Tire Choices

[spacemanspif]

It's looking like I'm going to need tires soon as my right rear tire is wearing faster than the left. Guessing an alignment is in order as well and since I replace tires in pairs I'll be buying 2 new tires and have a few questions on types and size.

1. I am currently running 195-60-15 and am thinking about getting narrower ones; 175-65-15 are 0.2" shorter than the 195-60s. Wondering if 175s on a 6" wide wheel are too narrow and/or MPG beneficial? I'd like to consider safety as well, I don't drive like a crazy person but I want to be safe in all weather conditions and will take a small MPG hit to retain safety.

2. LRR tires in both sizes seem to start around $80/each on tirerack.com and there are tires $20 less that aren't. Will LRR tires pay for themselves in savings? What are some realistic gains to be had from these tires?

For reference, with my taller geared trans I cruise at 2,000rpm @ 60mph. I think that it is about at the bottom of my eco range and think that spinning the engine a little more might be beneficial for my 95% highway commute. Thinking that a little more rpm might keep the engine from loading so much while climbing all the overpasses I deal with and might net a small mpg gain, or at least not take a hit (hopefully).

Thanks,

[2000mc]

I wouldn't be scared of the 175-65-15 size. 175-70-14 was an optional size, at least on the coupes, and both 175s get the same load rating.
That being said I'd get the 195s ,my pick in the 175 would be the Yokohama avid ascend, which is $5 cheaper per tire in the 195 size. The 195s also offer more tire options.
If you're expecting 95% highway, if anything I'd be thinking about a larger diameter. If you think the engine is lugging more than you would like then reduce the load with aero mods and lrr tires, rather than making the engine spin faster

[CapriRacer]

Originally Posted by spacemanspif

It's looking like I'm going to need tires soon as my right rear tire is wearing faster than the left. Guessing an alignment is in order as well and since I replace tires in pairs I'll be buying 2 new tires and have a few questions on types and size.

1. I am currently running 195-60-15 and am thinking about getting narrower ones; 175-65-15 are 0.2" shorter than the 195-60s. Wondering if 175s on a 6" wide wheel are too narrow and/or MPG beneficial? I'd like to consider safety as well, I don't drive like a crazy person but I want to be safe in all weather conditions and will take a small MPG hit to retain safety........

That is going the wrong direction for safety. That is going down in load carrying capacity and directionally that is towards increased risk of tire failure.

Also, not only is the vehicle being required to operate at a higher rpm for a given speed - which usually hurts fuel economy - but the rolling resistance is actually worse for a smaller size (all other things being equal).

Originally Posted by spacemanspif

2. LRR tires in both sizes seem to start around $80/each on tirerack.com and there are tires $20 less that aren't. Will LRR tires pay for themselves in savings? What are some realistic gains to be had from these tires? .....

I think this depends on how much highway driving you do compared to how much city driving you do.

Tires with low rolling resistance tend to wear more rapidly, and city driving causes tire to wear more rapid, so the combination might result in more money being spent to replace the tires more often.

But be aware that the term "LRR" is a relative term. It means "Better RR compared to other tires with similar wear and traction properties" - and with that in might, it would be better to have LRR than not. You need to decide what compromise you are willling to live with.

Originally Posted by spacemanspif

.........For reference, with my taller geared trans I cruise at 2,000rpm @ 60mph. I think that it is about at the bottom of my eco range and think that spinning the engine a little more might be beneficial for my 95% highway commute. Thinking that a little more rpm might keep the engine from loading so much while climbing all the overpasses I deal with and might net a small mpg gain, or at least not take a hit (hopefully).

Thanks,

Based on that you will get many miles out of a set of tires - and you would benefit from a larger diameter tire.

Try to fit as large a diameter tire as you can - best guess not knowing your exact vehicle is 2 sizes larger. (Even if you tell us the exact vehicle, we won't be able to tell what fits as there aren't any charts published that tell us how big the fenderwells are.)

The second part is careful tire selection. Unfortunately, RR values aren't published as there are a number of RR tests and they don't give the same value. To compare tires, the tests have to be the same.

[mcrews]

I use the tables at tire rack.com to determine accepted width selection.
But I also agrre that you should go UP in diameter, not down.
1. gives a 'little bit' more comfortable ride (w/ the higher psis we need that)
2. would probably only lower the rpm 75-100.

[California98Civic]

I agree with all three above responses as to gearing/mpg effects of tire sizes. Take mccrews' advice too and study the tirerack.com specs lists more. My Michelin Defenders are great (they were also my only choice in 13" tires, but I might have chosen them anyway for the 15" wheels I considered buying for gearing purposes). IIRC, some of the LRR tires got really great ratings for durability in terms of miles traveled too. Good luck!

[spacemanspif]

Thanks for the replies guys. I checked my alignment today with some hand tools my friends have and seems that everything checked out. Same reading at the front and back of tire and same camber as well. Not sure why the 1 tire seems to be wearing faster though. I think it has a fair amount of life left in it so I won't have to worry about new ones until maybe next summer or later this winter. Pretty sure I am going to stick with the 195-60-15 size as choices get slim when playing with sizes. FWIW I don't think that a taller tire would be beneficial with the tall gear trans that I have unless I started to drive faster on the road...but then I still have wind resistance to factor in to the mix...

A look at the BSFC chart shows why I think it might have been a good idea to go a little shorter. Seems that 2500rpm is dead center of the 250island, and 2000rpm is a little on the front edge but at a spot with engine making less torque. Less torque would mean harder to climb hills and even with better aero, I'd be fighting gravity.



Thoughts??

200mc; Joint team Saturn!!

[user removed]

Drop down a gear to climb the hills, coast downhill. When you don't need 4th use 5th or even better coast. Might try downshift pulsing uphill then peak speed coasting as far as you can downhill. Ay a certain grade and speed you car should downshift, unless you get peak speed at the bottom and bleed it off up the next hill.

It all depends on length and grade.

regards
Mech

[CargoBoatTails]

tirerack.com allows you to sort LRR only

[oil pan 4]

I was going to say
http://ecomodder.com/forum/showthrea...eum-26530.html
But they only make them in 16 inch and up.

[ksa8907]

I also am in the market for new tires. I found http://www.tirerack.com/tires/tires....RUEC&tab=Sizes

Im waiting on more reviews and surveys before I buy.