"davek" <[email hidden]> wrote in message
"]news:[email hidden]...
Quoted message said:I presume that over-inflating will quickly
(catastrophically?) reveal if there is excessiev wear in
the rim, yes?
Spectacularly, potentially! When the CTC published guidance
on this, they suggseted wearing safety glasses, which
sounds sensible.
The funny thing is, that for all the countless rims I've
known to fail in this way when being ridden, I don't
remember anyone having one fail in a "critical" situation
(fast descent, e.g.). This can only have been luck (or
people who are about to use their bikes in such a way
checking carefully first), and I'd have thought that
increased heat caused by braking, and possibly sideloads
too, would make them more likely to blow in such situations.
I suppose that air pressure is *much* the most important
factor, and that since the sidewall is permanently under
load when the tyre is inflated the probability of failure at
The Wrong Time is low.
Quoted message said:I forgot to add my other reason for prefering higher
pressure - they seem
to
Quoted message said:run faster at higher pressure (tbh, I rather thought that
was the point of high-pressure tyres). It makes the ride a
bit 'harder', but not uncomfortably so.
Yes, it's certainly true that rolling resistance reduces as
pressure increases. However, this is not a linear
relationship; you gain a lot more by increasing from 70 to
80 PSI than from 100 to 110PSI. There comes a point where
the returns (speed) are not worth the payoff (punctures;
harsh ride). Nonetheless, if you're finding it works for you
at 120PSI, who am I to argue? I would recommend keeping an
eye on your rims, though (whatever pressure you run your
tyres at). Don't get paranoid, but do be aware of it. You're
probably okay with other brands, anyway - I always [1] found
Mavic far and away the worst for this.
[1] "Always" is not true, actually. Much as I hate to feel
that I might be becoming an "Ah, it wasn't like that in
my day..." type, I have to say that the Mavic rims of
the early 80s never suffered this problem, IME. I think
milling the sidewalls was the first step in the wrong
direction, but there may be other technical reasons
(alloy, attempts to save weight, e.g.) for the changes.
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