from the tire calculator:Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
235/60-16 5.6in 13.6in 27.1in 85.1in 744 0.0%
225/65-16 5.8in 13.8in 27.5in 86.4in 733 1.5%

not much of a difference - good for me though.

another one:
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
235/60-16 5.6in 13.6in 27.1in 85.1in 744 0.0%
215/70-16 5.9in 13.9in 27.9in 87.5in 724 2.8%

dont think there is a 215/70 though

 

What's with the 60/65 series tires? We were never talking about them.

We were talking about the difference between
235/70-16s (factory size) and
225/75-16s (your recommended size, taller, narrower, same rims)

This comparison on the Miata calculator (I looked it up) is almost exactly what I said at the beginning:

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
235/70-16 6.5in 14.5in 29.0in 91.0in 697 0.0%
225/75-16 6.6in 14.6in 29.3in 92.0in 689 1.2%

I decided not to make the change. It's a 1.2% difference, approximately 1/3rd of an inch diameter, etc.

I don't know where you're going with the 60 and 65 series tires, or the 215s, I was never going to consider those.

 

got it mixed up;
was going to go out and look at exactly what it was
(but got lazy )
you got it corrected; thanxs.

 

I got the Pirellis today, shipped FedEx from the Walmart (I'll guess a warehouse) and they all look good. Original stickers, in what look to be perfect shape. I ordered on a Thursday and they arrived Monday around noon. Fast for free shipping over a weekend. I expect to have them mounted and balanced by Wed. or so. So far, so good.

 

Wow funky new look and new name to the forum. I guess we've been promoted and are all Electric now.

Got the Pirellis mounted. Initial impressions:

Ride height and wheel/tire spacing looks virtually unchanged from the factory size Michelins, which is good, because these are factory-size Pirellis.

The tread depth looks plenty deep to my eyes compared to the Michelins that came off. They're nice looking blackwall tires with a kind of satin finish molded into the sidewall rubber. Not as nice to my eyes as raised white lettering, but snazzy enough for blackwalls.

I only drove them 20 miles home and did not check the pressures that the installer used. Mileage looked to be approximately the same as the Michelins but I cannot be sure because the installer checked my fluids and accidentally left the hood partially latched, so there was more drag on the car in the first 10 miles from an open hood, until I noticed. He is gentle with his repair cars and probably did not drop the hood hard enough to fully latch it. Once I check the pressures and adjust them, I'll do a proper mileage test.

Subjective impressions:

They are very, very quiet on smooth roads. Virtually zero tire noise, the engine is much louder than the tires. This car will never be Lexus/Mercedes quiet but any noise is not coming from these Pirellis.
The cornering and braking are better by a significant and instantly noticeable amount than the old Michelins. The turn-in is instant and the tires bite firmly with authority and don't feel as though the sidewalls flex at *all*. Very happy with the cornering performance thus far. I pushed pretty hard into a couple of corners and the tires felt like they had more to offer, whereas the Michelins would be close to squealing and pushing. They also change direction very well without any mushiness. These tires make the FEH feel "sporty."
Bump/road noise: They seen a little bit more subdued than the Michelins over small road imperfections/cracks/slightly rough pavement. More of a "WHump" sound when you hit a road joint, less of a "THump". The harder "T" has been softened to a "WH".

Next up are photos (my phone battery died) and a proper distance mileage test.

I cannot wait to try them in the RAIN.

I paid $100 for mounting and precision balancing at a local shop I trust, and that's keeping the old ones. They did their usual excellent job. There is no vibration or pulsation at all that I could discern at any speed.

Very happy so far.

I still have the Michelins and I'm deciding what to do with them. I hope to get $70 for them on Craigslist. Two of them suffer from a little bit of dry rot/cracking in the rubber, but not excessive. They went 100MPH for 10 minutes a week ago without any trouble. These were relatively OLD tires and the Pirellis are a breath of fresh air.

 

Update: Today I took a longer ride on the highway with the Pirelli Scorpion Verde A/S Plus IIs. At 75-80 MPH on a rather gusty, windy day I noticed:

They're still very, very quiet at highway speeds.
Over bumps and pavement imperfections they are definitely quieter and isolate/suppress the impact noise better than the Michelins that came off.
They improve the car's on-center tracking in gusty winds by leaps and bounds. This car was getting "squirmy" at 75-80 with the Michelins in wind gusts. You almost had to fight it to stay in lane on big gusts. These tires cut that down by at least 2/3rds and it takes a lot less effort and attention to correct the steering, even on rather large wind gusts, making for a more pleasant highway cruise.
The mileage looks to be lower by about 1-2 MPG at highway speeds but I have *not* yet checked the pressures and it was a weird day with a lot of wind, including a pretty big headwind. Most of the time I was driving directly into the wind, which I'd estimate at constant 20MPH with gusts in the 40-45 range. I could see other people and large vehicles like tractor trailers fighting the wind, so these were not ideal mileage conditions by any stretch.

I haven't tried them in the rain yet, but I think it's going to be very good.

I know it's pretty common for people to praise their own decisions where money is involved, but really objectively I can say that the Pirellis are very good tires. They improved the car's handling, tracking, braking and so forth by a significant amount. The car feels newer, sportier and more sure-footed.

They are #1 rated on the Tire Rack in this size for this purpose and I can see why. If you live in an area with a lot of snow, you might want to consider something different, as these are "touring All Season" and not specially rated for snow.