The Roundtail: ringing the changes in frame design?

Sixty times the shock absorption of a traditional diamond frame, plus 'esoteric' looks...

by Dave Atkinson   April 10, 2011  

Roundtail bike

Anyone who's ever read anything written about bikes anywhere will probably be aware that the holy grail of bike design is a machine that's – let's all say it together – laterally stiff yet vertically compliant.

So when we saw the Roundtail on Bikebiz and read that Finite Element Analysis shows that the design provides ten times the vertical flex, and over sixty times the shock absorption, of a traditional frame... well, we were intrigued.

The man behind this brave new world of bike design is Lou Tortola of Windsor, Canada, whose epiphany came when he was out riding one day. What, he wondered, if you could do away with the straight-to-your-bum seatpost and replace it with something else? The something else he came up with, as you can see, is a design incorporating a ring at the rear instead of the usual triangle. Lou got experienced framebuilder Paul Taylor to knock up the prototype you can see in the video.

So what are the advantages? Well like we said at the top, the vertical compliance numbers thrown out by the big finite element analysis machine are very impressive. Tortola also claims that "the unique shape of the rings is expected to provide aerodynamic advantages" but we'll bite our tongue on that one; there seems to be an awful lot of metal involved and we'd be surprised if the Roundtail was any more aerodynamic than a standard diamond frame.

another claim is that the Roundtail "is ideal for promoting the corporate sponsors that cycling teams so greatly depend on", presumably because of its distinctive shape although you could also stick a panel in that circle if your company branding is the right shape... not sure what the UCI would think about that though.

And any disadvantages? Well, we'd encourage you to have your say on what you think of the bike's looks, as well as how you think it'll perform. Here in the road.cc office opinion isn't really that divided, we're afraid: it's an odd looking beast and no mistake. The charitable voices were calling it 'esoteric', whilst others were suggesting that it looked like you'd forgotten to unlock your bike after leaving it in town, and ridden away with the bike stand still attached.

The bike has been on show at the San Diego Custom Bicycle Show this weekend but currently there's no date for a full launch; the Roundtail website is still not much more than a picture of the bike. But when we hear more we'll let you know...

16 user comments

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have a feeling that won't be getting uci approval any time soon....

posted by henryrobertshaw1 [38 posts]
10th April 2011 - 23:19

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henryrobertshaw1 wrote:
have a feeling that won't be getting uci approval any time soon....

Is that because it costs too much to get approval, It doesn't comply to the secret UCI check list, because the design is less than 100 years old, or all of the above? Devil

That said it is just stretching the double diamond a little Thinking so it's not so far out there, and for what it's worth I'd ride one Wink

posted by 37monkey [143 posts]
10th April 2011 - 23:37

1 Like

I scoffed when I saw this being promoted by Boehmke and thought perhaps it was all a delayed April fools joke. Sadly, it's not.

The Allsop Softride failed because people didn't want to be seen riding a bike that fugly, the price tag didn't help. This is every bit as ugly as the Softride and will no doubt be just as expensive (if not more) for an 'advantage' that can just as easily be achieved within the design of a standard frame or with the addition of accessories.

I've got £20 that says it never gets much beyond the NAHBS / SDBS circuit. And of course tests in Road Bike Action, Wired and Bicycling magazine who will test anything for Schwag.

posted by Velo_Alex [65 posts]
10th April 2011 - 23:43

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I'll tell you something else that's wrong with it:

You drop the chain onto that little ring and you're going to have some serious issues with the chain wearing through what would be the chainstay on a normal bike.

posted by Velo_Alex [65 posts]
10th April 2011 - 23:49

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Few observations:
1. Its a prototype. Perhaps with some refinement, for example slim down the part of the circle that would be the rear stays on a 'normal' bike, might make it more aesthetically pleasing.
2. The trouble with cyclists is they tend to be traditionalists. Even the ones who think they're not scoff when someone comes up with something different.
3. The guy might actually be right - think Obree; how many timetrialists don't ride with tri bars?
4. If he builds it out of carbon fibre and claims it weighs half a miligram less than average all the weight-obsessed monkeys will want one.

Nothing really wrong with this, just we're not used to seeing things look like this.

Ticktock

posted by Michael5 [121 posts]
11th April 2011 - 7:12

1 Like

They all laughed etc. Maybe if they were elipses instead of circles, it would achieve the same effect but be less of a radical eyesore. On the UCI question, it. Would never get sanctioned .....BI cycle means two wheels,not four. I wouldn't be. Seen dead on it and I am known as a champion of all things weird Big Grin

"I thought of that whilst riding my Bicycle" Einstein on the theory of relativity

ribbledibble's picture

posted by ribbledibble [10 posts]
11th April 2011 - 7:27

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That looks aweful! Just cos you put Campag Boras and SR on it, doesn't make it look cool.

And surely if people want vertical compliance, they could get a FS MTB? Are we all getting too soft?

posted by Dane [12 posts]
11th April 2011 - 9:06

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and what is a 'Big Finite Element Analysis Machine'? Can you not run FEA on a design programme on a reasonable PC anymore?

posted by Dane [12 posts]
11th April 2011 - 9:09

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Dane wrote:
and what is a 'Big Finite Element Analysis Machine'? Can you not run FEA on a design programme on a reasonable PC anymore?

You can, but doing it on a Big Finite Element Analysis Machine is much more PRO, is you ask me.

Dave Atkinson's picture

posted by Dave Atkinson [7385 posts]
11th April 2011 - 9:11

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I'm quite excited by this. I take the point about the softride comparison, but I think this actually looks a good deal better than that. I'd like to try one.

Aethestically, if the top and down tubes and the fork were curved the way a Pinarello's are the contrast between the front end and the back would be rather less pronounced and less jarring. Or perhaps a double top-tube like a Jones.

Cool

posted by BigDummy [288 posts]
11th April 2011 - 9:15

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Don't Cannondale Synapses already have curved seatstays, and look a lot better to boot?

posted by Chuck [381 posts]
11th April 2011 - 9:48

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I like Chris Boardman's philosophy when designing his bikes that the shortest distance between two points is a straight line.

two wheels good; four wheels bad

posted by cat1commuter [1345 posts]
11th April 2011 - 11:05

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First of all, Velo-Alex, let me say I'm flattered that you seem to think I work only with great products, not novelties.

Secondly, let me say that I was involved with the beginnings of BMX, Mountain Biking, SPD shoes and pedal systems, HyperGlide cogs, underbar shifting, Mountain Bike Suspension, and the introduction of Ergon grips to the US Market.

ALL OF THESE PRODUCTS WERE LAUGHED AT OR DESPISED BY THE BIKE INDUSTRY.

The bicycle industry thought that BMX was a joke (now it's in the Olympics.) They thought Mountain Biking was the second coming of BMX (which had taken a dip in the 80's.) They thought you would die on mountain bike rides, because you would fall off a cliff 'cause you were clipped in, with HyperGlide cogs, you WOULDN'T BE ABLE TO CREATE CUSTOM COG COMBINATIONS (oh the humanity!)

I had to work for over a year to get the master himself - Ned Overend - out of toe-clips and into SPD. People said "No Way those forks will ever be used for anything but downhill! Top-mount shifters were more reliable (so underbar shifting evolved to be better) and NO ONE could get enough of their hand around an ergonomic grip until a teenie Russian with XS hands named Irina Kalentieva kicked their ass on gnarly XC courses)

There is no problem when using the inner chainring (at least on this double...) and there is less for a chain to get stuck on than a standard chainstay.

As far as the Boardman comment - A straight line is the shortest point between two lines, has the lightest weight potential, and works extremely well ON A SMOOTH WOODEN TRACK where there is no road "noise."

Straight tubes push what hits them DIRECTLY from one end to another. Curved tubes send shock in multiple directions and get dissipated quickly.

The shock absorption of rings is proven. That's why 29'er's ride better than 26'ers offroad on hardtails. Rings take the shock and internalize them to a much bigger percentage than straight tubes.

At this point we are not remotely concerned about UCI Certification (maybe next year we will be!)

We have no swag to give to the editors, and they've all had positive, open minded comments about the bike. They've been around long enough to know there is more than one way to skin a cat.

So anyhow, a lot of people are loving the design. Open your mind and take a chill pill. There's room for "different..." And it just may be better for most situations.

peace - SB

chunkyflyrite

posted by chunkyflyrite [1 posts]
13th April 2011 - 1:24

1 Like

Well said and I for one quite like it ... although I'd
have to also agree with bigdummy on the front triangle
"jarring" Smile

still on the 3rd switch-back of Bwlch !

posted by therevokid [714 posts]
13th April 2011 - 9:58

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KOOK-a-palooza!

posted by Viro Indovina [79 posts]
13th April 2011 - 13:57

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Surely it's missing ring forks?

posted by wheelist [5 posts]
13th April 2011 - 22:21

1 Like