db. said:I'm still looking for a touring bent, but I've changed my mind on USS
and maybe a 26" front wheel. Is there a real benefit to wheel size? I
mean, to see people ride different sizes, you can see a pedaling
difference, but does it change the experience? When is a smaller front
wheel better.
Or rather, when is a small front wheel worse... Dr. Moulton proved long
ago that a small wheel fitted with a high pressure tyre and some
reasonable suspension will largely overcome the rolling resistance
advantages a bigger wheel has, and once you've done that a small wheel
is stronger, lighter and easier to design with because it takes up less
space.
A lot of the reason people prefer bigger wheels is because that's what
their impression of a "proper bike" involves. Riding my Brompton I get
all sorts of questions about how the small wheels must make it slow and
a problem up hills, as if you can't use gearing!
A 26" back wheel is easier to get a high gear for high speed on, it's
naturally about 25% higher geared than a 20" using the same gearing.
This is a bit of a moot point on a tourer, of course... Another
advantage from the gearing perspective of a 26" or 700c wheel is if
you're using derailleurs then the rear mech is significantly further
from harm's way getting banked on kerbs or other obstacles. Not a huge
problem, but something to be aware of when riding down over kerbs or
along rough tracks.
Other good things about 26"/700c wheels are a bigger and better tyre
choice (especially 26"😉 that is more easily available.
But none of those things really give a 26" a significant advantage to my
mind on reasonable roads, and if you've got good suspension not really
on rough stuff either.
OTOH a 20" front means it's easier to get a seat positioned so it's easy
to put a foot down. There's less likely to be overlap between feet and
front wheel. All else being equal I'd take a 20/20 over a 26/26. As it
is I ride a 20/26 and I ride it because all else is /not/ equal. I just
prefer the feel of the Streetmachine for relaxed touring to anything
else I've yet tried. I've never felt its 20" front wheel was a limiting
factor in any way, except that I have to carry 2 sizes of spare tube.
Finally, don't get hung up on paper specifications. Ride all the models
you can and get the one which puts the biggest grin on your face. My gf
rides a Nazca Fiero 20/20 for touring which on /paper/ she'd dismissed
as unsuitable, but a ride of it revealed it had the Magic X Factor and
we did a 300 mile tour including roads and tracks last year with full
camping gear and it was never a problem because it had 20" wheels.
Unless you're riding across a desert or something daft like that which
wants bigger tyres with knobbly tread I really don't see any huge
justification for going to 26 /unless you try out a 26 bike and it tells
you It's The One/. A lot of the current trend for "highracers" is, I
suspect, just a trend and a fashion.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/
