Bridgestone EP422 tires swapped for Michelin Primacy MXV4s.

[DaveEV]

I feel like I took a small hit with them, but I also last a bar around the same time so it's hard to say.

If you're comparing the new tires to your old ones, they are very likely to be slightly worse. But they should improve after a thousand miles or so as they break in.

[TomT]

New tires - even of the same make and model - will always have higher rolling resistance than older ones. As the tires age, the tread depth decreases and the rubber hardens slightly, both of which decrease rolling resistance.

I feel like I took a small hit with them, but I also last a bar around the same time so it's hard to say.

[thankyouOB]

I did this swap, too.
and the first day's m/kWh went down from about 4.5+ to 4.1- for my commute of 50 miles.

is this logical, that m/kwh would drop so much?
is there such a thing as, the tire will wear in and increase its rolling speed?

by the way, the ecotopia's went bad with one hit by a nail and a bad patch job, and another with a gouge and a bulge from road hazards. i had 17.5k on them.

cost was about $175 per tire with tax, install, full road hazard and replacement, and lifetime rotate and balance. discount tire.

finally, the car has a slight shimmy now at 60mp and up speeds.
i first thought it was the gripping tread, now i am thinking there is a balance issue. what do you all think about that?

[thankyouOB]

in answer to a question (pm), there is not steering wheel jiggle or vibration.

[DeaneG]

in answer to a question (pm), there is not steering wheel jiggle or vibration.

I'd take it back to the shop and have the balance checked again. No steering wheel vibration might mean the problem is on one of the rears. Or just that it's too faint to feel through the wheel.

[LEAFfan]

Nope, I detected no real difference. And the latest CR test rates them both as having excellent rolling resistance. The MXV4 finished first in their tests and the Ecopia 422 last.

Tom,
do you still feel the tires had little impact on your efficiency? I need to reply my stock tires now and I'm curious about your experience.
Thanks, Bill

Tom, what tire pressure are you running?

[TomT]

Initially I was running 40 but I noticed little difference in ride at 44 so that is what I am now running.

Tom, what tire pressure are you running?

[thankyouOB]

a PM mentioned the possibility of tramlining--tires are so precise that they track road grooves.
a consumers reports buyer in AL said this:
I had the local retail store re-balance them (and they needed it) but, (even when warm) these tires still have an annoying vibration / shake betweem 60 -65 (they smooth out some on the interstate at speeds of ~ 70

makes me wonder if the tires are not a good choice as 60-65 is my driving/range freeway sweetspot.

[DaveEV]

I wonder if the tires are slightly out of round? I had a set of GoodYear FuelMax tires on our Prius where 2 of them were enough out of round that they were replaced. Might try rotating them and see if it's any different.

I had the MXV4s on my previous car, and they were really smooth at all speeds.

[TomT]

I do most of my driving on freeways at that same speed range and have not had a problem. They do tramline some but so did the Ecopias and I believe it to be more a result of the Leaf suspension design and alignment settings. The improvement in braking, handling, tire wear, and tire robustness was well worth the swap to me. My efficiency feel by only about 3 percent so that was not a big consideration either.

makes me wonder if the tires are not a good choice as 60-65 is my driving/range freeway sweetspot.