now if you paid much attention to bike
tech at all you will be well aware of
the huge push to wider ties and wider
rims now you might not be clear as to
why there's this huge push but that's
okay because we're going to dig in and
find out the reason we've been thinking
about this recently though was because
of the arrival of n B's new and really
rather lovely SES 4.5 aar disc wheels
the other day now at first glance they
are typically mb they've got the
different rim profiles front and back
and they're laced to Chris King hubs but
they're envies with a difference because
these are breaking new ground in a
really exciting way for start they have
a disc specific rim profile and then
they've also quite frankly that why this
rims I've ever seen on a road bike
measuring in a 31 and a half mil wide
width crucially 25 mil internal rim
width as well the design has only been
possible following a recent developments
in road bike design itself so the fact
that they are dis specific means that
they can be wide because there's no
restriction on rim width from brake
calipers and then again being dis
specific you can have much greater tire
clearance because again you're not
restricted by those brake calipers so
that is why we've been thinking about it
what about our initial question then why
this drive to wider tires and wider rips
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now one of the most intriguing but also
significant benefits is actually that
wider tires generate less rolling
resistance it's hard to know what we've
only really just gotten onto this bagg
given that rollin existence data has
actually been out there for quite some
time but nevertheless it is there and a
28 C tire is shown to roll 2 to 3 watts
faster on average than its equivalent 25
C tire and that is per wheel and at 40 K
now and the difference is even greater
on 23 and the reason or at least the
theory is that is because of the shape
of the tires contact patch and so that
as a tire gets wider the contact patch
gets shorter and that therefore improves
at the rolling resistance now what's
really important to note though is that
you need a wide rim as well as a wide
tire in order to maximize these benefit
because actually the cross-sectional
profile of the tire is really important
when thinking about that contact patch
shape but also the cross-sectional
profile is also important to minimize
deflection in the tire which is kind of
a little bit like that squirming feeling
that you get when you pressures are
really low because deflection means
friction and friction in this case it
means increase rolling resistance so
you'll see with this 28 C Schwalbe on
this wide entry rim which now actually
the time measures up close to 31 you'll
see the cross-sectional profile is
really square really well supported and
actually well rear that also means it's
more aerodynamic to now in a lab setting
using finely tuned equipment it is easy
to quantify these results but what is
becoming increasingly interesting is
actually testing out on the open road
spearheaded by bicycle quarterly they
pointed out that lab tests miss a
crucial aspect of riding and that is
vibration and it's the road buzz that
really slows us down and it's funny
isn't it because when we ride across
cobbles or pave it seems clear that the
jarring and the vibration is slowing us
down we can really feel it but why then
when looking at ordinary tarmac did we
not draw the same conclusions well
unfortunately bicycle quarter lead if
and when they tested it out
they found that a wider tire with less
pressure rolls significantly faster than
a harder one when we say less pressure
we really mean it I've got just 50 psi
in these 28 and the reason is because in
a lab setting a harder tyre rolls faster
because there's less hysterical loss so
that tyre deflection and the friction
generated that we just talked about
where as out on the open road those
losses are more than offset by the gains
made a reduction in vibration or what Y
School quarterly determing suspension
losses what you need to remember though
is that you stop letting pressure out
your tires when they start squirming
because at that point you're going to be
going slower again now I appreciate that
reducing rolling resistance isn't going
to be the be-all and end-all for all of
us but it seems pretty clear that a
fairly major benefit to reducing
vibration it's going to be increased
comfort for us Lacey you can run the
most comfortable frame in the world but
if you've got narrow hard tires on it
it's never going to be as comfortable as
a stiff racy frame with plush 28c tires
on it now that's not got you thinking
that wider tires yet I'm still not
finished wider tires give you more grip
when cornering now it comes back again
to that whole contact patch thing but
also a softer tire is more secure on the
road now I'll admit sometimes feel like
I'm getting a little bit old I don't
really want to test this one out
thoroughly
but even at my current speeds I feel
more secure leaning in
there is one other aspect to wider ties
there should be a tangible benefit to
all of us and that is puncture
resistance because a wider tire means
increased air volume which should mean
you're much less likely to pinch flat
even at lower pressures and then when
you add into the mix that these wheels
of designs we run tubeless well simply
pretty well insured against flats which
you find out
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now on comment that we see quite
regularly is why if why the ties are so
good a pros still running 25 and it's a
good point
pros tend to gravitate to whatever is
fastest so it must be downsides right
well firstly and foremost as I said
earlier you do really need a disc brake
bike in order to get baptized in gold
and so pros obviously can't use those
but then of course there's the fact that
wider tires are slightly heavier these
ones are about 20 grams per wheel
weightier than their 25 brothers and
then there's also the fact that there is
a slight aerodynamic penalty for wider
tyres admittedly it's really small on
these because they've been designed to
accompany wider tires but if you try and
fit a wider tire on a rim design for a
23 or 25 the penalties are much bigger
and then of course there is tradition
the pro peloton could sometimes be
described as being like an oil tanker in
there it takes them a very long time to
change direction we just witness the
amount of pros that are still not using
Aero bikes despite the obvious advantage
to them what tires are probably a little
bit like that it's gonna be interesting
though to see where this all ends up I
mean how fat are we going to go and who
is going to get onboard certainly
haven't seen the data it's hard to argue
with it so I think the future probably
looks a little bit better now if you
want to see a bit more information about
these wheels I'm riding and we've got an
unboxing video with just these very set
just up there but mitad Li you can't
winner anymore so apologies for that or
to see the out-and-out Guru behind MV
wheels in the wind tunnel click just
down there otherwise make sure you
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