New Tires = 5 to 6 Less MPGs

You purchased tires that have poor reviews on Tirerack.com. I always buy LRR tires for my hybrid card with my favorite being Nokian WR series tires. Yes, they cost a bit more, but are stronger tires (H-Rated, 51 PSI max), have better traction/handling is all weather conditions (they are as good as many winter tires in snow), and last more than 50,000 miles. The additional MPG will save you more than the extra cost over the life of the tires.

JeffD

 

because the new tires have a larger circumference, it does alter the speedo/odo

and new tires sometimes need to break in, so hopefully mpg's will improve a bit.

the rest is the type of tire, LRR does make a difference

 

A related thread (ignore the thread title)

See this message and a few before

Tesla has been cheating EPA on mpge and range numbers | Page 7 | PriusChat

 

Years ago TireRack used to have good article quoted here often about putting same tires back on you will see x% decrease in MPG due to mainly more rubber as some above mentioned and I forget if there are other factors

 

On my 2007 Touring:
Purchased Feb 2017 with about 143,000 miles

4/15/2017 was returning from an Atlanta trip when started getting a thumping noise about 5 miles from home. Found a huge bubble in front driver side tire sidewall. Limped my way to nearest tire store that was open on a Sunday. PepBoys.
All they had in stock for 195/55/16 was Falken Ziex ZE950. Had 4 of them installed and drove off. $447.77 out the door. 146,939 miles.

5/25/2020 Front tires were worn more than back, got a nail right at edge of tread on driverside front. Same PepBoys. New tires, front only. Same model tire and size. $212.85 out the door. 197,766 miles on the car. ~51k miles on the tires.

Middle of August 2022. Got a screw in driver side rear tire. Plug didn't seal perfectly, so still has a slow leak. Have to add air every 3 or 4 days. End of August hit the deepest pothole ever in my life. Felt like it ripped the driver front tire off. Put a wrinkle in the sidewall. Couldn't get new tires yet due to work schedule. The ZE950 no longer available. Just used backup 2008 prius for a while. ~226,000 miles on car. Plenty of tread on fronts, backs are at the wear indicators. The backs lasted from ~147k to 226k. That's not bad...79k miles....just going to replace all 4 due to the pothole damage. I've been surprisingly pleased with how the tires have performed. I've had plenty of 54+ mpg tanks.

The ZE950 has been replaced by the ZE960 I believe. They run about $110 each near me, but availability is sketchy. I said the heck with it and just ordered (4) 205/55/16 94V Solarus Starfire? (by Cooper) with installation scheduled for 9/17. $281.02 for the tires and I'll pay $17 each for install --> so $349ish out the door. Decided to go with the 205 just to gain a bit of car height for some speed bumps I deal with now and then, plus it will make the speedo dead nuts instead of reading slightly low. Will be interesting to see how these cheapass tires hold up and how the MPG changes, if at all.

 

There are at least 3 factors that contribute to lower MPG on new tires:
1. Larger diameter (pseudo lower MPG)
2. Heavier (more weight the car is carrying)
3. Softer (more deformation energy loss)

The reduction in MPG is normally around a few % (in comparison with old tires of the same brand/model). However, if you use different brands/models, then there will be more (and maybe bigger) variables.

 

Check EU tire labels when buying tires I'm assuming you're running the size: 175/65R14 (from memory that's what the Prius C runs?) Looking at the manufacturers site we see it gets a C rating on rolling resistance: Falken Tyres




a rating of C indicates the following rolling resistance (kg per ton of vehicle mass)
(see page 3 of attached PDF for full details).




Best rolling resistance, while still having very good dry/wet handling is the Continental EcoContact 6, it does sacrifice wear rating for this, but it's on a prius, it'll last forever anyway. Gets an A on rolling resistance, and B wet handling rating. Are you able to exchange the tires?

 

There's always some variability with tires, but also check your calendar. You probably weren't using as much air conditioning back in May.

Wait to see if the numbers improve as the season cools.

 

Falken is not a widely known brand in the US.
What caused you to choose them ??
Yes, I think you make a bad choice.
Others have explained why.

 

if it's strictly a money issue, and not fossil fuel conservation, you may be right

 

some here say that a fairly inexpensive tire (general altimax, or something) is an excellent tire, idk.
i spent $700. on michelin energy savers just to get a quieter ride and the same mpg's.

 

If the difference between a LRR tire and a normal tire is going to be something that one is truly worried about IRT fossil fuel and carbon footprint, I think that person needs to invest in good walking shoes and start putting down real footprints...Just having the Prius at 45mpg-ish is like filling a gallon jug with carbon footprint savings. A few more drops in the jug just doesn't matter enough to worry about. And when you have countries like China and India blowing the bottom out of the jug with dynamite, we're all just peeing in the wind anyway.....