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00:03
i think you'd struggle
to argue against carbon fiber being the
ultimate
frame material at least in performance
terms i mean it can be incredibly light
super stiff amazingly compliant
and bonkersly aerodynamic there are
though of course
stacks of other frame materials out
there from which you can build
brilliant bikes steel titanium aluminium
magnesium and then there's also wood
now i have seen wooden bikes before at
00:36
bike shows and the like
but i've always kind of thought they
were a bit of a novelty item
but are they today is the first day i'll
ever have been actually able to ride one
and i cannot wait
to find out what it's like
[Music]
01:13
this is a tumpus cycles gr1
and the frame as you can clearly see is
made
out of wood but this is no delicate road
bike built for nursing along smooth
tarmac this
is a gravel bike now it's made out of
ash which is a hardwood
actually one of the strongest out there
about on a par with oak
but a lot lighter so this frame weighs
just
1800 grams yeah that is considerably
more
than carbon but about on a par with top
end steel
and unlike both of those other materials
01:45
this one treads far
lighter on the planet it is of course
completely sustainable
and it requires a lot less energy to
manufacture
now before i get to take this for a spin
and see just how it feels to ride
fortunately for us
the owner of tumpur cycles has delivered
the bike
in person so i'm gonna go grill him now
and find out
just what this is all about andy you are
a lifelong cyclist right
engineer by trade furniture maker of 20
years
if i'm correct that's right so as
02:16
qualified as anyone to make a wooden
bike but i guess the question is
why why would um it's not the obvious
choice for a bike frame is it
i'm a woodworker and an engineer and a
lifelong
bike enthusiast and an opportunity arose
i had a conversation with
a furniture potential furniture customer
he previously had written a book about
bikes
it's all about the bike i think was the
name of that book i thought maybe we
should build
02:47
an ash bike in the end his publishers
didn't agree
the the publishing deadline was looming
uh we'd
never built a bike before and we built a
piece of furniture but in my mind
there was the idea for building a bike
out of ash and what's an idea
is in your mind if you're a maker then
it tends to stay there and so it
happened over a period of about two
years i built myself an ash bike
it was a purely personal project it was
never intended
03:17
as a business or as something for
for anyone else until i started riding
it
and then i became slightly
some people would say overly evangelical
about it so how's it compared to another
material like a steel or
or a carbon fiber in terms of the
strength of it
and the density of it so
it does offer different properties a lot
of the properties
of a frame as you will know are in the
design of the frame itself in the
03:48
geometry
of the frame not necessarily in the
material
wood has unique properties
at a micro structural
cellular level the the cellular
structure of wood is essentially
a vast complex of
spring damper combinations so
this frame is made up of a large complex
of micro suspension systems
04:20
and that has the effect of
damping the vibrations which come
through the road
and into the frame
first impressions well my very first
impressions actually were that
it feels it feels kind of normal
in the sense that having spoken to andy
04:56
at length
about this bike i still have this
preconceived
idea that it would feel like a wooden
bike
but yet it doesn't if i couldn't see
where i was on
it would be a normal bike
now to give you a visual illustration of
it one of the first things i do when i
get on a new bike
is the shakedown test which is
completely unscientific
not even very objective but i give the
handlebars a little shimmy
05:27
just to see what kind of torsional
stiffness
is in the front end of the bike and this
one
is totally within the realms of a of a
metal
bike or a lightweight carbon bike
so on a stiffness perspective
it definitely doesn't feel
it doesn't feel weird okay ready three
two one go
[Music]
that must be at least 600 watts
06:04
and what about the kind of the stiffness
and and the density
of it compared to perpetual steel so
1800 grams
for a frame yeah it is comparable to a
top end steel frame
but how strong is it in comparison well
obviously
the density is a lot lower than steel
and that means that you can
you can use a lot more of it without
exceeding the weight of a steel of a
piece of steel so the wall thickness
06:35
on these tubes varies between five and
six mil depending on whereabouts
it is um obviously as steel um
steel frames you're looking at sort of
0.5.8
that kind of thicknesses so if you have
a steel tube
and a wooden tube you can have a lot
more
wood in other words your wall thickness
can be a lot thicker the diameter can be
a lot thicker
for the same weight for the same mass of
material it has a greater strength to
weight ratio
and when you combine that with turning
07:06
it into a tube that magnifies that
effect
again so it's a it's a very suitable
material for building
uh bike framework which are essentially
choose
what then about these famed vibration
damping qualities
i've got to put a big caveat here and
say these are completely my first
impressions
i'm also using gravel tyres on here
well admittedly i've got 60 psi in them
but it definitely feels
07:37
very kind of quiet like
i mean audibly quiet but also
in terms of vibrations coming up through
the bike
now one way though that it does differ
quite significantly from
carbon fiber is what you'd call
compliance
which is kind of different to vibration
damping it's it's in a more pronounced
flex
and i guess that's one thing you can't
engineer
into a wooden frame or at least not at
this stage
whereas with carbon fiber you stick a
08:09
d-shaped seat post on there
and you can actually visibly see it flex
or some frames
have it designed in to the seat tube and
the seat stays
even up to 20 millimeters of movement so
whilst
you've got this whisper-like vibration
damping
it is perhaps more in line with
a metal bike like an aluminium bike or
titanium bike in terms of the compliance
which is not a good thing or a bad thing
08:41
it's just what it is i guess
so if you go crashing through potholes
you kind of
you can kind of you feel it but the sort
of
finer vibrations that come out from
rough surfaces
like gravel or uneven tarmac
they're just not there as much
managed bonkers i'm riding a wooden bike
[Music]
so so how is it actually made then like
the fact that it's hollow i guess i
probably should have guessed but
09:16
i mean i can see joins i can see like
is it like built in a modulus system so
it doesn't start these don't start as
tubes
and surprisingly they don't grow as
tubes um
the front triangle of this bike starts
off as
two triangles of jointed planks
jointed together with this jigsaw
joint here which locks those very firmly
securely the end to end
those are bonded um with epoxy
09:47
the planks are also laminated so that
the joints
are staggered to give so they
effectively reinforce each other
most of the machining is done on a cnc
router
the front triangle starts off then or
becomes two
machined half shells which are then
bonded together along the center line
and then
after that the rear triangle the seat
stays in the chainstays are bonded on
chainstays are laminated out of six
10:19
pieces of
of ash which is form on a former to give
us the curves that we need
they come together then at this end in
a non-wood component which is been one
of the most challenging aspects
actually of building a wooden bike which
are the the dropouts
is the is the design of the bike the
shape of the bike
a product of the properties of the wood
or have you got a bit of flexibility
in terms of the look i mean could you
for example make an aero
wooden bike by sort of tailoring the
10:50
tubes making them into aerofoils
you could do there's no reason that the
tubes need to be round
they will lose some strength if you
change the profiles because you start to
introduce stress concentrations
a circular profile has no point on it
that wants to act as a stress
concentrator if you start to focus
into into pointed sections then you do
start to create slight stress
concentrations but these are over
designed
and it's very easy to over design it to
to make sure that's not a problem this
11:22
this is intended as a gravel bike
and as such i anticipate heavier loads
greater impacts and things on the frame
if i was designing a an aero bike i
would
be able to reduce the sections slightly
of some of these members
and yes change the profile so they don't
need to be
circular section that's pretty cool so
actually you've kind of got almost the
same degree of flexibility as carbon
fiber
potentially in terms of shaping and yeah
yes you do yeah there really is
i mean there really is very little
11:52
limitation in the shape
as long as you're putting enough
material in the right places
um and you're joining the different
components the different elements of
timber uh in in the correct way yeah the
shapes are
shapes are hugely variable what you are
always going to be left with
is the need to sweep
these radiuses here
again the same about avoiding
sharp changes of direction which cause
12:23
stress concentrations
here we've got these smooth curves which
are avoiding those
stress concentrators so that's a detail
that i would
personally always want to maintain on a
design
[Music]
sorry i couldn't help myself it's a
gravel bike after all
i had to venture onto some gravel and
12:53
actually i'm really glad i did
definitely adds a whole new dimension
into that vibration damping quality
and it's best illustrated by the fact
that the front
and the back of this bike feel quite
different
in that the back of the bike is really
forgiving
and it does absorb the kind of the
gravel the bumps coming up from the
trail
whereas this fork which is an envy
carbon fork absolutely
top quality fork definitely still feels
like
it's translating more vibration and
that's partly because i've got the tyres
13:23
pumped up to 60 psi because i've been
riding around the road
but the back doesn't feel like i've got
60 psi in it feels like i'm running
about 35
which is a pretty significant difference
and testament
to the to the wood i guess what more can
you say
and like carbon fiber if you change i
don't know like the the grain of
of the wood or the direction you know
can you change the properties of the
bike or are you fairly
fixed in terms of you know wood is
obviously super strong in one direction
and
yeah you're right you're absolutely
13:54
right one of the one of the biggest
challenges
designing with wood is that wood is
great has a great strength and tension
along the grain
it's great bending as long as the grain
runs that way it will bend it's very
stiff
that way but as soon as you start to go
across the grain
that's when you get splits so designing
with grain in the right orientation is
absolutely crucial
so have you got the lateral stiffness
then if you've got the grain going down
14:24
the down tube like that
to mean that it's strong enough how do
you resist
torsional that's where the oversizing
right comes in
um and the and the wall thickness
because you're right
picking up on that is something that
very few people have done actually um
so that that twist um is something which
uh other manufacturers of wooden bikes
have uh
have used carbon internal
uh a layer of cardboard internally it's
just cheating which does seem like
14:55
cheating to me
well it's not cheating i mean you know
every way of building a bike is
legitimate
yeah when you did point out i wanted to
build a wooden bike and i don't think
there's any need for
um for carbon in there no and so far uh
i think i'm born out in in that belief
and what about
the toughness of the material i mean how
resistant is it to
to knocks and damage i mean could you
put a dent in it for example
you could dent it i'd rather you didn't
uh
that's all right yeah there's been a lot
15:25
of product testing
there's been a lot of uh a lot of hard
riding although of course most dents
don't tend to come
when we're riding our bikes most dents
come when we're taking them in and out
of cars and things like that well that's
it or if you lay it down on some
particular yeah
exactly the the ability to absorb shocks
which we've discussed before
also means that um makes that makes it
more resistant to
to um to denting so whilst of course
yeah you could damage it
um you could bang it it is more
resilient
15:55
to knocks than probably other frame
materials
now i'll confess until today i had never
thought of wood as a performance
material
i know humanity has made and continues
to make
incredible structures from it but to my
mind in a sporting context
wood has always kind of meant blunt
instruments like
bats and clubs and sticks
but here i mean firstly the scales don't
like 1800 grams per frame
16:31
is 1800 grams for a frame and it's not
nudely
so maybe my prejudice about wooden bikes
stems the fact that there just haven't
really been any and perhaps more to the
point
there haven't been any in pro racing
which for me and i suspect a lot of you
too
often serves like the barometer of
success
and credibility i've got no romantic
visions
of a pro cyclist dancing up maul von 2
a stride a wooden bike but that's not
actually what bike riding is to
17:02
well probably virtually all of us yes
performance really matters but
owning a bike is an emotional thing
and that emotion might come from knowing
that you have the fastest
or the lightest bike but it's also about
the look of it and the feel of it
and the the craftsmanship and the ethos
behind it and perhaps
yeah even the fact that it treads a
little lighter
on the planet certainly from talking to
andy
that side of things is really
17:34
interesting so he was explaining how
a ton of processed wood contains within
it about
five or half a tonne rather of carbon
whereas to make a ton of titanium
releases
about four and a half tons of carbon
into the atmosphere
so while it's small-scale stuff
that can really matter to an individual
and increasingly i think
it should matter to an individual what's
the future for
18:05
tumpur cycles then andy said
at the minute production is limited to
about 30 frames a year but he's
confident that it's scalable
until they can and hope to make more
than that
both stock sizes and also completely
bespoke
frames as well it's a premium product at
the minute
it's about 3 000 pounds or euros for the
frame
but you can certainly see
18:36
the time and the effort that goes into
making them
can't stop looking at it
[Music]
well hopefully andy's not gonna mind if
i don't bring his bike back for another
hour so
quite frankly i want to spend a bit more
time on it before i hand it back
be very interested to know what you
think though take part in our poll
over on the gcn app wooden bikes hot
or not would you ride one would you buy
one
please make sure if you enjoyed this
19:09
video as well that you give it a big
thumbs up
right i'm gonna do a little bit more
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