tires and gas mileage

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Jun 1, 2002
has anybody seen gas mileage drop with the installation of new tires? last fall i replaced the oem's with a set of continental contiextreme contacts, and i'd say my average is down between 1~2 mpg. even compared to similar times last winter (old tires) it's down a bit. these are high performance all season tires. the grip is fabulous. tia
New tires will always reduce mpg by a percent. I believe on truck manual quoted a numbr of some minus 3-5% (conservative) This is not a bad thing of sort....My 1st guess is the healthier new tire is grasping the road much better. As I see it better traction, better emergency braking more safety. Also if you move into any tire in the High to Ultra High Performance Tire category you will also see a definate mpg loss. I would not worry about the loss. As long as the Tire has a DOT traction/temperature rating of AA/A or A/B it is fine by me.
If you have more tread on your tires (everything else equal), you have a bigger diameter and your odometer will err in the direction of travelling less. Is probably only good for 1/2 % or so... [I dont know]
at this point, the tires are the only thing i can think of that have changed that would make this type of difference. these are the average mileage of each oil change:
02.26.02    23.40
04.27.02    24.72
06.18.02    26.62
10.17.02    26.46
02.07.03    24.80
05.31.03    25.29
10.27.03    25.90 (new tires)
02.20.04    23.72 

i dates on there so the seasonal effects could be considered. the car was brand-spankin' new when i got it. i am pretty sure it's the new rubber. (that was 10,000 miles ago, and they still look great).
It looks like your mileage dropped about the time the refineries changed over to their winter formulation. This is usually good for 2MPG. Now that they have switched back to the summer blend check your mileage and see if it improved. If it did then it was the gas, if it didn't it was the tires. [Smile]
there are so very many wild cers here, there's no way to pinpoint it. For instance: 1) Different temps may mean lower tire psi 2) Different driving conditions (one tank I had 28mpg, next tank was 23mpg). 3) Different fuel mixtures (and qualities) 4) strong head winds [Razz] 5) etc etc Also, the more weight the tire has on the outside of it, the better the highway milage and worse the city milage you'll get. New tires have proportionally more mass toward the outside... different tires have different mass, too.
I have noticed this with my S-10. My mileage has dropped .5 to 1 since I had Firestone Destination LE tires installed. OE were Goodyear Wrangler RT/S. The lower mileage, however, is well worth for how much better the Firestones grip the road. The increase in wet traction over the Goodyears is amazing! And they ride much softer too.
Originally posted by Asinine: Also, the more weight the tire has on the outside of it, the better the highway milage and worse the city milage you'll get.
Humm, more weight on the outside of the tire will yield better mileage? Is that because of the momentum generated by the larger mass will tend to want to stay in motion? There must be a point though were the extra mass will start to degrade mileage. For instance say I want to try out those new 10ft monster truck tires down at the local goodyear tire store. [Big Grin]
Different tires have different rolling resistance. Not sure how they measure it, but Consumer's Report recently had a test on high performance all-season tires, and found differences that they state could add/subtract 1-2 mpg. I have also seen reference to 'low-rolling-resistance' tires in articles on the high mpg compacts from Honda and Toyota.
Brett, FYI The Goodyear Wrangler RTS is a premium tire! You made an excellent choice [Smile] Look into the Michellin Cross Terrain, or Sears/Michelin XC LT4 for another set...also excellent LT/SUV/Jeep tires [Smile]
I really wanted the Michelin LTX M&S but the Firestone's were $136 cheaper for the set. At this point I couldn't be happier with them. I also have Firestone LH30's on my Civic and really like them as well.
if you could refill with helium then you could get that high, funny voice as well. man, i gotta stop posting after bowling. too much beer.
Helium it is then but I know my tyre dealer doesn't sell that unlike Nitrogen. The dealer (Bob Jane T-Marts) even tops up the Nitrogen for free many times as you like after initial fill. That's service!
Originally posted by tweeker43: if you could refill with helium then you could get that high, funny voice as well. man, i gotta stop posting after bowling. too much beer.
I prefer hydrogen, they make a dandy highway flare if you need to summon help. Hydrogen is lighter than helium too.
Not to address your question, but I also just put a set of ContiExtreme Contacts on my g/f's Eclipse, and these tires pWn! Nice grip in the dry (haven't seen much rain since I got them), and they are whisper quiet - much more confident feel that the Bridgestones that came on the car.
[Cool] I went to a bigger tire on my truck and definitely lost about 2 mpg. OE 245/75-16 Goodyear RT/S to 265/70-16 Wild Country all-terrain, bigger and a more aggressive tread.
Not to get too scientifical [Freak] and all that, but...In the molecular world, helium is a little teeny bugger, and leaks out easily through the pores of the tire carcass. Think back to our kiddy days when our helium balloons from the fair went dead within 24 hours. Nitrogen is a much larger molecule, and so can't leak near as easily. If you have a source of helium, use it for party balloons. Ain't no good for tires.
In your case JohnnyO, yes, you will lose MPG because of the wider footprint. Hope you weren't looking for height, as there essentially no difference in height between the two sizes (about 30.5 vs. 30.6" diameter). No speedo correction required there! I also hope nobody here thinks the Wrangler RT/S is a premium tire! One of the biggest POS truck tires on the market (and stock on way too many light trucks and SUV's). If anyone is looking for a solid truck tire these days, try out the Bridgestone Dueler A/T REVO. Best LT tire I've owned, bar none. That includes the BFG all Terrains. Bridgestone did their homework on this one...
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