Saturday, August 07, 2010

19 Alex Moulton Explains His Design Studies

Dr. Alex Moulton is a source of inspiration for me as a young engineer. I encourage you to watch these videos to see how a great mind thinks. The message couldn't be clearer. Good engineering is a hands-on job. If his biography weren't so expensive, I'd voraciously consume the book in one sitting overnight.


Mark Sanders Explains His Strida Concept
Design Case Study : Innovation Of The Brompton Folding Bicycle


  1. Its interesting that he states he found just tire inflation alone makes significance to rolling resistance. Every now and then, you hear another bike guru come and hammer into you that size of the wheel impacts rolling resistance. So really, a 29 inch wheel is not overly superior to a 26" inch is it?

  2. ...alas not affordable. :(

  3. Did I just hear him say 8000 pounds? :)

  4. His engineering ethos is admirable. The quote "...measure measure measure. Remember: nobody owns the laws of Nature." was music to my ears. A question I had after watching the video, though, is why haven't his essential conclusions about bicycle design--small wheels with high pressure tires, front and rear suspension, and a frame with no top tube--been adopted and experienced widespread use on road bicycles if these conclusions have great merit from an engineering perspective? I wonder if he knew or worked with J.E. Gordon. There's a tea I would love to attend.

  5. John, I think the idea has taken off with folding bicycles - when you look at the Strida or the Brompton or the Bike Friday, they all have small wheels don't they? Traditional bike geometry is just that - traditional. It won't allow the use of such small wheels (<20") without some major conflicts. Making forks even longer to accomodate them essentially means you increase their slenderness ratio and now you have to worry a little bit more about flexing and buckling and so on. Or you should keep the fork length the same, increase the length of the handlebars and push your bottom bracket height to a little above that of the front and rear axles from curb.

    What I'd like to know if why his suspension ideas aren't used in road bikes that race on say, the Paris Roubaix. It would be interesting to see the difference in energy consumption of riding two different bikes on the cobbles. Alex stated some 2-3% reduction with his bikes on road.

  6. Anonymous11:38 AM

    He's 89 and he rides 8 or 9 miles? Respect!

  7. Ron I suggest that the prime motivations for the small frames and wheels on folders is for the sake of portability and convenience of storage behind train seats or under desks, and not performance or rider energy application efficiency, which sounded like why Dr. Moulton incorporated them in his designs. Your question about Roubaix also bugs me--it seems with current suspension technology coupled with the large budgets of cycling teams, some combination of lightweight suspension with good lockouts for the non-pave sections would overcome whatever the problems were with previous attempts to use suspension on Roubaix, like Greg Lemond, or or team GB-MG:

  8. Anonymous1:20 PM

    Dr Moulton's machines were doing very well indeed at racing during the 1960s until the UCI stepped in and banned them along with all sorts of other subsequent interesting developments. See Graeme Obree etc etc........Nick Rearden

  9. The top most line of Moulton bikes cost some $16,000.

  10. I worked in a shop in Chicago that had a few Moultons. I rode one with Campy Super Record. I loved it!

  11. How did the suspension feel Jameson?

  12. Anonymous11:36 PM

    The problem with little wheeled bicycles is gearing. In order to get the bicycle front gearing to shift faster and smoother Shimano and SRAM keep reducing the size of the front chain rings, which means you have to goto larger wheels (29ers) to get your top end speed back. Bigger wheels also roll over obstacles better, such as curbs and pot holes. Ultimately the little wheeled bicycle will be a market failure.

  13. Anon : Did you forget about hub based gearing systems?

    And how will it be a market failure? i think the bikes have a definite niche and an elegance about them as well. Its unisex, has suspension and is convenient to move around.

  14. Interesting Article !
    NEW blog which i hope will keep people thinking about how they can help Paralympic Athletes get to London 2012 !
    M/while Parrabuddy has some entertaining items whilst content builds during the "Vuelta Espana " for which i need "Sponsors" as i am planning to then fly Madrid to Melb for World's !

  15. There has been front suspension in Paris-Roubaix. A specific fork was built for the race and the setup was ridden to at least one victory.

    It fell by the wayside largely with politics although it's debatable how much it brings to the table really. It's not all that hard to resurrect.

    Small wheeled bikes and frames whose primary load bearing is a single oversized tube have all sorts of drawbacks too. They make a lot of sense for the increasingly popular small form factor folders, but in the entirety of the cycling world that's still something of a niche.

  16. Anonymous2:04 PM

    RE: Mark's comment about 26" vs. 29" wheels.

    I'd say that 0ff-road riding is a whole different ballgame. It's more about grip and the wheel's ability to roll over obstacles than rolling resistance. Witness the rather rapid demise of semi-slicks for all but the smoothest XC races.

    The Moulton bike is intended for use on the road and probably crushed-gravel bike paths not the roots and rocks of technical single-track.

    What interests me more is studies I've read (or possibly just a study I's seen posted multiple places) where it was determined that on a smooth surface (rollers in a lab) higher tire pressure = lower rolling resistance but in the real world of old, cracked pavement lower pressure actually led to lower rolling resistance. The conclusion was that a high pressure tire bouncing off all the bumps in the road wasted energy. I wonder if the suspension on the Moulton bike helps keep the tires on the road over small bumps and over comes this?

  17. Anon : The presence of the suspension does not mean you can pump up your tire upto 140 psi if that's what you're getting at.

  18. Anonymous1:25 PM

    Ron: First off, apologies for my rather badly written reply last night! It's embarrassing to see all the mistakes I made, I must have been more tired than I thought.

    I wasn't saying that suspension is going to give you all the advantages of running tires at a lower PSI but it should give some (from a comfort POV).
    Especially when you consider:
    -The lighter weight of the unsuspended parts on the Moulton due to the smaller wheels.
    -The small amount of suspension travel.
    -The style of damping (especially on the front) which is probably better at absorbing small road imperfections and vibration than the more "conventional" bike suspension on mountain bikes.

    Of course I'm not an engineer and I've never been on a Moulton so it's all conjecture on my part.

    When Mr. Moulton was talking about the 2-3% efficiency increase over a regular road bike I did wonder if some, or all, of that was due to less aero drag from the smaller wheels than a decrease in rolling resistance.

  19. I've never sat on a Moulton either. Yes, the unsprung weight on his bikes don't seem to be that much. Its a good design. As far as his study goes, if any of you others know where to get hold of it, let us know. I can't make any conclusions without reading his experiment design. It could be very well possible that the 2-3% power output decrease for the same speed might have been due to aerodynamics. Good point.


Thank you. I read every single comment.