Tire Recommendation For Es300

[amf1932]

Same conditions, I drive exactly as I have driven the car for the last 50k miles, since I've installed the MXV4s my mileage is consistently 1.8-2.5 MPG better (10-15%).

What else would have caused this significant change, I drive the same speeds and places as I always have, and what are the odds whatever change has occured occured right after I replaced the tires?

The rolling resistance rating of a tire can have a significant impact on your MPG. Deflate your tires 1PSI and see what an impact it'll have.

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I would have assumed that the factory equipped tires that originally came with your car had a fairly low rolling resistance compared to the MXV4s that you replaced them with, so I find your increase in mileage has to be due to some other factors.

I would read this article from Tire Rack to see if you agree with their findings.

http://www.tirerack.com/tires/tiretech/tec...e.jsp?techid=29

[SW03ES]

They probably did, I just don't remember what kind of difference there was. All I'm comparing them to are the TPTs.

[jragosta]

Same conditions, I drive exactly as I have driven the car for the last 50k miles, since I've installed the MXV4s my mileage is consistently 1.8-2.5 MPG better (10-15%).

What else would have caused this significant change, I drive the same speeds and places as I always have, and what are the odds whatever change has occured occured right after I replaced the tires?

The rolling resistance rating of a tire can have a significant impact on your MPG. Deflate your tires 1PSI and see what an impact it'll have.

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So we're down from '20%' to '10-15%'. As I said, 20% didn't sound realistic and you're already dropping back.

Furthermore, what were your tire pressures before and after? And are you sure you didn't drive any long trips to try out your new tires?

Bottom line is that I'm skeptical of any claims of massive mileage improvements from simple things. Almost always, the improvement is overstated (by at least as much as you overstated it).

[SW03ES]

Once I did the math it wound up to be less than 20%, sorry. Why would I lie about something like this? Do you think that I have that little to do in my life that I would engineer a lie about MPG relative to tires? If you don't want to believe me, fine

Tire pressures are 30 all the way around, same they've been on the car since the day I bought it. There was some experimentation with as high as 32 and as low as 29, but I decided on 30 and have kept it there. The tire pressure is checked and maintained weekly when I clean the car up.

As for trips, maybe but I've been driving on these tires for getting close to 10k miles now and the difference in mileage is still there. I used to get 17MPG or so in the city, 24 or 25 on the highway and somewhere in between in mixed driving. Now I never see mileage under 19 and have seen 27-28 routinely during highway trips. I really don't track my mileage any more outside of that. Definately an improvement, and definately an improvement of 11.76-16.67% per my calculations (precise enough?) Anyways I don't see how a couple MPG is that "massive" as you stated it an increase anyways.

I post on and off on some of the Prius boards, these guys are SERIOUS about MPG and they're all incredibly intelligent and mathmatically minded people who keep long records and analysis of their gas mileage. You'd be shocked how much new tires change their mileage.

If you want to have a discussion about this, thats great I'd love to have one. If you're going to insinuate that I fabricated MPG figures and deliberately backed off from the % improvement I stated previously with some goal of what? Save it.

[mikek753]

I'm trying find any charts / tables that show rolling resistance for dif tires, so far no luck :cries:

Consumer Report has some data, but no real numbers

I've replaced OEM tires (no on Lexus) with LS-T and MPG dropped about 10% - that's my fact.

Yes, I got (on another car) better ride, less noise and less MPG

The next time I'll check for MXV's as those have the lowest rolling resistance in its group - IMHO.

[jragosta]

Once I did the math it wound up to be less than 20%, sorry. Why would I lie about something like this? Do you think that I have that little to do in my life that I would engineer a lie about MPG relative to tires? If you don't want to believe me, fine 

Tire pressures are 30 all the way around, same they've been on the car since the day I bought it. There was some experimentation with as high as 32 and as low as 29, but I decided on 30 and have kept it there. The tire pressure is checked and maintained weekly when I clean the car up.

As for trips, maybe but I've been driving on these tires for getting close to 10k miles now and the difference in mileage is still there. I used to get 17MPG or so in the city, 24 or 25 on the highway and somewhere in between in mixed driving. Now I never see mileage under 19 and have seen 27-28 routinely during highway trips. I really don't track my mileage any more outside of that. Definately an improvement, and definately an improvement of 11.76-16.67% per my calculations (precise enough?) Anyways I don't see how a couple MPG is that "massive" as you stated it an increase anyways.

I post on and off on some of the Prius boards, these guys are SERIOUS about MPG and they're all incredibly intelligent and mathmatically minded people who keep long records and analysis of their gas mileage. You'd be shocked how much new tires change their mileage.

If you want to have a discussion about this, thats great I'd love to have one. If you're going to insinuate that I fabricated MPG figures and deliberately backed off from the % improvement I stated previously with some goal of what? Save it.

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Sorry if you felt that I was saying that you were lying.

My point is that when people report huge mileage improvements, they're usually mistaken for one reason or another. It could be simply memory (as in your case, it seems) or it could be that something else changed (they got the car tuned up at the same time), or the driving conditions could be different (they liked how quiet the car was so they went on a long road trip). I believe that's a pretty universal truth - people almost always overstate the mileage improvement from changes like this, but that doesn't mean that they're lying.

Bottom line is that it's possible to improve the mileage of a vehicle by a little bit, but there's no magic bullet that increases the mileage dramatically (and, yes, a 20% increase in mileage is a dramatic improvement).

[jragosta]

I'm trying find any charts / tables that show rolling resistance for dif tires, so far no luck :cries:

Consumer Report has some data, but no real numbers

I've replaced OEM tires (no on Lexus) with LS-T and MPG dropped about 10% - that's my fact.

Yes, I got (on another car) better ride, less noise and less MPG 

The next time I'll check for MXV's as those have the lowest rolling resistance in its group - IMHO.

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Here's an article that covers it. They calculate that a 20% drop in rolling resistance will only increase mileage by about 3%.

Another report says that 20-30% difference from the highest to lowest rolling resistance is typical. They calculate a MAXIMUM mpg improvement of under 6%.

http://www.treehugger.com/files/2005/05/low_rolling_res.php

HOWEVER, the stock tires already have very low rolling resistance (for CAFE reasons), so most aftermarket tires will increase rolling resistance rather than decrease it.

Both numbers are based on how much energy is actually used to overcome rolling resistance.

There's another article which gives more information - and the PDF file on their site lists rolling resistances for a bunch of tires.

http://www.gotoreviews.com/archives/cars/r...ance-tires.html

The Michelin MX4 is about middle of the pack. This article also confirms that CAFE standards require new cars to have low rolling resistance tires. Almost all replacement tires are higher than the stock tires that came with your car.

You brought up the Prius. That's actually going to be a worst case scenario - because rolling resistance is a higher percentage of total energy usage on a tiny car like that than on a larger, more powerful car like the Lexus. Even there, I'm finding claims of no more than 10%.

Overall, based on published reports, single digit increases might be possible, probably toward the low end.