Bike size & wheel size

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8/7/2017 3:13 AM
Edited Date/Time: 8/7/2017 3:14 AM

This has been on my mind for a while. Over the past 5-10 years we have seen progression of wheel size and frame geometry in mountain biking.

Whilst many felt the move from 26 inch wheels to 27.5 and 29 inch wheels to be mere marketing tactics, it is evident that larger wheel sizes do provide an advantage in certain conditions and to riders with different heights & riding styles.

Alongside this, manufacturers have started to experiment with significantly longer and slacker frames (at the most extreme end you'll find brands like POLE).

Having rode a mountain bike with 29 inch wheels and "modern" geometry, I have picked up speed and confidence on pretty much all terrain. The bike felt more suited to my 6 foot height and long arms.

Some of you may have heard of Greg Minnaar, a 6 foot 3 downhill mountain bike racer. For the first time this season he is riding a 29-inch downhill mountain bike. Not only does the bike look like it fits him better, but he has gained confidence and is actually leading the series (at 35 years old!).

My point is this: It does seem that taller riders often struggle to ride the one-size motocross bikes. Sure you can bolt on all kinds of clamps, bars, pegs and seats, but these often feel like a compromise rather than solution (having tried them myself).

What is the reason for motocross manufacturers sticking to 21/19 inch wheels? Do you think we'll see more experimentation in the future? Is it crazy to think that guys like Jasikonis, De Dycker & Bloss would benefit from big-wheeled big-framed bikes?





8/7/2017 3:46 AM
Edited Date/Time: 8/7/2017 3:52 AM

I have wondered about this as well. When I got my first mx specific bike it was a CR85 Expert. The regular 85 had smaller wheels and that was the only difference. I remember when I would go to race the 80 class my dad would tell me you have a faster bike because you have bigger wheels. I never knew what that meant until I put some thought to it and realized that when you have a bigger circumference of a circle rolling it's going to have more momentum behind it and better roll. I mean just take a look at the supermini class and it pretty much validates this point as you probably won't see a small wheeled 134 in that class.

Why isn't there a "big wheel" MX bike? Obviously because there would have to be a "big" push from all aspects of production. Tire companies, Suspension companies would have to also make stuff to be longer/bigger. To suit one manufacturer. Not to mention basically having to create a whole new race class.

I think if there's a market for it then the companies might try it out. Unfortunately, it's a huge risk and there would have to be a guarantee of bike sales. At that point they would be making a new market. I'm 6 foot tall and I would definitely buy a Honda 23/21 with a larger frame, 450 motor, and a bigger cockpit if It was built right. I bet the ergos of a bike like that would be amazing. It's a pretty cool thought honestly.

KTM/Husky seem like they have the resources to make a prototype. They should look into it.


8/7/2017 4:25 AM

love my Demo 2 with 26in rims... I have ridden 27.5 and 29 in bikes and I like how my bike corners over those bikes any day.

I have had the pleasure of riding up the lift at Northstar with Greg Minaar and he followed me down Boondocks and gave me some awesome feed back as we came down each section, yes shameless name drop I know ... but it really did happen!


2021 KTM 350 SXF
2006 KX250

8/7/2017 4:27 AM

bvm111 wrote:

love my Demo 2 with 26in rims... I have ridden 27.5 and 29 in bikes and I like how my bike corners over those bikes any day.

How tall are you?


8/7/2017 5:06 AM

29ers feel big and clumsy to me.

I do not think large wheels would be much of an advantage. A larger frame/cockpit for the 6' 5" guys couldn't hurt,,,,but is there really a market for that?


Tomac and/or Anderson for 2020.....

8/7/2017 5:22 AM

BobPA wrote:

29ers feel big and clumsy to me.

I do not think large wheels would be much of an advantage. A larger frame/cockpit for the ...more

What model/year 29er did you ride?

I rode an old Orange 29er and it felt quite weird and clumsy. However with the recent geometry changes most manufacturers have now gotten it right.


8/7/2017 8:01 AM

Honda tried a 23" wheel, didn't work so great.
Personally I like my 26" mtn bike.


8/7/2017 9:40 AM

Manufacturers don't do this because of complexity. It would require a different frame, otherwise the geometry would change due to the increase in ride height and trail. Also, AMA rules require specific wheel sizes. Not sure about FIM.

I'd be very interested, however; I've ridden a modern 27.5" MTB and compared to my 26er it was a night and day difference. (There were plenty of other advantages as well, but the wheel size was definitely noticeable.)

I could imagine different-sized bikes for SX vs. MX, in much the same way that MTB disciplines seem to prefer different wheel sizes for different sports.


Braaapin' aint easy.