I run a 27.5 because I'm short (5'5") and find I can control the bike better, than with a 29 tire.

I spoke to someone at the trail yesterday and he said 27.5 is better at climbing... but he has a 29er.

I don't know if what he said is true, so I ask here...

There are reasons to go with one size over the other. Climbing is not one of them.

If anything the 29er should climb better. It's physics. As for rider size, my ex g/f is 4'10" and rides a 29er.

im 6-2 and 240 and love riding my 27.5 compared to my previous 29

Honestly i had lots of 26 and one 29 buyed 1 year ago.
The bike with 29 seems to be easy for climbing because the whells height roll easy on rocks and small bumps. But the 26 is a lot more agile.
For me a 26 without rocks and perfect terrain will be a lot more faster than 29 , but at the same time in a bad terrain a 29 seems to be more faster because the rocks and bumps do not impact on the bike overall handling.

The 29 tire will have a greater contact area but whether this is going to make a noticeable difference on the trails is doubtful. When buying many bikes one needs to decide if the size of the tire or the model is more important. My Specialized Stumpjumper was available only with 29 inch tires as was my Scott Scale. If I wanted 27.5 tires I would have had few choices. The bike manufacturers made the choice for me.

Go mullet, young man, go mullet!

Maybe he meant that for any given gear ratio the smaller 27.5 was easier to turn. There was no way I could pull the steep pitches around these parts with the 32 x 42 my bike came with. Because I like high volume tyres I ended up with a 26 x 50. Put me on a 29'r I'd need a Sram 52 cog. At least.

Lol. I wouldn't speak to that person again.

In order of importance as far as "better at climbing" is concerned.

1.) Fitness Level / Strength
2.) Skill
3.) Type of bike...Hardtail or full suspension...Some full suspension bikes suck at climbing due to pedal bob.

Least important...

4.) Tire size.

It does not matter what mountain-bike you use as long as you are well practiced in riding and handling it. A good rider that is used to their bike, who is in good shape and well practiced will out-ride and perform any rider who is not in shape, used to their equipment or practiced. As long as your bike is maintained and reliable then it can do anything you can do.

Periodically bicycle manufacturers have to change minor things about bicycles just so they have something new to market and can maybe sell new equipment to those who believe that the equipment makes a worthwhile difference. In any riding it is the rider that is 90% or more of the equation as long as the bike, whatever it is, is reliable. You could buy a $10,000 mountain-bike, and a pro will beat you on any course with a thirty-year old used 20" bmx bike.

I never would have predicted this, but my 5'5" wife's 26" Santa Cruz Superlite was stolen a few months ago and replaced with a 29er. This transformed her riding and she's a better climber (we have pretty serious ascents in socal) and better and more confident at bike handling. There will be all kinds of opinions so who knows why she improved so dramatically.

There are many differences between an old 26er Superlight and a pretty much any modern bike beyond wheel size. Modern geo is a major improvement for both climbing and descending and overall stability for most riders.

The aspect that surprised me and the objective of the post was that an individual relatively diminutive in size was comfortable on a 29er in the event that this was a concern for the OP.

I can only compare 26er to 29er as I recently (finally!) upgraded from an old hardtail with 26er to a new full suss (140/130) trail bike with 29er. I will also get a new hardtail with 29er.
I am pretty tall (190cm) so the large wheels feel good to me. I have only very limited experience with 27.5er when I borrowed such a bike.
Of course, as already pointed out, there is much more than just wheel size and my new full suss has many advantages over the older hardtail with 26er besides the wheels.
The 26er were very agile and great for tight u-turns on narrow fire roads and trails. My 29er climbs really well but as already said, I have limited experience.

If possible try out different bikes, ideally with a very similar overall setup so you can compare the differences between the wheels without adding too many additional variables like very different geometry, suspension, etc.

2 Thumbs up for this one

I have all 3, on the trails the, 29 does not have as much tendency to wash out the front wheel, and is much smoother over the ruts. I don't notice much difference between the 26 and 27.5, they are "snappier" and have a sharper turning radius.

27.5..........or for that matter 26 will have a shorter turning radius and will be better for turning in tight spaces.

29ers are better for rolling over large objects.

I tried a 29er a few years ago and did not like it. It was ungainly. I prefer my old 26er Cannondales with the Headshok.

None of these are any better climbing hills than the others unless you factor in that a smaller diameter tire will give you slightly lower low gearing. That is really a moot point since most mountain bike gearing is already very, very low.

I have a 10 mile loop that I run 3 to 4 times a week. It has a lot of variety including multiple switchback sections and about 1300 feet of climbing. I can clear that in an hour six on my 29er, a SB130 FS heavy tank. Granted I have to thread the rocks and swing a little wider on the 29er in switchback sections. My old 26" hardtail is a legit XC race setup... scandium, XTR, sub 20#, blah blah blah. It's always 5 to 10 minutes slower than the Yeti. I've all but given up on the 26".

When 26" was it we were told we needed a 29".
When 29" was it we were told we needed a 27.5"
Now that you NEED a 27.5", it's about time the 26" comes back.....

Or monster gravel, or skinny fat tire, or carbon 26, or ......

Nothing wrong with trying new things for new experiences, but updates in technology make for the difference, not really wheel size. Curved top tubes, aluminum then cf frames, shifting, brakes and other tech had much more to do with mountain bikes getting better rather than wheel size.

Good luck with your search.

Curved top tubes? And what does this achieve besides a certain aesthetic some people like?

Better standover clearance and geometry.

Which can be achieved just as easily with a sloped top tube.

the new E bike , which is basically a current generation stump jumper EVO with a motor From what I can tell, is a mullet bike. The tires are so beefy I can’t really tell at a glance

But it’s supposedly reins in the tendencies of a big travel 29’er to want to climb out of ruts, — Maybe the best of both worlds situation if you’re running longish travel ?

I don’t know I still don’t have enough time on the bike to give an educated opinion

I did note that the analog stumpjumper states that you can run a mullet set up on it too but I didn’t see it available that way from the factory

Off-road motorcycles have been running mullets ups for decades

26 inch is almost dead and extinct
27.5 will soon be going on life support
29er is the king and is here to stay

You were doing so good.

26 is not almost extinct it is still very much used maybe not as much as it was but it is not near extinction or close to dead.
650B is not going anywhere it is an old French size that became quite popular again and will still be around a while. If it were dying I wouldn't be using it and I am using it on my mountain bike and my commuter and have plans for a gravel bike down the road that is 650b/27.5.
29 is fine no complaints not necessarily royalty of any gender but a fine size.

For instance QBP a very large distributor of bicycle parts lists 151 models of 27.5 tires (Not all MTB some have different sizes under those models) and under 29" you get 154 models (again with a bit of a mix and different sizes under that model) and for 26" you get 168 models (same thing as before with maybe a bit more road stuff maybe only because 27.5 and 29 usually is MTB specific where 26 is a bit more catch all) so I think if things were dying and extinct or on life support there wouldn't be nearly an equal number of each tire. If Schwalbe, Panaracer, Continental, Kenda and Cheng Shin (owners of Maxxis and they make some low quality stuff under CST) stop making 26" and 27.5/650B then yes we know things are on the way out. Right now not so much.

I am using both 26 inch and 700cc or 29er and I was thinking of maybe adding 27.5, but cycling trends just change so fast, I am not sure if it would be worth investing in 27.5 wheels. I love my my 26 inch rigid MTB, it was my first real bike I purchased but none of the LBS in my area offers many choices of tires in that size. I am just wondering if 27.5 will meet the same fate as 26 inch has. I prefer frames that are designed to run two different size wheels as it gives me more options.