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Tires for Economy
http://www.teamswift.net/viewtopic.php?f=34&t=44401
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Author:  xrw44 [ Sat Jul 18, 2009 10:21 am ]
Post subject:  Tires for Economy

Last summer, i wore out the 155/70-12 that came with my Mtero
So for the front i got 50psi 185/70-14 24.2"D +21% more Circumference than 145/70-12. But they rub on bumpy turns.
On the rear i put some free 35psi 185/60-14 . They noticeably drag!

I did some calculating (see below) and looking around i found
TOYO 310 - 155/80R14 80S TL £25.80, $42, speed S, load 80
This tire has low drag (155mm)
and 23.8"D which is +19% greater than original circumference and MPG.
speedo and odo will show 19% lower than actual.
I got used to that. Anyway I seldom exceed the speed limit!
likely will not rub, since my 24.2"D slightly does only on bumpy turns.

i will be checking to see if Toyo dealers here can get it for my fronts at least.
(I have torture tested Toyo Proxy on the track for over 100 mi and up to 150 mph. Great grip. Likely a dif. compound but they made a good tire.)


got these numbers using
http://www.miata.net/garage/tirecalc.html

originally 145/70-12 20.0"D 62.8"Circumference


FRONT - FOR MPG

185/70-14 24.2"D +21% more Circumference -- RUBS on bumpy turns.

155/80-14 23.8"D +19% TOYO 310 - 155/80R14 80S TL £25.80=$42, speed S, load 80

175/70-14 23.6"D +18.3%

195/55-15 23.4"D +17.3%

155/80-13 22.8"D +14% Firestone, Cooper or Hancook or Kumho $48+

165/80-14 22.4"D +12%

195/60-14 23.2"D +16.1%

165/70-14 23.1"D +15.5%

155/70-14 22.5"D +13%

165/80-14 22.4"D +12%


REAR - FOR LOW DRAG

155/80-12 21.8"D +9% Kumho Power Star 758 155/80R12 400AB 35psi $43+15or172+35

165/70-12 21.1"D +5.5%

155/70-12 20.5"D +2.8%

Here is a ranked list of tires with Low_rolling_resistance:
http://en.wikipedia.org/wiki/Low_rollin ... ance_tires

Author:  mxmikie [ Sat Jul 18, 2009 11:30 am ]
Post subject:  Re: Tires for Economy

they also make a "LRR" tire low rolling Resistance tire that make a diff it will be stamped on the sidewall

Author:  sbergman27 [ Sat Aug 29, 2009 6:17 pm ]
Post subject:  Re: Tires for Economy

xrw44 wrote:
Last summer, i wore out the 155/70-12 that came with my Mtero
So for the front i got 50psi 185/70-14

Careful with the inflation pressure. And make sure strut mounts are still available for your model. High pressure will destroy the strut mounts when you hit that strip in the road, where the construction starts, at 65mph, that you didn't realize was so high until you were right on it. It only takes one mistake.

I'm looking for a strut mount now, with little success, after running my mk1 with 15580R12 tires at 44psi.

For reference, have a look at this Toyo document:

http://cache.toyotires.com/sites/defaul ... ntable.pdf

I spent some time today working out that fully loaded, with 4 passengers and 88 lbs luggage (688lbs), and with the P14580R12's that came with the car, 26psi front, and 23psi rear would be adequate. So the 35psi/35psi recommendation on the door jamb of my 1988 Sprint Metro is already very generously inflated (if you'll pardon the expression) in the interest of the 2% or 3% difference in fuel economy it makes. Moving to P155/80R12's, as most everyone has, the adequate pressures work out to 23psi front, 20psi rear.

Now... for 185/70-14 tires... the adequate pressures have to be extrapolated since the tables don't go down that far. But it works out to about 18psi front, 16psi rear. And keep in mind that this is fully loaded with passengers and luggage. So if you are running anywhere near 50psi, you may as will just go with solid steel tires as far are your suspension is concerned because your are at triple the pressure called for by the tables.

50psi in the P185/70R-14's is roughly equivalent to running 72psi in your original tires.

Looking at it another way... if one wants to maintain the same capacity moving from P145/80R12 to P155/80R12, then the factory recommended 35psi front/rear becomes 28psi front/rear according to the tables. Moving from P145/80R12's to P185/70R14, 35psi corresponds to 22psi.

Me? I'm running my P15580R12 tires at 32/32 now. This works out to be equivalent to running the original P145/80R12 tires at 38psi. But I'll never run P15580R12 tires at 44psi again.

Author:  Burnsside42 [ Tue Mar 01, 2011 10:06 am ]
Post subject:  Re: Tires for Economy

This is all very good information to know! My Metro had 155/80/12 on it when i bought it - its due for tires now. I've been running them @ 42PSI front and 38PSI rear since I've owned it and yes - one of my strut mounts is bad. lol

I plan on sourcing out a suspension system from a later Geo in order to improve the ride quality and handling - as well as the brakes.

I also have the full intentions on doing another tune up shortly as well.

How does one go about adjusting the timing to the mentioned 8*

Any suggestions on a good budget tire? I can pick up some Nankang's for about $200 out the door. Again - in the 155/80/12 size. Should I consider getting a 165/70/12 as this is almost dead on with the speedometer - 60mph will really be 59.9MPH as opposed to how it is now @ 61.8MPH when showing 60.

Author:  blueturbofly [ Tue Mar 01, 2011 7:56 pm ]
Post subject:  Re: Tires for Economy

i run 24 psi in winter,(175/65r14)50 psi summer 185 65 r 14 .excellent braking,mpg with 50 psi....tires dont fold on curves.....

Author:  xrw44 [ Tue Mar 01, 2011 8:29 pm ]
Post subject:  Re: Tires for Economy

Burnsside42 wrote:
How does one go about adjusting the timing to the mentioned 8*

Any suggestions on a good budget tire? I can pick up some Nankang's for about $200 out the door. Again - in the 155/80/12 size. Should I consider getting a 165/70/12 as this is almost dead on with the speedometer - 60mph will really be 59.9MPH as opposed to how it is now @ 61.8MPH when showing 60.

I have run 8* timing for almost 3 yrs with no problem. Search for timing adjustment and you will find detailed instructions.

I value hi MPG more than accurate speedo
so i'd run 155/80/12
or better yet
155/80-14 23.8"D +19% TOYO 310 - 155/80R14 80S TL £25.80=$42, speed S, load 80
or others I mentioned above

I ran tires above their Max. psi and potholes etc. have knocked the belts out of place. i have 3 tires that are trash and 4 that are out of round. the car bounced and waddled ! I got fed up and put on some nearly new ones at 32 psi last week. they are much better.

I dont think the hi psi was worth it.
but the larger diameter tire does really improve mpg
try to get 155 or 165 width to keep drag down.

Author:  Phil N Ed [ Wed Mar 02, 2011 1:04 am ]
Post subject:  Re: Tires for Economy

xrw44 wrote:
I have run 8* timing for almost 3 yrs with no problem. Search for timing adjustment and you will find detailed instructions.

Hey meester,
I serched n kant find dee timing adjustment thread.
Kan u help mee find it?
My car runs 8* timing, is dat OK?
:lol: :lol: :lol:

Author:  xrw44 [ Wed Mar 02, 2011 7:34 am ]
Post subject:  Re: Tires for Economy

Phil N Ed wrote:
xrw44 wrote:
I have run 8* timing for almost 3 yrs with no problem. Search for timing adjustment and you will find detailed instructions.

Hey meester,
I serched n kant find dee timing adjustment thread.
Kan u help mee find it?
My car runs 8* timing, is dat OK?
:lol: :lol: :lol:

found this
viewtopic.php?f=2&t=18091&p=136767&hilit=timing#p136767
took 30 sec
searched TIMING in How To.
=)

PS pics are gone but any shop manual has them. Google the web. :)

Author:  Phil N Ed [ Wed Mar 02, 2011 11:28 am ]
Post subject:  Re: Tires for Economy

thanx, meester :!:

:lol: :lol: :lol:

Author:  blueturbofly [ Wed Mar 02, 2011 8:00 pm ]
Post subject:  Re: Tires for Economy

just run the max psi as called for on the tire sidewall.my winters are cheap wal-mart tires,if i wreck one i'm not out too much money.

summer tires are hankook mileage plus,not a cheap tire,but worth it.50 psi max(6 ply) for these tires.


instead of 32 psi most shops around here run 35psi....and nitrogen fill is not really worth it.did the nitrogen on the wifes truck,we dont notice a difference....plus most shops charge for it........regular air is 78% nitro,you pay for the extra 22% :huh:

Author:  Burnsside42 [ Thu Mar 03, 2011 6:31 am ]
Post subject:  Re: Tires for Economy

I am picking up some new Nankang 155/80/12's today - I think I'll try running them @ 35PSI and see how that goes.

I am also picking up suspension and brakes from a 1998 Metro this weekend to upgrade the ride. There is also a set of 155/80/13's with the deal - with maybe 40% tread on them. I'll at least have some tire options to play with once I have them.

Author:  xrw44 [ Thu Mar 03, 2011 8:46 am ]
Post subject:  Re: Tires for Economy

Burnsside42 wrote:
There is also a set of 155/80/13's with the deal - with maybe 40% tread on them. I'll at least have some tire options to play with once I have them.

The holes in the 13s may be bigger than in the 12s. I used ATV caps with the 14s.
The 12s smaller hole may not fit on the 98 wheel studs.
The 13s will save you gas.

Author:  xrw44 [ Thu Mar 03, 2011 3:45 pm ]
Post subject:  Re: Tires for Economy

Surprisingly my MPG is +5 at least
since i changed tires.
now tires are round and 32 psi at 50F
old tires were out of round, warped and 35-45 psi

Author:  blueturbofly [ Thu Mar 03, 2011 7:02 pm ]
Post subject:  Re: Tires for Economy

12inch wheels will not fit over the front brakes on a factory equipped 13'' cars. 12 inch wheels are weak.small brakes suck.roller bearings on 12's suck.better options when you change those hubs out!!!! 8)

Author:  Burnsside42 [ Thu Mar 03, 2011 8:38 pm ]
Post subject:  Re: Tires for Economy

blueturbofly wrote:
12inch wheels will not fit over the front brakes on a factory equipped 13'' cars. 12 inch wheels are weak.small brakes suck.roller bearings on 12's suck.better options when you change those hubs out!!!! 8)


Damn - wish I knew this before I bought the 12" Tires... lol Guess I'll run them until I swap the hubs over. I can put the updated suspension on I would gather in the meantime. Anyone want to buy a set of 12" wheels with new tires for $200? lol

Author:  banadictaustin [ Fri Jul 06, 2012 12:25 pm ]
Post subject:  Re: Tires for Economy

Tires defiantly improve your vehicle fuel economy, the tires moving level of resistance is one aspect that straight impacts energy consumption. The most important thing is Check cold pressure in the morning and inflate to the proper pressure it helps to improve mpg.

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