Anyone choose 27.5?

Yep

Love my am 160 in 27.5 and my mmmbop in 27.5

6'2"

Bernard Kerr actually spoke some sense in his recent pinkbike podcast where he said something along the lines of (paraphrasing): "When I'm racing I want to go as fast as possible, when I'm riding I want to be having as much fun as possible."

If to you a 27.5" wheeled bike makes riding more fun then go for it, I have a 29er/mullet now after riding short travel 27.5 for years beforehand (5010) and the current bike is still fun but there are trails where I know I'd be having more fun on the 5010.

the only justification i've seen for 29ers are to go faster

i don't need to go faster.. I'm not racing anyone

I'm coming from a short wheelbase long travel 26er (for for the trail riding usage) and in certain situations the 29er feels less.. pinned, somehow.

Top one does look 'good' somehow.

6'0.5", love my Santa cruz 5010 for trails, general enjoyment.

the only justification i’ve seen for 29ers are to go faster

I got one to go faster, because I want to go further in the same amount of time. There are loads of trails that are a ride away, and on my old 26er it took forever to get out there leaving little time to ride the actual trails. However on an XC bike it wasn't too bad. Hence the Reactor rather than the Mega, and the 29 option. I've no idea how much difference either choice would have made.

Yes, more fun.

Bigger wheels normally = more grip and faster. But... so what? Are we all racing all of a sudden? Fun for me is feeling like I'm pushing the bike, and smaller wheels have lower limits.

I have all 3: 26" 140mm hardtail, 170mm 27.5, 100mm 29er. The 26" is definitely the most fun! 29er is great but I'd only want it on an xc bike or if I'm racing.

Same principle as "driving a slow car fast is more fun than driving a fast car slow"

Recently bought a Ragley mmmbop. Love it, no regrets not getting the Big Al. Was bought for fun and that's exactly what it is.

The 'go faster' thing isn't the only reason, I swap from mullet to full 29er every couple of weeks and on some peaks routes where you're riding on the armoured paths like the one that connects the top of jacob's ladder over to cavedale you can definitely save a lot of energy with 29er, all those little square edges and holes definitely get muted with the bigger wheels, that adds up over a ride and I definitely feel it in the legs (and arse) more after 5 hours on the little wheel.

For me I loved the 29ers that I've had ,np mega,orange stage 6 ,they were faster on open sections of trail if that matters to you ,it does to me to a point

I loved just been able to plough through stuff easier and hold a line

but the absolute drawback for me was the extra weight in the areas my legs felt it.

The extra size of the wheels tyres and forks can easily add up to 800 grams and that near 2 pound difference in the rolling department meant whilst i was faster on certain sections I wasn't as dynamic as I'd liked and it took a bit of fun out My riding .

I've since got a giant trance x  full 650b and it's like putting on a comfy pair of slippers ,just feels right to me .

I don't obsess about weight but I did recently get a mondraker foxy carbon rr that still weight 36lbs and whilst that's quite the norm I'm the sort of person who gets blown around in the wind and whilst the raker was fast it wasn't fun .

I'm also struggling with a e bike I've recently purchased a mondraker crafty r ,it's fun on the ups but instead of feeling planted on the dh it just feels like if holding on to a steam roller bounding my way down the hill with absolutely no finesse .

This is only my take on it and is not my opinion of  everyone else's bike build style it's just what I prefer and what works for me .

I have the latest version of the transition patrol, it came mullet, i now run it 27.5 all round. For most of the riding I do it's made it more fun, I wouldn't say it's made my bike any slower either. Mullet is probably better on rough stuff perhaps

I tried my Rail as full 29, mullet and full 27.5. The 27.5 felt the best on tight, twisty trails but the low BB was a problem. The 29er front rolled over obstacles far better than the 27.5.  As a short arse the 29er rear was an issue with flossing on the steep stuff so I settled on mullet.

My hardtail is 27.5, had an option of both sizes at the time but all my bikes were 27.5 so stuck with that.
My trail bike is 29, the only option and I wanted to try it for long day efforts.
My Enduro bike is 27.5, was the only option at the time.

I want all my bikes to be 29 now as I'm addicted to the stability. Strange considering I'm a short arse at 5"7' with slightly stumpy legs!

I went from a 26" Orange Five to a 26" commencal Meta AM, to a Cotic Solaris then a 29" NP Reactor. I love 29ers and I'm only 5'9" ish ...

TBF though, I haven't actually ridden a 27.5.....

Absolutely. mainly as i`m a luddite cheapskate though haha!

I`d not run a 29er rear just yet though as i buzz my arse enough on teh 27.

i agree 29ers do feel huge. My wifes one feels mahoosive. they do also roll nice. for XC 29s a no-brainer. for anything 'fun' i wouldnt. I'd probably get used to it though but i'd be dreaming of something more entertaining.

I still think my local spot was way more entertaining on a 100mm jump bike than any of my new bikes. yes we were slower and crashed alot but we also went sideways more and every root and jump was a challenge.

I'm happy with my 27.5" Occam. I'm glad I managed to buy it when I did and I'm definitely not in a rush for a 29er FS. OTOH I also have a Ti hardtail currently set up with 29er wheels which is the more XC/bikepacking setup.

Horses for courses.

PS I'm 170cm / 5'7" ish. I might have a different experience if I was taller.

It's not as simple as smaller wheels = more fun. My hardtail is a 29er with around 510mm reach, my full sus is 650b with 530mm reach. The hardtail is much more playful. It's a blend of the geometry as a whole plus wheel size.

I am 172cm or so. I have always thought 29" wheels would be too big for me. I have a 27.5" wheeled Mythique and a 2022 Levo, but running 27.5" front and rear. I have never ridden the Levo with the 29" front wheel, assuming I'd prefer the 27.5" wheel shod with a 2.8" tyre.

hard tail is 29" and feels quite big/tall.

rigid is also 29", relatively similar geo, and feels just right.

Gravel I elected to go for 650b and feels great.

The SS is still at 26" and feels vv twitchy now.

Recently bought a brand new bike/frame and had this condundrum, 27.5 or 29. Obviously the cycling industry tells us 27.5 is dead and only for small people and children. I really thought about this long and hard and I was coming from a full 27.5 Whyte T-130 which I loved and was so capable.

I also ride mostly in the lake District and more of an "all mountain" rider, so maybe the 29er would be a better option.

I demo'd some bikes, borrowed some bikes, all 29 or mullet. Then had a go on full 27.5 transition scout. And I fell in love with it. I'm a large guy at 6,2 and 100kg but still prefer the full 27.5. I don't know if I'm faster on the full 29er or the Mullet, but I also don't care too much about times.

I have a full 29er Hardtail which I use to commute and do some trails with, so felt it would be a good balance.

I went from a 29er Fuel Ex to a Trek Remedy 27.5. Love it. Honestly don’t find it slower….but maybe at my pootling speed it’s less noticeable.

My hardtail is also 27.5. Just my personal preference….but I am tempted by a longer travel 29er, I just don’t get to ride enough to justify the spend!

I’ve got a 29er HT and I think next time I get a bike it would either be a mullet or full 275. While I like the 29er as it rolls over everything better, I think a lot of my riding would be more fun on the smaller wheels. My wife isn’t convinced about 29ers either, she definitely prefers the smaller wheels (she’s 5’7 so not a total short arse).

I don’t think the smaller wheels would make me any slower as I’d just have an extra 10-20mm of travel but having ridden both I think I’d have more fun.

the only justification i’ve seen for 29ers are to go faster

Bollocks. I've got no interest in going fast. 29ers are good because they make techie 'natural' all mountain terrain more rideable.

My Enduro is 27.5, never regretted it

I have all the sizes (26, 27.5+, 29, 29+) and they're all fun 🤷‍♂️

My Mojo3 was 27x2.8 and it was fantastic. Not really got on with any 27.5s since.  Bought a Mojo4 and really could not get on with it at all. It's all subjective if you're not racing, but 29ers just feel 'better' for me.

Still I rode a mullet e-bike in Spain in March and just thought 'well this is a nice thing to ride', so I'm not a reliable witness. A lot of stuff we ride in the FoD tho is tight between the trees but also tends to the steep and nasty. Overall I'd rather be on a 29er.

I shan't ever ride a 27.5 bike.

It remains the most cynical, profit led, corrupt, marketing driven money grab by any industry I've ever seen.

Bullshit sold to idiots by shysters.

Despite being average height, high front ends just don't agree with me or rather my seating position on the bike and 29er stack height is getting way high on modern fs 29ers so very happy with my 27.5 160mm travel bike although my xc bikes are 29er

It remains the most cynical, profit led, corrupt, marketing driven money grab by any industry I’ve ever seen.

😂

Does sketchier at a lower speed mean equal fun and less damage when you fall off?

If so 29er gave two uses - boring racing types and the inherently slower riders in a group to equalise the pace and therefore the group fun.

Ban 29ers from good riders unless their doing something anal like racing.

Discuss.

RustySpanner, I get that in principle but for those of us that were happy to carry on riding smaller wheels, it happened, we had no choice so we got over it if we wanted another bike. It feels like a long time ago. I stuck with q 26" Rocket until I felt like I needed a longer dropper post, then I had no choices left.

I love that video of the laughing man with no teeth discussing wheel size, especially as I own a fat bike too 🙂

27.5 Crush and a brand new Airdrop Edit here. 27.5" till I die, get a mullet or till they decide I need a 28"...

Mugboo what's the Edit like? Airdrop are pretty much the reason I'm still undecided about 27.5!

Recently bought a brand new bike/frame and had this condundrum, 27.5 or 29. Obviously the cycling industry tells us 27.5 is dead and only for small people and children.

Not at all... I was recently told by a bike manufacturer we will have no choice as soon as they can force 29 only and the benefits of 29ers are for short people as well

.. anyway so I bought a 27.5

I did and kind of regretted it. Was 7 years ago though and my choice was between a V2 5010 and the original Hightower. 5010 was very poppy and manoeuvrable but also got hung up on sharp edges, big roots and big lumps. Great for playing in the woods but not so great on natural trails. Still happily rode it for 6 years though.

On a V2 Sentinel now, which despite having 20mm more travel and being a lot longer and slacker, is just as much fun to fling about while rolling over stuff much better and carrying more speed. Not quite as easy to pop off stuff, but that’s as much to do with geometry and 2 extra kilos than wheel size. I’m 5’9 with short legs and have only had a couple of tyre buzzed and that was more due to getting caught too far off the back of the bike in a bad body position.

Lots of comments above about having 29er for going fast, for me it’s the opposite. I find they make rocky, awkward trails easier to ride at lower speeds. Better riders than me on 27.5 will go fast anyway and skip over stuff. At my comfortable speed, the smaller wheels bucked, jerked and got hung up in holes. 29ers roll over this stuff better at the same speed. I ride much more smoothly and carry more speed out of sections on bigger wheels. Skill compensator, probably but so is suspension and modern geometry. I rode Top Chief last month for the first time and there’s no way I’d have ridden as much as did on smaller wheels. For rocky Scottish trails, 29er is a no brainier. If you like to hang out in the woods pretending you’re Josh Bryceland then you may have different opinions.

@molgrips it’s still early days  for you. So much will have changed geometry wise since your last bike that’s it’ll take months to adjust your riding style. I got my bike in February last year, rode for 4 months and was still getting used to it. Had some skills coaching to help get my body positioning adjusted to a longer,slacker 29er which helped a lot. Had a day with same coach that trip to Top Chief and she couldn’t believe the difference in my riding this year now I’m used to it.

I've never even thrown a leg over a 29'er. Although, I am considering mulleting my 27.5 eeb.

I do have two 26" HT's though

Reading with interest as considering a new bike next year and mulling over 27.5 or 29. Currently on a 2018 Whyte T-130 and very much value the poppiness of it and at 170cm I fear I'll lose that if I go to 29.

I ride mostly on the Quantocks and Exmoor so it's not mega technical, but enough for the Whyte to feel on the edge a lot which adds to the fun. I do break it a fair bit though which makes me think 27.5 and take the travel up to 140-150.

Then the voices in my head say '...but everyone else is on 29 now...'

ride mostly on the Quantocks and Exmoor so it’s not mega technical

lots of amazing singletrack but also some steep tech there!

I’m 6 foot 2 and a bit. Always liked a 29r since riding one of the first on-one inbreds. Geometry now has them brilliantly set up for a range of riding types and styles. Changed my hardtail this year for a Canyon Stoic which has a (very) short rear which makes it very fun for wheelies manuals etc.

If the right bike was 650b I’d still consider it but don’t really see the need. I still have a stooge with plus tyres on which is a lot of fun.

Agree that the airdrop edit looks very good.

I just like most bikes. OP I think you just need a period to get used to it. When I first started riding them they seemed ridiculous, especially compared to a 26”. Now if I go back to a smaller wheeled bike they now feel like I’ve stolen one of my kids bikes.

I chose 27.5 until 29ers got good. I demo'd loads of 29ers in about 2017/18 and they all felt like big gangly XC bikes. Fast in a straight line but short and twitchy and reluctant to change direction.

I was forced to find a replacement bike due to a burglary in the middle of lockdown when there was almost nothing available. I went with a Norco Sight in full 29 and it's mint. Great handling, really lively, loads of pop for jumps and stuff.

So yes I was a reluctant 29er rider but now I've got 2 and they're both mint. Fun is about so much more than just wheel size.

I shan’t ever ride a 27.5 bike.

It remains the most cynical, profit led, corrupt, marketing driven money grab by any industry I’ve ever seen.

Bullshit sold to idiots by shysters.

I wonder if the industry has been affected by your boycott.

It remains the most cynical, profit led, corrupt, marketing driven money grab by any industry I’ve ever seen.

Oh behave, in a world where the motor industry exists, bike manufacturers choosing an additional couple of new arbitrary wheel sizes over an existing arbitrary wheel size doesn't even make the needle move.

I shan’t ever ride a 27.5 bike.

It remains the most cynical, profit led, corrupt, marketing driven money grab by any industry I’ve ever seen.

Bullshit sold to idiots by shysters

Yeah, it makes the finance industry look like altruist saints :-).
Are you all right though?

Back on topic, I built a Meta HT last winter which takes both wheel sizes but I kind of did a half way house with 27.5 tyres in 2.8F/2.6R (Rekons). Really please with the result. Rided like a dream for a HT, compliant, responsive, not too heavy. Makes 26' utterly obsolete I'm afraid IME.

Yep, just finished building a 27.5 hard tail. Got a 29" full suss so wanted something a little more playful and from initial rides it was a good decision.

Just bought an older 29" full suss XC frame to build up and replace my gravel bike so reckon I'll have my bases covered with nothing treading on another bike's toes.

Obviously the cycling industry tells us 27.5 is dead and only for small people and children.

Growing market segment especially if you include women - there's more women and children on mtbs then ever before. The smart money would be on having a 27.5 offering for this segment.

I'm 6'3" and ever since having a go on a 29er they just felt and looked right. A bike that finally fitted and didn't feel like a gate to ride.
This proved very expensive as I pretty much immediately sold all my 26ers and went out and bought equivalent 29ers.

Not once have I looked back, or at smaller wheels.

I would quite like a go on a 27.5 as I've never actually ridden one.

Though I have just built a 26" jump bike.

shan’t ever ride a 27.5 bike.

It remains the most cynical, profit led, corrupt, marketing driven money grab by any industry I’ve ever seen.

Bullshit sold to idiots by shysters.

Please Rusty, don’t hold back on our account - say what you really feel.

I’ve had and still have two 650b bikes - an original Transition Patrol and a Stanton Switchback Ti Mk2. They are some of the best handling bikes I have had and huge fun.

If I could still ride them well, I would. The only reason I don’t is that the two e-bikes (Health reasons) I have had were 29’ers.

Yep, I chose my first 27.5, after being a 26 fan for too long.
That was a Pace, superb bike.
So I bought another one when the next gen came out. It's the RC627, and is very LLS according to the geometry of similar HT's. But, as it's the perfect size for me, Large, with me 178cm, 76kg, it feels just right. I have tyres and wheels that are actually bigger than the maximum reccomended, but clearance is fine, 40mm rims and 2.65's. Climbs brilliantly, and descends as fast I dare!

Wrong thread, sorry

I'm still on a 26" hardtail and my next bike will probably be a 27.5 FS frame so I can easily move all my stuff over til I can afford to "upgrade" to 27.5". Still a bit skeptical of 29" for what I ride which is a mix of "bike park" style trails, trail centre and more mellow but twisty woods/bridleways. Just seems like something that would plough through everything will take the fun out of it, but maybe the ploughing through is a different kind of fun! I do get annoyed with repeated small bumps/edges knocking me about a bit when I'm trying to pedal, maybe bigger wheels would help but I feel like rear suspension would be a bigger help!

I haven't ridden a modern 29er either so there's a bit of the unknown whereas I imagine 27.5 feels basically the same as 26. I also have a 29" inside leg so feel like it would feel massive and gate-like.

Bigger wheels are better, and 29" is the biggest practical wheel size.

If you think smaller wheels are better, get a BMX or a Brompton.

<p style="text-align: left;">I prefer 29ers, but I see why some would prefer smaller wheels. I wish they had never pushed 27.5 though, and kept 26 as the smaller option as classic mountain bikes would still be better catered for. Plus there would have been a bit more difference between the main two sizes.

I think we’ve ended up in the right place for adult MTBs regarding tyres - 29” front for most, 27.5” front for v small or tricksy bikes, and then 29 or 27.5 rear depending on various things (riding style, height, trails, etc).

We only got stuck with 26” tyres for about 30 years by accident - it’s just what was available at the start of the sport and no-one dared spend a load of money on making bigger diameter tyres happen. I wish my first MTBs had had bigger diameter and fatter tyres (you forget how skinny MTB tyres were in the ‘80s).

However, we might not have got suspension happening or working as well so soon if we’d all been rolling on 29s!

“If you think smaller wheels are better, get a BMX or a Brompton.”

I’ve tried both of these in my local woods - they’re hopeless!

However, we might not have got suspension happening or working as well so soon if we’d all been rolling on 29s!

And I think it's easy to forget that the change to 29" changed not only sizes of some parts, but has forced the need to introduce both Boost and 1X systems. So while the change to 29" wheels may mean faster speeds and better stability, at least the change the 27.5" didn't need the additional changes to bike components to make it work. Arguably all you need with the change from  26" -27.5" would've been a slightly longer fork lower and slightly revised geometry, the change to 29" as forced wholesale changes making many more components obsolete.

Son has an airdrop so 27.5" He rides wharney and places like that so works really well for him.

I'm more of an XC bimbler and at 6'5" a 29er suits me and my riding style.

We only got stuck with 26” tyres for about 30 years by accident

Yeah, that extra 12.5mm wheel radius has made a world of difference.

I can't even imagine what our lives would be like today if 650b, sorry 27.5, hadn't been invented specifically for mountain bikers 😉

I'm still sticking with 27.5 for now. I'm in no doubt that 29" wheeled bikes are able to travel faster over rough terrain, but I can go faster than I want to on my 27.5.

I demo'd a Specialized Enduro for 3 days in the Alps, but preferred my own 27.5 'enduro' bike with very similar geometry. While the greater ability to roll over terrain and obstacles was noticeable, it was not by a huge margin. On the flipside I found it harder to hustle, which affected my confidence in slow technical sections, and being relatively short legged, I did buzz my behind more (which I know is a flaw in my technique). Add in the additional weight of rims, tyres and forks for 29" and I'm happy on 27.5. If full 27.5" bikes do disappear I'll be looking at mullet bikes, when I do eventually need/want a new bike.

Another +1 for those singing the praises of the Santa Cruz 5010. Had my v4 for a couple of years now, it's just a fantastically trail versatile bike.

<p><span style="caret-color: #000000; color: #000000; font-family: Roboto, 'Helvetica Neue', Arial, 'Noto Sans', sans-serif, -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji'; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); -webkit-text-size-adjust: 100%; background-color: #eeeeee;">And I think it’s easy to forget that the change to 29″ changed not only sizes of some parts, but has forced the need to introduce both Boost and 1X systems.</span></p>

Bollocks  I had a 29er that worked perfectly with 135 qr and a double up front. Current 29er hardtail is 142 and the wheel has barely seen a spike key in 7 years. Boost was just the bike industry doing bike industry stuff  </p><p>Can’t see many on here choosing smaller wheels if it meant having to run two or three rings at the front.

"Boost was the bike industry just doing bike industry stuff"

What, like making your bike work better? They're bastards the lot of them

What, like making your bike work better? They’re bastards the lot of them

Tell me you are very susceptible to marketing without telling me you're very susceptible to marketing.

I'd missed that Yeti have launched a new 27.5 wheeled bike...

https://yeticycles.com/bikes/sb135

Looks good. A brave/strong move.

Well, my current bike is better in pretty much every way than every mountain bike I rode from 1990 to about 2015, and every incremental improvement has stayed the corse has contributed to that. If that's Boost, or 1x systems, or forks that actually work, or rear suspension systems now work better becasue of the freedom to experiment, then I guess I'm guilty as charged.  Most MTB used to suck balls most of the time, unless you just rode bridleways; now they pretty much don't. That hasn't happened becasue of the sales and marketing team

Well, my current bike is better in pretty much every way than every mountain bike I rode from 1990 to about 2015, and every incremental improvement has stayed the corse has contributed to that. If that’s Boost, or 1x systems, or forks that actually work, or rear suspension systems now work better becasue of the freedom to experiment, then I guess I’m guilty as charged.  Most MTB used to suck balls most of the time, unless you just rode bridleways; now they pretty much don’t. That hasn’t happened becasue of the sales and marketing team

There's a few key numbers that influence how a bike handles and they have nothing to do with hub spacing or 1x systems.

These numbers are affected by wheel size but wheel size in itself does not make a bike better or worse.  It's just another input in the system.

I'd recommend reading Motorcycle Dynamics by Vittore Cossalter and Motorcycle Handling and Chassis Design by Tony Foale.  Unless I've missed something there aren't any push bike specific books that explain the dynamics in question better than these books.

There’s a few key numbers that influence how a bike handles and they have nothing to do with hub spacing or 1x systems.

Well, when it comes to rear suspension, the move to 1x absolutely changed how they are designed and work.

There’s a few key numbers that influence how a bike handles and they have nothing to do with hub spacing or 1x systems.

I was talking mostly about mountain bikes capability to manage the sorts of terrain that the adverts back in the day promised we could, but couldn't really becasue they were pish and made with bits of bikes from the roadie world. Most MTB's back in early days of mountain biking were good for bridle-paths, much beyond that, they'd break with boringly regularity. Now they don't. Part of that is hub spacing and reducing the amount of bits needed for a good spread of gears.

I'm not remotely interested in difficult maths or the theoretical physics that influence handling. Sorry.

Well, when it comes to rear suspension, the move to 1x absolutely changed how they are designed and work.

Just wait until gearboxes with Jack Shaft or idlers become the norm.

You'll look at them and go, 'Huh, is that it? That's just a pivot and a shock absorber'.  It'll be mind blowing.

Part of that is hub spacing and reducing the amount of bits needed for a good spread of gears.

No it's not.

I imagine 27.5 feels basically the same as 26.

No the extra diameter does actually make a difference, much the same as 27.5-->29 does!

Here's anecdotal evidence: I found some mounds of dirt and rubble to ride my 26" hybrid over to make my commutes home a bit less dull. There were a few dips in which the front frequently became stuck, but my 27.5" rigid MTB just rolled through them. It was doable on the 26" but it needed the perfect line and well timed body language.

The other advantage the 27.5" bike had were much wider handlebars than the hybrid which I had cut down old MTB bars very narrow for errrrr aero.

Basically, big wheels and wide bars are just skill compensators 😉

No the extra diameter does actually make a difference, much the same as 27.5–>29 does!

The difference in radius is 12.5mm (or an increase of 4.5%).  If it was a stem it would be like going from 35mm to  36.5mm.

There is so much else going on you cannot possibly say for sure what the one specific factor making the difference is.

In fact, did you just say your 26" bike was a hybrid while your 27.5" bike was an MTB?

There is so much else going on you cannot possibly say for sure what the one specific factor making the difference is.

True, but you can't deny small wheels get stuck in dips more easily than big wheels do. Here's an illustration:

Tell me you are very susceptible to marketing without telling me you’re very susceptible to marketing.

So do you recommend total resistance to change irrespective of tangible benefits just in case someone on the internet thinks you're a victim of marketing?

Sounds like binary thinking.

True, but you can’t deny small wheels get stuck in dips more easily than big wheels do.

You forgot to say, 'It's basic physics'

Yes, it is basic physics.  However, bikes are designed by engineers, not physicists.  Physicists can look at a problem from a theoretical point of view and make assumptions to isolate the unknown factors.  Then can then create experiments to prove their hypothesis.

Unfortunately engineers have to live in the real world where they have to take into account every other factor including actual tyre size, fork travel, rear wheel travel, rear wheel path, wheelbase,  front centre, rear centre, front mechanical trail, rear mechanical trail, etc

Once you've taken all that into account the difference your extra 12.5mm wheel radius makes is pretty minimal.

So do you recommend total resistance to change irrespective of tangible benefits just in case someone on the internet thinks you’re a victim of marketing?

Nope.

I was the first in my club to get riser bars and run tyres that were bigger than 2.1".

I got my first dropper post in 2006.

As soon as I found a 12-36 cassette I started using 1x.

I was running 800mm bars and a 35mm stem as soon as I could find them.

And as soon as someone makes a full suspension bike that ditches the rear derailleur and properly takes advantage of this in the suspension design I'll be buying that (we're close but I've waiting for a Williams Racing Products to sort their system out

View this post on Instagram

)

Just please don't try to tell me adding 12.5mm to the rim diameter and 6mm to the hub spacing (when DH hubs were already available) is progress.

And don't even mention 15mm axles!

The difference in radius is 12.5mm (or an increase of 4.5%). If it was a stem it would be like going from 35mm to 36.5mm.

If it was a handlebar it would be 770 to 800mm, if it was a head angle it would be 66 to 69 degrees, if it was reach etc. etc.

If it was a handlebar it would be 770 to 800mm, if it was a head angle it would be 66 to 69 degrees, if it was reach etc. etc.

None of those things are clad in 50mm to 75mm of inflated rubber.

An increase of 12.5mm in rim diameter is a negligible difference.

If it was a stem it would be like going from 35mm to 36.5mm.
If it was a handlebar it would be 770 to 800mm, if it was a head angle it would be 66 to 69 degrees, if it was reach etc. etc.

None of these work as analogies because they dont have the same limits.

a stem - or an effective stem once you get shorter than the diameter of the fork steerer can go from maybe zero or possibly even negative up to 150, 170 maybe.

head angle, maybe betwen 75 and 55 is about the limit that would physically function, assuming offsets, stem lengths being in the normal range.

handlebars, the minimum physical size is 2 hands plus a stem (it would be awful, but would technically be feasible), so maybe 200mm, not zero.

so what would the smallest possible wheel be? for something that you could reasonably define as off road cycling? which would be rubbish but would sort of functional? 10"? 20"?

Just please don’t try to tell me adding 12.5mm to the rim diameter and 6mm to the hub spacing (when DH hubs were already available) is progress.

And don’t even mention 15mm axles!

All significant progress IME.

All significant progress IME.

You went from 20mm to 15mm and you thought, 'Wow, what an improvement!'?

Regards the magic 12.5mm, progress would have been a standard measure for tyres, not just in terms of width but also in terms of aspect ratio.  But then people might have realised just how insignificant the 12.5mm actually was.

Just please don’t try to tell me [ ] 6mm to the hub spacing (when DH hubs were already available) is progress.

The 3mm addition allowed for (at the time) 11 speed 2X systems that Trek were developing for 29ers (which at the time, were not at all certain to take over like they have now) while keeping the BB spacing realistic, wheels strong and rear triangles shorter and without changing the Q-factor. Had they known 29" was going to be the nailed on certainty they may have gone direct to DH spacing, or Tandem 145 but that meant (at the time ) a difference in how through axles and QR rests in the drop out. They settled on 148x52mm centreline and 3 different chain ring offsets to accommodate all centreline options and rear axle widths

Boost essentially made the modern 29er (as it exists now) possible.

You went from 20mm to 15mm and you thought, ‘Wow, what an improvement!’?

Regards the magic 12.5mm, progress would have been a standard measure for tyres, not just in terms of width but also in terms of aspect ratio. But then people might have realised just how insignificant the 12.5mm actually was.

Never had 20mm, you invented that, weird. I went from the old skewer thing to 15mm through axle thing, significant improvement.

Regarding 27.5, it increased the diameter by one inch. Significant improvement, all other things being equal. 29 goes a little too far for my taste however so 27.5 a near perfect balance for me. I would have liked to try 28 but that doesn't exist.

Just based on my experience of course, good progress and despite the marketing. I am quite happy if your experience has been different, perhaps you're not very sensitive to stuff.

Diffent people can be...different. No need to be belligerent, weird or emotional about it.

I’m not sure why Bruce is arguing about a 12.5mm change in radius?

29” front wheels are 31.5mm bigger in rim radius (and bigger still in total tyre radius thanks to wider rims and larger volume tyres). For some riders that’s a bigger tyre than they want on the back, which is where 27.5 is most useful. How many riders want an even smaller wheel on the back?

IIRC the first Boost frame I saw was a Rocky Mountain with the 3" B+ tyres. I knew right away that it fixed an issue for me and managed to get Brant to design and procure a hardtail frame for me. I've not regretted that at all and that bike is still doing the job it was designed for.

Boost essentially made the modern 29er (as it exists now) possible.

As Scotroutes said, Boost solve a problem for Plus size tyres.  Nothing to do with 29ers.  And regardless of the problem it solved, the already existing 150mm hubs would have solved that problem absolutely fine.

Never had 20mm, you invented that, weird.

I'm going on record here to say that I definitely did not invent 20mm axles.

Regarding 27.5, it increased the diameter by one inch. Significant improvement, all other things being equal.

I've explained several times now, all other things were not equal.  Multiple factors were changing at the same time in terms of geometry.

Diffent people can be…different. No need to be belligerent, weird or emotional about it.

I agree, and there's no need to start becoming insulting about it either.  Admittedly I started it by jokingly suggesting you were easily taken in by marketing.  However, that's just me.  When you do it it looks like you're becoming flustered.

I’m not sure why Bruce is arguing about a 12.5mm change in radius?

29” front wheels are 31.5mm bigger in rim radius (and bigger still in total tyre radius thanks to wider rims and larger volume tyres). For some riders that’s a bigger tyre than they want on the back, which is where 27.5 is most useful. How many riders want an even smaller wheel on the back?

You're the one who started this by suggesting 27.5 was a significant improvement over 26.

It wasn't.  If there was an improvement it was dwarfed by other geometry changes that were happening at the same time.  A more significant change was the increase in rim width, something that marketing departments didn't feel the need to shout about.  Can you think why?

Here's a hint.  You can change the rims on your existing bike without falling foul of any new standards.

The last new bike I bought came with 19mm rims (on a 2017 bike).  I guess because they were cheap to spec.  I rebuilt the wheels with a 30mm rim on the back and a 35mm rim up front and it was like a different bike.

I'm not against progress.  I am against marketing bullshit dressed up as progress.

the already existing 150mm hubs would have solved that problem absolutely fine.

Not convinced. A 148mm hub fits into recesses in the dropout, making the whole thing stiffer (and marginally easier to fit/line up) than a 150mm hub. Remember, by this time we were also starting to see much wider hubs for fatbike frames too and for a while we had 170, 177, 190 and 197 all cropping up. 170 and 190 basically died off for much the same reason that 150 wasn't right.