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

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.

64 comments on “27.5″ Vs 29″ Wheel Size Debate Nerd Edition | Your Questions Answered

  1. Looking for a comparison between 27.5 and 29 with plus sized tires 3" and 4" fat tires.
    I've recently come across a Motobecane where you can swap out Plus 3" for fat bike 4" on the same bike. The bike comes with the 3" installed. Now I need to choose the 27.5 or the 29…
    Got money burning a hole in my pocket and don't know what to do haha!

  2. 26" will return in 10 years time as the "new" nimble and light trail wheel. But the manufacturers will ensure the axle sizing will be a new standard to drive new frame sales.

  3. Would love to see a short rider-height comparison between the 650b and 29er. I'm 5'6" with a 28" inseam, add an inch to both with shoes, and I sit on the high end of a small frame and the low to mid end of a medium. I'm in the process of choosing my first full-sus bike and testing both out. 650b feels natural but I'm coming from a 26", I haven't been able to lift the front wheel up on a 29er yet; probably technique.

  4. Nino did use 27.5 for a long time. That said, it was a position on the bike he was after and at that time, he couldn't get that with the 29 wheel. Scott worked with him in development of the Spark and Scale with 29 wheels so that he could get the position he was after.

  5. I chose 29er based on the trails I ride in the southeastern part of the US. Many of our trails have a lot of XC to them, so you gotta be able to peddle and climb quite often. 29inch wheels and 120mm travel.

  6. i recently moved on to a 29er enduro bike, you definitely feel like you're going faster. Sometimes i don't feel comfortable and have to give it a little brake. No problem with maneuverability though.

  7. ..Canyon are releasing a Ebike,called the 'Spectral On' ,on march 9th,which is running a 29" wheel,up front,and a 27.5 on the back,so they must think this is a great idea….

  8. Where's the tech, Nerd Edition? Compare the moments of inertia at the very least. Perhaps then quantify the agility somewhat: for a given force, how much longer does it take to lean the big wheels over to the same angle?

  9. There are advantages and disadvantages to both . No one is better than the other however if you do add the larger size you are adding more weight (just a tip there) . It's all marketing and judging by the attitudes of some at MTBR and Pinkbike it seems to have worked very well .

  10. #askgmbntech What's better, a 29er frame fitted with 27.5 plus wheels or a 27.5 plus frame fitted with 29 wheels?

  11. the Bulls Copperhead Max has an 29er wheel upfront an 27.5 Plus on the back an the Bike is quite good, so the idea is nothing new. ^^

    good video tho 🙂

  12. @gmbntech I have to disagree on the rider size/height and wheel size topic. At 6’3” my full squish is a 27.5 and my aggressive hardtail is a 29er. The hardtail benefits from the bigger wheels as you mentioned about rollover and keeping it at speed. Although the smaller wheels feel way better on the full suspension, especially on a tight single track! Now that I think about it, I don’t disagree. I believe that there is a correct tool for each job, just grab the one you need for the day! Just my opinion, happy trails!

  13. If we're talking grams, we're talking cocaine. If we're talking rotating mass….then the wife is drunk and frisky. 29 is the way if you're bi or gay. Discuss……

  14. I'm 5"10 and rode a 27.5 for just over a year. I switched about 6 months ago to 29er and it took some getting used to at first, however now I'm about to upgrade my bike again to the Scott genius and I'll definitely be sticking to the 29er. I think that the benefits outweight the negatives (hence why all the pros are switching to 29ers now).

    The thought of them being to big is all in your head. Match it to your frame. If you have a XS frame riding 26-27.5 would make sense. A Small frame would be 27.5 Medium frame 27.5-29 and a large frame 29er.
    I'm sure in the next few years manufactureres will start matching wheel size to frame size.

  15. Something I don't understand really, and I hope someone can clarify for me. Talking about 27.5 and 29" wheels, isn't the overall outside diameter about the same since the tire is larger on the 27.5+?

  16. You said that there was a 20mm actual size difference between the height of the wheels. And that the 29 inches makes you drag your ass, but in reality it only brings you butt 10 mil closer. That is not alot of difference. Expecily with the 27.5 is a wider tire.

  17. Can you explain why there is a view that bigger frames should have bigger wheels. Surely that only exacerbates the issue of a larger bike naturally having a longer wheelbase so reducing manoeuvrability even further?

  18. I’m still riding 26 and I like these videos cuz I’m looking at getting a new bike . I’m 6 foot tall wide shoulder kind of guy but I like dirt jumps and a lot of trails around here are tight single tracks with lots of roots and rocks . If I’m gonna drop 4000$ plus on a bike I’m gonna get as much info as I can get , it’s also cool that companies have demo days more often now so you can just grab a bike and test it further than just the parking lot of your local bike shop .

  19. I´m a short human being (165 cm). My main problem with 29ers is the height of the handlebar relative to the height of saddle. My 26" have the handlebar 7 centimeters below the height of the saddle, and for me is perfect. I had 3 29ers and in all of them the handlebar was above or the same height of the saddle. Thats causes that i was putting my weigth on the saddle and delivering less power and weight over the pedals.

  20. I would think a more nimble handling bike would benefit more riders than going for a bit faster bike for non-pro non-racing use. Only one second difference isn't even significant?

  21. You mentioned Greg Minnar, isn't he like 6ft 2? Nino 5ft 6? didn't loose races on 27.5. (Also Scott quit making the regulat 27.5)

  22. GMBN Tech
    Just wondering what your height is to be scraping your bum on the 29ers? I'm 6.4" and have never experienced bum scrape on my 29ers so it may just boil down to the size of the person. What's your opinion on this?

  23. Neil there is not such a huge difference in angle of attack between the two sizes… Although it looks impressive with your example with tapes. However it’s like comparing a 14’ wheel with a 30’ wheel….. On other things you said you are spot on.

  24. imo 29 if your in competition where tens and thousands of a second can mean the difffernce between qualifying and spectating and 27.5 if your you just like riding (why spend more)

  25. no don't agree that 29nr are that much faster because if you got a lot of stop and start sections a 29nr on the trail is a lot slower when it comes to acceleration and deceleration so you lose time. I think A 650B is a happy medium. for all bikes especially if you are a bigger heavier person the 29nr wheels cant take a lot of side load.

  26. Of course it is down to preference, so why would you just discontinue the 26 tech? Will there there absolutely no advantage to smaller wheels, not even in the future? I think it is clear there will always be advantages for 26. This could be a classic example of the market being driven by greed and not demand.

  27. nice one neil very usefull im just building a 29er carbon cube to get fit for mega-avallanch not ridden for years so strugling haulin my summum i built for it! through the local trails im gonna build a set of 27.5s and put 3" tyres on for an experiment hahaa should be fun!!! cheers keep up the good work!

  28. At 2:50 you’re talking about BB drop (BB compared to axles), but you’re showing BB height (height of BB from the ground). And unless you’ve got concentric axles that you’re changing when you change wheels – the BB drop isn’t going to change. And the BB height will be greater on bigger wheels.

  29. Im quite heavy, I find the 29 more stable for me. Having said that, not a thing wrong with 27, like you said more nimble. But 29 feels more secure. (IMO)

  30. The best thing about 27.5 vs 29 is that excellent 26" MTBs can be bought used at bargain prices by people who ignore bullshit industry trends and just like to ride bikes.

  31. i switched my tyres from schwalbe (650B) 27,5 x 2.50 to Michelin (650B) 27.5 x 1.3 world tour tyres becouse i am 95% street riding and they roll great awesome speed

    but in the forrest and on trails i have say wider and bigger is better and faster

    by the way if anybody knows some cheap alu wheels i am all ears

    thanks and nice subject about the tyres

  32. Its simple for me: I am a moderate 6'4'' cross country rider and for me the perfect combo is HT + 29" wheels. If I were shorter trail/enduro or DH rider, I would use FS + 27.5" wheels.

  33. How about wheelieing and manuals? I've just got my first mtb, a Trek X-Caliber, a 29er with a fairly relaxed geometry and long stem. I'm trying to learn to wheelie and manual but feel like I can barely get the front off the ground, despite having watched a lot of tuition videos! Is wheel size a factor or is it solely down to practise?

  34. i just recently, less than a month ago, bought myself a 27.5, upgraded from a 2010 specialized stumpjumper fsr. i personally have tried both 27.5 and 29 and i personally think i can be quite a bit quicker on a 27.5 than a 29, and it all comes down to being able to move on the bike, i am pretty short, with even shorter legs, so i have a hard time putting the bike where i want and in addition to that do i feel the extra rotating mass since i am really light so accelerating feels heavy which i'm not fond of.

    still, let's just put the 29vs27 to rest, both bikes are fast and it is just down to personal preferences

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