So it's been 2 weeks with new LRR tires...no improvement in mpg!

Gas formulae change with the seasons and I've found that in the Winter/Spring my mpg takes a bit of a hit.
Here are my figures for the past couple of years:

2014:Winter=39.83; Spring=46.17; Summer=51.21; Fall=44.92;
2015:Winter=38.05; Spring=49.71; Summer=50.59; Fall=48.61;
(both years running Michelin EnergySavers 46F/44R, but around end of October 2015 switched to Blizzak WS-80s running 40F/38R)

(where Winter=Jan->March; Spring=April->June; Summer=July->Sept; Fall=October->December)

…and don't forget YMMV!

 

good point^ and the tyres may need some more breaking in. but you would be better served to track by manual calculation each time you fill up.

 

i don't know how the michelins compare to the tyres you replaced. there are err tyres, and there are err tyres. i think the best michelin is the energy saver. but 10 mpg seems too much for any tyre change.

 

on the car? i doubt it. are they the exact same size? the old tyres would be slightly smaller due to tread wear, and show a false mpg number.

 

What were the old tires? Just curious.

 

My experience is that LRR tires have a fairly lengthy break-in period. It takes 1-2K miles for them to get "worn in". I have no technical explanation for this, but it is what I have observed. Additionally, as was previously mentioned, your LRR tires are bigger than your old tires due to tread wear, so that's a small factor as well.

An abrupt seasonal change can have a dramatic impact on mileage by 10-15% easily. Couple that with the 2-3mpg hit I see before tires are broken in, and you're easily at 10mpg.

Unfortunately, unless one logs ambient data with mileage records, one can't factor that into perceptions. I suggest you review the weather record for the time period of ±1 week of when the tires were changed and see if you can identify a noteworthy drop in temps. Temperature drops are usually accompanied by increased defroster use, which has a hit to mpg too.

Steve

 

Probably the Fuel Max version?

 

There is an article on Tire Rack.com explaining new tires of the same type can show as high as x% less MPG. I forget the value of X, but it's because the rubber is thicker and other things. Not to mention the many otehr variables this time of year, and alignment, brakes dragging etc

Bisco ...isn't it spelled tires? y the y

 

…it's always been spelled "tyres" where I come from, and where the colours of the Union Flag¹ are red white and blue!

¹ the Union Jack being the name of the flag-staff from which the Union Flag is flown

 

I miss that flag up here. Liked the look.

I'm not so sure that a good LRR tire will initially drop your mpg, for sure not markedly. My experience with EP20 on a previous car, they were good right from the start. And I've read similar accounts re Fuel Saver A/S: first tank better.

This is not cheering up the OP I'm sure. Bit of a mystery. All I can think still is it's weather, driving variations. Hopefully will recover.

 

I don't know about Michelin Fuel Savers but I got the same problem low MPG with my Ecopia 422 (not plus) a little more than a year ago. I bought them at Costco and at only 1,200 miles I did a Re-balance and Rotation (Free of charge) with no question asked even they recommend at every 7,500 miles: it was like day and night. The ride got smoother and the MPG jumped right back and more than before.

 

the only thing separating y and i is you.

 

I would look at balance, alignment and to a degree break in period.

If your balance and alignment are good? Then you might expect a degree of improvement with break in.

Michelin Fuel Savers have an excellent reputation.
I'd be hard pressed to believe it was the tires themselves.

 

How many miles on them?

This might not be related to tires but just wonder you have anything blocking the air vent of the battery in the rear seat behind you?

 

check your wheel temps after driving to make sure one of the brakes isn't rubbing. shouldn't be too hot to touch. i'm just trying to think of what they might have messed with whilst changing the tyres.
did you get the tyres from a toyota dealer?