ssp@dutoit.UUCP (02/26/86)
Can someone explain what difference wheel/tire size makes to a car's acceleration top speed road noise economy road holding 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. And are there any physical limitations on the wheel/tire choice for a given car? Shamim Pirzada att-bl research!ssp
tohaapanen@watrose.UUCP (Tom Haapanen) (02/26/86)
In article <2096@dutoit.UUCP> ssp@dutoit.UUCP writes: > >Can someone explain what difference wheel/tire size makes to a car's > > acceleration > top speed > economy None, unless the overall diameter is different. In that case your speedometer will be off as well. > road noise > ride Better performance often means more road noise and a rougher ride. > road holding > handling Here the big differences. The improvement comes from a number of sourrces: 1. Wider wheels provide more support for the tire 2. Lower tire sidewalls don't flex as much 3. Stiffer sidewalls don't flex as much 4. Better compounds provide better grip 5. Aggressive tread provides better grip (not in snow!) >Also what the different numbers mean:eg. 185/60 HR 14 80 H tires >on 6 J x 14 wheels, alloy/steel etc. 185 / 60 H R 14 | | | | | | | | | | | --- Rim diameter | | | | --- 'R' means radial. Bias ply has no indication | | | --- Speed rating. V > 210 km/h | | | H <= 210 km/h | | | U <= 190 km/h | | | S <= 170 km/h (the last 2 from memory) | | --- Aspect ratio. 100 * (overall height) / (overall width) | --- A slash. Indicates that this is a tire. :-) --- Overall width. != tread width The /60 or whatever is optional; eg. 165SR13 is valid and indicates a 165/78SR13 or 165/80SR13 tire (depends on manufacturer). >And are there any physical limitations on the wheel/tire choice for >a given car? Yes. If it doesn't fit, you can't use it. :-) As in, if the bolt pattern is wrong, or the tire is too wide to clear suspension and fenders. You should also retain approximately equal overall diameter. This can be calculated as follows (in millimetres): OD = (rim size) * 25.4 + (overall width) * (aspect ratio/100) * 2 This is only approximate, though; the actual aspect ratio of a given tire will vary with the rim width (wider rims will 'spread' the tire and give a lower aspect ratio, lower OD, and better handling). An example of various tires with same approximate OD: 175/70SR13 on 5.5J13 205/60HR13 on 6J13 185/60HR14 on 6J14 (known as 'Plus 1') 195/50VR15 on 6J15 (known as 'Plus 2') As you go down the list, both price and performance increase... \tom haapanen watmath!watrose!haapanen I'm all lost in the Supermarket I can no longer shop happily I came in here for that special offer Guaranteed personality (c) The Clash, 1979
ugzannin@sunybcs.UUCP (Adrian Zannin) (03/11/86)
> >Also what the different numbers mean:eg. 185/60 HR 14 80 H tires > >on 6 J x 14 wheels, alloy/steel etc. > > 185 / 60 H R 14 > | | | | | | > | | | | | --- Rim diameter > | | | | --- 'R' means radial. Bias ply has no indication > | | | --- Speed rating. V > 210 km/h > | | | H <= 210 km/h > | | | U <= 190 km/h > | | | S <= 170 km/h (the last 2 from memory) > | | --- Aspect ratio. 100 * (overall height) / (overall width) > | --- A slash. Indicates that this is a tire. :-) > --- Overall width. != tread width [] In this example, the 185 is the aspect ratio, the 60 is the tire width, and the H is a designation of the tire sidewall height...I have a set of sport radials that are supposed to have a speed rating of 180 *mph* (they are Swedish tires too) and there is no other leter before the R that means radial... -- Adrian Zannin SUNY at Buffalo Computer Science ..{bbncca,decvax,dual,rocksvax,watmath,sbcs}!sunybcs!ugzannin CSNET: ugzannin@Buffalo.CSNET ARPANET: ugzannin%Buffalo@csnet-relay.ARPA BITNET: ugzannin@sunybcs.BITNET
junk@ur-tut.UUCP (Jan Vandenbrande) (03/17/86)
In article <2924@sunybcs.UUCP> ugzannin@sunybcs.UUCP (Adrian Zannin) writes: >> >Also what the different numbers mean:eg. 185/60 HR 14 80 H tires >> >on 6 J x 14 wheels, alloy/steel etc. >> >> 185 / 60 H R 14 >> | | | | | | >> | | | | | --- Rim diameter >> | | | | --- 'R' means radial. Bias ply has no indication >> | | | --- Speed rating. V > 210 km/h >> | | | H <= 210 km/h >> | | | U <= 190 km/h >> | | | S <= 170 km/h (the last 2 from memory) >> | | --- Aspect ratio. 100 * (overall height) / (overall width) >> | --- A slash. Indicates that this is a tire. :-) >> --- Overall width. != tread width > > In this example, the 185 is the aspect ratio, the 60 is the tire >width, and the H is a designation of the tire sidewall height...I >have a set of sport radials that are supposed to have a speed rating >of 180 *mph* (they are Swedish tires too) and there is no other >leter before the R that means radial... > > Adrian Zannin NO, the first message is correct. Jan
tim@ur-cvsvax.UUCP (Tim Takahashi) (03/20/86)
> I have a set of sport radials that are supposed to have a speed rating > of 180 *mph* (they are Swedish tires too) and there is no other > leter before the R that means radial.. Get out of here! Unless you own a Countach or a Testarossa with special Pirelli P7's (normal P7 are only worth 150 mph) your tires are NOT rated for 180 *mph*. A speed rating of 180 kph (~110 mph) is an SR rated tire, which is quite possible. Tim Takahashi