155/80-13 tires (looking for LRR options)

[PaleMelanesian]

The Firestone FR380's are not a great tire. That was my previous set. I don't know about mpg, as that was before I was tracking the numbers. They wore down pretty quickly - I can't remember, but 40k miles or so. They also had poor traction, especially on wet roads. I'm not talking about hydroplaning, just a wet road surface. Very easy to spin the tires on a start, or to skid sideways on a turn.

My new Michelin Destiny's are in another class altogether. Too bad they don't come in your desired size. (175/70/13 is what I have)

[Daox]

I suppose I'd consider a slightly wider tire if it was a nice LRR.

[PaleMelanesian]

It's probably not the best for RR. I'd ask basjoos about the other options in the 175 sizes - he's tested a few.

[solarguy]

Most of the tire talk that refers to "good mileage" will refer to how long the tire will last.

If they DON'T mean that, they will talk a lot about fuel economy, but that's rare.

I suppose a few will use the term dishonestly to make you think they are talking about FE, when they are really talking about tread wear. In general, very long tread wear will mean more/worse rolling resistance.

As a broad generality, lower rolling resistance will negatively affect both tread life and traction. Pick one, you get to maximize that one.

Finest regards,
troy

[Daox]

I've been doing a bit more digging. Apparently, the Goodyear Integrity is available in 175/70-R13. This is the LRR OEM tire used on the Prius. The question is, is it worth going to a wider LRR tire, or skinnier regular tire?

155/80-13 = 6.1" wide

175/70-13 = 6.88" wide

Its a sizable increase in width.

[Laurentiu]

My standard tire size on the Corsa was 165/70/13 but when I bought it had a very unusual configuration, 175/70/13's on the front axle and 155/80/13's on the back...

A few months ago I needed tires because the back ones were in a bad shape so I was looking for that exact size (155/80/13 but it was very difficult to find, only pair I could find were Toyo's and for some reason a pair was costing 110 EUR (over 150$) so i decided not to spend so much on a pair of tires.
The ones I ended up buying 175/70/13's, Dunlop's and I found them quite satisfying, especially when it comes to being very-very quiet...
Anyway, I'm rambling here, I just meant to say that I also went for wider ones because of lack of availability/pricing and also because one axle had that size already so I thought it would be better to match it..

According to "Green Seal" the lowest rolling resistance tyres are the Bridgestone B381 P185/70R14. But I guess that doesn't fit your car

[MetroMPG]

Originally Posted by Daox

The question is, is it worth going to a wider LRR tire, or skinnier regular tire?

You could estimate the trade-off, but only if you know the difference in rolling resistance between the two tires you're comparing.

The negative impact of increasing tire width on Cd has been quantified on numerous vehicles.

See: http://ecomodder.com/forum/showthrea...g-cd-7475.html

Don't forget frontal area also increases slightly with wider tires.

If you know the values, you can plug them in to the aerodynamic drag / rolling resistance tool: http://ecomodder.com/forum/tool-aero...resistance.php

.

[Daox]

Yeah, I know its a guessing game. Add to the variables; what is the difference in RR of the tires once they are pumped up to the pressures that we run?

[Jyden]

I allways chek here:

tires online @ tires-easy.com: cheap passenger, summer, winter tires and tire dealer

[wyatt]

Originally Posted by PaleMelanesian

The Firestone FR380's are not a great tire. That was my previous set. I don't know about mpg, as that was before I was tracking the numbers. They wore down pretty quickly - I can't remember, but 40k miles or so. They also had poor traction, especially on wet roads. I'm not talking about hydroplaning, just a wet road surface. Very easy to spin the tires on a start, or to skid sideways on a turn.

My new Michelin Destiny's are in another class altogether. Too bad they don't come in your desired size. (175/70/13 is what I have)

These are the tires that I am running now. The 40,000 miles you quote is what they are rated at, so no surprise there. They are a 35psi tire, which hurts my FE a bit from the last tires that I had. I did some coast down testing last year and the Cd,Crr for my car came out to 0.28,0.012 at sidewall max pressure (before starting), and with tires warmed... I don't know what qualifies tires as LRR, but I think some tires get down to the 0.009 range.

I tried to get some 80,000 mile Michelin's, but they were only available at CostCo (and I don't have a membership). They were 44psi max, so I figured the extra pressure would offset the wider tire. They were almost exactly twice the cost of the Firestones, so the dollars per mile calculation was about the same for both.

EDIT:
Oh, and I think Basjoos has said that he sees increased FE with wider tires. He speculates that the reason is because he does such a good job deflecting airflow from in front of the tires. When you think about it, it makes some sence... for the same tire pressure, there will be the same amount of AREA in contact with the ground... this means that the thinner tire will have to flex more since it's contact patch is longer, where the wider tire flexes less.