[Healeys] TYRE SIZE for RIM

[Eric (Rick) Wilkins]

Your info is on the right track (no pun intended) but not accurate in  
application.

The tire width is measured at the widest part of the tire, not the  
rim bead.

Example:
You quoted Beetle tire size as being 145 and 155. Beetle tires are  
165/SR/15 (same as a factory Healey in radials).

The rim size of 6" would be fit with a tire that is roughly 1" wider.  
185 is a perfect fit. As on my Healey with Minlite replicas at 6" wide.

Wilko
http://ewilkins.com/wilko

On Jul 3, 2007, at 8:06 PM, 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
> _______________________________________________
> wilko2 at cox.net
>
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