Are MTB Wheel Sizes Getting Out of Control?

Mountain biking has evolved massively over the years, and nowhere is that more obvious than wheel sizes. Once upon a time, every mountain bike rolled on 26” wheels. Simple. Easy. No debates. No mullets. No geometry charts longer than the bike itself.

Fast forward to today and we’ve now got 27.5”, 29”, mullet setups, mixed rim widths… and somehow a 32-inch wheel has appeared too. Yes, really — 32”. At this point, it feels less like product development and more like a wheel-size arms race.

So let’s ask the question everyone’s thinking:

Have MTB wheel sizes finally gotten out of control?

Back When 26” Ruled the World

If you go back a decade or two, things were simple:

26” wheels were the only option.

Every bike had them, every tyre fit, every fork matched. Life was easy.

Then someone tried putting bigger wheels on a mountain bike — and that’s where everything started to change.

An old-school Kona Stinky — a classic example of the 26” era that shaped modern mountain biking.

Technically, 29" Came First… But Nobody Wanted It

Here’s a bit of MTB trivia:

29ers actually existed before 27.5”.

But early 29ers were… let’s say experimental. They were:

heavy

slow to turn

limited by poor tyre and fork availability

mostly used by niche XC riders

So while 29” was technically first, it absolutely did not take off.

Most riders ignored them completely.

27.5”: The First Big-Wheel Size to Actually Take Off

27.5” (or 650b) was the first larger wheel size to go truly mainstream.

It hit a sweet spot:

quicker handling than 29”

more roll-over than 26”

lighter than the early big wheels

easier to design bikes around

From around 2010–2013, 27.5” completely changed the industry.

Trail bikes and even downhill bikes — all switched to 27.5”. It became the new “standard.”

For a while, it looked like 27.5” had won.

29ers Return… Properly This Time

It wasn’t until modern geometry, better tyres and lighter components arrived that 29ers made their real comeback. And this time, they stuck.

Updated 29ers brought:

more stability

smoother rolling

better traction

increased confidence on rough terrain

By the mid-to-late 2010s, 29ers were dominating enduro and even downhill racing, something nobody predicted when the early versions were wobbling around trail centres years earlier.

A modern 29” trail bike like the Kona Process shows how wheel size and geometry have evolved — and why bigger wheels genuinely make sense up to a point.

Enter the Mullet: Business at the Front, Party at the Back

Then came the mullet setup: 29” front, 27.5” rear.

It didn’t take long for riders to realise how well this works:

stability and roll-over from the 29” front

agility and clearance from the 27.5” rear

more confident cornering

more room behind the saddle on steep terrain

Racers jumped on it. Park riders jumped on it. Smaller riders loved it.

Suddenly mullets were everywhere.

But with yet another wheel-size combination available, things got even more complicated.

And Now… 32” Wheels Exist

Just when you think the wheel-size debate couldn’t get any more chaotic, someone releases a 32-inch wheel.

Is it a joke?

No. It’s real.

A 32” wheel brings:

insane roll-over

massive straight-line stability

endless momentum

But it also brings:

extremely long wheelbases

slower handling

limited tyre options

extra weight

geometry challenges

a bike so tall it could need its own postcode

It’s niche, unusual and definitely not something most riders will benefit from, but it perfectly highlights how far the wheel-size experiment has gone.

So… Are Wheel Sizes Getting Out of Control?

Yes… and no.

YES, they are when:

bikes become too big for average riders

trends change faster than riders can keep up

geometry pushes extremes

smaller riders struggle with big wheels

choice becomes confusing instead of helpful

NO, they aren’t when:

modern bikes genuinely ride better

riders get more options to suit their style

geometry improves performance

mullet setups solve fit and clearance issues

The real issue isn’t wheel size — it’s assuming one size suits everyone.

What Wheel Size Should You Choose?

Forget the marketing. Think about your riding.

29" suits riders who want:

stability

smoother rolling

confidence on rough terrain

enduro-style speed

27.5" suits riders who want:

pop and playfulness

quick acceleration

easier handling

more fun on jumps

Mullets suit riders who want:

stability and agility

better clearance on steeps

a balanced, confidence-inspiring bike

32" suits riders who want:

straight-line speed

extreme rollover

attention

a new challenge in garage storage

Where Does It End?

Honestly? Probably nowhere.

As long as bikes evolve, wheel sizes will keep shifting too. Maybe 32” stays niche. Maybe it becomes normal. Maybe we end up with a 36” downhill bike one day.

But here’s what really matters:

Modern bikes — whatever the wheel size — are the best they’ve ever been.

Riders now have more choice than ever, and that’s a good thing.

At the end of the day, the best wheel size is the one that makes you excited to ride your bike.