Citroën Day

Citroën Day

A recent ride with BQ contributor Mark was typical: a combination of great training, enjoying the sights, and stimulating conversation. Except that this one was enriched by encountering some of my favorite cars… (I am aware of the many problems cars have caused, and I rarely drive them, but I do enjoy them from an engineering and design perspective.)
After warming up on the Burke-Gilman Trail on our way out of Seattle, Mark and I raced each other up Juanita Hill. This long hill has just enough variation in pitch to make it truly challenging. By myself, I never ride it as fast as I do when Mark is either pulling ahead, or right on my tail. On this day, I thought I had made a winning break, until Mark reeled me in and passed me a few meters from the top. My legs were so exhausted that I hardly could keep the bike rolling on the plateau at the top. (I did a similar from-behind comeback on the climb out of Holmes Point, so we were even.) It’s fun and great training for the long-distance rides we have planned for the summer.
As we rolled into Kirkland, we noticed a rare Citroën DS convertible parked on a sidestreet. Somehow, the two-door body accentuates the futuristic profile of the DS even further.
I explained to Mark that Henri Chapron, the coachbuilder who made these Citroën convertibles, was located in Levallois-Perret, not far from René Herse’s shop. So my bike and this car are from the same place. Then I remembered that my new Herse was made in Colorado… and because original DS convertibles are incredibly rare, this “Décapotable” (convertible) may well have been converted from a standard Citroën DS in the U.S.
Just then, we spied a rare Citroën SM in the driveway. This luxury coupe used a Maserati engine and was probably the most advanced car of the 1970s. As a little boy, I always looked inside exotic cars to see how far the speedometer went. The SM’s goes to 160 mph…
One of the most amazing features of the European-spec SMs are the six headlights. The innermost ones turn when you steer the car. Only Citroën would dare to make a car like that – totally different from anything else on the market, and yet making a lot of sense. Looking inside, we admired the oval steering wheel. From the outside, we could see how the car tapered to the rear for better aerodynamics, which meant that the rear track is much narrower than the front. It’s even more unconventional underneath the avant-garde sheetmetal… You have to admire the audacity!
There was a third Citroën parked on the street, a 1980s 2CV. A much more prosaic machine, but no less audacious. Designed in the 1940s, this utilitarian car had a 602 cc flat-twin engine that revved to 7000 rpm. Who but Citroën would put a miniature race car engine in an economy car? And make the suspension interconnected, so the rear wheels react to bumps encountered by the front wheels, to smooth out the ride? There even was a four-wheel-drive version with two engines, one for each axle…
The 2CV was also one of the last (perhaps the last?) car to feature separate headlights. On this “Charleston” model, they are round and chrome-plated…
After this pleasant interlude, we stopped at a café. To continue the French theme, I ordered an almond croissant, and to my surprise, it was just as good as those I had eaten in Levallois-Perret, where the Citroën factory was located.
Looking at my bike, I realized I really have to re-wrap the handlebar tape… The wear pattern shows that I mostly use the “on the ramps” position that makes the Maes Parallel handlebars so comfortable.
We then continued our ride, with Mark excitedly describing his recent interest in Bayesian Statistics. In short, Bayesian statistical modeling involves specifying initial beliefs by defining a prior distribution and comparing it to each new piece of data, adjusting the distribution as you go along. This is radically different from the standard approach of testing a “null hypothesis”. It eliminates many opportunities for error and yields a more reliable result. It’s also more intuitive – it sort of replicates what we do when we make real-life decisions based on emerging data… (Mark and I rarely talk about bikes on our rides, since there are so many fascinating topics.)
On the way back into Seattle, we saw a fourth Citroën, this one a late-model DS in my favorite color (photo at the top of the post). It was a pretty good day out on our bikes!
Recommended reading: Wikipedia on the fascinating history of the Citroën 2CV.

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Comments (62)

  • ascpgh

    What a ride of fresh automotive coincidences!
    Couldn’t find more Citroens in an area unless you went to ride in the Kentucky Bluegrass around Versailles, Kentucky:
    That is a very scenic area of magnificent horse farms, legendary distilleries with tours and the odd oasis for resurrection of surviving examples of the French marque.
    Andy Cheatham
    Pittsburgh (previously, briefly, Lexington, KY)

    June 30, 2015 at 5:45 am
  • Scott Snelling

    Looks like a fun ride. Does Mark have any recommended reading for Bayesian statistical modeling? Do you have ideas about how to apply it to your bicycle research?

    June 30, 2015 at 6:23 am
    • ORiordan

      It is an interesting subject… here is an article about how statisticians used Bayesian analysis to locate a crashed Air France plane in the South Atlantic.

      June 30, 2015 at 3:30 pm
      • Scott Snelling

        Interesting. I had recently read that Warren Buffett and Charlie Munger basically use a Bayesian statistical approach to analyzing investment opportunities.

        July 2, 2015 at 11:03 am
    • Mark Vande Kamp

      The best articles depend very much on your background and level of interest. The article that had the biggest impact on me was “Bayesian estimation supersedes the t test” by Kruschke. It’s definitely on the technical side.

      July 1, 2015 at 7:35 am
      • Scott Snelling

        The article is quite technical, despite a quantitative background (engineer) I am not sure if I will be able to understand it upon a slow read, but this intro section was quite helpful: “Bayesian inference is merely the reallocation of credibility across a space of candidate possibilities.” “Just as the fictional detective Sherlock Holmes said (Doyle, 1890), when you have eliminated the impossible, all that remains, no matter how improbable, must be the truth.” Thank you for the link.

        July 2, 2015 at 10:58 am
  • Patrick Moore

    Citroen made truly innovative cars, back to the Traction Avant, the world’s first production front wheel drive model in the 1930s. Actually, the initial plans for the 2 CV date from the 1930s, as a few models were hidden from the Nazis when they invaded.
    I owned an Acadiane tradesman’s van for about a year, based on the 2 CV, and around town the miniature 602 cc engine, outstanding gearbox, and good road holding (despite a great deal of body roll) kept the little — 1750 lb — van up with modern vehicles with 5X the displacement. In terms of useable volume and load — 500 KG capacity — to overall size and weight, it must rank as one of the most efficient vehicles ever made. Alas it needed more work that I could afford and I sold it.
    I daresay modern cars are in their own way also technological marvels, but they certainly don’t have the appeal or the fresh-thought approach to technological questions that these Citroens had.

    June 30, 2015 at 6:30 am
    • Jan Heine, Editor, Bicycle Quarterly

      The Traction was an awesome car – my dream car as a teenager. However, it wasn’t the world’s first production front-wheel drive car, although perhaps the first truly successful one.

      June 30, 2015 at 7:44 am
  • Alejandro

    That picture of you looking at the speedometer has brought to me good memories of the seventies, when we, during our holidays, in the spanish coast, used to do the same when we saw a french or German car, at a time, when certain types of cars were so rare in Spain. Good years, the seventies, in regard of car design. Cars are so boring nowadays.

    June 30, 2015 at 7:05 am
  • david

    Et vive la France! Ah! I’m not sure about the inter connected suspension on the 2CV tho…

    June 30, 2015 at 7:46 am
    • Jan Heine, Editor, Bicycle Quarterly

      I haven’t taken one apart, but from all I have read, the 2CV suspension was interconnected fore-and-aft. See for example this scientific paper

      June 30, 2015 at 2:27 pm
      • Garth

        A lot of them look really saggy parked, but when you started them, the leaky hydraulics refilled and the car lifted to its proper stance.

        July 4, 2015 at 12:01 am
  • Luis Bernhardt

    Brings to mind my days in 9th grade in Berkeley, CA, back in the 60’s when I was first introduced to bike racing by one of my school friends. His name was Denis Hammond, and he had an older brother, Steve, who raced locally. Denis would regale us with stories of Jacques Anquetil, and of his brother’s less-than-stellar antics in the local races (crashing in feed zones and the like). I think I went with him once to Peter Rich’s Velo Sport to look at the neat bikes. The family was very Euro; the parents would sometimes drive Denis to school in the family Citroen. It had the air-oil suspension, so just to impress us 9th graders, they’d often stop and lower the car. Very cool.
    Wasn’t there a Citroen with a corrugated metal body that you could take apart with just a screwdriver?

    June 30, 2015 at 8:12 am
  • somervillebikes

    “Only Citroën would dare to make a car like that – totally different from anything else on the market, and yet making a lot of sense. ”
    Just for clarity, the rotating headlight was used on at least two production cars that I can think of prior to Citroen’s incorporation of the concept– first on the Czech Tatra (1940s, pre-communist, when Tatra was a very innovative car manufacturer), and later in the 1940s on the American-made Tucker, another car that was perhaps too innovative for its time.

    June 30, 2015 at 8:38 am
    • Jan Heine, Editor, Bicycle Quarterly

      Individually, most of the solutions Citroën used had been tried before, whether it was front-wheel drive or rotating headlights. Citroën was the only one to pursue them in a mass-production setting long after others had abandoned them. Funnily, I recently saw a modern car ad that touted headlights that can shine around corners as the latest and greatest…

      June 30, 2015 at 1:14 pm
  • somervillebikes

    Refs for the Tatra and Tucker rotating headlights:
    That model dates to 1935, and had a V8 engine with a top speed of 93 mph!
    The Tucker dates from 1948.

    June 30, 2015 at 8:43 am
  • B. Carfree

    I’m not a car person at all. However, I thought I had seen something about headlights that turn with the steering wheel somewhere, so I looked it up and found that the Tucker 48 had a third headlight that turned when the wheels turned more than 10 degrees. I suspect 1948 is a bit earlier than the production year of the Citroen you looked at.
    Of course for all of Tucker’s audacity he was quickly put out of business.

    June 30, 2015 at 8:45 am
  • Jon

    Did you knock on the door to talk to the owner?

    June 30, 2015 at 9:17 am
    • Jan Heine, Editor, Bicycle Quarterly

      No. I appreciate that they park their cars in the street for all to enjoy… but I respect their privacy.

      June 30, 2015 at 1:15 pm
      • Jon

        That makes sense. I can see it both ways: I would appreciate someone respecting my privacy, but I would also like conversing with someone else who loves Citroen’s too (were I this Citroen collector).
        Random question, Jan: When you list a bike’s geometry in Bicycle Quarterly, are the seat tube dimensions center-to-center? In issue 50, the seat tube of the J.P. Weigle randonneuse appears to be a bit longer than the top tube, which seems rare to me. Most builders seem to build equal lengths or make the top tube longer. As someone with very long legs for his height, I am very attuned to looking at that.

        June 30, 2015 at 1:51 pm
        • Jan Heine, Editor, Bicycle Quarterly

          If the owner had been outside, we would have chatted.
          To your seat tube question – we list all measurements center-to-center. It’s actually quite common on taller frames to have longer seat tubes, especially on bikes that have the handlebars not ultra-low, but just an inch or two below the saddle. Raising the top tube a bit allows you to get the bars where you need them without riser stems or ugly extra-tall stems.

          June 30, 2015 at 2:29 pm
  • Steve

    delightful post, Jan. Where did you find the almond croissants as good as from Paris?

    June 30, 2015 at 3:19 pm
  • Jeff Lyon

    My first car was a 1974 Citroen Dyane, which was really a “squared-up” 2CV. Gear shift came out of the dash and was like playing a 4 speed trombone. The suspension was so different from any car I’d ridden in up to that time, I thought I was going to roll over the first bend I went around at speed! Only sold it cause I was leaving England to return home and couldn’t take it with me.

    June 30, 2015 at 3:29 pm
  • John Hawrylak

    very enjoyable. Did all the Citroens have pneumatic suspensions??. I remember they had it in the mid to late 60’s
    Is it possible to have the blog appear in the browser vs just in the e-mail?? I do not see a line to select “View in Browser”.
    John Hawrylak
    Woodstown NJ

    June 30, 2015 at 4:24 pm
    • Jan Heine, Editor, Bicycle Quarterly

      The top-of-the-line Citroens had hydropneumatic suspension until the 1990s. The lower-level Citroens were based on the 2CV and had the interconnected torsion bar suspension.

      June 30, 2015 at 8:50 pm
      • RobStC

        Actually the 2CV did not end up using torsion bar suspension – they did try it in the prototypes, but could not get it to deal with the changes in ride height between laden and unladen.
        The production 2CVs did have interconnected front and rear suspension, through a rod-linked spring mechanism horizontally placed in tubes running along the length of the body. Worked very well, if a bit different from the norm…..
        From an ex 2CV owner!

        July 1, 2015 at 4:16 am
  • Paul Glassen

    Andre Citroen was the odd man out among European auto makers in the 1930s – he was Jewish. During WWII his company was headed by his successor, Pierre-Jules Boulanger, who is said to have ordered slow downs and sabotage of the trucks the company was obliged to provide the occupying German Army. Over a long history, a company that produced many remarkable designs.

    June 30, 2015 at 5:19 pm
  • CJ Arayata

    Heading out from Philadelphia to UW for a Statistics workshop next week…. I bet I’d get along just fine with Mark 🙂
    As a side note, I’ve posted on SiR to look for riding partners/food and drink buddies in the evenings next week (July 6th to 10th). Would love to meet some of you.

    June 30, 2015 at 7:07 pm
  • marmotte27

    No comparison to the very pedestrian cars Citroën makes today. Just as with bikes (and a few other areas) unfortunately the French today satisfy themselves with very second rate things, where they once lead the world.

    June 30, 2015 at 9:31 pm
  • David Brown

    I think the TA Citroens had torsion bar suspension, but that the 2CV and its derivatives used a system with helical springs. The system is described at some length in the Wikipedia article about the 2CV.

    July 1, 2015 at 3:18 am
  • Frank

    My partner just returned from a ‘Bayesian statistics applied to animal movement behaviour’ conference in Scotland! I still don’t understand what she spends her days doing. It meant that I was 10 days without a bike ride or jog (seemed silly to organise a baby sitter just so I could nick out and exercise). I thought about getting a bike trainer, but purchased a skipping rope for $5.95 instead. Have treated myself to a set of Barlow Pass tires now that I have a nightly ‘leave pass’ to properly ventilate my skeleton … thanks for that!

    July 1, 2015 at 3:53 am
  • Matthew J

    Sorry for the tangent, but speaking of bar tape … My understanding is Viva/Toshi has or is going out of business. Viva / Toshi cotton tape is made to a standard with texture and coloring that none of the other cotton tape brands – Planet Bike, Newbaums, Tressostar come close to matching.
    Not sure if there is enough of a market to try and resurrect Viva / Toshi production. A pity if their product is gone for ever though.

    July 1, 2015 at 5:25 am
    • Garth

      Newbaum’s is a disappointment, imo, unless you shellac it. If you leave it bare the minimal adhesive causes it to slip down the bar. The color also fades quickly. Tressostar is ok. I had an idea to dye white tape in artists pigments so they wouldn’t fade so quickly.

      July 4, 2015 at 12:12 am
  • Andy Stow

    One of my aunts in the UK had a 2CV. It had the interesting shift knob that Jeff Lyon mentions above. In the UK, 2CV drivers all waved to each other like (most) motorcyclists do in the states.
    Going up a hill at 45 MPH, if you’d managed to achieve that speed due to a tailwind, the 2CV would lose speed the whole way up. The amusing “turbo” sticker she had on the boot lid didn’t help. I did love the openness and simplicity of the fabric top, though.

    July 1, 2015 at 6:53 am
    • Andy Stow

      I also recall that it only had synchromesh in gears one and two. Not sure if that was peculiar to her car, or by design.

      July 1, 2015 at 6:54 am
      • Garth

        My uncle had a similar car called a Rollscanardly. It could roll down one hill but hardly make it up the next…

        July 4, 2015 at 12:15 am
  • R Luis

    Ha! 2CV – briefly had an insanely modded 2CV with an Aprilia engine. & for sure the Citroen-Maserati was one of the most desirable cars of it’s era. They sell at a deep discount now. Were I in a locale in which long trips were a part of my routine, I’d have one in a heartbeat. Maybe I should move!

    July 1, 2015 at 8:01 am
    • Jan Heine, Editor, Bicycle Quarterly

      Hm, an Aprilia engine in a 2 CV… Wow, from flat-2 to straight-4! I once read about a 2CV with a 4-cylinder Citroën GS engine, which gets me thinking about flat-4s. What about a Subaru WRX engine…? Or perhaps easier, a BMW motorcycle flat-2 should drop right in…

      July 1, 2015 at 10:49 am
      • RobStC

        Back in the 1930’s, the very earliest prototype 2CV’s did actually use a BMW motorbike engine initially, prior to the development of Citroen’s own flat twin…..
        I believe the current BMW flat twins are possible to fit, although the gearbox fittings need a fair bit of work to function properly, plus the carburation needs to be majorly altered. Lots of extra oomph from something like an R80 engine though.
        In Europe there are still a fair number of 2CVs on the road, and a lot of people try to ‘improve’ on the original in all sorts of ways. Apparently someone once fitted a modified Ferrari engine to one – downright scary!!

        July 1, 2015 at 2:12 pm
      • William M. deRosset

        Dear Jan,
        Or a BMW Brick (K-series) motor–side-mount 3 or 4. You’d miss out on the leaking oil rings though given that the motor sits pretty flat at rest (I had to put my K75 up on the center stand or it would emit a short puff of blue smoke every morning. Apparently the problem was common).

        July 1, 2015 at 2:29 pm
  • R Luis

    The motorcycle engine was light, and didn’t rebalance the machine too badly. WRX I’d think would be too weighty. However – brakes were inadequate to say the least. And since it could only be out at night [hello officer] the lights needed upgrading. Flying over the Tappan Zee or GW bridge at 2 or 3 in the AM…no REAL nostalgia for any of that / except maybe the acceleration?

    July 1, 2015 at 11:33 am
    • Steve Green

      The 2CV gears were laid out in the same pattern as used by Ferrari and ZF!
      I had a Charleston, like the one in the picture. By then they had front disc brakes, with extra callipers for the parking brake; they looked like giant V-brakes.

      July 1, 2015 at 4:33 pm
  • TerryA

    In the late 70s I took a bike trip through Holland and West Germany and used to think of the 2CV as a “Te Koop”, with Koop sounding like ‘coupe’. It seemed like every other 2CV had a Te Koop sign in the window, which I later learned means, “For Sale”. I still think of them as ‘te koops’.

    July 1, 2015 at 5:54 pm
  • neilfoddering

    Hi Jan, great post! The Caterham 7 is still being built here in England with separate headlights. We’re still waiting for the 21st. century to arrive here.

    July 2, 2015 at 12:26 am
  • marmotte27

    If you like 2CVs you should visit the Ile d’Yeu, off the French Vendée Coast (
    Lots of people keep old Citroëns (2CV et Méharis) as well as Renaults R4s there to drive around the island.
    On another subject, Jan, you seem to have discarded the cork tape you initially put underneath the tressostar on your bike. I suppose, as always there is a reason to it?

    July 2, 2015 at 1:58 am
    • Jan Heine, Editor, Bicycle Quarterly

      The cork made the bars too thick, and I was getting issues with numb hands. So the thinner bar tape, by itself, seems to work better for me.

      July 2, 2015 at 6:20 am
  • Tom Howard

    During the 70s a couple of people drove a Citroen across the country to visit my college roommate. The guy who owned the car spoke fondly of the car’s variable suspension. But otherwise, the car wasn’t very reliable, if I recall correctly. I doubt the same complaint could be made about Jan’s Rene Herse.

    July 2, 2015 at 3:27 pm
    • Jan Heine, Editor, Bicycle Quarterly

      Unlike the Citroën, which was a middle-class car spec’d to a price, the Herse is built to the highest specifications… And yes, the mechanical audacity of the Citroën means that more things can go wrong. In some ways, perhaps the better analogy is a modern bike with electronic shifting and hydraulic disc brakes. Perhaps it’s lovely when it’s new and working properly, but if it goes wrong, it’s not something that you easily can fix.

      July 2, 2015 at 4:02 pm
  • David Pearce

    Now I have to look up “Bayesian Statistics”.
    Like they say, there are, “lies, damn lies, and statistics!” I look forward to finding out what these are!

    July 2, 2015 at 6:04 pm
    • Jan Heine, Editor, Bicycle Quarterly

      A mathematician once replied to this with “It’s much easier to lie without statistics than with them.”

      July 2, 2015 at 6:20 pm
      • marmotte27

        As you have shown in your tests and analyses, getting good reliable statistics and interpreting them correctly is not an easy task. And it is perhaps not easy to lie *with* statistics (it happens all the time though and it takes some wariness and know how to unmask those lies), but to lie *about* them definitely is easy, and lots of people do it every day.
        Unfortunately, most lay people just dont have the wariness and expertise to see those lies. I say that as someone who once miserably failed the stochastics semester at school (I appreciate your approach to statistics and bringing it accross to your readers in BQ all the more)…

        July 2, 2015 at 9:28 pm
        • Jan Heine, Editor, Bicycle Quarterly

          You are right, it’s not that difficult to waive colorful graphs and big numbers in front of people (even scientists) and convince them of anything… although few cycling studies even bother with statistics to show that their results are meaningful. Most just measure a few things and report that a bottle cage on the seat tube is 2% more aerodynamic than one on the down tube. A statistical analysis probably would show that the two results are within the noise of the data, so they are meaningless.
          During my Ph.D. studies, probably 50% of my classes were about dissecting others’ studies and finding the flaws in them, and then evaluating whether those flaws changed the conclusions or not… It was good training for my current job as editor of Bicycle Quarterly!

          July 2, 2015 at 9:33 pm
  • Jon Blum

    Bayesian logic is now the standard approach to interpretation of tests in clinical medicine. Instead of looking only at the test result, one considers the accuracy of the test, the result, and also the prior probability of the condition. The prior probability is the likelihood of a particular condition before the test is done. The likelihood of a condition after the test result is known is affected by all the variables mentioned above. There are fairly straightforward ways of combining these variables to arrive at disease probabilities (simple algebra), and the Bayesian approach greatly increases the accuracy of test interpretation. In practice, the formal calculations are often impossible at the individual patient level because the prior probability is only an estimate, but Bayesian logic can still be applied in a semiquantitative manner to improve diagnostic accuracy.
    It may sound like mumbo-jumbo and lies, but it really works.

    July 2, 2015 at 6:43 pm
    • Jan Heine, Editor, Bicycle Quarterly

      Thank you for elaborating. It’s surprising how many statisticians there are among the 6-8000 readers of this blog!
      As I understand it, it means that instead of blindly testing the same hypothesis until the very end, the hypothesis is adjusted with every new piece of data that comes in. Which is what you do in everyday life anyhow, just not in a formalized way. Of course, you need a lot of computing power for the formalized implementation of Bayesian logic, which may be why it wasn’t used earlier.

      July 2, 2015 at 6:51 pm
  • Michael

    Speaking of cars… I really enjoyed your article on your Urban Bike in this issue of BQ and how the story of your son’s toy car were intertwined. Made for a very peaceful and somehow restful reading experience – reflections of the years with the bike and the whirring of the car in the background going on. Family comfort on an outing together. Very nice effect.
    BTW, what do you use for security while errands brining around town on the Urban Bike? U-lock? Cable? How do you secure the front wheel when locking up?

    July 2, 2015 at 10:16 pm
    • Jan Heine, Editor, Bicycle Quarterly

      I use a cable lock if I am parking the bike for a short time, and a U-lock and cable for longer parking. It’s perhaps overkill, the rear wheel is bolted on and requires tools to remove… and a 6-speed 650B wheel with 130 mm spacing is probably of little value to most people anyhow!

      July 3, 2015 at 7:34 am
  • Walt

    The steering on the SM for sure and perhaps the DS is unique. I think you’d appreciate it.
    Kinda/sort of a “low trail” car! It’s hydraulically assisted but unusual in that it always returns
    to center. Even when standing still. Turn the wheel full lock (which isn’t much) let go of the wheel,
    it returns to straight ahead.

    July 3, 2015 at 12:56 pm
  • TimJ

    Great photos, love the SM! Most of them burned up as the Maserati engines tended to do that. My favorite cycling/car story: A couple years ago I was cycling on a narrow farm road, really only wide enough for one vehicle. Sensing a car behind me, I kept going for a kilometer or two until there was a widening in the road where I pulled off to let the car pass. It was a beautiful vintage Aston Martin…followed by a dozen more vintage Aston Martins! I always chuckle that I had a few million dollars worth of sports cars patiently waiting for me to get out of the way!

    July 4, 2015 at 12:16 am
    • Jan Heine, Editor, Bicycle Quarterly

      At a bike show a few years back, I met a BQ reader who owns a beautiful Aston Martin DB 2/4. But all he wanted to talk about were our Allroad bikes… He was so excited about them!

      July 4, 2015 at 12:49 pm

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