Tires. Skinny/wide? Tall/low pro?
 

I've been readin a lot of the tire forums and there seems to be a lot of controversy with not a lot of conclusions so I thought to make a new thread. And I'm about to buy a set of tires for my 🇨🇦 1998 civic si 🇨🇦 . I have a pretty good baseline mpg since I have a route that I drive on the regular. My record is 47mpg U.S. With an average of 43 mpg. And that's running stock size 185-55-r14.

Now I've just bought a set of 16" wheels and I've narrowed my decision on tires to three sizes. I'll put the stock size first for comparison.

185/65r14 85h 23.5" tall 4.7" sidewall
195/50r16 84v 23.7" tall 3.8" sidewall
185/55r16 83h 24.1" tall 4.0" sidewall
195/55r16 87v 24.4" tall 4.2" sidewall

My idea is to buy the 195-55r16 since it has the highest load index and tallest tire for better gear reduction. And it's slightly wider for lower rolling resistance (from what I've read)

Now out of what I've read with tire width some argue that the wider the tire the more areodybamic drag and then some say that the wider tire gives a better rolling resistance which overcomes the drag. I believe that capriracer said that. I am just wondering what people's experience has been with buying different tires.

Another thing I've been contemplating is going with a sport tire. My thought behind the sport tires is they have a stiffer tire construction so wouldn't that give a lower rolling resistance? If anybody has tried this please post about. I'd be interested to read about it. And I'll also update on how the tires go once I finally pick and buy a set.

"Sporty" tires will lean towards having more grip from a softer compound, which is more resistance and faster wear. Yes, stiffer sidewalls and all that, but here we get stiff sidewalls by going to at least the max sidewall pressure rating. I think the "less rolling resistance" of wider tires is more of a "lower PSI on the contact patch" thing, and not less actual resistance. Cars get pneumatic tires for traction and a cushy ride, while trains get steel rollers for efficiency. Stuck with pneumatic tires, ecomodders make them as hard as they can.

Personally, I've been in love with my Avid Ascends for some time now and would go with it in either the 185/55/16 or 195/50/16. If you think you could fit a 24.9 inch tire, I'd look at the 205/55/16.

Hey, it's nice to see another fellow Albertan on here. I can only speak from my very limited experience, none of which has been with a Civic. It may just comlicate your decision more, but I hope not.
first, be prepared for a slight drop in mileage with new tires. From what I've read they need a little time to break in.
Next, consider the type of driving you do and the gearing of your car. You don't state what your commute is like. Better gear reduction isn't always a benefit. Also, is the larger tire/rim combo going to be heavier than what you have now?
Softer tread compounds on sport tires are designed for better traction and handling, not better mileage. The tires that have a reputation for the best mileage are poor performers otherwise. (like potenza RE92)
If you do a lot of stop and go in town, added weight will more than offset any gains from gearing. Even on the highway, if the taller gearing takes the engine out of it's most efficient run range, It may hurt. Hopefully you get some response for other Civic owners, but on My Rondo I found that taller/heavier tires hurt my mileage, both city and highway. In town, because of the added weight and on the highway because the added load keeps it from dropping into it's light load fuel reduction mode. In contrast, my Eco does better with my larger summer tires (which are worn out and almost bald by the way). They are about the same weight and that engine benefits from a little lower rpm's. All that to say, each situation is unique and you need to try and identify as many variables as possible. Good luck.

We have some strange efficiency related taxing on cars over here. Manufacturers recognize the need to stay within certain tiers to be competitive, so they tweak their cars to just make the threshold.
That usually means raising the OEM tire pressure (Chevy set it to 3.0 Bar for its Dutch Aveos where its 2.2 or 2.4 for the same model elsewhere).
Another trick is narrow tires with high sidewalls (R15 instead of R16 etc).

My 175/65R15 winter tires are more economical than my 185/55R16 summer tires.
It would show in my tank log if it wasn't for warmer conditions in summer...

Regarding sport tires;

My experience was with General G-Max AS-03 tires which are no longer in production and not likely still available anywhere. They are Ultra High Performance All-Season tires. I had about 45k miles on the first set when one got a hole in the sidewall and I replaced the set since it was early winter and snow season was starting. Those tires still had about 5/32nds left, so around 25-30% remaining at 45k miles.

Regarding tires in general, each driver has their own priorities and you should consider yours when shopping. Personally, I look for the whole package. I would not buy a tire that performs poorly in wet/dry/snow (we don't consistently get enough snow for snow tires). Once I find a tire that hits those categories, I look for the highest mileage rating per dollar cost.

I have Firestone FR 710's on my volt right now since that is what the dealer put on before I bought it. I don't particularly like them. Decent traction I suppose, cornering is ok in dry but seriously lacking when wet.

For reference, late this year I'll likely be buying either general gmax as05, general altimax rt43^2, or continental truecontact.

The VW XL1, the most efficient production car ever made (limited run, otherwise Honda Insight takes that crown) calls for 115/80R16 tires. Or, in other words, very narrow tires with a large aspect ratio.

The Insight calls for 165/65r14, which has a similar diameter - I don't think such narrow tires were available when it came out.

The BMW i3 calls for 155/70r19 on the normal model, and 195/50r20 on the sport model. The wider, lower aspect tires result in a significant range penalty in EV mode.

Size? You're on the right track.

Width? Same.

Sporty? Wrong. Sporty tires generally have high grip tread compounds = high RR!

If fuel economy is your goal, then the best approach is to choose the make and model tire first, and see what sizes they come in. Best guess is the 14" will have the best RR values.

But don't forget that low RR is obtained by sacrificing wear and/or grip. So if overall cost reduction is your goal, it might be better to go for a good wearing tire labeled LRR.

The power it takes to overcome RR is tiny compared to the power it takes to overcome drag at highway speeds.

On the Insight, the difference between RE92's and grippy tires in the same size (or slightly wider) can be -25% fuel economy or more on the highway.

I'm not sure why you're concerned about the tires' load rating, on a Civic Si virtually anything that comes up is going to easily cover the car's max GVWR.

If you're willing to order online, Tire Rack has a 185/60-16 for a 24.7" tall tire that is a skosh narrower than the 195. It has a AA traction rating and a 240 treadlife rating, suggesting it's a fairly hard compound.

I generally think taller/narrower is the way to go, other factors being equal.