pitzel Posted September 2, 2005 Report Share Posted September 2, 2005 Turned up the inflation on my tyres to 42psi all around (from the 35psi that I was running), and mileage went from approx. 38mpg to 41mpg, driving at roughly 47mph, 1580rpm on the engine. Yes the car rides like ass over every bump, and slight wind gusts throw the car everywhere on the road, but my fuel bill is down 8% which should handsomely pay for a prematurely worn out set of tyres with plenty of money to spare at current petrol prices. Any comments? Or am I crazy for even bothering to make my W-body achieve 41mpg (on the DIS) on the highway? Quote Link to comment Share on other sites More sharing options...
Prospeeder Posted September 2, 2005 Report Share Posted September 2, 2005 well, the high psi will cause some problems, possibly tire blow out, horrible handling, lowerd stoping distance, lower tire grip, its just not safe Quote Link to comment Share on other sites More sharing options...
pitzel Posted September 2, 2005 Author Report Share Posted September 2, 2005 Well I limit my speeds to 100km/hr or under (63mph), do not carry excessive weight, and do not operate in conditions where the tires would otherwise get hot and fail. Remember that the psi limits printed in the doors are specified for no possibility of tyre blow-out under the absolute worst conditions one can imagine -- in the +130f Arizona desert, driving over 100mph. Heat is the factor that causes the failure of most tyres, unless their treads are completely worn out. Quote Link to comment Share on other sites More sharing options...
supreme_style21 Posted September 2, 2005 Report Share Posted September 2, 2005 At the point right where it drops into OD? Quote Link to comment Share on other sites More sharing options...
GutlessSupreme Posted September 2, 2005 Report Share Posted September 2, 2005 nah.. OD drop is lower than that. Good cruising speed though.. low 50s (mph) Quote Link to comment Share on other sites More sharing options...
sonyman87 Posted September 2, 2005 Report Share Posted September 2, 2005 The problem with 42psi. is that its at your tires max limity boarderline blowout. one sharp rock and its gone.. but the real damage is longterm. you will wear the shit out of your tires in half the milage they are warrentyed for. and over inflashion Voids any tire warranty if they catch you. so basicly the money you save in gas you are going to spend on tires! Quote Link to comment Share on other sites More sharing options...
pitzel Posted September 2, 2005 Author Report Share Posted September 2, 2005 Well, over 50,000 miles, at 38mpg, 1316 gallons of fuel burned. At 41mpg, 1219.5 gallons of fuel burned. Fuel now costs me $5.42/gallon. so $525.74 saved over 50,000 miles. The guys on TV are saying we will see $5.80/gallon soon. The big question is....just how bad are the risks of blowout elevated, and will tyres last twice as long at 35psi as opposed to 42psi? The set of tyres put on by the previous owner cost $540 in 2000. Probably gone up to $700. Quote Link to comment Share on other sites More sharing options...
RareGMFan Posted September 2, 2005 Report Share Posted September 2, 2005 Well, one other thing you have to take into consideration is how long you intend on running this way. The manufacturer did not have in mind that you plan on making maximum inflation a permanent change. It was merely the most allowed under extreme loads and conditions. Once the need for it is gone, they should be deflated back to average. It wasn't meant to be run at continously. So it's tough to say how long the tires will withstand maximum psi. Quote Link to comment Share on other sites More sharing options...
supreme_style21 Posted September 2, 2005 Report Share Posted September 2, 2005 nah.. OD drop is lower than that. Good cruising speed though.. low 50s (mph) Mine drops around 45 if its held constant.. I can easily get 48 mpg at that point. And thats at the regular 35 psi in the tires. And a lot of dead weight in the trunk. Quote Link to comment Share on other sites More sharing options...
pitzel Posted September 2, 2005 Author Report Share Posted September 2, 2005 48mpg, eh? My plugs are a bit old, but thats amazing for your car. Are you running new plugs or anything really different than my car by any chance? Just to clarify, the MPG's I am talking about are quoted as US MPG's. Where 1 gallon = 3.87L, and 1mile is roughly equal to 1.6km. Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted September 2, 2005 Report Share Posted September 2, 2005 I run 45 PSI in the tires in my car - they are rated to take 45 PSI, so I run them at that - no premature tire ware, no problems on the road with bumps - and in fact I have seen improved handeling, less steering wonder, better gas milage, and a more responsive ride. Remember, if your tires are rated to take 45 PSI, running at 42 will not hurt them. (look at the pressure lable on the tire to make sure) --Dave Quote Link to comment Share on other sites More sharing options...
Canada Posted September 2, 2005 Report Share Posted September 2, 2005 I find its best to do what the engineers tell me. Also, its spelled tIres. Quote Link to comment Share on other sites More sharing options...
Hairdo12 Posted September 2, 2005 Report Share Posted September 2, 2005 I run 45 PSI in the tires in my car - they are rated to take 45 PSI, so I run them at that - no premature tire ware, no problems on the road with bumps - and in fact I have seen improved handeling, less steering wonder, better gas milage, and a more responsive ride. Remember, if your tires are rated to take 45 PSI, running at 42 will not hurt them. (look at the pressure lable on the tire to make sure) --Dave yeah, same here. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted September 2, 2005 Report Share Posted September 2, 2005 I run mine about 37psi roughly. Thats getting me about 26mpg around town. Even though my tires are rated for 44psi max. Quote Link to comment Share on other sites More sharing options...
Redwingvksm Posted September 2, 2005 Report Share Posted September 2, 2005 IF you look carefully - some tires say Max. Pressure at 42 psi. some even more. Just look! Quote Link to comment Share on other sites More sharing options...
bve32k Posted September 3, 2005 Report Share Posted September 3, 2005 My tires have 44.5 PSI in them. They are supposed to take 44 PSI. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted September 3, 2005 Report Share Posted September 3, 2005 I think thats kinda pushing it. Quote Link to comment Share on other sites More sharing options...
supreme_style21 Posted September 3, 2005 Report Share Posted September 3, 2005 48mpg, eh? My plugs are a bit old, but thats amazing for your car. Are you running new plugs or anything really different than my car by any chance? Just to clarify, the MPG's I am talking about are quoted as US MPG's. Where 1 gallon = 3.87L, and 1mile is roughly equal to 1.6km. I don't use the metric system. I live in the US. And no, I don't see how thats so amazing. The thing drops into overdrive and the engine runs at like 1k rpm.. how is that so mystifying? Quote Link to comment Share on other sites More sharing options...
Stevo Posted September 3, 2005 Report Share Posted September 3, 2005 well, the high psi will cause some problems, possibly tire blow out, horrible handling, lowerd stoping distance, lower tire grip, its just not safe Yeah man. I think we are trading it all for better gas milage. I'm gonna double that milage and crank it up to 84psi and see if I can get 80mpg. w00t! Quote Link to comment Share on other sites More sharing options...
Brian P Posted September 3, 2005 Report Share Posted September 3, 2005 I've been running 40psi for about 15k miles on a set of Eagle GT +4's that are rated a max of 44psi. I noticed no abnormal wear at all and this is going by a depth gage, not just visual. Fuel economy did go up, maybe around 5% Quote Link to comment Share on other sites More sharing options...
1990lumina Posted September 3, 2005 Report Share Posted September 3, 2005 48mpg, eh? My plugs are a bit old, but thats amazing for your car. Are you running new plugs or anything really different than my car by any chance? Just to clarify, the MPG's I am talking about are quoted as US MPG's. Where 1 gallon = 3.87L, and 1mile is roughly equal to 1.6km. I don't use the metric system. I live in the US. And no, I don't see how thats so amazing. The thing drops into overdrive and the engine runs at like 1k rpm.. how is that so mystifying? For the convertion for u.s. gallon to liter it is 1 u.s. gallon = roughly 4.5L IIRC Quote Link to comment Share on other sites More sharing options...
sonyman87 Posted September 3, 2005 Report Share Posted September 3, 2005 48mpg, eh? My plugs are a bit old, but thats amazing for your car. Are you running new plugs or anything really different than my car by any chance? Just to clarify, the MPG's I am talking about are quoted as US MPG's. Where 1 gallon = 3.87L, and 1mile is roughly equal to 1.6km. I don't use the metric system. I live in the US. And no, I don't see how thats so amazing. The thing drops into overdrive and the engine runs at like 1k rpm.. how is that so mystifying? For the convertion for u.s. gallon to liter it is 1 u.s. gallon = roughly 4.5L IIRC no the US gallon is smaller then 4Liters.. its 3.8something.. haha ohh look there it is.. in the quote you selected.. 3.87.. or its on a 1 gallon jug of milk.. its on there 2 Quote Link to comment Share on other sites More sharing options...
MoTox8410 Posted September 3, 2005 Report Share Posted September 3, 2005 ive always been told for best gas milage and tire wear ect..... use what the tire manufacture says...ive used 45 psi since new tires and never any problems gm is not worried about gas or tire life all they are woried about is ride quality Quote Link to comment Share on other sites More sharing options...
lakefxgp96 Posted September 4, 2005 Report Share Posted September 4, 2005 I've been running at 40 psi (summer) since i got the GP 5 years ago. Never had a blow out...my valves stems have all messed up a dozen times, but the tires have always been fine. i run at 32 psi in the winter on the front tires and 38 on the rear. with my new yokos, i've been running at 38 psi just cuz they are lower profile and ride nicer. (17" rims) I never get that good of gas mileage, but I also have a 70 mph speed limit that no one else follows and goes 75 mph, and i usually follow. With the 3100 i was at 29 mpg, now i run about 26 mpg on the L67. normal daily communte though with city/highway nets me more like 20 mpg!!! yuck. Quote Link to comment Share on other sites More sharing options...
sniperi311 Posted September 5, 2005 Report Share Posted September 5, 2005 so what is the "proper" psi to run your tires at, or is it more of a what you feel is correct, cuz my buddy has an 02 impala, the tires say 44 psi max, and his low tire pressure light is on, should he lower his pressure or just keep it, i run mine at 38, tires say 44 max, thanx Quote Link to comment Share on other sites More sharing options...
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