Tire Pressure: Sonata 1999, 2000, 2001

I recently bought a 2000 Sonata. It's got 15" wheels with what I believe is the original stock tire: Michelin MXV4 Plus, size 205/60 R15.
Hyundai's specified pressure for these is 30 lbs all around. I
had my tires rotated today at Big O Tires. The shop inflated the tires to 35 pounds, claiming that I'd get better wear at that pressure. Of course, I don't know how the previous owner maintained his pressures. What I can see with my tread depth gauge is that there's slightly less wear at the middle of the tread than at the sides. So, if these tires have been run at Hyundai's recommended pressure, the tires have been running slightly under-inflated.
On my drive home, I liked the tires at 35 pounds. The handling was crisper, more secure. Ride on the freeway was smooth. On city streets, the ride was a bit rougher, but still civilized.
What have your experiences been with inflation with the 1999, 2000, and 2001 Sonatas, especially with 15" rims?
Richard
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Richard Steinfeld wrote:

Although I don't have Sonata, there are several tire pressure related issues that are universally true of front wheel drive cars.
- The recommended pressures are designed to provide a smooth ride. This is apparently what most people want, or what the manufacturer thinks they want. If you look at the sidewall of your tires, you'll probably see that they're rated for a max pressure in excess of 40 psi. When I took delivery of my Elantra GT, it still had the shipping pressure of 48 psi in the tires.
- The recommended pressures are designed to create plenty of understeer in corners. Most people don't know how to control a FWD car in a rear end skid, so manufacturers go to great lengths to prevent this from happening. Tire pressures have a large effect on handling, so they're used to tune in understeer, without having to compromise other aspects of the suspension.
- Manufacturers are not concerned with tire wear, since tires are not warranty items except under special circumstances. If their recommended pressures result in premature wear, oh well...
- Since FWD cars carry much more weight on their front tires, those tires need higher pressure than the rears in order to support the weight optimally. Low pressures result in premature edge wear, though that's often masked by the normal edge wear that occurs from cornering.
I've found that my FWD cars have handled best with tire pressures 2-6 psi higher than recommended and 3-5 psi more in the front than the rear, which varied a bit from car to car. Manufacturers rarely recommend this, since it makes the ride a bit rougher and the handling more neutral. On my EGT, I run 36 psi front and 32 psi rear, which provides a reasonably smooth ride and good handling. Higher pressures improve the handling a bit at the cost of ride quality. That should be a reasonable starting point for your Sonata, though you may find that slightly different settings suit your needs better.
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"Brian Nystrom" wrote: > Richard Steinfeld wrote: > > I recently bought a 2000 Sonata. It's got 15" wheels with > what I > > believe is the original stock tire: Michelin MXV4 Plus, size > > 205/60 R15. > > > > Hyundai's specified pressure for these is 30 lbs all around. > I > > had my tires rotated today at Big O Tires. The shop > inflated the > > tires to 35 pounds, claiming that I'd get better wear at > that > > pressure. Of course, I don't know how the previous owner > > maintained his pressures. What I can see with my tread depth > > gauge is that there's slightly less wear at the middle of > the > > tread than at the sides. So, if these tires have been run at > > Hyundai's recommended pressure, the tires have been running > > slightly under-inflated. > > > > On my drive home, I liked the tires at 35 pounds. The > handling > > was crisper, more secure. Ride on the freeway was smooth. On > city > > streets, the ride was a bit rougher, but still civilized. > > > > What have your experiences been with inflation with the > 1999, > > 2000, and 2001 Sonatas, especially with 15" rims? > > Although I don't have Sonata, there are several tire pressure > related > issues that are universally true of front wheel drive cars. > > - The recommended pressures are designed to provide a smooth > ride. This > is apparently what most people want, or what the manufacturer > thinks > they want. If you look at the sidewall of your tires, you'll > probably > see that they're rated for a max pressure in excess of 40 psi. > When I > took delivery of my Elantra GT, it still had the shipping > pressure of 48 > psi in the tires. > > - The recommended pressures are designed to create plenty of > understeer > in corners. Most people don't know how to control a FWD car in > a rear > end skid, so manufacturers go to great lengths to prevent this > from > happening. Tire pressures have a large effect on handling, so > they're > used to tune in understeer, without having to compromise other > aspects > of the suspension. > > - Manufacturers are not concerned with tire wear, since tires > are not > warranty items except under special circumstances. If their > recommended > pressures result in premature wear, oh well... > > - Since FWD cars carry much more weight on their front tires, > those > tires need higher pressure than the rears in order to support > the weight > optimally. Low pressures result in premature edge wear, though > that's > often masked by the normal edge wear that occurs from > cornering. > > I've found that my FWD cars have handled best with tire > pressures 2-6 > psi higher than recommended and 3-5 psi more in the front than > the rear, > which varied a bit from car to car. Manufacturers rarely > recommend this, > since it makes the ride a bit rougher and the handling more > neutral. On > my EGT, I run 36 psi front and 32 psi rear, which provides a > reasonably > smooth ride and good handling. Higher pressures improve the > handling a > bit at the cost of ride quality. That should be a reasonable > starting > point for your Sonata, though you may find that slightly > different > settings suit your needs better.
I consider handling more important than ride comfort, but I consider fuel economy and tread wear more important than both of these. Does running tires 4 or 5 psi above manufacturers recommendations consistently increase economy and reduce wear. (im in an Accent, by the way, but i doubt the answer would be different)
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I'd think you'd get the best tire wear around 32 psi or so. I notice the same edge wear at 30 psi. Above 32, I think you're entering the trade-off area of mpg vs. tire wear. Ultimately, you'll need to decide for yourself; your driving habits will affect your tire wear as well.
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Balfa wrote:

In the case of Hyundai's recommended pressures, I would say yes.
What happens with low pressures (particularly in the front) is that the sidewalls deflect more and force the edges of the tread against the road surface harder. This also tends to cause the center of the tread to cup upward slightly, reducing pressure against the road surface. The end result is that the edges of the tread wear out much faster than the center. Increasing the air pressure corrects this problem, but too much pressure can create the opposite effect. The trick is to find the optimum pressure to achieve even tread wear. The edges will always wear somewhat faster due to cornering, but not excessively so unless you drive aggressively.
Low pressure also increases rolling resistance and heat buildup in the tires, which if it becomes extreme enough, can cause tire failures (as in the Ford/Firestone debacle). Of course, Hyundai's recommended pressures are safe, as long as you maintain them.

No, it wouldn't be, at least not much. The difference in stock tire sizes between the various car models creates somewhat of a self-compensating effect, so optimum pressures really don't vary all that much.
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| Richard Steinfeld wrote:
| > On my drive home, I liked the tires at 35 pounds. The handling | > was crisper, more secure. Ride on the freeway was smooth. On city | > streets, the ride was a bit rougher, but still civilized. | >
Well, not exactly true. They _said_ that they inflated the tires to 35 pounds (but I later realized that, well, I'd driven off and on a few times that day -- the shop worked way too fast; repaired a flat, balanced the wheels, and rotated them all in under 22 minutes. Today I measured the pressure cold and found every tire with a different pressure, all between 30 and 32. I then filled them to 35 all around to see how it'll do. (Will I ever in my life find a tire decent tire shop?)
| Although I don't have Sonata, there are several tire pressure related | issues that are universally true of front wheel drive cars. |
| - The recommended pressures are designed to create plenty of understeer | in corners. Most people don't know how to control a FWD car in a rear | end skid, so manufacturers go to great lengths to prevent this from | happening. Tire pressures have a large effect on handling, so they're | used to tune in understeer, without having to compromise other aspects | of the suspension. |
What I've found in recent years is that the car makers seem to be specifying the same pressure all-around, and it seems to be 30 lbs. Maybe I'm wrong.
| - Manufacturers are not concerned with tire wear, since tires are not | warranty items except under special circumstances. If their recommended | pressures result in premature wear, oh well... | | - Since FWD cars carry much more weight on their front tires, those | tires need higher pressure than the rears in order to support the weight | optimally. Low pressures result in premature edge wear, though that's | often masked by the normal edge wear that occurs from cornering. |
Not always true -- see below for an interesting exception.
| I've found that my FWD cars have handled best with tire pressures 2-6 | psi higher than recommended and 3-5 psi more in the front than the rear, | which varied a bit from car to car. Manufacturers rarely recommend this, | since it makes the ride a bit rougher and the handling more neutral. On | my EGT, I run 36 psi front and 32 psi rear, which provides a reasonably | smooth ride and good handling. Higher pressures improve the handling a | bit at the cost of ride quality. That should be a reasonable starting | point for your Sonata, though you may find that slightly different | settings suit your needs better.
What's an EGT? I'll keep this in mind and later fool with a distribution as you mention. |
In days of yore, shrouded in the mists of time, I owned a '62 SAAB sedan, the kind with the 3-cylinder 2-stroke engine. In fact, these were the only motors that they made. It was a really tough car that handled extremely well and was great in snow. A friend who was into racing turned me on to radial tires, so I replaced the bias tires with Michelins. At the time, one could not choose from different tire models. There was one model that fit the car and that was that. My choice was between Michelin and Pirelli, which SAAB fitted to their model that was rigged out for racing.
So, I picked up a Michelin application book at the tire shop, which gave recommended pressures for every conceivable car. Now, I notice that tire makers simply recommend the car makers' settings; hell, it keeps 'em from being sued. But then, Michelin actually tested their tires on the cars, and gave their own inflations. After all, all the car makers were putting bias ply tires on their cars and gave pressures for those -- the radial makers had to come up with their own. For almost all cars, Michelin advised more pressure in the front than in the back. But for SAAB it was the opposite, and the opposite of what SAAB themselves recommended for their normal tires. Michelin said 18 lbs in the front and 22 in the rear. This seemed most peculiar, so I wrote to Michelin for an explanation. (For whatever reasons, everyone used much lower pressure in those days; remember, this was during "yore," and shrouded in the mists.)
Michelin replied that the unusual pressures were due to the weight transfer to the rear while the car was in motion. And I got it: SAAB was (and is) an aircraft company. They only got into cars after WW II. Their cars, unusual for the time, were aerodynamic -- befitting for a company that made fighter planes. I used those pressures for years with perfect success. The car tracked as if it was on rails.
Richard
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"Brian Nystrom" wrote:

What is the GTs weight over each axle?
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Balfa wrote:

I haven't seen any specs on it, but I assume that it's ~60/40 front/rear. That's pretty typical of FWD cars.
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