Yes, nearly all car wheels are sized in inches, but for a short time
the xj40 used a metric rim size (390mm). As the tyres were only ever
made in this size for a couple of years of Jaguar, they are
ridiculously expensive, and only a few brands are available (Dunlop
SP100 Sport being the most common).
Metric tyres were fitted to many vehicles from 1980 onwards - BMW, Jaguar,
Vauxhall, Peugot,Audi, ferrari,saab, etc normally as an extra cost optional
extra on the performance variants.
I believe it will cost about the
same to change the rims for 15" ones and fit 15" tyres to suit as it
will to replace my metric tyres with similar, and I will be able to
get a better choice of tyres.
Phil Lee, Bordeaux '88 XJ40 Sovereign,
.157,000 Miles, Cambridgeshire, England.
I don’t believe it will cost the same. Wider choice yes, but I doubt you
will be able to get new alloy rims AND a quality tyre for the �120 price of
a quality metric Dunlop. Also remember that the design of a metric tyre was
different for performance and comfort reasons, it isn’t just a normal
sidewall shape tyre that has been made in an odd metric size to make life
difficult for us.The design of the tyre means it needs a different shape rim
and to prevent the tyre being fitted to ordinary shaped rims the size was
made different.
By all means change to imperial sized tyres but it will take 2 or 3 sets of
tyres before you can show a saving in money. I went for 16" rims when I
changed from metrics but I’ve haven’t finished the project yet so cant
comment on handling and ride changes but I’d be interested to hear from
people who have had metric and inch tyres of similar sections how the
handling and ride differed.
I don’t believe it will cost the same. Wider choice yes, but I doubt you
will be able to get new alloy rims AND a quality tyre for the 120 price of
a quality metric Dunlop. Also remember that the design of a metric tyre was
different for performance and comfort reasons, it isn’t just a normal
sidewall shape tyre that has been made in an odd metric size to make life
difficult for us.The design of the tyre means it needs a different shape rim
and to prevent the tyre being fitted to ordinary shaped rims the size was
made different.
By all means change to imperial sized tyres but it will take 2 or 3 sets of
tyres before you can show a saving in money. I went for 16" rims when I
changed from metrics but I’ve haven’t finished the project yet so cant
comment on handling and ride changes but I’d be interested to hear from
people who have had metric and inch tyres of similar sections how the
handling and ride differed.
FWIW I did the switch and DID save. Metrics were costing me 720 for a
set of 4. I switched to 15 inch alloys and paid 500 for a full set,
fitted and balanced. They aren’t Jaguar originals, I’ll grant you, but
on the other hand the choice was those tyres or no tyres - I just
couldn’t afford to keep up with the metrics!
I will say that there definitely seems to be a handling and ride
difference. The metrics seemed to eat up the road surface - very few
bumps made it through! The inch tyres definitely feel rougher, and the
car feels a bit less positive in the handling. If I could / can afford
it, I’m going back onto metrics. For now though inch tyres are my only
choice.–
Tal