How Big is Too Big? 39-inch Wheels on a Mountain Bike

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Vital MTB member bturman
109 bturman,109/all 08/01/09 1116 96 6155 939,109/setup 279 1357 2350 169 41

Posts: 1636

Joined: 8/1/2009

Location: Durango, CO USA


2/17/2016 10:19 AM

A lot of odd things come across our desks here at Vital, and this one is too wild not to share. Designer Patrick Ng, who previously poked fun at the growing number of standards and geometry changes in our industry, has come up with a bike that takes the "bigger wheels are better" philosophy to the extreme. It's called the Interpolate, and it has MASSIVE 39-inch wheels.

What's perhaps more interesting, though, is how Patrick kept the riding position similar to contemporary XC bikes using a patent pending pulley steering system. By mounting the fork so far forward and repositioning the steering controls, he's to eliminated toe-wheel collision which can be a problem on big wheel designs.

You can swap sprockets to speed up or alter steering characteristics. It's shown here with a 1.16:1 steering ratio and integrated steerer chain tensioner. Pretty clever.


While just a concept at this point, it makes one wonder if a bike like this could have its place? How big is too big?

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Vital MTB member nmpearson
6087 nmpearson,6087/all 01/06/11,6087/setup 11 8 1

Posts: 11

Joined: 1/6/2011

Location: Salt Lake City, UT USA

2/17/2016 10:59 AM

That's one of the prettier bikes i've seen in a while. I'd give it a try on some of the trails here in utah that are in the desert


Vital MTB member aw_gooner
30835 aw_gooner,30835/all 04/29/14 3 1,30835/setup 2 27 43

Posts: 29

Joined: 4/29/2014

Location: Riverside, CA USA

2/17/2016 11:02 AM

How many hours does it take to get rolling on this thing?


Vital MTB member Gregspecialized
28926 Gregspecialized,28926/all 12/21/13 1,28926/setup 5 90 1

Posts: 5

Joined: 12/21/2013

Location: FRA

2/17/2016 11:10 AM

my friends is 2 meters 11 for sure it would be a solution for these big guys


Vital MTB member AGR97
36532 AGR97,36532/all 07/17/15,36532/setup 6 73 40

Posts: 79

Joined: 7/17/2015

Location: GBR

2/17/2016 11:57 AM

At what point is a bicycle not a bicycle? That's a seated pedaling machine rather than a mountain bike that you can hop, wheelie, manual, and generally throw around. Sketchy if you ask me, I'd rather have more control and 29 is plenty big enough for my 6ft 3 height thank you


Vital MTB member Startgas
28842 Startgas /images/default/avatar/c50.png,28842/all 12/15/13 4 17

Posts: 4

Joined: 12/15/2013

Location: SWE

2/17/2016 12:00 PM

Why not? I would love to try it out!
But I would have made the fork slacker instead so a linkage wouldn't be necessary.
And I don't see any reason to keep the seat tube straight. Bend it, and the chain stays could be way shorter.

Mr. P

Vital MTB member Mr. P
2744 Mr. P,2744/all 05/08/10 37 438 1 1

Posts: 37

Joined: 5/8/2010

Location: Rocklin, CA USA

2/17/2016 12:46 PM

Warming up the arm chair...

Super-long wheelbase and chainstay lengths! Super-stable in a straight line? Turning not so much.

This illustration made me realize that though the attack angle of the wheel to a bump/rock might be lower with the large size, it still has to go over the bump/rock the same amount as the smaller wheel. Meanwhile the suspension in the other bike soaks up the bump/rock maintaining forward momentum. So I am guessing the negatives outweigh the positives at some size.



Vital MTB member Shrockie
25918 Shrockie,25918/all 06/25/13 1 17 91

Posts: 17

Joined: 6/25/2013

Location: Berkeley, CA USA

2/17/2016 12:55 PM

Nicely executed design and rendering.

If your trail/path is long and arduous, lacking tight turns, this would probably get you there faster. A sweet weapon for the "Cross Kansas Trail Classic".


Vital MTB member Varaxis
4776 Varaxis,4776/all 10/07/10 2 55 314 5

Posts: 57

Joined: 10/7/2010

Location: CA, USA

2/17/2016 1:30 PM

Make it real and ride it!


Vital MTB member RMghost806
30660 RMghost806 /images/default/avatar/c50.png,30660/all 04/22/14 4 9 8 1

Posts: 13

Joined: 4/22/2014

Location: Houston, TX USA

2/17/2016 2:38 PM

Honestly I think the only hold up for building this would be tires and maybe wheels. otherwise grab some steel and get welding


Vital MTB member Skidz
5206 Skidz,5206/all 11/05/10 3 1 12 42

Posts: 12

Joined: 11/5/2010

Location: Seattle, WA USA

2/17/2016 2:40 PM

Flat bar? Unrideable.


Vital MTB member mnebraska
9343 mnebraska /images/default/avatar/c50.png,9343/all 07/01/11,9343/setup 5 12 1

Posts: 5

Joined: 7/1/2011

Location: Manchester Center, VT USA

2/17/2016 4:26 PM

AGR97 wrote:

At what point is a bicycle not a bicycle? That's a seated pedaling machine rather than a mountain bike that you can hop, wheelie, manual, and generally throw around. Sketchy if you ask me, I'd rather have more control and 29 is plenty big enough for my 6ft 3 height thank you

its no longer a bicycle when it has more or less than 2 wheels............


Vital MTB member T-Dawg
19887 T-Dawg,19887/all 11/16/12 3,19887/setup 30 136

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Joined: 11/16/2012

Location: Portland, OR USA

2/17/2016 4:55 PM

Hell, let's take it up to 52-60 inches. That way - we can all look like TOTAL. A**holes


Vital MTB member loris_74
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Joined: 6/11/2012

Location: FRA

2/18/2016 2:29 AM


Vital MTB member slimshady
10766 slimshady,10766/all 09/16/11,10766/setup 18 43

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Joined: 9/16/2011

Location: ARG

2/18/2016 3:49 AM
Edited Date/Time: 2/18/2016 3:49 AM

This is the kind of crap which led Waki to become a sort of celebrity on PB, while being not much more than a guy with a wild (and most of the time, boring) imagination outside of that site. There's a fine line between geniality and stupidity, and my feeling is we have been crossing it too often.

Reformed Roadie

Vital MTB member Reformed Roadie
26959 Reformed Roadie,26959/all 08/18/13 9 66

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Location: Paoli, PA USA

2/18/2016 7:24 AM

Kill it with fire.


Vital MTB member dust
39483 dust,39483/all 02/17/16 26,39483/setup 2 12

Posts: 2

Joined: 2/17/2016

Location: Seattle, WA USA

2/18/2016 8:09 PM

I hope it has power steering.


Vital MTB member Falcon
37457 Falcon,37457/all 09/06/15 3 74 1

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Joined: 9/6/2015

Location: Menifee, CA USA

2/19/2016 3:33 PM

Q: How big is too big?
A: 39 inches.