Functionalist answer:
The original factory size was a 145(/80)-13. (The "/80" is parentheses
because it wasn't stated.)
Theoretically the rolling diameter is: ((145mm * .80) x 2) + 13" = 22.134"
(or 562.2mm). I say "Theoretically" because there are differeces in actual
rolling diameter (especially with bias-ply tires, which change diameters
with tyre pressure).
Now you won't actually get right on the money with other tyre sizes, but
there are some standard sizes that are pretty close:
145R13 Same size tyre in a radial. Still available.
155/75 - 13 Does anybody make these? It is a possible size that I've not
seen. 0.5mm larger diameter.
155/70 - 13 Almost 1.5cm smaller rolling diameter. Not the best option.
165/70 - 13 Only 1mm smaller rolling diameter. Fills the wheelwells nicely
without rubbing.
175/65 - 13 4.5 mm smaller rolling diameter. Acceptable if you can get
them in the wheelwells.
I've been happy with Dunlop SP20s in 165/70 - 13. That's on a '77 Midget,
so the narrower rims on a Frogeye may make a difference.
Chris Kotting
ckotting@iwaynet.net
On Saturday, September 12, 1998 7:05 PM, Martyn Ridley
[SMTP:ridleymj@bis.on.ca] wrote:
> Summary: For those that skim read only!
> 1. What is rolling diameter for original Frog(BUG in US)eye Sprite?
> 2. Name a modern BRITISH radial that will fit
> 3. Reply please!!!!!!!
<SNIP>
>
> Cheers,
> Martyn
>
> It's the going, not the getting there, that's good.
> (Harry Chapin - Greyhound)
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