Why is our MPG so different?

Tire pressure he same. Outside temp the same, how about rain? More traffic? Type of gas?

 

Westlake SP-06 is not a low rolling resistance tire whereas the Ecopia is.

 

You need LLR tires! It does make a difference I've read other threads with this exact same problem! They switched the tires out with LLR's and back to great mpg's. a really great tires is the Michelin Energy or the Defenders. If you can find Energy's go with those. They are designed for good MPG

 

No problem. I had em on my 2010 Mazda six and they were great. But when stock Prius tires are worn ill be looking for the michelins! I think the Energy line is being discontinued bc of downsizing. Which sucks bc it's a good product.

 

True. Price wouldn't outweigh gas savings in the end. 45 mpg is nothing to sneeze at! It may get better as they get broken in with more mileage!

 

You can swap the Westlake to the Pearl and Ecopia to the Gray and you can know for sure if it is the tires or something else.

Vincent

 

It's already proven that LRR tires get better mpg than non-LRR.

 

Yes, LRR tires have better mpg but it can't be that much difference of 11 mpg. My point is that there may be other factors, not just tires alone. By swapping wheels, OP can determine how much % is due to tires and look for other factors beyond tires.

Vincent

 

I've never heard of Westlake tires before until now. Are they by any chance made in China?

 

Assuming the life of the tires is 60k miles with gas price at $4. The LRR tires will save you about $1000 in gas. However, there are pros in using regular tires. I think regular tires will give you a more comfortable ride especially on bumpy roads. Regular tires have more surface area touching the road. This is something you would want when you're driving in the rain.

 

non-LLR tires don't account for all of that difference but it's worth looking into as you investigate. I suspect it's a combination of things: start with tire pressures as that can make a big difference. It's also possible they used the wrong weight oil at the last change, etc.

I went from the OEM Yoko LLR's to non-LLR ContiProContacts and lost about 2mpg on average. I deliberately chose a non-LLR tire and am very happy with the trade offs as I have MUCH more tread depth (resulting in fewer punctures and better dirt road, wet, and light snow traction) as well as noticeably better ride and overall handling.

 

ContiProContacts is a very good tire that results in minimal mpg loss. Worse tires can account for a 10% mpg hit, which on the Prius can be 5 mpg. The best LRR tire can get 2 mpg better than the worse LRR tire. But, yes, other factors may be at play. Tire pressure, oil used, stuck brake caliper, etc.

 

Well said, I've never heard of Westlake tires either, but I've never had off-brand (non major name) tires perform as well as good, name brand tires. Google tells me that Westlakes are indeed Chinese made, of dubious quality (reviews generally negative and they have had past recalls).

So you may be right, a particularly subpar, non-LLR tire might indeed make a large drop like that.

fwiw, I really hate when dealers do this and I see it all the time. They rehab a used vehicle and put it on the lot with brand new tires, but they use the cheapest, no-name crap they can find to save a few bucks.

 

That's an understatement for so cal in August!!

 

I had a new set of Accelera tires when I bought my 2012 Prius a month ago. I found out that they were just a marginal tire at best. I had to work at it very hard to get 50 mpg. I bit the bullet and traded them in on a set of Michelin AS Energy Savers Saturday. The mpg increase was instant. I took a short 40 miles trip and with minimal P&G and very little EV mode my mileage shot up to 65 mpg. I am seeing a tremendous increase in mpg. An off brand set of tires can make a huge fallout in your MPG. I couldn't wait for the tires to wear out and bought the new tires. When continually seeing posts from 0others getting 65 plus and I was hardly getting 51 the decision was easy.