Don Marshall wrote:
> I've never had a problem getting tires mounted, but I've had two occasions
> where the installer has cut the bead on a tire going onto a TR6 wheel.
This was not because of the below, but rather because the installer was
careless.
> Recently, someone explained that the TR6 wheels are "sided", meaning that
> the tires have to go on from one side only. Apparently, if the installer
> tries to put them on from the "big" side, the tire will bind and the
> machine can cut the bead getting it back off. It may be that modern wheels
> don't have this and some younger installers aren't aware of it.
With all due respect (very little necessary) to tire installers, the
above is absolute horse hockey. Next time anyone has a bare rim to
examine, measure the circumference and/or diameter of both sides of the
rim, measure the angle of the bead-retaining flanges of the rim, and one
will discover they are the same.
The reason why this is so is very simple. If one flange diameter were
smaller than the other, and the beads were able to be seated equally on
each flange, the tire itself would be distorted after mounting and
proper inflation, which would cause it to fail prematurely and would
also cause tread wear problems. But, such a tire/rim combination can't
be seated properly.
Quite simply, _all_ tires have two sides, both of equal diameter and
cross-sectional profile. An asymmetrical rim would create an improper
fit of bead flange to tire bead on one side, because the diameter of the
rim at the bead retention area and the diameter of the tire bead itself
would be mismatched.
Whoever told you this tale deserves a dopeslap.
Cheers.
--
Michael D. Porter
Roswell, NM
[mailto: mporter@zianet.com]
`70 GT6+ (being refurbished, slowly)
`71 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
`80 TR7 (3.8 liter Buick-powered)
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