MrKinn

I just got new wheels and tires. Oem 18" tl wheels ( look fantastic btw ). On the highway I was usually getting 29 to 30 mpg. 79 mph. I am currently driving on the highway at 78 mph. And im only getting 23 mpg. WTF??

pohljm

Thats not possible to get a 20% reduction in mileage by that subtle of a change? R compound tires with 20psi? the 29-30 mpg is correct. you need to check pressures, reset mid or run another tank of gas or something because there is an issue that cannot be attributed to only a tire change.

NBP04TL4ME

Did you get an alignment? Are your new tires fighting themselves by being out out alignment? Make sure you have them properly inflated as well.

Jackass

I beg to differ. Depending on what tires were originally on the car to what are on there now, 15-20% mpg change is not completely out of the question. I went from 31-32mpg down to 27mpg going from EL42 to Pilot Sport AS+.

I agree with the other posters that for sure you should check the psi and alignment anyways, but if you went to a tire that has a higher rolling resistance you will get a drop in mpg.

NBP04TL4ME

Did you increase the width? Just another thought.

pohljm

You have got to be kidding me! U think you can reduce your highway mileage by 20% simply by changing tires between standard issue tires running at proper pressures? That is just not possible. If it were they would have figured out how to increase your mileage by 20% by simply changing tires. OP's original mileage was spot on to an average TL. That significant of a reduction cannot be attributed to a tire change assuming that pressures are correct and we are using typical passenger car tires appropriate for the vehicle. A sticky racing compound run at low pressure perhaps

I hate cars

Agreed. I run 255 width tires with a soft compound and I saw maybe a 1mpg hit.

OP, what size tires do you have? You can possibly throw the MID off but they would have to be significantly larger as in 4x4 larger, soft, and very heavy with low air pressure to even approach those numbers. Have you run a full tank through it or did you just take it out on the highway for a few miles? At a minimum you have to drive it both ways to account for wind and incline. My car gets 26mpg on the way to work and 34+ on the way home. There's a slight incline almost the whole way to work but I had no idea, the mpg tipped me off and I verified with GPS.

It's not a TL but my other I commuted 210 miles round trip a day in and I saw no difference going from a street tire to a drag radial. I also saw little difference with a wrinkle wall slick on the street. It takes a lot to get a 20% hit in mileage.

Jackass

I didn't think it was possible either. I will update everyone this fall when the tires get replaced. Check all my posts over the past year or two complaining about it. My MPG dropped the week my tires got changed out and has stayed low ever since. Prior to my tire change, my MPG was spot on what everyone else gets. The only way for me to get 30mpg these days is to stay under 65mph and flat out baby it getting it up to speed.

imakeholesinu

Did you have any other service performed at the time? I had a Saturn that had a huge issue with a Fuel Filter that cut my gas mileage almost in half.

I hate cars

I will be very interested in your results when you swap tires.
That's the reason I asked how it runs at full throttle. It virtually eliminates any fuel system issues if it runs fine at full throttle.

NBP04TL4ME

I usually see a little drop in my mileage when I switch over from my Snow tires to my Summer tires, but not 20%. Usually 1 to 2 MPG, but the tire compounds are obviously different and I'm 10mm wider on the Summers.

Jackass

Hoping to get them replaced before winter. I am having the odd wear on the PS+ and waiting for them to run bald before Costco/Michelin will replace them. But with me driving less than 100 miles per month....that is taking forever.

I think I got my tires put on in roughly the October time frame. I noticed my MPG drop by quite a bit, but initially wrote it off as tires + winter gas hitting. By the time next spring and summer came, my MPG was still down in the mid 20s instead of the upper 20s. Even on trips from KC to STL where I previously got 31-32, I now get 27. My car has been aligned twice since the new tires and it is perfect. I "feel" the PSI is low, but Costco puts it at the 35/32 that is on the door sticker which is what my EL42 ran with.

newkatbie

iTrader: (1)

Did you reset the mpg display? Check tire pressure. check your e-brake for engagement. Losing 1-2 mpg is acceptable with bigger, heavier wheels. Lift your car and check for stuck brakes by turning the tires by hand. 23mpg on the highway is like a pickup truck with a v8. That should never happen in a v6 Honda. Something is wrong or you did not reset the display.

MrKinn

OK UPDATE... When i came back across the ally i set my cruise at 77 and it got me about 28 mpg.. These are brand new tires.. OEM wheels 245/40/r18.. I had an allignment done tire presure is right on.. I going to continue to monitor it.. In the past the best i ever got was 31 for about 120 miles avg speed of 78 ish...

Sotiris

different tires would effect your MPG but not that drastically. If you want to get a little better increase the PSI by 2-3.

NBP04TL4ME

Absolutely not telling you how to drive and stating the obvious - if you shave some speed off, your mileage will climb. I also know you are trying to do an even comparison.

csmeance

Tires can make a difference in MPG, but nothing more than a few MPG. I lost a couple MPG going from summer tires (Khumo's) to the Pilot Sport A/S Plus on my 760. It could be that your wheels are VERY heavy and thus is killing MPG.

What wheels did you get? Tire Size?

Majofo

so it was the alignment?

MrKinn

I absolutly LOVE these wheels... The tires are a sonar tire. What i was told they are a cooper tire.. YES i had an alignment done and i assume the proper air is in the tires.. everything seems to be fine perhaps i had a bad tank of gas..