- The Scott Genius has always been designed to be
a very versatile bike.
And this is the latest edition,
it's had a full frame re-design, but one of the really cool
features about this bike is that you can swap out
the two different wheel sizes really easily.
So in this video I'm going to try the 27.5 wheels,
swap them out for 29,
and let you know how it feels on the trail.
How it actually changes the ride characteristics of the bike
How it stacks up against the clock, and ultimately,
try and decide which ones I prefer the best,
but also give you guys, hopefully, a bit of an insight
as to how it affects the characteristics of this bike.
But first, let's get back to the workshop
for the nitty gritty.
- Right, let's start off with some facts
in the workshop about these wheels,
The 27.5 wheel has a two-point-six inch tyre,
the 29er has a two-point-four.
Let's start with the weights, so the 27.5 weighs in
at 1.87kg and the 29er weighs in
at 2.12, so a 25g difference.
Don't forget that's just for one wheel
so when we've got a pair of 29er wheels you're actually
going to be 50g heavier.
Don't forget, that's actually rotating mass
so that does make more of a difference than just
static mass on a bike.
So I'd expect I'm going to be able to feel that on a trail,
and I'd expect the 29er to actually sort of
plow through rough stuff a little bit better
and carry its speed a little bit better
but be a bit harder and slower to accelerate and decelerate.
The two-point-six inch tyres on the smaller wheels of course
are wider than your average mountain-bike tyre
getting into those 'plus' sizes,
but also they're deeper and that will make a big difference
to how the bike feels.
It's about ten millimeters deeper, so when we talk about
the whole diameter of the wheel,
it's about a 20mm difference
so it's 20mm bigger on the 29er.
That does mean that the angle of attack,
when you're rolling over bumps, is going to be lowered
on the bigger wheel so it should roll over those bumps
a little bit faster.
Let's talk about tyre pressure as well,
on the plus-size tyres you'd get away with running,
I find, a couple of psi lower
because of that extra volume of that tyre,
you can get away with running slightly higher pressures
on the bigger wheel.
So from those numbers, I think on the trail
I'd expect the 29er to feel heavier, feel smoother,
but harder to start and stop.
The 27.5, I would expect a bit more grip
because of that wide tyre,
I'd expect the bike to feel a little bit more lively
and be able to change direction a little bit easier
and stop quicker.
So how do the wheels actually
affect the geometry of the bike?
So let's look at the head angle first,
it's slightly slacker on the 29er, 65 dgerees vs 65.6
so not a huge amount.
Bottom bracket is going to change slightly
so it's six millimeters higher on the 29er
so it's not going to corner quite so well,
but you do have more clearance
for peddling through the bumps.
The big one here for me I think,
is going to be the BB offset.
So you've got a seven 7.5mm more offset on the 29er
so it feels like you're stood sort of more down
and into the bike on the 29er.
That definitely helps for trying to get through the bumps,
you're going to drive that bike a little bit better.
Okay, enough of that chit chat in the workshop.
Let's do the fun part.
So, I've been riding this bike with the 27.5 wheels
for probably two or three months now.
It feels great, it feels like you can get
really rowdy on this bike, really aggressive down the hills,
it doesn't feel like a true sort of 'plus' bike to me
so a 'plus' tyre could find the biggest disadvantage really
is in the mud, where they float, they don't really dig in.
It doesn't feel like that on this bike.
The tyres are 2.6" but the treads are evenly spaced ,
they clear the mud, it digs in, it feels like
an aggressive little bike.
So it's time to try out the 29er wheels
and I've not tried them in this bike yet,
so I'm excited to stick them on, see how it feels.
I actually raced a lot of Enduro on 29er wheels,
so I think this bike, could work really well
150mm travel, great for British Enduros, not quite EWS
you might want a little bit more travel for that,
but for my style of riding
I think this could be a rocket ship on 29er wheels
but I'm looking forward to trying them out.
So I've got a set of 29er wheels set up with tyres,
both are tubeless by the way, so it's actually really simple
to swap just the cassette and discs over.
So realistically, you could have two sets of wheels
for the same bike and swap them over as you please.
Cassette is on, time for the rotors.
One final thing to do is just flip the chip.
The chip has been flipped, the wheels are on
and don't they look big.
Actually I can see a lot of wheel
sticking out in front of me, the tyres are quite narrow,
I'm back on 2.4's now, so, let's go give them a ride.
Right, I've put a time in on the big wheels now
and it felt good, it felt like a really consistent run,
felt like 29ers always have done for me
when I've raced in Enduro.
So on the stuff at the top where
it's quite a mellow gradient
but it is a bit chattery with bumps,
it felt like I was absolutely flying.
It felt seconds faster than the smaller wheels,
but when it got a bit more technical,
it feels like you have to be a little bit more cautious.
So, yes, they do Monster Truck over stuff,
don't drop into holes quite so much,
but when I hit something big
and I'm really trying to use my body to soak something up
I find that I stick my bum into the back tyre
and I did do it on that run.
So, I'm 5'10", pretty much average height
which is a bit taller than Martyn and Blake
would have you believe, but I do find that on 29" wheels
that sometimes I stick my bum into that back tyre
when I'm really trying to use my legs to soak something up.
I guess, if I just rode a 29er, I would get used to that
but swapping between them... it's always been
a tiny problem for me.
So, I'd be interested to see the times,
because that felt really fast actually.
So that's enough about the feel,
let's talk about results, and the time.
Which one was the winner?
So, it was the 29er, but there was nothing in it.
I did a 1:42 on the 29er, 1:43 on the 27.5,
so there was only a second in it.
But the interesting part for me comes
when you look at the splits.
The top section of that track was fast, flowy,
stuff where actually it felt really fast on the 29er
but I was three seconds slower up there,
so not an inconsiderable amount,
but it was four seconds faster on that rough lower section.
I think we can say that's down to that roll-over
it's where I'm hitting all those bumps
and there were some big breaker bumps on there.
The 29er doesn't dip in quite so much,
so it's less tiring to ride
but also faster over those bumps.
So actually for me, that's a really interesting test.
And as a racer, I'm going to go with the faster wheels.
I've been riding that bike an awful lot with the 27.5's
so I think it's time to leave the 29ers on there.
Feels great fun to me, I think the biggest disadvantage
with the 29ers is stopping the bike.
I've always felt that when I've tried to race the bike
and there wasn't much of it on that test,
so I could bear that in mind in future
but for now, I'm sticking the 29ers on there.
It's one of those great features I think
of some of these modern bikes,
that it's really easy to swap out wheels.
Realistically, you could have two pairs of wheels
for your bike at home, the smaller and the bigger,
and just swap them around for different conditions,
or you might find you prefer one over the other
and just sell the other wheels.
So actually I think it makes the bikes really versatile.
If you have any questions about this video,
leave them down below because I'll be
doing a follow-up video on the GMBN Tech Channel
so I can get into the nerdy facts.
If you want to see how a tyre is made, click up there
for a Continental factory tour
and down there for the Scott Genius First Ride.
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