Low tires

[LINC400]

On my 1994 Regal coupe, the drivers front tire always seems to be low. I had new tires and rims and valves put on it a couple years ago, and still the drivers front tire always needs to have air put in it, about 15 lbs. once a month.

Rotated the tires, and same deal. So I don't think it can be the tires or rims. Is this a common thing with these cars or FWD cars in general? None of the RWD cars I owned ever had this.

[Guest Kingoftheroad]

Been eating to many cheeseburgers lately? lol that can make the tires go down.... j/k...

[NTX5467]

If you rotated the tires and the tire at the same position on the vehicle went down, yet the tire that WAS at that location does not lose air in its new location, that might indicate some sort of environmental issue rather than a tire issue/wheel issue.

Tires are dumb, they don't know if the car they're on is front wheel drive, rear wheel drive, all wheel drive, or whatever. They just know that they're built to hold air and go round and round, round and round, and round . . .

Do you hand wash the vehicle or use a drive-thru automatic car wash???

Regards,

NTX5467

[LINC400]

It goes through an automatic car wash, but only once or twice a month. I don't think that would affect tire pressure. It never did with the RWD cars that went through the same car wash.

I thought since the main drive wheel is the one that is always low (drivers front), maybe it has something to do with more pressure/force being exerted on that wheel from acceleration and handling? The car is driven fairly hard. I just find this really annoying to always have to put air into that tire. Never had that with any of my RWD cars. But this is the first FWD car I have ever owned.

[Guest Kingoftheroad]

WOW, I'm surprised you take one of your cars through a car wash.. I've used one of those do it yourself car wash deals but never an automated one.

I try washing by hand, easy way to find out if the auto car wash is the problem with your LF tire.

[NTX5467]

Well, you see . . . the offset on the wheels for fwd cars and many rwd cars (which still used bearing hubs which were either separate or a part of the brake drum/disc rotor) are different. How does this matter? All fwd cars use a wheel bearing hub assembly, which means the mounting flange with the lug studs is, when the wheel is mounted to it, very near the outer edge of the wheel rim. Why's this important, it places the valve stem, even a short one, pretty much at the edge of the width of the tire. This can make it much more vulnerable to the rails which guide your vehicle through the automatic car wash.

I recently purchased a 2000 Impala. It is the base model with the plastic wheel covers. Almost all of the wheel covers have "marks" on them which could well have been from these guide rails. They are all too much the same to have been caused by a random source. I've also seen other similar Impalas with similar marks.

So . . . as you put the vehicle into the automatic car wash, the lh frnt wheel is also the "guide wheel" for the vehicle. By necessity, the guide rails will need to be pretty close and tight to the tire's sidewall . . . and the valve stem ends. I suspect that as the wheel turns, the valve stem might contact the rails several times, flexing it, but not breaking it. This, over time, can put some small cracks in the base of the valve stem, such that when they flex, some air is lost. When they don't flex, no air loss.

Initially, the tire pressure monitors for newer GM cars were solid metal, looking similar to a truck tire bolt-in valve stem. The newer ones have a detachable rubber valve stem which is attached to the monitor with a brass machine screw, inside of the rim. This way, if it breaks, it can be replaced . . . or looks like it can be.

On the rwd cars with the mounting flange for the wheel more toward the middle of the rim's width, the valve stem is placed more recessed away from the outer edge of the wheel rim. Hence, the need for "valve stem extensions" on many cars of the 1960s when wheel covers became more popular, and not needing the long valve stems. Even on the Lincoln in your avatar, the placement of the valve stems is enough inboard from the edge of the rim, much less the outer edge of the tire's sidewall, that you'll mar the rim edge before the valve stems would contact the guide rails in the automatic car wash, even for similarly-wide tires.

THAT's why I asked if you washed your cars by hand or did the automatic car wash action.

Regards,

NTX5467

[Guest WEB 38]

Take the car to your Buick dealer and ask them to fill the tires with genuine GM air it should not cost more than $50 per wheel. Bill

[Guest Straight eight]

Do you have "Touchless" washes in conjunction with the "quarter" washes. They use high pressure water and suds n stuff, but no brushes or rotating stuff. Its all I used on my 2007 Lucerne, and the finish always looks just fresh from the factory. No rub marks, no scratches, just the sun shinning back at you. (when the sun shines!!)

[LINC400]

Take the car to your Buick dealer and ask them to fill the tires with genuine GM air it should not cost more than $50 per wheel. Bill

Nitrogen would not cost anywhere near that at a Buick dealer. I don't see what that would solve except having to pay instead of filling with free air.

Unless, as I suspect, this was supposed to be a lame attempt at humor which failed.

[LINC400]

The Regal is a daily driver, and has already been repainted once. So I am not overly concerned about taking it to a car wash. Besides, the one it goes to specializes in limousines, and they have all the extra stuff to do a really good job and make sure there is no damage to the car. When the 1979 Mark V was a daily driver, it went to the same car wash and never had a problem. Same with the 1988 Town Car. The touchless ones always ended up blowing water into the interior around the weatherstripping. So I don't go to those. The Givenchy is usually hand washed, but it has the original paint and had the brush marks from the old style plastic brushes before I bought it. So again, not a real big concern on the rare occassions it goes through an automatic with soft cloth.

Interesting theory on the valves in the car wash. But the valves do not stick out at all on the Regal. In fact they are not that easy to access when putting air in. Besides it would then be both front and rear driver's side tires if the valves were hitting the rail. I don't think it would go down 15 lbs. going to the car wash once in a month. Due to it raining every other day for the last month and a half, the car hasn't been to the car wash in a month and a half, and still it was down 20 lbs. So I don't think it is the car wash.

Edited June 17, 2011 by LINC400 (see edit history)

[buick5563]

Unless, as I suspect, this was supposed to be a lame attempt at humor which failed.

Nice.

[NTX5467]

Nitrogen would not cost anywhere near that at a Buick dealer. I don't see what that would solve except having to pay instead of filling with free air.

When was the last time you priced a nitrogen fill? A "lifetime nitrogen fill" usually goes for about $149.99 around here, on new cars.

"Genuine GM Air" would be what goes in at the assembly plant. NO known replacement "in the field". Dealers only have "regular air" or "nitrogen". I haven't seen any listing for "Genuine GM Air" in the GM Parts/Accessory listings, either. But it might be a good profit center!

A main reason for the "Lifetime Nitrogen Fill" is that nitrogen doesn't expand and contract as "air" does, with temperature changes. Those temperature changes can cause the Tire Pressure Monitor warning to activate when the weather gets cold (if the tires were "to spec" in warmer weather), or even if the air pressure gets past the upper specs of the monitor. This can be a customer satisfaction issue and quite bothersome for some dealership techs, although they would get paid to remedy the situation.

Personally, though, "normal air" from a humidity-controlled air system has worked pertty well for ages and decades.

Enjoy!

NTX5467

[Guest Kingoftheroad]

When was the last time you priced a nitrogen fill? A "lifetime nitrogen fill" usually goes for about $149.99 around here, on new cars.

"Genuine GM Air" would be what goes in at the assembly plant. NO known replacement "in the field". Dealers only have "regular air" or "nitrogen". I haven't seen any listing for "Genuine GM Air" in the GM Parts/Accessory listings, either. But it might be a good profit center!

A main reason for the "Lifetime Nitrogen Fill" is that nitrogen doesn't expand and contract as "air" does, with temperature changes. Those temperature changes can cause the Tire Pressure Monitor warning to activate when the weather gets cold (if the tires were "to spec" in warmer weather), or even if the air pressure gets past the upper specs of the monitor. This can be a customer satisfaction issue and quite bothersome for some dealership techs, although they would get paid to remedy the situation.

Personally, though, "normal air" from a humidity-controlled air system has worked pertty well for ages and decades.

Enjoy!

NTX5467

I don't think there is enough benefits to convert to Nitrogen.

Edited June 18, 2011 by Kingoftheroad (see edit history)

[Guest Rob McDonald]

"Unless, as I suspect, this was supposed to be a lame attempt at humor which failed." LINC400, au contraire, I think it was a fine attempt. If you find it hard to appreciate this type of chuckles, you're in the wrong Forum. You ought to spend some time over on the Packard side. Boo-o-oring.

I tried to get some information there about late '40s Station Sedans because I was trying to buy one (that didn't work out). For a couple of weeks I monitored their oh-so-serious chat.

It made me realize what a great group of wannabe comedians also happen to love old Buicks. Maybe it's the wide-mouth cartoon smile that inspired the trademark waterfall grille. Somehow these cars attract a very considerate and helpful sort of person, most of whom are pretty darned funny, too.

Regarding your tire mystery: no clue.

[LINC400]

"Unless, as I suspect, this was supposed to be a lame attempt at humor which failed." LINC400, au contraire, I think it was a fine attempt. If you find it hard to appreciate this type of chuckles, you're in the wrong Forum. You ought to spend some time over on the Packard side. Boo-o-oring.

I tried to get some information there about late '40s Station Sedans because I was trying to buy one (that didn't work out). For a couple of weeks I monitored their oh-so-serious chat.

It made me realize what a great group of wannabe comedians also happen to love old Buicks. Maybe it's the wide-mouth cartoon smile that inspired the trademark waterfall grille. Somehow these cars attract a very considerate and helpful sort of person, most of whom are pretty darned funny, too.

Regarding your tire mystery: no clue.

I think I have pretty good sense of humor. But I found that post to be neither helpful nor humorous. It just rubbed me the wrong way.

If you are looking for info on Packards, try the site Packard Information. Not only are they much more helpful, but they also have a sense of humor. Unlike the rude and stuffy group here. Plus they are not delete happy with deleting comments they don't like or agree with as one moderator is here.

Regarding nitrogen, the local Chevy dealer here offered it for $79.99 for the Monte Carlo SS. We didn't get it because we didn't feel like it was worth it when air is free. Also did not like the thought of ugly green valve caps on the all black car with polished aluminum wheels. Now that I think about it, I'm convinced it must be a FWD thing, because the SS also tends to have the drivers front tire low, and that car does not go through an automatic wash.

[NTX5467]

Regarding nitrogen, the local Chevy dealer here offered it for $79.99 for the Monte Carlo SS. We didn't get it because we didn't feel like it was worth it when air is free. Also did not like the thought of ugly green valve caps on the all black car with polished aluminum wheels. Now that I think about it, I'm convinced it must be a FWD thing, because the SS also tends to have the drivers front tire low, and that car does not go through an automatic wash.

Well . . . if the Nitrogen valve stem caps are as popular as they tend to be in my part of the world (at least the part I reside in!), you wouldn't have to worry about them clashing with the color scheme of your Monte Carlo SS as they have a tendency to be "reappropriated" by unknown actors ("unknown actors" = cop-speak for "somebody stole them").

Better keep an air pressure gauge in the car as if it has the tire pressure monitoring system which runs off of the anti-lock brake system's wheel speed sensors, they can get down to 16psi before it'll turn on the warning light, by observation.

A "fwd thing", like the lh rear tire being low was a "Ford Explorer thing"? If so, "gotta do the tire checks" . . . with a gauge. OR, you can walk up and knock on the tire's sidewall with your #1 finger's joint, comparing the troublesome location's tire with that of the one on the rear. Taking a cue from the long haul trucks and their "knocking rods" (if that's the correct term"). It's quite easy to spot a low tire that way, by observation. More vibration and lower pitch sound = lower air pressure . . . quite simple and quick. But if that "flat spot" on the ground is too long, that's another tip-off too.

Of course, for the "knocking on the sidewall" trick to work, there will have to be at least one other tire with known "good" pressure in it, to specs, for a correct baseline comparison. After you do it for a while, the sound will be easier to gauge, too.

Enjoy!

NTX5467

Edited June 18, 2011 by NTX5467 (see edit history)