avatar382 Posted May 11, 2005 Share Posted May 11, 2005 My front tires are wearing unevenly - on the inside. I have Kumho Supra 712's @ 40 psi. Max tire rating is 44 psi. I guess my alignment needs to be looked at, but the car doesn't pull to the side. Suspension seems to be in good shape, the car handles like it always has - and it doesn't feel like the suspension has worn out. Maybe the cause is my tire pressure? Though, I would expect if overinflation was the cause, the uneven wear to show on the middle of the tire, not the inside. Any have a similar problem, or have any advice? Link to comment Share on other sites More sharing options...
mudduck Posted May 11, 2005 Share Posted May 11, 2005 My guess would be the alighnment is off a little bit. Link to comment Share on other sites More sharing options...
Caboobaroo Posted May 11, 2005 Share Posted May 11, 2005 yes, overinflation will cause tire wear on the middle of the tire. Unfortunatly, it sounds like you're suspension will need some things replaced to fix the problem. Nothing expensive, just time consuming. Sounds like the ball joints are going out causing it to camber the tires in just a bit more then usual. Best way to find out is to jack up the car on both sides and start wiggling stuff around like the wheel. Wanna get in a little deeper? Pull the wheel off and start moving stuff around with a prybar just make sure not to bend anything. Link to comment Share on other sites More sharing options...
85Sub4WD Posted May 11, 2005 Share Posted May 11, 2005 don't condemn the suspension to failure yet - inside tire wear is common when the "tow-in" is too great (meaning your front tires are pointing in towards each other) - that is easily adjustable by screwing in/out the tie rod ends (they are designed to be adjustable) - an alignment shop would be able to tell you by how much and adjust it to the proper position if you still are having problems, an alignment shop would be able to diagnose the cause (they have expensive equipment that can look at the whole geometry of your car) Link to comment Share on other sites More sharing options...
KStretch55 Posted May 11, 2005 Share Posted May 11, 2005 Also, how long has it been since you had your tires rotated? Link to comment Share on other sites More sharing options...
ballitch Posted May 12, 2005 Share Posted May 12, 2005 good question beat me to it. Link to comment Share on other sites More sharing options...
NoahDL88 Posted May 12, 2005 Share Posted May 12, 2005 if you lowered the car in anyway suspension wise that will make it wear on the inside, but i'd get an alignment first, or at least check your toe. Link to comment Share on other sites More sharing options...
Dennis ex24 Posted May 12, 2005 Share Posted May 12, 2005 40psi is too much. should be somewhere in the neighborhood of 32psi. the max rating is the limit the tire can handle before it heats up and explodes. Link to comment Share on other sites More sharing options...
KStretch55 Posted May 12, 2005 Share Posted May 12, 2005 Therein is another good question I've never heard a good answer to: The side of the tire has a max pressure for max load printed on it, the door post or owners manual has a recommended pressure for the front and rear listed. Which is correct? I've asked this of tire folks and lots of car dealers and mechanics and get several answers. Consensus seems to be this: The pressures listed by the car maker are for the most comfortable ride, not necessarily for the best wear and life of your tires. The max pressure/max load listed on the tire is the pressure that your tires will perform and last longest at, if you are running at that load. Since every car would be running a different load at any given time the best pressure will always be different. You would constantly have to take a guess and change your pressure to fit the load. Instead they (the tire mfr) recommends you with the optimum pressure listed on the tire. Actually, some very reputable and experienced tire guys tell me to run just a couple psi under the max listed on the tire, since most of us rarely run anywhere near max load rating. They tell me to watch the tires and keep them at a pressure that shows even wear and always, always, always have them rotated on a regular basis. Link to comment Share on other sites More sharing options...
NorthWet Posted May 12, 2005 Share Posted May 12, 2005 On Topic: I would strongly suspect that your toe-in/-out is out of spec and needs to be checked. Any other suspension quirks, such as steering wheel vibrations/shaking? Therein is another good question I've never heard a good answer to: The side of the tire has a max pressure for max load printed on it, the door post or owners manual has a recommended pressure for the front and rear listed. Which is correct?... What does "redline" on your engine mean to you? Is it the engine speed that you should run at to get best mileage and wear? No, it is the maximum engine speed that the manufacturer says that you COULD run your engine without it being likely to handgrenade on you, but it is not recommended that you do so. The max-pressure/max-load on the tire sidewall is analogous to redline: It is the maximum set of conditions that the tire manufacturer says that this tire will safely handle without failure. In practical terms, it is the maximum amount of weight(mass) that the tire can handle. To support that weight(mass), you need to inflate the tire to that max pressure. If you are running only half of the maximum load, then the tire pressure should be approximately half of the max pressure. The car manufacturer's recommended tire pressures are usually set for how the manufacturer wants the car to ride and handle at that load. This has little to do with what is best or what you would prefer it to be. Example: (IIRC) A 1971 Ford Capri had recommended front tire pressure of 16PSI!!! The prevailing interpretation of this very low pressure was that Ford marketed this car as a "sporty" car, but wanted to keep drivers out of trouble by making it strongly understeer. The car handled 1000% better with tires inflated to around 28-32PSI. Link to comment Share on other sites More sharing options...
KStretch55 Posted May 12, 2005 Share Posted May 12, 2005 Perfect example of the differences of opinion you'll will always get when asking about the subject of tire pressure. For one thing, most people wouldn't have the foggiest idea what their vehicle weighs, let alone how they would figure out their tire pressure to compensate for it. I also doubt that the formula of 50% of recommend pressure for 50% of rated load would hold water. You'd be driving on some seriously underinflated tires. Just to add to the confusion I checked my vehicle, a '92 Loyale AT wagon. I've got 175/70R13 tires, load rated at 1047 lbs @ 36 psi. So, in theory @ 36 psi my tires are rated to hold 4188 lbs. Presuming the load is spread evenly over all 4 tires. My vehicle Gross Vehicle Weight Rating is 3665 lbs. 1770 lbs on the front axle and 1895 lbs on the rear axle, according to the data plate. Presuming they weigh the vehicle "wet", which is with fuel, oil, coolant, etc. Max load (passengers and cargo) is 900 lbs. So total "curb" weight would be 4565 lbs. (GVWR + load = curb weight). Note that is more than my tires are rated for. I'm sure the stock 165SR13 tires are rated even less. Even if I'm the only one in the vehicle and have no cargo I'd be very close to max load on the tires (3665 + 240 = 3905 lbs) That's only 283 lbs short of the max load rating of my tires. 93% of the max load rating of my tires. So, by your theory I should reduce my tire pressure by 7% of the max pressure (roughly 2.5 psi). Hmmmm, sounds logical and I might try it, since that's how I drive most of the time. But, what happens when I take a trip with two of my teenage kids and I'm over the load rating? I know this sounds like a lot of glop, but I went through it just to try to illustrate why if you ask 10 people what the correct pressure to put in your tires is, you will get 8 different answers. Link to comment Share on other sites More sharing options...
NorthWet Posted May 12, 2005 Share Posted May 12, 2005 ...My vehicle Gross Vehicle Weight Rating is 3665 lbs. 1770 lbs on the front axle and 1895 lbs on the rear axle, according to the data plate. Presuming they weigh the vehicle "wet", which is with fuel, oil, coolant, etc. Max load (passengers and cargo) is 900 lbs. So total "curb" weight would be 4565 lbs. (GVWR + load = curb weight)... Maximum Gross Vehicle Weight is just that: The maximum allowable weight of vehicle, consumables and cargo. Driver, passsenger, and luggage is already included. Again, it is a never exceed value. *edit - Oh, and the total GVWR (the 3665) is supposed to be reached within the individual axle ratings of 1770 and 1895... can't just throw 4000 lbs on one axle and call it good - end edit* Link to comment Share on other sites More sharing options...
calebz Posted May 12, 2005 Share Posted May 12, 2005 40psi is too much. should be somewhere in the neighborhood of 32psi. the max rating is the limit the tire can handle before it heats up and explodes. My tires are extremely underinflated at ~32psi Max pressure on them is 51psi Link to comment Share on other sites More sharing options...
PoorManzImpreza Posted May 12, 2005 Share Posted May 12, 2005 yeh I run 29-30 PSI on the fron and 28 PSI on the back.. sorry if this offends but 40 psi is almost insane.. I did that once 'cause the tire pumps pressure gauge was faulty and the car handled and road like turd..not recommended IMHO Link to comment Share on other sites More sharing options...
calebz Posted May 12, 2005 Share Posted May 12, 2005 sorry if this offends but 40 psi is almost insane Depends on the tires;) Link to comment Share on other sites More sharing options...
avatar382 Posted May 13, 2005 Author Share Posted May 13, 2005 I swear, my car handles better with the extra air... Seems to have helped with treadwear, too. Link to comment Share on other sites More sharing options...
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