12" Tires

[Darlo]

agreed the second number is a factor but if you are comparing 145/80's to 155/80's.... they are smaller in diameter. Thus higher rpms. It would really matter what type of driving you are doing with them....city or highway.



Tire Size Comparison

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
145/80-12 4.6in 10.6in 21.1in 66.4in 954 0.0%
155/80-12 4.9in 10.9in 21.8in 68.4in 927 3.0%

To be honest, I didnt realize they were both 80's (second number).....I thought the overall diameter was the same for both, in which case the narrower tire with larger psi would win.....

With a larger diameter, you would reduce the rpms (like you said), and therefore increase your mpg at hwy speeds (or at any speed other than crawling). (more important in an automatic which runs high rpms at hwy speeds!)

I usually run 45psi in my 145's and get around 48mpg average. I only run 32-35psi in the 155's and only get 44mpg...... It would be interesting to run my 145's with 35psi and see if I match the 155's, and run the 155's at 45psi (for a couple fills only, lol) to see the converse effect.......

Ps. This site is neat for tire size comparisons......http://www.miata.net/garage/tirecalc.html

[88FestivaLX]

I keep seeing Nankang tires on ebay. Are these decent tires?

[Larry Hampton]

I got my 155's at Discount tire.

[Movin]

Tires are rated by rolling resistance as well and vary a bit. On level ground tow your car by hand with some fish scales and see how many pounds it takes to keep it rolling. If you have doubts tow both directions. If your alignment is off it will affect this as well.
The "skinny" tire will have little affect on mileage until you reach highway speed, then
they have a much nicer air flow . Bigger tires for lower RPM will work until the air dam is lifted enough turbulence is induced under the car, and intake vacuum starts to fall enabling fuel enrichmen/power valve.

[Movin]

Heh this is sure to make the neighbors curtains flutter !!

[Safety Guy]

Here are some Nankang all-seasons or Hankook snows in 155/80-12 from Tires-easy (careful, some are trailer-only tires!):

http://ssl.delti.com/cgi-bin/rshop.pl?dsco=135&sowigan=&Breite=155&Quer=80&Felge=12&Speed=&kategorie=6&LoadRange=&Marke=&ranzahl=4&suchen=View+tires

They are cheaper than the 145s.

Here are your two 165/70-12 choices from Yokohama and Nankang:

http://ssl.delti.com/cgi-bin/rshop.pl?dsco=135&sowigan=&Breite=165&Quer=70&Felge=12&Speed=&kategorie=6&LoadRange=&Marke=&ranzahl=4&suchen=View+tires

I have two Nankang 165/70-12s on Twin's front and they seemed to do just fine. Also, I've always had good service from Tires-easy. I've bought the following from them:

-two Nankang 165/70-12s
-four Falken 175/60-13s
-two more Falkens and four 175/70-13 General snows

Three separate orders over the past year or so, each order delivered within a week, no problems. Can't complain, can I?

Hint: If you can, wait till they have one of their 5% off sales. It helps a bit.

Tires-easy seems to specialize in unusual sized closeouts, so they do sell out. However, keep looking and see what they get in next. It changes.

Karl

[kumalaba]

if you ebay motors & type in 155 80 12 tires they have a set of four delivered for 245.00 chinese

[88FestivaLX]

Thanks everyone. I've found some, I was just wondering if anyone is running the Nankang's. I know I've heard the name before, I just wanted to make sure they weren't terrible, ha.

[litesong]

Don't want to buy a communist chinese tire. U.S. tire would be best, but 12 inch tires are probably not available in a U.S. tire. The NanKang tires are fortunately from Taiwan, the HanKook from S. Korea.

The lower rpm running 155mm tire is very necessary with Festivas with the 4 speed manual tranny. Would really like a 165mm tire(any such animal around?).

Got to drive a Festiva with a 5 speed tranny & really really want one to swap for my 4 speed for much better highway driving. But my 4 speed is wonderful & maybe I shouldn't try to fix it if it ain't broken.

[bhazard]

no way....smaller diameter means higher rpms....the difference in size is not enough to matter on start off IMO, so overall I would say it would not matter except on a trip...giving you better mileage out of the 155's.

Besides....my 155's make my speedo spot on, never ran 145's to see the actual difference though.

Lighter weight > maybe 50 rpm drop at cruise