires down to a 5 minute or less job at the local station. That is, after I find the $1 in quarters...

euromodder 04-27-2014 02:46 PM

Quote:

Originally Posted by Xist (Post 421761)
My problem is that whenever I take my car somewhere, they "fix" my tire pressure.

I specifically tell them not to, using a Post-it not to lower tire pressure when it goes in, and it seems to work.

Changing cars has meant a change in fuel type, thus a change in fuel stations as well, and the ones I now (have to) go to have free air - which used to be 0.5 eur/5 minutes at the previous fuel stations.

You CAN win 'm all :)

serialk11r 04-27-2014 08:18 PM

You guys pay for filling your tires? Jesus. I just pump them up with a bicycle pump. Takes like 20 pumps to top off the pressure per tire but it's a nice workout, which I don't get often.

Xist 04-27-2014 08:27 PM

Quote:

Originally Posted by serialk11r (Post 421840)
You guys pay for filling your tires? Jesus. I just pump them up with a bicycle pump. Takes like 20 pumps to top off the pressure per tire but it's a nice workout, which I don't get often.

No! When we get our oil changed!

Vman455 04-27-2014 08:47 PM

You guys pay someone else to change your oil?

:D

UltArc 04-27-2014 08:49 PM

I used to never buy gas at a place that charged for air. Now that I only use E0 (in one car), I don't have much of a choice :/

My dealership people know not to screw with my settings, other than Ford and my seat position- which is pretty tough if you have a bit of a gut.

user removed 04-27-2014 10:16 PM

Change my own oil. My air compressor is one of those small pancake jobs, close to 15 years old and I built two houses with it.

regards
Mech

Xist 04-28-2014 06:16 AM

Quote:

Originally Posted by Vman455 (Post 421843)
You guys pay someone else to change your oil?

:D

No, I don't, and when it turns out that the sixteen year-old with an impact wrench that the previous owner had change the oil stripped the oil pan, I do that myself, too.

http://ecomodder.com/forum/showthrea...ads-28519.html

I will be fixing all of the stuff that I broke replacing the pan, too, and all of the stuff that breaks when I fix that stuff!


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