Tire pressure - crossbars and mpg.

torker · Post by **torker** » Fri Jan 21, 2011 11:41 am

I know this has probably been beat to death. I looked for a recent thread and they were all a couple years old. If there is one let me know and I will post on it and let this one die I have an 04 Vibe base auto 2 wd I've had it 2 years and have put almost 40,000 mi. on it. It is almost 180,000 now. I have averaged 27 mpg. lowest 22 highest 32 I just put more air in the tires than I have ever run. It is the smallest car I have ever owned and seems to ride fairly stiff to me. I was running 32 r 35f I went to 35 and 38. I am not too worried about the front but in back they were already barely showing any contact at the edges. In the front they showed contact a little bit around the corner. They are 205-55-16 on stock steelies w hubcaps. The tires seem plenty wide for stock rims so I am going to keep an eye on them. I don't want to wear the centers. Today I also removed my crossbars so we will see if these 2 changes make any difference. I have a 3 day a week 60 mi. roundtrip right now so I will update in a few weeks. Next I will check the plugs . I haven't looked at them since I've owned it. My bad I know. After that I want to check the oil valve control filter and clean the throttlebody and pcv. The stock type air filter is clean. It should be a methodical approach and I have a good baseline average the last 2 yrs. Chime in if you think of other things to try. Also if you think I can safely run more tire pressure. Dave

TONY TAT2 · Post by **TONY TAT2** » Fri Jan 21, 2011 9:58 pm

last fall I bumped the tire pressure up top 40lbs all around,so far so good even with a few snow storms/lot of days driven thru slush. I bumped the pressure up in the wifes G6 to 35lbs all around at that time also,no problems with that also.

cptnsolo77 · Post by **cptnsolo77** » Fri Jan 21, 2011 11:36 pm

I am interested to see if removing the roof rack increases your MPG. Please keep us posted ! I average about 27-28 city/hywy with the AC on most of the time. I also run my tires at 37 PSI & never had any wear issues. Last set of tires wore totally even with proper rotations of course. We have had a cool "winter" here & when I dont use the AC I can get 30 MPG city/highway. I also run a drop in K&N and use the cruise whenever possible.

torker · Post by **torker** » Sat Jan 22, 2011 1:06 am

That makes me feel better about the tire pressure. I'm a little hesitant to run 40 out back but if I get the front back too different it would probably upset handling. So I will keep an eye on it and maybe go with 38 all around. I average the same mpg. summer and winter unless we get a lot of snow, then it suffers a little. I run the AC all summer here and I only run the defrost when I need to. It keeps the AC off. I also use cruise a lot. I'll give it a few tanks and see if I notice any trends.

lovemyraffe · Post by **lovemyraffe** » Sat Jan 22, 2011 7:14 am

Removing the cross bars will not make a significant difference. If you had a ski rack or a cargo box on top, that would make a difference, but not the cross bars alone.

star_deceiver · Post by **star_deceiver** » Sat Jan 22, 2011 7:22 am

I ran 40-42 front and rear on the RS-A's with no problem, and bumped it up to 51 for the last 2 months of their lives... and I run 40 in my winters.

torker · Post by **torker** » Sat Jan 22, 2011 7:43 am

Wow that is pretty high. I put Cooper CS4 Touring tires on a year ago. I bought them the day we had a 8" snow last year. The ones that came on the car wore like iron but were totally helpless in snow. These do 100% better. I know what you mean about the crossbars, they were less than a 1/2" thick and rounded corners but I like the look too. I may pick up an infrared thermometer at Harbor Freight and do some edge-center-edge checks right after some hiway runs. Not sure I want to run much over 40 psi though. We'll see how stiff it rides and see. What surprises me is my wife knocks down 23-24 every tank in her 04 Caddy CTS and she has a leadfoot. Now get the two cars in town and it would be totally different I'm sure. I know that CTS is over 4000 lbs.

Old Tele man · Post by **Old Tele man** » Sat Jan 22, 2011 10:06 am

...I run 40 psi in both of our Vibes (her '04 and my '09) and both are shod with OEM Goodyear RS-A's

Mark · Post by **Mark** » Fri Jan 28, 2011 1:08 pm

'04 Base bought almost exactly 5 years ago with 38k, ~110k now.Low mileage around 25 mpg, high 49 (~250 miles with about a 40mph tail wind). Lots and lots of 34 mpg tanks running at 80 mph with a/c on, and average about 36 at 70 mph. Wife is driving it now and averages around 4 mpg less per tank than I got. Oh well. I took the crossbars off a few month after I bought it, and run my tires at about 36 psi. I'm running Goodyear triple treads, love the traction and handling but I think there's definitely a fuel penalty.

Salsa Guy · Post by **Salsa Guy** » Fri Jan 28, 2011 9:36 pm

2 years ago my wife was complaining about the riding rough after getting it serviced. I went to check the pressure and all the tires were above 45 psi. They all were ruined (cupped).

torker · Post by **torker** » Fri Jan 28, 2011 11:02 pm

Well, First tank 29 We will see if that holds up after a few more tanks. And I am driving the same . I don't baby it and this tank was more city than usual. Probably 35% city. 27 has been the highest until now. Pretty sure this is just from higher tire press. I am running at 38f 35r I can feel the small bumps a lot more and can hear the fronts thump on the bumps more. I probably won't go any higher. I don't want to stress suspension components just to save 1 mpg.

Tire pressure - crossbars and mpg.

Tire pressure - crossbars and mpg.

Re: Tire pressure - crossbars and mpg. (torker)

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Re: Tire pressure - crossbars and mpg. (torker)