Which tires for best Fuel Economy? 2001 Corolla CE.
 

Looking at keeping my steel wheels with their winter tires and getting 14" alloy rims. I'm looking at the FAST Static 14" x 6" alloy rim as it is lighter than the stock steel 14" wheel. The tires I am chosing from are:

175/65-14
185/65-14
195/60-14

So, any advice as to the tire size and which model? The 175/65 and 185/65 can both be found in the common Michelin Harmony/Destiny. The 195/60-14 is not available in that model, so I need suggestions.

thanks,

:)

My research indicates that, contrary to popular belief, a wider tire will have less rolling resistance. The 185/65-14 is the tallest among the three listed sizes and will give you a slight gearing advantage.

Generally, I recommend buying long treadwear tires and not worrying about rolling resistance too much. You can be sure a long treadwear tire will save money. You can't be sure of rolling resistance numbers.

I heard the 'gearing advantage' has caused some to experience reduced fuel economy. Not sure how that works. In some ways, you'd think lower rev's = less fuel used, but, maybe taller gearing equals a higher load on the engine? Interestingly, many Corolla's came with 185/65-14's with no change in speedo calibration. I think the LE and sport had 185/65-14's. Anyways...a taller tire won't be as resistant to flex, so I believe it would use more fuel. The 175/65-14 and 195/60-14 are almost totally identical in height.

I have been doing some research, and just recently, after I posted this question, I found some people saying that narrower tires have an aerodynamic advantage. I suppose the best choice would be a 175/65-14 in terms of frontal area aero-dynamics. So, it's kinda tricky to figure it out. I'd love to buy two ot three identical sets of rims and run a bunch of sets of wheels and calculate fuel economy...but hey, I can't afford that science experiment...heheh...

thanks for the feedback,

:)

Certainly, the benefit of taller gearing through taller tires is limited to cars that don't come with the best gearing for fuel economy. A Corolla may already come with the best gearing for fuel economy, and changing it in either direction might reduce fuel economy. I think most cars probably come adjusted for better acceleration instead, at least a little bit.

It's my guess, based on my research, that the aerodynamic difference is miniscule but the rolling resistance difference (if you expect one) is worthwhile.

Again, the most sure way to save money in the long term is to get long-lasting tires.

People are saying BMW did some research about aerodynamics of tires. I find it hard to believe that a 2 cm difference in tire width would make much difference. The wider tire has a larger contact patch, but since it's not higher, it shouldn't make much difference. I am torn between the two tire sizes that are nearly identical in height. I am trying to decide between 175/65 and 195/60. I'll flip a coin.

The 195 will deliver more fun cornering, in addition to what I believe would be lower rolling resistance.

The Goodyear low rolling resistance tire is rated for 51psi max and has a narrow than usual tread for the same size conventional tire. TireRack also says that a taller tire has MORE rolling resistance than a shorter tire but by how much is not stated so there may be some small gearing / rpm advantage to a slightly taller tire. I am contemplating that right now along with some 9.9lbs mag wheels to lighten up the stock 19lbs steel rims on my 06xB. 185/60R15 vs 185/65R15 for a little taller profile.

Why would the 195 have lower rolling resistance? I'm not sure I understand that. I admit that other Corolla owners have said that switching from their 185/65-14 to the 195/60-14 caused no drop in fuel economy. I just thought a narrower tire gives you lower rolling resistance. Maybe that's not true, as you say. I just wonder why.

Well, there are a number of theories and few measurements. The theory I continue to use until proven otherwise is as follows:

• Given an inflation pressure and a load, the contact patch will be a certain size. For example, at 10 pounds per square inch inflation with a 100 pound load, the contact patch will be 10 square inches.
• A major component of rolling resistance, probably most of it, comes from deformation of the sidewall to produce the contact patch.
• If the contact patch size doesn't change with the width of the tire, then its shape must. As you make it narrower, it gets longer; that means more deformation of the sidewall. If the contact patch is going to be 10 square inches and your tire is 2 inches wide, then the contact patch will be 5 inches long. If the tire is 4 inches wide, the contact patch (and required sidewall deformation) will be 2.5 inches long.

That is definitely true of bias ply tube-type tires as found on bicycles. It is possible that something about modern automotive tubeless radial construction fundamentally changes that effect. However, without good data to tell me for sure, I have little reason to doubt it.

There are other issues that make me think that a wider tire would have lower rolling resistance, but that is the largest and easiest one.

Yeah, I guess it's totally impossible to decide what will be the absolute best in the end. The stock steel wheel I have is 5.5" wide x 14" and from most sources, weighs about 18 LBS. The replacement rim I intend to use is a FAST 'Static' rim at 6.0" x 14" and 13.6 LBS. I have asked what the weight of the 15" rim is but so far haven't heard back.

The stock tire I have is:

175/65-14

The common upsize is:

185/65-14

but this is both significantly taller, at close to 1/2" AND also wider.

The other options are:

185/60-14 (slightly shorter than stock 175 by 1/4" or 5 mm)
195/60-14 (slightly taller by about 5 mm)

or

185/55-15 (essentially identical in height to stock size...but an oddball size and a heavier wheel (6.5" wide x 15"))

Not sure what to do....

I wonder which is worse for Fuel Economy vs stock 175/65-14...Taller and wider 195/60-14 or shorter and not as wide 185/60-14?

I agree you guys and others have found little difference in MPG when going with a slightly wider tire, but some have found the Cd goes up noticabley. I guess it's possibly only significant when you go up more than 2 cm in width.

"Given an inflation pressure and a load, the contact patch will be a certain size. For example, at 10 pounds per square inch inflation with a 100 pound load, the contact patch will be 10 square inches.
A major component of rolling resistance, probably most of it, comes from deformation of the sidewall to produce the contact patch.
If the contact patch size doesn't change with the width of the tire, then its shape must. As you make it narrower, it gets longer; that means more deformation of the sidewall. If the contact patch is going to be 10 square inches and your tire is 2 inches wide, then the contact patch will be 5 inches long. If the tire is 4 inches wide, the contact patch (and required sidewall deformation) will be 2.5 inches long."

I think this is true in certain cases but not mine.

In my 1800 lb crx, running the 175/70/13s it had on it when I bought it, I could not exceed 35 psi on the rough roads around here or it would feel like the wheels were going to come off on bumps in the road. With 155/80/13s I can run my tires 20% higher pressure and get the same ride. So I am having the same sidewall deformation and the same ride on the new tires with a smaller contact patch and skinnier aero profile.

If your car rides nice and smooth already at high psi then this would not be an issue for you in your corolla

Actually looking now at Konig Helium 15" x 6.5" wheel at 11.6 LBS and not very expensive...with 195/55-15's....or FAST Synergy 14" x 6" with either of 185/65-14 or 195/60-14. I hate how many tires are not available in different sizes. I want a LRR tire in 195/55-15 or 195/60-14 and they're not easy to find...and especially hard to find is the 185/55-15. The 185/65-14 is easy to find.

I'm looking at some Enkei Racing RPF1 Bright Silver Paint rims from TireRack at 9.9lbs and $199 each I figure I may as well spend a little more money and get some seriously lighter rims and put some Pirelli P4 tires on them which someone in Chicago used on an xB and said they were WAY better than the stock Goodyear Eagle LS factory tires in the snow and have a much higher wear life. Also thinking about the 65 series instead of the 60 series for a little taller tire.

I TOTALLY AGREE I AM GETTING 42MPG AT 68MPH WITH SOME TOYOS THAT HAVE WIDER TREAD THAN MOST OTHER TIRES OF THE SIZE 195 65 15 ON MY SATURN. IM NOT TRYING TO HYPERMILE EITHER, TO IMPATIENT RIGHT NOW.

THE BETTER YOUR CAR HANDLES THE LESS YOU HAVE TO SLOW DOWN ON CORNERS, I ALSO HAVE A SET OF 1/4 INCH ALUMINUM SPACERS ON THE BACK WHEELS BECAUSE THE CAR WAS A LITTLE SHAKY BEFORE(20$), ALL BETTER NOW.ESPECIALLY IN THE 1999 VS 1991-95 BODY STYLE THEY CHANGED THE CAR AROUND BUT YOU CAN GET THE SPACERS AT ANY LOCAL SPEED SHOP.

I HAVE NEVER HAD MPG READING OF LOWER THAN 31 ON THIS CAR. EVER. :eek: AND THE WIDER TREAD= LESS ROLLING RESISTANCE.. I AGREE BECAUSE THE WEIGHT IS MORE PROPORTIONATELY DISTRIBUTED ON THE GROUND LESS WEIGHT PER UNIT. HENCE LESS RESISTANCE, PLUSS LESS SLOWING DOWN.:cool:

THE TOYOS ARE JAPANESE TIRES KNOWN TO LAST TO 70-80K MILES, PLUS ARE WIDER, AND HANDLES WAY BETTER THAN OTHER TIRES FOR THIS CAR IM SURE OF THE SAME SIZE BUT COST 130$ A PIECE NEW......360$ AFTER ALIGNMENT OR SOMETHING.. WORTH IT

no, the contact patch vs pressure is the same no matter the tire construction type (bias/radial) it's physics. if you go to a narrower tire, it will become a narrower longer contact patch BUT you also have to remember that the tire is round and the road is flat. thus the tire will have to flex more to conform to the flat surface, IE higher rolling resistance. you get a softer ride because of the extra flex. the wider tire, having a shorter wider contact patch will flex less to conform to the flat road (since width wise, the tire is essentially flat) so less heat, less RR, better cornering.

as for which size to go with, I'd go with the widest you can fit, as tall as you can fit. as mentioned above, unless the car's already geared crazy high, you'll get better FE (once you adjust your odometer numbers). If your mileage goes down, try going slightly faster: higher revving engine=more power to maintain speed. If the distance payoff outweighs the power/fuel pay-in either you'll get the same FE at higher speed or better FE. not guaranteed but a good chance of gains.

Too tall too wide.
 

My new car is an 02 Ford Focus auto, gas logs soon to come, it has the ZX3 rally rims and thy're huge. The door sticker calls for a 205/50 R16, the previous owner has 205/55 R16 on the front and smaller 205/60 R16 on the rear. I can't imagine the car with 50's all the way around. I have gone to the junk yard and and checked other Focus' door stickers for the stock sizes and they all come in at either a 185/60 R14 or a 195/60 R15. Now using my GPS I found my car is 3 mph faster and I have a problem on hills, I have to use the AC like a boost button. If Im on a hill and I dont take off the AC, I drop down a gear on hills, so I ride the AC button and turn it off on hills.

The tire I would like is the 195/60 R15, that way I get a 100 PRM boost to keep me from dieing on hills and I go with a skinnier tire. Currently I pull 2800 at 70, but Im doing 73. So what Im reading here is I should stick with as wide a tire as possible. So I have to see if they make a 195/50 R16. Honestly the 16's ride hard, I was hoping for a smaller rim that would give a bit of cush to the ride. I guess Ford doesnt care about speedo's either, the 185 will read 3 under and the 195 will read right on.

I do so much city driving and roaming parking structures the tires it has now are hard on parking handling, the 50's would be a pain. If I get a chance, I'll swap the fronts for the back and see what that will do, it wont change RPM, but it might play with some rolling resistance. As for rim weight, I was just going to go with a set of junk yard steelies, I have to weigh the aluminum rims and see how close they are.

Through a series of fate and luck I found a pair of cheap 205/50/16's, the diameter was of large concern, the tires that car came with were too tall and I'd bog out on the high way, meaning I'd have my foot in it and go no where, when you open up the throttle on a large hill, the extra air makes the computer throw in more fuel and create less gas mileage. I just got the new tires and so far my new numbers seem to be good since the engine is in its correct RPM on the high way.

I got Kumho's touring, a 60,000 mile tire and the ride is great, I need to build up some gas receipts to see the increase in mpg.

Your rears are larger in diameter than the fronts, not the other way around.

Yes, the rears come in at 26 inches tall and the front are now the factory 24 inch diameter tire. I got torque back on hills, the engine accelorates easier, less sticking your foot in the car to get it moving. Holy Cow set me straight on what the 3 numbers mean ie. 205/50/16, I used to think the first number was the overall metric height. Next month when I get paid, I'll throw another set of proper sized tires on the rear, that will lower the tail one inch, less of a stink bug profile.

This month's (May 2010?) Car and Driver magazine has actual test data regarding fuel mileage from a test car fitted with a range of tire widths. Here's the skinny:

Wider tires gave worse mileage and accelerated more slowly than skinny tires.

Wider tires cornered and stopped better.

Micheline has LRR, for good grip at high psi, the extra money is worth your life

Got to new Pirelli P6 tires installed somewhere in this tank or previous. Rolling resistance is low but I would not recommend this tire. It does not roll round and follows grooves in payment like some Bridgestone tires have for me. Michelin and Toyo do not do like those. 54.32 edit
05/16/2009 602 10.721 2.2 56.15 edit
04/25/2009 612 10.312 2.06 Bought some new Pirelli P6 tires but have not installed them yet. 59.34 edit
04/06/2009 589 10.82 1.86 Removed the Michelin Harmony tires and installed used Toyo 175/65 R14 tires. Corrected for the smaller tires. The improvement is more than one would expect from the tire size change. Don't know about those Michelin tires. Sold them on Craig's List. 54.43 edit
03/16/2009 527 10.363 1.699 Pulled the Michelin tires after about 300 miles of this tank. 50.85 edit
02/25/2009 320 6.291 1.72 Those new Michelin Harmony tires are really draggy. I did not expect that. 50.86 edit
02/15/2009 550 10.25 1.76 I just installed new Michelin tires. I think they are going to cost me a few miles per gallon. Those old Toyo Z800 Ultra tires were about like people describe those Bridgestone RE92's. Anyway the quieter ride is maybe worth a few mpg. It sounds like I am going soft when gas only costs $1.75. Oh well. Maybe a stimulized plug in hybrid system will get me going someday. 5