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Toyota RAV4 pre-2006

2123 messages,  Last post on Aug 20, 2009 at 7:57 PM

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#1694 of 2123 by 719b Dec 07, 2004 (2:06 pm)
narrow tires have more weight per square inch to the contact point.
#1695 of 2123 Re: Tire Contact Pressure by capriracer Dec 07, 2004 (3:42 pm)
FYI:   Tire contact pressure DOES change with width.   To demonstrate: Let's assume you have several tires that have the same maximum load rating and are inflated to the same pressure. It turns out that these tires would have about the diameter overall diameter.   Now load them to the same load. Does it now make sense that the narrower tire would have a longer footprint? No! The overall diameter's are the same, and the deflection is the same, why would the footprint length be different?   Put another way, inflation pressure doesn't equal footprint pressure.   Hope this helps.
#1696 of 2123 contact point. by 719b by petl Dec 07, 2004 (6:22 pm)
In simple terms, I believe you have it. Thanks for jogging my memory.
#1697 of 2123 Wet traction by suvshopper4 Dec 10, 2004 (4:35 pm)
To repeat what I wrote back in 11/01 (just a couple posts before the dudleyr post that Steve_Host linked us to above), the way the magazine (R&T? C&D? Autoweek?) article described it was as follows:   A constant vehicle weight and a constant inflation pressure will lead to a contact patch that is the same area (total square inches), no matter what the tires' aspects are. The thing that varies is the shape or configuration of the contact patch (narrower/longer v. wider/shorter).   And narrower/longer is better in the wet stuff because it has to fight its way thru less of it, and disperses it out to the side of the tire better than a wider/shorter tire.   Net result: If you are more concerned about wet traction, the narrower tire is the better choice. Replies to this message: kdshapiro (Dec 17, 2004 6:13 am) suvshopper4 (Dec 17, 2004 4:21 pm) kdshapiro (Dec 17, 2004 6:22 pm) spleck (Dec 28, 2004 8:05 am)
#1698 of 2123 Re: unhappy fuel mialage [01rav4owner] by concept15 Dec 16, 2004 (3:50 pm)
Replying to: 01rav4owner (Dec 09, 2003 12:38 am) I agree. We love the car but get only 18-19city and 23 hwy. We have a 2004 Rav4 L type. I thought this is a little strange too.
#1699 of 2123 Tires, After Market Stereo by ravraptor Dec 16, 2004 (8:48 pm)
Just got new 2005 L package two weeks ago.   I like the car but the standard audio equipment sucks of course.   I'm having the speakers replaced with MB Quart components in front and Infinity's in back. Also installing an Alpine XM-Ready Head Unit CDA-9833, and a four channel amp. The Good Guys will be installing this Sunday. No issues with replacing the factory equipment Im told.   I am wondering if anyone can speak to the replacing the 215/70R16's tires with the larger 235/60R16's? If anyone has done this can they explain the difference in ride and handling characteristics? And can I keep my factory alloy wheels? The dealer gave me the Toyo Tranpath A-14's, which seem okay so far. However I may change at 15-20 K miles if the handing and ride is signifcantly better with the larger tires.   Thanks. Replies to this message: daniel6 (Apr 24, 2005 9:02 am)
#1700 of 2123 Re: Wet traction [suvshopper4] by kdshapiro Dec 17, 2004 (6:13 am)
Replying to: suvshopper4 (Dec 10, 2004 4:35 pm) My experience with 20 some odd years of driving in snow is this, I don't really care about the theoretical, here is the reality.   In snowy conditions, starting and stopping go to wide tires, handling goes to small tires. Agreed hitting a patch of deep snow from a dry road is much easier to navigate with narrow tires. Getting out of a deep patch on a steep hill is much easier with wide tires.   So since most of us don't drive around 24x7x365 in a foot or more of snow, wide tires are the better all-around choice. Replies to this message: suvshopper4 (Dec 17, 2004 4:21 pm) kdshapiro (Dec 17, 2004 6:22 pm)
#1701 of 2123 Whose reality? Re: Wet traction [kdshapiro] by suvshopper4 Dec 17, 2004 (4:21 pm)
Replying to: kdshapiro (Dec 17, 2004 6:13 am) "So since most of us don't drive around 24x7x365 in a foot or more of snow, wide tires are the better all-around choice." For you, maybe.   I agree with the first part, about not needing a tire for driving in the snow full time. But what about in the rain? Narrower tires are better for this too because they have to displace less water/snow than wider tires, as already explained.   And the better dry grip that is provided by wider tires, that matters more to someone driving a vehicle at 9/10ths of its limits. Doesn't matter much to me in my everyday driving.   As is often stated, all tires are a compromise. I'd rather have the benefit in the sloppy weather.   Narrower tires are the better all-around choice for me. Replies to this message: kdshapiro (Dec 17, 2004 6:22 pm)
#1702 of 2123 Re: Whose reality? Re: Wet traction [suvshopper4] by kdshapiro Dec 17, 2004 (6:22 pm)
Replying to: suvshopper4 (Dec 17, 2004 4:21 pm) I forgot emergency handling. The wider the tires the better the skidpad, the better the handling in emergency lane change situations.   To some, that may make a difference.
#1703 of 2123 Re: Wet traction [suvshopper4] and others by spleck Dec 28, 2004 (8:05 am)
Replying to: suvshopper4 (Dec 10, 2004 4:35 pm) The conversation is 3 years old, but it ignores a number of factors, enough to basically make it incorrect. Only changing the width of the tire will not help. Changing the sidewall height (larger rims), using better materials (stiffer sidewalls), and better tread patterns (contact tread vs water channels, etc) WILL affect the contact area.   In order for the contact patch to be the same regardless of tire width, all tires would have to be made of the same material and have the same sidewall height. Hence the original statement: "Wider tires don't have a larger contact area" is a very conditional one. Switching to a wider tire of the same material and keeping the same sidewall height (not ratio, actual height) will widen the contact patch and shorten it (even then, that ignores the fact that the tire will deform slightly differently due to its different shape and the tread pattern will probably be stretched width wise, but not shortened length wise).   Stiffer materials will cause the tire to deform less, decreasing the contact area and increasing the PSI applied to the ground. A shorter sidewall will also allow the tire to deform less with the same result. These are probably the reasons that you want a wider tire when you switch to a larger rim and sportier tires: you're making up for the lost lengthwise contact with widthwise contact. Hopefully you will also realize that getting a "stiffer" (sportier, etc) tire may improve handling, but unless the tread is better, you will lose traction (due to smaller contact area) and therefore lose braking ability and be easier to spin the tires.   If you still don't believe, use extremes to disprove:   Assume that tire rubber is in fact rigid steel. In this case the contact patch over a flat surface is a line the width of the tire. This is regardless of the pressure of the air in the vehicle. A wider tire will have a larger contact area.   Now assume that the tire rubber is similar to a balloon and is easily capable of elongation and stretching. At the same air pressure, the air will move to the top of the tire, elongating and stretching the tire leaving none at the bottom and allowing the rim to touch the ground. The contact area is only as wide as the rim, while the "tire" angles up from the edge of the rim.   How about a bicycle tire? The actual rim would have to deform to make the contact area long enough to match a tire 10 times wider.

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