Fuelly Forums - '95 Civic CX HB with '93 VX wheelset-Tire Question

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cool, thanks.

here's the review of the 175/70/13s

Quote:

Originally Posted by theclencher (Post 77573)

You're welcome! :thumbup:

p.s. that tire in the pic looks reasonably ribby

Heh, well they advertise the tire as "reasonably low rolling resistance"

Yikes.
This thread is loaded with approximate unconfirmed old wives tales.

Wider tread does not make a larger contact patch.
Contact patch size is determined by weight of vehicle working against the tire's air pressure. So a wider tire gives a different shape contact patch but the area in sqare inches remains the same.

What does give a performance improvement - in practical terms - is a larger wheel diameter. Because to keep the same overall (outer) tire daimeter, you now use a tire with shorter sidewalls. Shorter sidewalls will flex less and so give you a handling improvement. Keeping the outer tire diameter constant is needed so that your speedo and odometers will be correct.

OK. Next.

All that above is only about handling. Handling affects fuel economy only in that better handling would theoretically enable you to control the car better. That's all, though that can be critical at some times.

Skinnier tire will give better fuel economy. I wouldn't get anything skinnier than whatever was stock, but I wouldn't go 30-40 mm wider either. Considering that many cars from early '90's still had pretty skinny tires, 10-20 mm. wider might be reasonable.

Rolling resistance has little to do with tire size. Has a lot to do with tire pressure and has a lot to do with rubber compounds and tread design.

More tire pressure = reduced RR. Most of us run our tires AT LEAST at "max sidewall", the spec you'll see on the tire itself. The car maker's spec is mainly for the comfort of your backside. Higher pressure also improves handling. Again, because the now stiffer tire will hold up better when stressed in fast cornering and braking. Also gives longer tire life, due to less flexing of the rubber. That flexing creates heat and stresses the material. Less flex, longer life, better handling, reduced rolling resistance.

Tire makers have avoided giving us standardized RR specs for their tires. Sorry. There's some information out there but very little, and much of the most detailed information is from '05, so the tire models have changed since then. Vote in some green liberal politicians, we might get more/better information that way.

Sorry for the rant.
Sorry too that I didn't give references.
Google searches can help.
Also tirerack.com has some tech information re. tires.

Quote:

Originally Posted by brucepick (Post 77810)

Wider tread does not make a larger contact patch.
Contact patch size is determined by weight of vehicle working against the tire's air pressure. So a wider tire gives a different shape contact patch but the area in sqare inches remains the same.

Maybe. The weight of the vehicle distributed over the contact patch of all four tires... The air pressure in the tire would distribute the weight of the car over the back of the tire's contact patch. If you increase the weight of the car, the patch's area would grow to compensate. But that assumes that the tire is infinately flexible. If you had no air pressure, the theoretical tire would have an infinately large contact patch unless the car had no weight.
In fact, the tire has structure in the form of steel and textile reinforced rubber. When you have no air pressure, the tire's structure still applies force to the road. Yeah, a wider tire may result in a wider, shorter contact patch, but I don't think it's area would be the same as the original tire's.

here's an email correspondence I had with the people at vredestein tire about the Quatrac 2. Thought I'd share with everyone:

-----Original Message-----
From: Jason Root [mailto:chesterules@yahoo.com]
Sent: Saturday, October 20, 2007 6:50 PM
To: info@tiresunlimited.com
Subject: Low Rolling Resistant tire

Hi, I am interested in buying the most low rolling resistant tire possible for my car. You have mentioned that the Quatrac 2 are a "reasonably low rolling resistant tire". Just how LRR are they? I was thinking of buying a set of four Quatrac 2 tires in the size 165/70/13. I am wondering just how Low Rolling Resistant the tire is? Do you have any comparisons or results from tests or some other kind of information on the LRR of the tires for me to read? It's very hard to find a LRR tire in this size! (Honda no longer makes the original LRR tire for the Honda Civic VX)

Thanks,
Jason

Jason,

You don’t have many options. In your size we have a Marangoni Trio and the Vredestein Snowtrac and Quatrac. The Quatrac is the only tire I will put on my car, my wife’s car, my three son’s cars and their wife’s and fiancée’s cars. Period. And it’s not because of the low rolling resistance but because it’s a world-class tire and I haven’t seen anything that can beat it.

Thank you,

Allen W. Rowe

Tires Unlimited, Inc.

How the hell is a snow tire LRR?

How the hell do you reply so fast? I think he's talking about the quatrac 2 which is all season and which is what I was referring to.

He also mentions some snowtrac tire besides that one, which I assume is a snow tire.

right, he does. But he says the quatrac is the only one he puts on his wife's car, not for LRR but for performance or whatever. He doesn't say snowtrac. He only mentions that there is a snowtrac tire.