Bicycle Design

Are beam frames making a comeback?

My post from last year about pro triathlete TJ Tollakson’s 1996 Zipp bike is still generating a fair bit of traffic here at Bicycle Design, so I assume there must be some renewed interest in beam frames.  If the reaction to Graeme Pearson’s Z1-Eleven frame design on the Slowtwitch forum is any indication, there is definitely interest and excitement…among triathletes at least. As mentioned in the Slowtwitch thread, Tollakson himself is coming out with a new beam frame bike next year. Also, the Cycpro tri bikes are picking up in sales, indicating that there is a market for TT/tri bike designs  that will never earn a silly little UCI sticker.

For triathlons that are not governed by the UCI’s equipment regulations, beam designs may make sense.  I am definitely not an expert on aerodynamics, so I don’t know how a disc wheel equipped Pearson Z1-Eleven would compare with something like a Specialized Shiv or a Cervelo P5 in the wind tunnel (or a real world race against the clock). The frame certainly looks aero, but I suspect that eliminating the seat tube introduces new issues to workout with air flow over the rear wheel.  I would love to hear thoughts about that from any of you who are more knowledgeable on the subject of frame aerodynamics.  Beam bikes have always been about more than just aerodynamics though. Comfort is a big part of it, and as Graeme points out, his design “features a beam that can be tuned for flex or locked rigid”.

Pearson will offer the Z1-Eleven frame in standard version and a “radical aero” version (shown here), which features an “integrated aerodynamic front end”, and forks that “have hidden minimalist carbon fiber V- brakes”.  Check out the Pearson Bikes  website for more information about the bikes, and the cars that Graeme also designs.

So what do you think? Not just about the Z1-Eleven, but about these types of frame designs in general. If they make inroads in the sport of triathlon, what are the chances that we will see a change to the UCI’s diamond frame requirement as dictated by the Lugano Charter? I won’t hold my breath, but Pat and the gang are working to improve the organization’s image among cycling fans. Who knows? Stranger things have happened.

 

Images provided by Graeme Pearson

Posted

in

by

James

Tags:

, , ,

Comments

20 responses to “Are beam frames making a comeback?”

  1. cole Avatar
    cole

    From what I’ve read, the idea is that decoupling the drive train from the seat allows the two to have different degrees of rigidity, so that the drive train can be as stiff as possible without the deleterious effect on the rider that occurs when such is done on a standard frame.

    Reply
  2. Nicholas Hardrath Avatar
    Nicholas Hardrath

    I think it’s great. I would like to think there’s always room for some interesting design and engineering efforts – especially where the UCI enforce a lot of the silly laws they like to (most recent, the new rule that outlaws “compression socks”, it’s just ridiculous). I think some true controlled tests need to be done by Mr. Pearson to see whether there is a tru benefit aside from the software tests he has tested on the frames thus far. And let’s be honest (coming from a road cyclist and triathlete)- triathletes will buy into any marketing hype- but I would get behind it with positive results.

    Reply
  3. Champs Avatar
    Champs

    It goes without saying that they’re ugly, but the design is certainly practical for smooth rolling in triathlons and casual rides.

    At the race level, I don’t see anyone wanting to go beam. They’re still working out the engineering to keep saddles in place on compact frames.

    Reply
  4. Nick F Avatar
    Nick F

    I couldn’t be more excited. That Z1-Eleven is beautiful, and beam bikes in general are an incontrovertible affirmation of what concept design and this blog are all about – letting new materials and an open mind build a better machine.

    I hope they take over the racing world (leaving a shamed UCI in their wake) and I hope they trickle down in to more general cycling as well – I’ve been commuting daily on a Softride for about 2 years now and the comfort is fantastic.

    Reply
  5. Bubba Nicholson Avatar
    Bubba Nicholson

    Bicycles do not ride themselves. A spandex “coat” that enwraps the rider, front wheel, rear wheel and drive train would be far better aerodynamically and much less expensive.

    Reply
  6. art Avatar
    art

    I would expect the aerodynamic advantage to be minimal. Rider comfort is key though. I think the market is finally responding to the reality that regardless of what the UCI says about TT bikes, they’re governing races that are a quarter to a third of the length of an Ironman bike leg, and none of those guys are running a marathon when they’re done. The optimal solutions for the two kinds of racing might be very different.

    Reply
  7. Christian Wendenburg Avatar
    Christian Wendenburg

    I have Graeme’s 2009 NZ-1 frame (se my photos and posts). I can tell anyone that Graeme’s frames are AWESOME. I’ve put 8-9 IM races on it, and will continue to use if for IM NYC, IM Cozumel, and IM KONA 2013. Yes, that’s right, I will be on Graeme’s frame at KONA in 2013.

    http://www.facebook.com/media/set/?set=a.459251490758565.124709.100000211550281&type=3#!/photo.php?fbid=459266830757031&set=a.459251490758565.124709.100000211550281&type=3&theater

    Reply
  8. Christian Wendenburg Avatar
    Christian Wendenburg

    I just counted the races I have done on my Pearson GC-1 Concept since 2009. I have done 10 full Ironman races on your frame. So, that’s 1120 miles (1814Km) of racing. That does NOT include the additional number of 70.3 races I have done since 2009 on the frame. So, anyone who wants to know how well your frames hold up, can contact me for validation.
    I stand behind Graeme’s frames 100%.

    Reply
  9. Christian Wendenburg Avatar
    Christian Wendenburg

    Also, by the way….I also stand behind 3T Ventus aerobar, Rotor TT cranks, Nokon cables, KMC chains, Look Keo Blade Ti pedals, and Simkins Eggs brakes.

    Reply
  10. Hot New Urban Commuter « Urban Velo

    […] kidding. Via Bicycle Design. Published by Urban Jeff on June 19, 2012 in News & Views. 0 […]

    Reply
  11. Enrico Avatar
    Enrico

    aerodynamic? is there anything better than a “good” recumbent bike? … even without fairings

    Reply
  12. Ron George Avatar
    Ron George

    I would love to see some aerodynamics testing done against a comparable bike that had a seat tube. Perhaps the best way would be a CFD simulation ? I don’t know if comparing to a other TT bikes like Specialized or Shiv will give you reasonable conclusions, I mean you’d have to be pretty sure you’re only seeing the effects of a missing seat tube when you do that sort of comparison, and other features on the Shiv or Cervelo should not affect results.

    Reply
  13. Kimmo Avatar
    Kimmo

    Beam bikes are win. F*** the UCI; damn them and their retrotech fetish to hell.

    Leaving aside aerodynamics for a moment, such a beam design craps all over the diamond frame from a simple engineering perspective. The refinements and tradeoffs between stiffness and comfort managed with the diamond frame up to this point are all rendered a sad joke when you remove the seat tube and seatstays. Now, you’re free to make the chainstays deep as possible for maximum beef around the BB. And given that it’s a natural for a beam bike to have a separate beam, that introduces a whole world of sizing flexibility, and makes it feasible to offer optimised off-the shelf frames for folks who may be short but heavy and powerful, or tall but light. You could have four or five frame sizes in two different weights (perhaps with a longer head tube option), and maybe as many options for the beam, et voila. But the best part of all? No more futzing around with chainbreakers or special links – just remove a jockey wheel and your intact chain is free. That alone is reason enough to run with any excuse to get rid of seatstays.

    Then there’s the fact that it’s simpler than a diamond frame. And if it’s simpler and it does the job better, it’s more elegant. And if it’s more elegant, it’s more [u]beautiful[/u]. Simple as that; if it looks ugly to you, it just means you’re not looking at it right.

    As for aerodynamics, there are a few thoughts that seem obvious to me… first, air in the region of the seat tube is already turbulent, so my feeling is that changing the silhouette of the bike around here (as viewed from the side) perhaps isn’t going to do a very great deal… it strikes me as diminishing returns stuff. However, seatstays hang out in the breeze, and the brake… and by basically removing everything behind the head tube except the back wheel, it does seem possible there’s quite a bit less turbulence involved for the air passing between the rider’s legs. I imagine the aerodynamics of the rear wheel would matter a little more on a beam bike. At a guess, I’d say the aerodynamics of the Z1-Eleven here would have to be at least as good or better than the best diamond frames, but probably not quite as good as a Z frame like the Lotus Sport 110, which was designed with aero as priority #1.

    That’s my 2c…. you might not think such armchair musings are worth even that, but I’m pretty sure I haven’t gone out on a limb anywhere.

    Reply
    1. Kimmo Avatar
      Kimmo

      No editing is a bummer.

      *beautiful*

      Reply
      1. Kimmo Avatar
        Kimmo

        Hmm, no underlining either. Oh well, got it right the first time I guess.

        Which I’ll have to get good at to post around here it seems, otherwise I’ll look like a spammy mcspammerson replying to myself all the time.

        Reply
  14. Kimmo Avatar
    Kimmo

    Check out the Pearson Bikes website

    Lolwut

    Reply
  15. Ride your bike « Circus Politicus

    […] supers beaux vélos pour aller très vite. Attention à la […]

    Reply
  16. Mike Avatar
    Mike

    Just a few additions from an old rider who used to train and race a Zipp 2001; first, the Zipp frame was tested against the other leading aero frames (double diamond, softride and z frames (hotta, lotus) back in the late 90s/early 2000s and was far faster for aerodynamic calculations. When paired with a deeper rear wheel, that advantage becomes increasingly important. Also, the rider is more aerodynamic on a beam frame with a wider aerobar position than current UCI competitors (it allows for less turbulence over the complete package and greatly reduces the vacuum behind the rider otherwise experienced on a double diamond frame). Finally, the Zipp frame allows for slight side to side movement besides the up and down of the shock in the beam; this allows the rider todeliver far greater power and for a very long time, as it allows the rider to move in a natural wave pattern (all animals move in waves and fighting against this movement is counterproductive for long term performance). I have my own experiences which make me a believer (including hit 78 mph in a national park) but i hope this provides the opportunity for those interested to know that those of us who were lucky enough to race them, there were percieved advantages and for those still skeptical, i hope you understand that it is fine that you do not appreciate a beam bike’s looks, but that is fine, because we are all allowed to enjoy different things.

    Reply
  17. Composite Hybrid Leaf Springs

    […] beams, there are the softride triathlon bikes and there are other people doing things like this: Are beam frames making a comeback? | Bicycle Design Attached Thumbnails     Reply With […]

    Reply
  18. Joe Frisbie Avatar
    Joe Frisbie

    The advantages of being an old fart. When Softride came out with their beam bikes they often railed on about the 14% decrease in aerodynamic drag by losing the seat tube. Also the loss of road shock through the lower spine from the seat tube.

    Of course the bike rides slightly differently but the same can be said with the advent of aerobars and disc wheels.

    Actually unless your putting a motor on it or in it for 99.5% of us does it really matter what the UCI says.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *