[Healeys] TYRE SIZE for RIM

[Dave & M]

Hi Joe,

In theory you may be correct. In reality, with radial tires which many
folks use, the tread tends to sit pretty flat but the sidewalls are
very flexible & so don't lend much to tire tread stability. Also,
inflation pressure affects the tread flatness very little on radials.

Radials feel down right squirmy  & always look under inflated when
compared to the other designs. Once you get used to the handling
quirks, they DO work very well although they have a rather sudden
breakaway when they let go. Much more so than a non radial design.

Many race tires are not radial & your concerns certainly do apply to
them. Many of us just prefer radials for street use.

Regards,
Dave Russell

sebring at illawarra.hotkey.net.au wrote:
 > I am a little perplexed at yhe variety and range of poinions and
 > sizes that are being listed for Healey rims.
 >
 > The metric system is very easy to understand. ie. 185 in the
 > 185x70x15 size designation is the nominal cross section width of
 > the tyre as designated in the industry standards.
 >
 > Now 185mm is 7.2 inches, or between friends, 7 inch rim width. The
 > recommended rim width for 185 will most likley range from approx.
 > 6.5 to 7 and a bit.
 >
 > 185 on 4.5inch rim would be way outside the acceptable range, Far
 > too much bag in the side wall and the tread may not sit flat and
 > therefore wear uneven, brake less than designed and handling likely
 >  to be sloppy due to side wall flex. The tyre will not carry its
 > designed lateral load. Alternatively 4.5 inch would equate to a
 > tire size of 115 !!! The smallest I am aware of is 145 0r 155 as
 > used on Beetles of old -- now thats a handling benchmark
 >
 > Check any race car where handling and braking is optimised and the
 > width apart of the tyre bead should be very close to the tread
 > width which should match ( within reason ) the rim width.
 >
 > Looking good is only one small part of the safety and performance
 > equation. The best power, the best brakes, the best suspension are
 > only as good as that little contact patch so please optimise it.
 > Pressure is also part of the equation to control this contact
 > patch. The wear pattern is only an indicator of how much of the
 > tread face/contact patch is in touch with the road surface and this
 >  controls braking and roadholding.
 >
 > Joe