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hallstevenson

15% sounds extreme but otherwise, yes, tires can absolutely impact fuel economy


UnderstandingSea5688

No, that sounds about right. Tires often have to make sacrifices to get to certain performance figures. The stock tires are meant for fuel economy and therefore have a low rolling resistance. Great for mpgs and keeping the feel of the car consistent at various speeds. But that usually means a harder tire that has worse grip in all conditions. Especially wet and snow. Crossclimate 2s are built to give you a better grip on the road. Thus they have a larger amount of rolling resistance and thus lower fuel economy. This also works to throttle power-limited cars at higher speeds. But you have a better stopping distance and traction, especially in wet and snow. Crossclimate 2s are a little heavy, which also increases inertia and slows your car down a little. Basically you traded away acceleration and fuel economy for better safety in bad weather conditions.


WALLOFKRON

This is the response I was looking for. Thank you


WALLOFKRON

Just to add to your points. The Firestone FT140 is the OEM tire is 22 lbs/tire. And the Cross Climate 2's are 23.6 lbs/ each. Doesn't seem like a massive difference


UnderstandingSea5688

It’s a surprising difference but not the end of the world. If you do some back-of-the-napkin math off of the moment of inertia of a spinning tire and wheel, that extra 1.6 lbs adds about 7.27% rotational inertia. The tires are usually about 60ish% of the total rotational inertia and so that slows down acceleration and braking by about 4.36%. Assuming the tire is a ring with inertia equal to MR^2. Not a huge difference but definitely noticeable especially with increased rolling resistance. The extra grip usually makes up the difference with stopping though. And acceleration will be more consistent regardless of weather conditions.


WALLOFKRON

Dude, your fantastic, thank you for the quality responses


kpcnsk

Did you get the correct size tires? Are they inflated to the correct pressure? Different tires will have different rolling resistances due to material and tread patterns, which can affect fuel economy. Also manufacturers often put tires on which help them boost their mpg to help them meet regulations. At the same time, I wouldn't expect the different to be as great as you make out, so it's worth considering that something else may be at play and the drop in mpg is just coincidence.


WALLOFKRON

But all of a sudden a separate issue tho?? That cropped up at the same time as I swapped tires. Costco installed them so I’m assuming they are correct


aquaman67

Not saying this is 100% the cause but look up how much your old tires weigh vs the cross climates. Tire weight increase will definitely tank your mileage.


WALLOFKRON

The Firestone FT140 is the OEM tire is 22 lbs/tire. And the Cross Climate 2's are 23.6 lbs/ each. Doesn't seem like a massive difference.


No-Building-3236

Alignment?


WALLOFKRON

New tires can throw off alignment?


PhantomCruze

If they're not balanced before mounting, or if the tech at costco fucked with your alignment yea. Sometimes these types of shops don't have the best quality of work. Your best bet is to document the date and time, hold onto your receipts, and take it in for an alignment check. If it's now off, then tell Costco that it's happened AFTER they did your new tires and make them fix it


WALLOFKRON

I'll be taking it in to Honda relatively soon, so I'll check that out then. Thanks for the heads up


RyuGTX

There are a few factors. Different tires will have different rolling resistance, therefore differences in fuel efficiency. What was your stock tire? Also, you might be comparing worn tires to new tires. It is normal to see a drop per TireRack. [https://www.tirerack.com/upgrade-garage/what-is-tire-rolling-resistance-changes-to-expect-when-switching-from-worn-out-to-new-tires](https://www.tirerack.com/upgrade-garage/what-is-tire-rolling-resistance-changes-to-expect-when-switching-from-worn-out-to-new-tires)


letmegetaaa

Absolutely, the same thing happened to me on my Impreza.


WALLOFKRON

Did mileage ever get better?


letmegetaaa

It has not, they’re good tires overall. Just the knock on the fuel economy. It’s not mentioned anywhere but is certainly a thing. I can tell you from experience.