"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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