27.5″ Vs 29″ Wheel Size Debate Nerd Edition | Your Questions Answered

– This is a tech followup
to the 29 versus 27.5 video I did recently on GMBN to get
into the facts and figures, but also answer some of your questions. (drum pounds) (knife rings metallically) – The first thing that
a lot of you pointed out is that I got the weights wrong, of course I did, I said
50 gramme difference, in fact, it’s 500
grammes, so you definitely would have felt that on the trail. Rich Piana is one of those people, actually, almost everyone
who watched the video noticed I got those numbers wrong,
so apologies for that. Yeah, definitely 500 grammes,
you will feel the difference and of course, it’s rotating mass, so let’s talk about that straight away. When we’re talking about the whole mass of a bike and the rider, in fact, you’ve got the rider, you’ve got the bike and rotating mass, so the
wheels, once they’re spinning is said to make only 2% difference to the actual accelerating
and decelerating of a bike. So, it’s not a huge
amount, but 500 grammes is a reasonable amount,
but also rotating mass does depend on the diameter of the wheel. So, a 29-er is obviously
bigger than a 27.5 and it’s heavier, so it is gonna
make a bit of a difference, And I do think it makes a difference to the feel of the bike,
that smaller wheels that are lighter do make
the bike feel more nimble. So, for both different
wheels, the 29-er and 27.5 I ran the same model of wheels. They are the DT Swiss M1825 spline. They’re an alloy rim, they’ve got a 30 mill internal width on both sizes, so that doesn’t affect
the profile of the tyre. I ran tubeless on both sets of wheels. There were a few questions about why I ran the Baron’s on the smaller wheels and the Kaiser’s on the bigger wheels. Basically I went with
what I thought would be the bst set of tyres for those conditions, so Kaiser’s are super grippy, great for enduro-style riding, and Baron’s are also, but you can’t get a Kaiser in
a 27.5 at the moment, on the bigger 2.6 I must say, in the plus. So, that’s why I went for the
Baron on the smaller wheel. It’s a really good tyre
for those conditions. So, I just wanted to go for what I thought was gonna be the fastest. That’s something I want to address slightly, as well, in that video. I know we have done a
29 versus 27.5 before, but I felt this was different because it’s just one bike that
can run two sets of wheels, and for me, it wasn’t all
about what was the fastest. It was about, what would I
choose if that bike was mine? Would I have two sets of wheels? Of course, that is the
more expensive option, buying two sets of wheels. Or would I decide that one
really suited me a little bit better, which I’ll come to
at the end of this video. Let’s talk about the geometry changes when you change out the wheels. So, it slackens off by naught .6 degree when you put the bigger wheels on, so the head angle does
come out, but that for me is not enough to make a
difference to the bike. I really don’t feel that, if
you let your rear tyre down or run more sag on the smaller wheels I think it makes just
about the same difference. The BB drop is something
that I think you do feel. So, BB drop is the
measurement when you compare the axles of the wheels
to where the BB sits. On the bigger wheels the BB sits lower, so, in relation to those axles. Obviously your weight
goes through the pedals and that feels like you can drive the bike better over obstacles. And I do think that does
make a big difference. Also, I’ve got some props to show. If you couple that with
the angle of attack, so when your wheel rolls
over a bump, obviously a bigger wheel will roll over
that a little bit easier. If you’ve got a smaller wheel that’s gonna get more
hung up on that bump. So, when you’ve got that and
the difference in the BB drop, that’s where you do feel that the 29-er just sort of monster trucks over those smaller bumps a little bit better. I think that’s where we saw the difference in the times at the bottom of the track. There’s a lot of breaking
bumps, it’s quite rough, the bigger wheels were just, you won’t get as much feedback to your body, but also the tyres will roll
over that little bit easier. Let’s put the times aside for a second and let’s talk about how the bike actually feels with the
different size wheels. Well, the 29-er feels fast everywhere, even climbing, it feels really compliant. You don’t feel the bumps
when you’re riding downhill, but also when you’re going
up through the saddle. It feels like a really smooth
ride and it feels fast, but it doesn’t feel as
agile as the smaller wheels. I talked about in the video a little bit where I do drag my rear tyre, my bum, I do that quite a lot on 29-ers. Also, just throwing the bike around, so in corners I do feel
like the smaller wheels are just that much more aggressive. Also, it sounds stupid, but
getting on and off the bike I sometimes swing my leg over and on the big wheels I catch
it and almost fall over. Smaller wheels do feel like a much more old school normal
mountain bike to me, whereas bigger wheels does feel like a sort of trail-y, fast
cross country bike, although everyone has
proved, races have proved that they work enduro,
they work for downhill, of course, we saw that last year. Certain courses, I think, they’re gonna feel good and they will be fast. Let’s have a look at what
you guys have been saying. Well, we had a poll on Instagram to see how you would choose. We’ve got 8,625 votes for
the smaller wheels, 27.5. But for 29 we got 5,144,
so a pretty big margin going for the smaller wheels. I would say that’s probably what we see on the trails, especially in the UK, if you’re looking at
what people are riding. Much more people are riding 27.5, although, let’s talk about the 26 ’cause a lot of people were starting that in the comments section. We don’t talk so much
about 26 inch wheels now, generally because not many manufacturers are making those bikes any more. I guess you can still buy free ride some downhill bikes maybe, maybe not even downhill bikes actually, but it’s all dirt jump
bikes and kids’ bikes all still come with 26 inch
wheels, but when we’re talking about your higher end bikes,
they all come in 27 5’s. So, I think, really,
that has become the norm in let’s say the last five,
six years, I would say. But, yeah, there’s a lot of people kicking off in the comments section. Will Mockel said, “It’s
funny how the vid is about “27.5 versus 29 but the
whole comment section “is people defending 26.” Which is fine, a lot of
people saying, “26 for life.” Perrocan Atakes says,
“Really? Wheel size debate? “Is that all you’ve got?” I know this has been raging on for years and years, hasn’t
it, since 29-ers came around, but I still think it’s a valid point. There’s still a lot of people trying to decide which
one suits them best. I think I still am, to be honest. There’s some situations where
I really do like the 29-ers, others when I want to get rid of them, I chuck my smaller wheels back on. Just a couple more comments
on the wheel size debate. The Chosen Dude says, “It ended years ago, “when cross country and enduro racers “began widely using and winning on them. “No one cares about downhiller’s opinions. “They were always the last and loudest “to adopt new technology, clipless pedals, “carbon frames, tubeless, air shocks, 27 5 wheels, et cetera.” I do kind of agree with
that last statement. Downhillers are always
pretty stuck in the mud. They do take a little
while to get used to them, but it’ll soon come like we saw with Greg Minnaar
grabbing the bigger wheels and starting to do really well on them. The rest of Santa Cruz team, everyone else joins suit after that and bigger wheels started appearing everywhere. But, I would say that Nino Schurter, up until a couple of years ago, always ran 27.5 wheels, so he’s the one person cross country that really didn’t want to use the bigger wheels, and obviously he’s won a lot of races. I know he uses bigger wheels now, but I don’t think that statement
stands completely true. One last one, this is from Some Judo Guy. “Is there still a debate about wheel size? “Choose your ride and
go and have some fun. “It’s all down to your preference. “29 just feels too big for me,
but for some, it’s perfect.” And that brings up a
little bit of a point, that a lot of people say that 29-ers just suit bigger riders, and the 27.5 are better for shorter riders is something that I
really do want to test. I don’t know if that has
been completely proven. I know there are some shorter riders, people like Tracy Moseley,
Danny Hart have used 29-ers to a good a mount of success, so I really want to test that out. Get a smaller rider,
put more bigger wheels. Is it gonna limit them at all, who knows? We need to try that one out. A few people have asked this question, but Jog Bird asked it,
“How about a mix up? “A 29-er on the front
and 27.5 on the back.” That’s something we’re
seeing come in with E-bikes. I’ve seen quite a few people riding that. I’ve not tried it yet,
definitely would like to run it, see if it works,
obviously you’re gonna run a wider tyre on the
back with the 27.5 plus, and then a smaller one up
front, the 2.4 and the 29-er. Yeah, not tried, I’m really
interested to try that one out. Could it work, I don’t know. It might be the best of both worlds, it might be the worst of
the two together, who knows. Neil Blundz raises a point, he says that, “It’s always been 80% rider and 20% bike. “The small margins are just that…small.” Yes, it’s definitely more the
rider than it is the bike, but I would say it’s
probably more than that. I would say it’s more
like 90, 95% the rider, ’cause if you put a really
good rider on anything, a 26 inch fully rigid bike,
they’re still gonna be fast. But, if we’re talking about racing, where hundredths of seconds,
especially in downhill and enduro, make a difference between winning and coming second, then
small margins are important, but, of course, we’re
not all racers, we don’t always have to have the
fastest equipment on our bikes. Maybe it is down to preference. And then Bob Brusk Fruco
brings up that again, he says, “Hi, there, actually a question to Neil: “In this video you focused on the time “and the speed advantages of
using different wheel sizes, “but what are your impressions “in the case of agility,
manoeuvrability on steep “and narrow technical sections,
hair pins, et cetera.” I’ve talked about it a little bit already, but I’d say hair pins,
I don’t really notice the difference between the wheel sizes. It does seem to me like you would notice that 29 inch wheels were harder
to get around a tight turn, but I don’t actually feel that. They do feel pretty, sort of, I guess it’s the grip more than anything. You do have really good
grip on the bigger wheels, But, that’s not something I really know. It’s just more about
those times when I’ve got to move around on the bike,
so soaking the bike up. I’ll finish this video
with a final question. If I had to choose one set of wheels, only one, which one would I have? Actually, that’s a really difficult one. I find it really hard to decide, but if I could only have one I would probably go with the 29-ers. Just feels like a really fast bike and, according to my test,
it was one second faster, so why not, I’ll have that one. If you want to see some more videos click up there for the original video, down there for how tyres are made, I think that’s really interesting that it does make a difference, that rotating mass of the wheel. Hit the button to subscribe to GMBN Tech and give us thumbs up if
you like these nerdy videos.

About the Author: Michael Flood

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