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

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bturman
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Durango, CO US
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Edited Date/Time 2/19/2016 3:33pm
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.

Geometry:


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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nmpearson
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Salt Lake City, UT US
2/17/2016 10:59am
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
aw_gooner
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Riverside, CA US
2/17/2016 11:02am
How many hours does it take to get rolling on this thing?
AGR97
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GB
2/17/2016 11:57am
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
Startgas
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SE
2/17/2016 12:00pm
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
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Rocklin, CA US
2/17/2016 12:46pm
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.

P

Shrockie
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Berkeley, CA US
2/17/2016 12:55pm
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".
Varaxis
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Lake Elsinore, CA US
2/17/2016 1:30pm
Make it real and ride it!
RMghost806
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Houston, TX US
2/17/2016 2:38pm
Honestly I think the only hold up for building this would be tires and maybe wheels. otherwise grab some steel and get welding
Skidz
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Seattle, WA US
2/17/2016 2:40pm
Flat bar? Unrideable.
mnebraska
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Manchester Center, VT US
2/17/2016 4:26pm
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...
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............
T-Dawg
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Portland, OR US
2/17/2016 4:55pm
Hell, let's take it up to 52-60 inches. That way - we can all look like TOTAL. A**holes
loris_74
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FR
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2/18/2016 2:29am
Reminds me this 36" bike seen in Switzerland.


This kind of bike makes 26" look awkward.
slimshady
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AR
2/18/2016 3:49am Edited Date/Time 2/18/2016 3:49am
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.
dust
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Seattle, WA US
2/18/2016 8:09pm
I hope it has power steering.
Falcon
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Menifee, CA US
2/19/2016 3:33pm
Q: How big is too big?
A: 39 inches.
4/15/2023 6:47am
Mr. P wrote:
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...
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.

P

Actually bump/rock creates far less resistance for a bigger wheel. Like a skateboard, the smallest pebble will stop the board completely putting you on your face. That same size pebble merely gets stuck in your tread with 26 or 29in wheel, 39 in wouldn't even notice if it did. All this means the wheel will be able to carry more forward momentum. And unless your lazy or simply enjoy a sore bum, you would probably be riding knees bent to carry you just above your seat, creating MUCH more suspension than that silly spring gimmick actually creates. You're welcome.

Fred_Pop
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11/26/2017
Location
FR
4/15/2023 10:50am Edited Date/Time 4/15/2023 10:53am
bturman wrote:
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 [url=http://www.vitalmtb.com/videos/member/Sneak-Peek-2018-MTB-Geometry-and-Standards-Presented-by-Ridiculous-Bikes,29951/bturman,109]previously...
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.

Geometry:


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?

That's a 36incher not 39er. Why they kept the seat angle so slack is strange. If they had a steeper seat angle or bent seat tube then they could have shorter chainstays. 

I messed around on bikecad a while back and came up with this:
Screenshot 2023-04-15 19.48.42.png?VersionId=.

Reach: 515mm

HA: 67º

SA: 77º

BBH: 330mm

CS:480mm

Also trek has been testing bigger wheels:

https://www.pinkbike.com/news/interview-treks-travis-brown-on-experimen…
2

 

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