Found another way to save on gas.

[Compaq888]

Originally Posted by CosmicMC

Compaq888, so, since you checked it by measuring everything, what was the diameter change in the tire that you measured before and after overinflating the tires? What did you use to take the measurement? I'm asking because you're citing a 3.1% change in speed and that seems excessive to me for a few more PSI in the tires. Without the numbers, though, it's purely speculation on my part. Please educate me, as I am ignorant of the possibilities here.

As far as the speeding part, I never suggsted anyone should exceed the speed limit. I posed a hypothetical situation and asked a question about whether it's worth it to speed to keep up with the flow of traffic instead of impeding it and potentially causing an accident. I never said it would be more fuel-efficient overall. I was asking a series of questions and so far nobody has offered any answers but SVOBoy is trying to imply that I'm crazy for making a statement that I never made. It probably sounds like I'm leaning in one direction or the other, so shame on me for not wordsmithing my post more effectively.

So there are no answers so far. The question stands: Is less fuel consumed overall if you speed to keep up with traffic instead of driving the speed limit when everyone around you is speeding? Need someone with statistics on that one.

How are my numbers going to help you?? All i know is it works. I used a string to measure it, since it can bend anyway you want it. Then measure the string with a ruler.

And to answer your question, more fuel is consumed to keep up with others, not just for us but more fuel is used when we wreck due to driving 80+mph and the ambulances, fire trucks and the police have to use fuel to get to us and help us out. Not only does driving the speed limit waste less fuel but so do fire trucks, ambulances and etc waste less too because they don't have to come to us.

[chesspirate]

Originally Posted by Matt Timion

ACtually, in Southern California (where Compaq888 lives) they do. 80mph is normal "flow of traffic." The only people going 65mph are the semis.

Matt you should know better. It's pretty dependant on the freeway, and what section, honestly. I drive a bunch for work and I can tell you for some untold reason North/South freeways seem to run faster than the West/East freeways. I've driven at all different times of day, weather conditions, etc. and it is almost 100% valid (for my area around San Diego) And a lot of semis don't get to 65 (especially going up my mountain! I drafted one the other day for 15+ miles going between 55-60, and in normal driving for me i just drive 60mph anyway, if people don't like it they can go around; and i see it as a public service, if they have to slow down for a while waiting to pass, they too will be saving gas! I've become a gas saver for two!!!

[Compaq888]

Yeah 18 wheelsers do go 55-60mph, but the smaller trucks go 55-70mph

[Flatland2D]

FWIW, when I bought my car it had 18" wheels on it. Drove along side my wife and my speedo was 3mpg off. Put some 14" wheels on and the speedo is accurate again. Even though the total outer diameter was not a difference of 4" (the 18" wheels have low profile tires) it took a pretty big change just to net a 3mph error. If your tires were really low I could see a 1mph difference though.

As for going with the flow of speeding traffic, they're not going to help you pay your ticket when you get pulled over, or chip in to pay your increased insurance rates. I've been driving for 7 years now and have a spotless record, no tickets or accidents. Always drive right on the speed limit, though sometimes slower on the highway if there's not much traffic. Our speed limits are around 65 to 70mph and my MPG really drops off at those speeds, so I try to do 55 to 60mpg if I can.

[wadak1234]

To check your speedometer use a hand held GPS on MPH. You will find out fairly quick if rim/tire combination is causing inacurate speedometer readings. Just my 2 cents worth.

[Matt Timion]

Originally Posted by wadak1234

To check your speedometer use a hand held GPS on MPH. You will find out fairly quick if rim/tire combination is causing inacurate speedometer readings. Just my 2 cents worth.

I was actually thinking of doing this for a custom MPG readout. I have a little handheld GPS unit, but I'm not certain it has a data port. I also work with GPS a little for my job and I know that these little units arn't the most accurate (+/- 10 meters usually). This is fine for camping, boating, etc. to get an approx location, but might not be good for our applications.

[JanGeo]

Hey guys you think some air pressure is going to stretch the steel belts??? Think again. The tire gets rounder the center of the wheel moves up from the ground a little but the circumference of the tire remains the same. Of course I am assuming that the belts are not flexable and are wrapped around the tire and not crosswize so that they could streatch...But I am pretty sure the circumference is not changing. The GPS is not extreemly accurate for location although it puts me right at the grave marker of my Dad every time I visit but for speed and distance it is very accurate with some noise. I have checked against stationary radar units and been dead on every time. I also used it to calibrate my ScanGauge and it remains consistant.

As far as the speeding goes keep in the right lane and keep to the speed limit as close as possible without causing traffic problems - I constantly have a line of cars behind me doing 30 in a 25 around here but Jan don't speed in school zones. Going the limit has saved me plenty of tickets like not one in the last 12 years or more - havign a little metalic gray Geo really blends into the road. Now with the xB I notice the cops looking as I drive by all the time so I go slow and enjoy the ride. My last stop was at midnight on a 35mph road doing 40 on cruze control in the yellow wabbit - cop said he clocked me at 50! as he came flying up behind me and got so close that I couldn't see his lights as they were above my roof line of sight. Went to coart about the ticket and gave the judge a good laugh about never being drunk when asked if I was ever dwi. I think the shoulder length hair has something to do with the stop. By the way the cop speedos are way off as they handed me the calibration sheet where as the Wabbit speedo was dead on as timed with a stop watch and the calibrated odometer doing 40 should take 1:30 to go a mile. Ticket was dismissed because of my clean driving record.

The only problem I have about being the slowest on the road is that everyone passes and then pulls in front of me - my new xb has pits in the windshield already from the sand being kicked up as passers cross the line too close in front of me.

[MetroMPG]

on the tire topic - i'm sure it's been said before, but the super-high-pressure folks are probably prematurely wearing down the centre of their treads.

on the slow topic - i'm also usually the slow guy in the right hand lane with the blue-haired old ladies and hat-wearing old guys with the turn signal flashing. i passed i think 3 or 4 cars today in a 5 hour highway trip.

however i do try to accomodate the trucks, since i'm in "their" lane - e.g. if there's one coming up from behind and i can see he hasn't got a gap in the next lane to get around me, i'll boost my speed until a gap opens and he can switch lanes. it's a lot harder for them to speed up & slow down than it is for me. same thing if there's one on my *** during a descent into a "valley". i know he wants to build up speed to climb up the other side, so i will accomodate if he can't easily get around me.

[SVOboy]

on the tire topic - i'm sure it's been said before, but the super-high-pressure folks are probably prematurely wearing down the centre of their treads.

That's been mentioned to the affect that no one has seen it yet. My tires also seem to be wearing evenly.

it's a lot harder for them to speed up & slow down than it is for me. same thing if there's one on my *** during a descent into a "valley". i know he wants to build up speed to climb up the other side, so i will accomodate if he can't easily get around me.

You're a sweetheart,

[JanGeo]

Yeah wear the center out going straight and do some cornering and get the sides a little.

As for the trucks yup givem room and when they pass and are clear to pull back in in front of you, flash your high beems and let them know - that trailer they are pulling is really long and it is hard for them to know when they are clear to pull back in. If the truck driver sees your flash they usually blink their running lights back at cha.

Never stops amazing me how half asleep people can box them in - especially the gas trucks YIKES! givem ROOM!! We have had a few jack knife around here from people not keeping out of their way.