New Tires and 10% hit to MPG.. OUCH!!

I get better MPG with the MXM4 than I did with the Kumho ecsta ASX of the same size but only by about 2mpg. The hit from going to the 17s from the 15s is about 6mpg.

My MPG is creeping up after 2,000 miles so there is still hope. Please keep us posted on your MPG. If the MPG doesn't get closer to what it was with your OEM tires then maybe we should avoid the Primacy.

 

Tire Tech Information - Tire Rolling Resistance Part 3: Changes to Expect When Switching from Worn-Out to New Tires

 

I put a set of Michelin Primacy MXV4 in 196/65R-15 on mine July 26th and also noticed the immediate drop although not a huge drop. I expected a change due to the much deeper tread depth and heavier tire weight than my stock Avid's. Michelin has a 30 day free return and I considered returning them for a while but I didn't like the alternatives available. I have about 1,800 miles on these and I've decided to keep them. I'm running 42/40 PSI.

The Primacy was not my first choice but the Michelin Energy Savers are just not available here from anyone due to a national back order. Michelin was offering a $70 rebate that I didn't want to miss by waiting. Yes there are other brands but I wanted to stay with Michelin.

After 3 weeks I'm satisfied.

 

I did the very same thing with the Primacy MXV4 and for the same reasons. I wanted the Energy Savers but they were not available. I took a pretty big mpg hit but it is slowly coming back after about 1000 to 1500 miles.

I really like the smoother ride and especially the much lower tire noise than the OEM Yokohama Avid S33's.

 

What were your MPG's before the change and what were they after the change?

 

I went from worn out Toyo A20s to new Michelin Pilot Sport A/S tires about 5K miles ago. I took a fairly big mileage hit as predicted by the Tire Rack article referenced by 32K.

I think (hope) my mileage is coming back a little now. I can't give a percentage because I don't keep good enough mileage records to do so. But even if the mileage is down a little permenately the Michelins are worth while to me because of improved performance in other areas. As good as Prius mileage is a few MPG doesn't really matter to me.

 

What tires did you have originally?

 

That is how I feel regarding my swap to 17" Primacy MXM4s. They handle so much better than my 15" tires and they are much safer when it comes to stopping distance, evasive maneuvers and wet traction. My mpg hit was fairly large at 6mpg but in reality the economic difference is quite small. Besides, the car looks 100 times better with the 17s.

 

It almost seems like these tires need a little time to break in. It's hard to explain but they "feel" different now that I'm approaching 2,000 miles on them. They coast better.

My wife has them on her 3.5L Altma "hotrod" in the 17" but we didn't see much change on it in the mpg area (up or down)

That seems like an easy question to answer but It's not that easy because of the change in my driving trips.

I can't attribute a specific number to it but I know I had to work a lot harder to maintain the levels I was getting previously. (63 - 70 mpg) It acted almost like when the weather starts to turn colder for the season and the high mpg's are harder to hold onto. Even at 42 psi, these tires don't coast as easily as my stock Yokohama Avid's did but the Avid's were nearly down to the wear bars and that makes a big difference.

 

Your car looks about as good as any Gen2 Prius I have seen. I wish they still had Salsa Red as a Prius color, it was my favorite.

 

Besides that above great article, http://priuschat.com/forums/other-cars/95536-car-driver-mileage-no-its-your-gallonage-really-counts.html might help put things in perspective...

 

When I first got my Michilen Energy Saver tires I noticed a
2-3 MPG true increase over the factory AVID YOKO tires I replaced even though they had over 10,000 miles.

alfon

 

I have Primacy MXV4s too, My avids were bald and my last trip on them netted like 55mpg but we all know that wasn't "true".

I just had my first over 50mpg trip since I got them. I do agree there is a drop with the Primacys but man the handling is 1000x better, wait for a good storm you won't even hydroplane and you will realize how scary those Avids were.

 

Why tnak you, my friend.

That is an important point. Sometimes we sacrifice a small amount of efficiency for better handling and safety. That is why I chose the MXM4. With sunflower seed oil in the compound the wet traction is supposed to be outstanding. We'll see come winter.

 

I agree with the different "feel" after some miles on them. I seem to be gaining a little mpg back with the more miles on them.

We put them on my wife's Honda Accord and did not see much change from the OEM Energy MXV4's.

I agree with the superior handling and noise reduction from the Avids. I haven't had a chance to try them in a good rainstorm. The benefits certainly outway any mpg loss I may end up with.

 

A lot of that article is about EPA ratings vs "what people get". Which is never what the EPA ratings were intended to be. They're supposed to compare different vehicles under identical conditions. The conditions are intended to be somewhat similar to typical vehicle usage in the HOPE that this will enable comparisons between vehicles' fuel economy. IOW, if one vehicle is rated at 50mpg and another at 45mpg on the tests, the hope is that their relative rankings would remain roughly the same for drivers/conditions getting 40mpg in the first vehicle, as well as for drivers/conditions getting 60mpg in that one.

Unfortunately the EPA standards have come to be perceived as a guarantee of the mpg one will get. Even worse, what one will get no matter how/where the car is driven! So people feel they can stomp on the gas/brake and should still get EPA.

As for mpg vs gallons/100 miles, it really doesn't matter to the pickup driver: burning 10 gallons vs 9 gallons per 100 miles is just as depressing as getting 10 vs 11mpg. MPG vs gal/100 miles doesn't matter so much to me either: getting 65mpg vs getting 50mpg is worth it to me no matter how it is expressed.

But there is a tendancy to use gal/100 miles for comparative mpg. I'm getting 50mpg, so why should I bother trying for more? That pickup/SUV driver over there needs to step up and drive more efficiently because that will save more gallons. It becomes basically an excuse for me to turn off my brain.

Well how about the neighbor here who has a pickup which he really uses as a work truck for his carpentry business? It's always packed with stuff and it's all beat up. He can't do that in a Prius. Now maybe he doesn't really need a 4x4 in metro Boston, so switching to a Ford Transit or Sprinter might make economic sense for him, but he'll still need to burn a lot of fuel no matter how he drives.

 

I really think that focusing on improving fleet efficiency will do better for us as a planet and eventually our wallets too. If companies can get product to us cheaper and more efficiently and with less pollution/gas use then we all win.