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From: tim@ur-cvsvax.UUCP (Tim Takahashi)
Newsgroups: net.auto,net.auto.tech
Subject: Re: the art of tire selection
Message-ID: <260@ur-cvsvax.UUCP>
Date: Thu, 27-Feb-86 15:15:51 EST
Article-I.D.: ur-cvsva.260
Posted: Thu Feb 27 15:15:51 1986
Date-Received: Sat, 1-Mar-86 23:04:52 EST
References: <2097@dutoit.UUCP>
Organization: Center for Visual Science, U. of Rochester
Lines: 56
Xref: watmath net.auto:9616 net.auto.tech:844

> 
> Can someone explain what difference wheel/tire size makes to a car's
> 	
> 	acceleration
 A tire wheel setup with a smaller overall diameter will
  improve low-end acceleration (the engine runs faster)

> 	top speed
 If your car is red-line limited in top speed, larger o/d tires
 will improve top speed. If your car is power limited, smaller o/d tires
 will improve top speed.
 > 	road noise
 Road noise generally varies from tire make to tire make. One point - ultra
 high performance tires are not designed to sacrifice grip for a quiet
 ride.
 > 	economy
 Varies greatly from model to model.
 > 	road holding
 The wider the contact area, the better the handling both in acceleration,
 braking and cornering. However, the tires must be matched to the wheels.
 > 	handling 
> 	ride
> 	etc.
> 
> why and how much??!! 
> 
> Also what the different numbers mean:eg. 185/60 HR 14 80 H tires
> on 6 J x 14 wheels, alloy/steel etc.
>
 185 - the tire is appox. 185 mm. wide at its widest point
  60 - the sidewalls of the tire are approx. 60% as tall as the
	tire is wide.
  H  - european speed rating (slowest S-T-H-V fastest)
  R  - radial

  14 - designed for a 14 inch rim

  80 - load rating for tire

  6J - wheel rim (at the bead) is 6 in. wide
  14 - wheel rim is 14 in. in diameter

                               
> And are there any physical limitations on the wheel/tire choice for
> a given car?
  1) physical space in the wheel wells, 2) your sense of aesthetics and 3)
  your pocket book.
  
  >                    
> 	Shamim Pirzada				att_bl research!ssp
 
					       Tim Takahashi
					       (Mr. Volvo)
					       Ctr for Vis. Sci.
                                               University of Rochester
					       Rochester, NY