If you choose a tire width and aspect ratio to approximate the same outer diameter it shouldn't be an issue.
Put 235 45 18 in for the OEM tire and the 17" winter tire size you are buying in the other... https://tiresize.com/comparison/ Have you already purchased the 17" wheels?
Not yet. The tire I'm buying is Michelin xi3 225/50/R17 which is on clearance, and save around $100 each compared to the xi3 at OEM size. The tireshop told me it can be used on Clarity. I know the size difference, just wonder if I can adjust the odometer and speedometer.
You'd need to get one of the aftermarket devices that intercepts the signal from the speed sensor and allows adjustment of the signal to reflect different tire sizes/gearing. You'll have to decide if it is worth it to correct for a 1.5% difference. Most cost close to what you are saving by fitting the non OEM size tire.
We have a stand alone Garmin for the Kia and it tells you how fast you are going. After noticing it said we were going 2 mph slower at highway speeds we did some testing using those signs that flash your speed and found it held true at lower speeds as well. Now we drive +2mph everywhere. So if you know someone with a Garmin that tells you how fast you are going it's a good way to find the difference. Then look for those "This is how fast you are going" signs.
A possible unit is the Dakota Digital SGI-100BT. I recently purchased one for a different car after I changed out the final drive gears, but I was looking at a net 14.7% difference rather than the insignificant amount here. This would be really uncharted territory, I don't think anyone's ever pulled the cluster and posted about it on here.
" We have a stand alone Garmin for the Kia and it tells you how fast you are going. After noticing it said we were going 2 mph slower at highway speeds we did some testing using those signs that flash your speed and found it held true at lower speeds as well. Now we drive +2mph everywhere. So if you know someone with a Garmin that tells you how fast you are going it's a good way to find the difference. Then look for those "This is how fast you are going" signs." The Waze app on your phone will also tell you how fast you are driving.
I run slightly larger tires on another vehicle and have no problem just mentally adding the right mph to the readout. Simply run the numbers on one of the on-line tire size calculators and mentally make the change. The odometer difference is irrelevant to pretty much everything it’s used for.
The diameter difference between the 2 tire sizes here is almost statistically irrelevant. Tire diameter changes as tread wears, and nobody cares that speedo reading changes slightly. For a simple speedo that’s probably more accurate that Honda’s Just to to App Store and pick a free speedometer app for phone. Dozens available and all work perfect. That said, I don’t know many drivers that pay any attention to posted speed limit anyway so....
The nice thing about the Clarity, no automatic transmission shift points such as a ICE vehicle to mess up.
ICE-powered vehicles with CVTs don't have shift points. I always laugh at our 2010 Insight's "shift paddles" that force the car's CVT to pretend it has gears. I haven't touched them in a decade, but I almost do before I remember I'm not in our Clarity.