WMB Suspension Demystified - Nmad

The TRUTh AbOUT
LONG
TRAVeL
T
AVeL
SUSPENSION DEMYSTIFIED PART 3
Words: Guy Kesteven Photos: Callum Jelley
How much power does suspension soak up?
Would you actually be quicker without it?
n our first two instalments we
looked at what’s really going on
inside your shocks, and then how to
make these complex systems work
for you. Now we pull back and examine
suspension in general – specifically one of the
chief bones of contention. Does suspension
movement really rob you of power that could
be going to the trail? And if so, how much
‘efficiency’ are you losing? Are you in fact
better off on a hardtail?
We mixed science, sweat and three bikes –
zero, mid and long travel – with a bloody great
rocky hill, Strava and an HRM to find out.
i
The theory
On a smooth surface – such as Tarmac – a rigid
frame is clearly the most efficient device.
There’s no point wasting energy bouncing a
bike up and down instead of driving it forwards
if there’s nothing to test the travel on the way
back down the hill. In the early days of
mountain bike suspension – which included
poor or nonexistent damping, no ‘platform’
systems to firm up pedalling, high weights and
potentially large amounts of flex – there was
a lot of bouncing going on. Full suspension
has long been thought of as something to
benefit descending only.
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“The Nomad’s complexly curved
suspension arc drives over blocks
and scree with easy contempt”
But once you add the far more
sophisticated suspension of 2013
to rough, technical climbs, does that
popular idea still stand up? Can the
extra traction and energy-saving
smoothness of full suspension beat
the traditional ‘efficiency’ of a
hardtail on a real-world trail? We
already know full suss bikes can
descend quicker for any given level
of control, but wanted to find out if
they’re really so far behind on the
climbs, too.
The test
We took a tough climb – a 900m
avalanche of fixed blocks and loose
rocks – and three types of bike.
These are a 130mm hardtail, a
130mm full susser and a 160mm full
susser (see right for more details), all
from Santa Cruz. Bike weights are
within a pound of each other, and
the rider each time is the same –
me, Guy Kesteven. And this is a
climb I’m familiar with, to avoid
times changing due to me
learning the hill.
There’s justification for launching
any of the three bikes at our
challenge first, but eventually we
decide to leave the theoretically
more efficient and fractionally
lighter hardtail till last, and use the
bump-absorbing traction of the
Blocks and loose
rocks added to the
test climb challenge
Nomad to cope with unseen
obstacles first.
LONG TRAVEL FULL SUSSER
The big carbon beast gets off to a
bad start. The loose, rocky, ridged
doubletrack start is a line-choice and
traction challenge at the best of
times, but I’m still gutted when the
rear shock (which I’m running fully
open) sinks and lets the front end lift
under power. Suddenly I’m sideways
across the trail, foot down and
swearing furiously just 10m from
the start…
The Nomad feels slightly soft as I
grunt the big ring along the flatter,
smoother pull towards the next big
challenge. At 300m the trail
channels into a steep 1:5 to 1:4 gully
that’s always wet and full of big,
loose boulders. It’s normally a case
of dropping to the inner ring,
snaking round as many of the really
big rocks as possible, then making a
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The bikes
We borrowed sample bikes from Stif
in Summerbridge (www.stif.co.uk)
just south of our target climb, choosing
26in-wheeled machines for
circumferential consistency across
the 0-160mm travel range.
Knowledge
The efficienT
hardTail
We rode the versatile Santa Cruz
Chameleon R hardtail (£2949) in its
most basic complete build, but
upgraded to a Fox 32 Float CTD
130mm fork. Weight 28.6lb
The big, bouncy
full susser
Our long-travel bike is the
all-singing, all-moshing 160mm
Santa Cruz Nomad Carbon XT
(£6235). Kashima gives ultimate
smoothness to the Fox shocks at
both ends. Weight 29.7lb
lunge across a couple of unavoidable
blocks onto a thin, smooth offcamber slope on the left. The Nomad
swallows the rocks without a hiccup
– but then I make a dumb choice.
Rather than trusting what it just
told me about rocks not being a
problem, I try to keep it high on the
side of the gully, but steering
wander and wet mud spins the back
wheel. Cue more swearing as I scoot
back across onto the firmer footing
of the rocks. Being clipped in and
crushing the pedals, the Santa
Cruz’s complexly curved suspension
arc drives over both blocks and loose
scree with easy contempt. A short,
flatter section reloads the legs for
some treacherous S-bends with their
mix of rounded slabs, loose cobbles
and a steep-stepped top. Knowing
the bike’s strengths now, I hold it as
straight as possible, keep power
delivery smooth and let the
suspension suck up the
The Trail-ready
middle ground
The alloy Santa Cruz Blur TR XT
(£4909) gets slackish, lowish trail
angles, Shimano XT-kit and an
upgraded Kashima-Fox shock and
fork. It rocks 130mm up front
and 125mm at the rear.
Weight 29.6lb
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“The slightly more supportive character
of the Blur’s shorter suspension
keeps things more controlled”
stoppers. I heave onto the moor top
with a riding time of 7:36 and a
stopped time of 0:20 – so a total
of seven minutes and 56 seconds.
My average heart rate is 151bpm,
and my average output stands at
170 Watts.
The wider bars of
the Blur TR helped on
the climbs too…
SHORT TRAVEL FULL SUSSER
Next it’s the 125mm rear, 130mm
front Blur TR. The slightly more
supportive character of the shorter
suspension – plus noticeably wider
bars – keeps things straighter and
more controlled up the first section.
The next flatter section still feels
like a trudge with second-attempt
legs, but there’s enough travel to
cope with bigger rocks, and I learn
from my last mistake and put my
faith in the suspension. With only a
The direct-driving
hardtail feels the
fastest up the hill,
but does the
clock agree?
brief swerve onto the soft side, I
drop back into the rocks as soon as
possible… By the time I reach the
S-bends I’m still dab-free, but
breathing hard.
Then idiot disaster strikes! I
spin the rear wheel on a big smooth
slab I hadn’t even registered as a
potential issue. I’m back-pedalling
immediately and storm the final
section, thoroughly enjoying the mix
of poised pedalling and blithe
ignorance to lumps and steps. The
lack of significant stops has pushed
my heart rate slightly higher to
158bpm, but average wattage is
close to the previous run at 173W.
There’s no doubt the shortertravel TR is faster at just 7:25 for the
climb, and it felt easier too.
THE HARDTAIL
A pinch flat before we even start
means the Chameleon gets off to a
really bad start, despite a tiptoe
pace. Tube replaced, pressure
restored and riding position tweaked
to mimic the other bikes, I roll onto
the climb with the direct-drive
advantage clear in the first few
meters. I’m really having to move
about to nurse it over the bigger
lumps without losing traction
though, and it’s a big relief to lurch
onto the smoother intermediate
section without dabbing.
There’s no suspension bob
when pedalling out of the saddle
towards the gully, but the rear
tyre is rimming out despite a
reasonable pressure. I’m trying
to be smooth but the pedal
The eNGiNe
Tester Guy Kesteven has been pitting
himself against Scar House climb for over
two decades. We based testing on an
average sub-maximal 150bpm effort
level, recorded via Strava’s Premium app
on an iPhone 4 with Wahoo Blue SC heart
rate belt, for segment comparison and
nominal wattage data.
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The hiLL
In Moor Lane is a 900m long, 92m-elevation
climb running south east from Scar House
reservoir up to Middlesmoor top in Nidderdale,
North Yorkshire. 1 in 10 doesn’t sound too bad,
but it peaks at steeper than 1 in 3 in places, and
the often loose, cobble or block-rock surface
is a gruelling test of traction, torque and
tenacity. Frankly, you’re having a
damn good day if you clean it at
all, whatever bike you’re on.
stroke is really choking on every
rock, so I switch high and risk the
smooth but muddy line. It pays off,
just, and I lunge over the rocks at
the top. There’s a quick respite
before the S-bends, but while my
breathing might not be so strained,
my balance and traction-finding
skills are working overtime – I’m
pedalling squares trying to lever the
rear wheel up and over lumps.
Given the number of near-miss
moments I’m not surprised when it
finally hangs up too hard to get
moving again on the rocky, steppy
The high BB of the
long-travel bike
actually helped it
climb in some spots
final furlong. With momentum lost
it’s a real struggle to find enough
smooth-rolling space to get going
again, and I stumble the last 100m.
The end result is 7:54 of riding, 0.25
stopped for a total climb of eight
minutes and 19 seconds. My heart
rate is lower at 148bpm, as is my
average power output at 165W.
The results
The fact the hardtail was so much
slower, but also lower for power
output, was a genuine shock. The
Chameleon felt the fastest and
hardest, and that’s probably because
every rough section was a real
struggle. Cross-referencing the
runs, the time lost even in the first
section was a real surprise, with
the gully and then the final section
all significantly slower. With
momentum lost, it didn’t even pull
much time back on the 160mm
Nomad on the flat.
The rest of the day we play about
trying to find the optimum climbing
setups for each bike. Tyre pressure
is dropped as low as we dare for
less rattle and more traction on the
Chameleon, but it’s still a skillintensive ride – and still slower than
the others. In contrast we increase
shock pressure and compression
damping on the Nomad to stop
wallow and keep the nose down, and
it makes a big difference, closing the
gap noticeably on the TR. In fact, at
some points the extra travel and
higher ground clearance get us over
big steps more easily.
Yet even this can’t compete with
the ‘just right’ middle ground
represented by the Santa Cruz Blur
TR. Its low-slung, wide-bar
character makes a far bigger
difference to what is or isn’t rideable
than suspension travel does, and it
beats the firmed-up Nomad and
the supposedly ‘efficient’
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TURN YOUR
bOMbeR iNTO
A CLiMbeR
Whatever bike you run, you can tune it
to climb better than ever. Here’s how
What can you do? Look
ahead to go straight and
increase the time you have
to react. Tear your eyes from
close rocks, or you’ll stall
as soon as you touch them.
If there’s no compression lever,
increase shock pressure in 5psi
increments until obvious
bounce is reduced.
Try reducing pressure so tyres
can conform to the surface –
grip beats low rolling
resistance.
Concentrate on pedalling circles,
pushing evenly all the way round
– avoid stomping or pulsing.
Choosing a gear midway between
crazed spinning and knee-blowing
grind will enable this, and let you
feel for grip through your pedals.
Slack angled, short-stem bikes
wobble at low speeds,
especially pointing uphill. Keep
a big travel bike as straight as
possible and let the suspension
climb over lumps, rather than
trying to dodge around
and losing balance.
For maximum power and
traction, pull back and down
on your bars, elbows low,
to pull your weight down
onto the back wheel.
Kill excess bounce by adding low-speed
compression (blue dial) or engaging ‘Trail’
on Fox CTD shocks. Don’t lock it out
completely (or use ‘Climb’) on anything
but totally smooth surfaces.
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hOW We
LeVeLLeD
The FieLD
“A hardtail just can’t put
all that direct power down
on challenging surfaces”
Chameleon when sessioning any of
our test climb’s tricky sections.
Final reckoning
All this makes the TR the clear
choice for one last attempt at a
full-power assault, just to check
it wasn’t my dying legs that
influenced the Chameleon’s
disappointing time. The result? A
clean run with no dabs and a 7:04
complete time, at 158bpm and
183W averages. It’s still an
undoubtedly challenging run,
but it’s way more controlled than
it is on the Chameleon.
In other words, sorted handling
and a middling amount of
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With the climb dealt
with there was the
descent left to enjoy,
before doing it all
over again...
suspension is king of the off-road
hill. A hardtail just can’t put all that
direct power down on challenging
surfaces – so much so that even an
‘inefficient’ long-travel bike beats it.
Our rudimentary trail lab proved
that even six inches of travel can
contest the climbs if it’s set up right.
Perhaps we shouldn’t be so
surprised, given the popularity and
success of such ‘big’ bikes in enduro
racing. It’s worth noting that we also
took the Blur TR to within one
second of the Strava KOM for the
descent on the way back home too.
Bottom line? For off-road climbing
efficiency, overall speed and carefree
descending fun, full suspension wins
every time. WMB
To make the test as much about
suspension as possible, we equalled the
rest of the metrics as much as we could.
All three bikes are from the same brand,
and ran on the same Maxxis High Roller
26x2.35in tyres. All were run at the
same pressures for the initial timed
runs. While the forks were inevitably
different, gearing was identical on the
suspension bikes, and the cockpits were
similar too. The full sussers shared the
same VPP2 suspension systems running
at the same sag, albeit with different
travel and linkage architecture.
By using a lower-spec hardtail and a
carbon framed long-travel bike we were
able to get weights within a pound of
each other without even ballasting
them. The only disparity was price,
which was irrelevant for this test.
The other options
We concentrated on equalling weight for
‘scientific’ reasons, but for most of us,
direct price comparison is more
relevant. If we’d equalized price with
the Nomad C we’d have been riding a
Highball carbon 29er with SRAM XX1
and ENVE carbon wheels (£6499) or a
2lb/900g lighter Blur TR Carbon frame
with SRAM XX1 equipment.
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