<VV> Temporary tyres

[Emperor Ming]

I read with interest the comments here regarding the advisability or 
otherwise of using tyres of the space-saver type as a viable alternative 
for daily use in place of those specified for any particular vehicle.  I 
am astonished that anyone would consider that these tyres would be 
acceptable when used in this manner.

In all cases that I have seen, these tyres are much thinner, and rather 
smaller in diameter, than the tyre they are replacing. The advice given 
by most contributors here regarding their relative lack of grip, 
propensity to wear more quickly, liability to damage certain 
differentials, handling and etcetera, is sage advice. Further, it falls 
exactly into line with the advice given by tyre manufacturers, and 
vehicle manufacturers; at least, that is the case here in Britain, and I 
have little doubt that the advice is virtually identical to that given 
to vehicle owners in the United States. And everywhere else, I'd think.

In Britain, when a breakdown service serviceman replaces a standard tyre 
with the owner's spacesaver/emergency tyre, a sticker is attached by the 
serviceman to the tyre warning in no uncertain terms that the tyre must 
ONLY be used at speeds up to 50 mph; and for no further than 50 miles. 
Additionally, when he or she fills out the "job" sheet, and before 
handing a copy to the car's driver, attention is drawn to a section that 
reinforces the 50 mph/50 mile stipulation.  And the car driver has to 
sign that form.

Does the 50 mile maximum distance stipulation pertain to protect drivers 
from differential damage because of disparate tyre sizes on the same axle?

On my wife's Mitsubishi, the spare tyre is very skinny, and smaller in 
diameter than the standard tyre. This is the case with all others that I 
have ever seen.  And the car sits low at that corner. Surely, it is 
plain as a pikestaff that these tyres are strictly for emergency use 
only; and that use in place of a standard tyre, at higher speeds and 
extended distances, is dangerous and extremely foolhardy.  So say the 
manufacturers of the things; and they, of all people, should know.

David Neale, Leicestershire, England. 1965 Monza 140 convertible with 
4-speed ... JR Read's old car.