[Top] [All Lists]

Re: Fw: Going to look at a '71 B tomorrow

To: <>, "MG List" <>
Subject: Re: Fw: Going to look at a '71 B tomorrow
From: Larry Macy <>
Date: Sat, 18 Dec 1999 16:02:57 -0500
Duh, I missed the obvious. I really meant an indentically sized diameter 
wheel, i.e a 13" or 14". However the example you site still makes the 
point about contact patches.

(Who live in PA and misses the snow in Wyoming. where I love to drive in 
the stuff all winter)

>>>>On 12/18/99 1:34 PM so and so ( said. (And I quote:)

>Can I toss in my $.02 here?
>Lets say you have a car that has 185/75/14 (just to pick a size) if you go 
>a 195/65/15 the tyre will have the same diameter.  This is called plus one 
>(One inch larger rim = shorter sidewall) If you then go to a 205/55/16 again 
>same diameter.  This is called plus two.  Go up one more size to a 215/45/17 
>plus three.  Now I haven't been to the tire store today, but I will be 
>willing to bet that at 215/45/17 is wider, and has a larger contact patch 
>(square inches) than a 185/75/14, yet they will have the same outer 
>This whole discussion reminds me of when I sold tires and a customer would 
>come in and ask for a 15 inch tire.  What size 15 tire I would ask, and they 
>would reply it doesn't matter.  So I would roll out a 165/15 VW tire and an 
>L70/15 tire for a caddie.  The look on their faces was worth it.
>(Who lives in California where we have lots of snow, but we keep it in the 
>mountains where we can visit it when we want to, we don't live in the stuff) 
>(gonna be 75 today)
>In a message dated 12/18/99 7:04:00 AM Pacific Standard Time, 
> writes:
>>  - I have no idea where you grew up and learned to drive but anyone that 
>>  thinks that wider tires perform better in the snow is asking for trouble. 
>>  Look at any snow tire anywhere and what do you find - A narrow tire with 
>>  an aggressive tread pattern. I am not talking about a worthless 
>>  "All-Weather" tire. I mean a real snow tire. A wider tire decreases the 
>>  weight to surface area of the tire. So that for the same weight car a 
>>  narrow tire has more of the weight on the tread than a wider tire. (PS I 
>>  also disagree with the concept that a wide tire of the same diameter has 
>>  the same contact patch than a narrow tire). This information is based on 
>>  reading, and personal experience. Try taking a RWD car with the factory 
>>  tires out in the snow. Take the same car with a wide "sport" tire in the 
>>  same snow. Wanna see the ass end in front of you real fast??? BTDT Wide 
>>  tires do not hold in the snow. Wanna go out in the boonies in the winter 
>>  to go hunting?? You will never get there in one of those 4x4's with the 
>>  fat tires. Unless you are talking balloon tires and that is a whole 
>>  'nutter concept of moving over the snow - not through it. Tread pattern 
>>  has more to do with the ability to move in the snow than any other idea. 
>>  Larry
>>  >>>>On 12/18/99 8:52 AM so and so (Allen  Hefner) said. (And I quote:)
>>  >In a message dated 12/17/1999 5:41:36 PM Eastern Standard Time, 
>>  > writes:
>>  >
>>  ><< Simple. It doesn't. They have the same contact area, just different 
>>  > length & width dimensions. More width x less length = same area.
>>  > 
>>  > Let me repeat: wider tires do not give you a bigger contact patch 
>>  > you also lower the tire pressure). They just change its shape. It just 
>>  > happens that the shape makes a difference. >>
>>  >
>>  >- - - - - - - - - - - - - - - - - - -
>>  >
>>  >Keep in mind that what we are comparing is two tires that are EXACTLY the 
>>  >same.  The same rubber compound, the same sidewall height, the same 
>> sidewall 
>>  >stiffness, the same tread, AND the same tire pressure, all on the same 
>>  >In that case, the contact patch will be the same area, even with 
>>  >width tires.
>>  >
>>  >Back to the real world.  Wider tires are of no advantage if they have the 
>>  >same sidewall height and stiffness.  They aren't much stickier (for 
>>  >competition use, at least) if they don't have a softer rubber compound, 
>>  >etc.  
>>  >So in the real world, narrower, taller tires tend to have a smaller 
>>  >patch area than wider, lower tires (that you probably bought to make the 
>> car 
>>  >corner better in the dry), and so they are better in snow.  
>>  >
>>  >Ok...back to LBCs.

Larry Macy
78 Midget

Keep your top down and your chin up.

Larry B. Macy, Ph.D.
System Manager/Administrator
Neuropsychiatry Section
Department of Psychiatry
University of Pennsylvania
3400 Spruce St. - 10 Gates
Philadelphia, PA 19104

 Ask a question and you're a fool for three minutes; do not ask a 
question and you're a fool for the rest of your life. 

<Prev in Thread] Current Thread [Next in Thread>