Monday, May 08, 2006


The wire beading in my rear tyre has worn through its housing.

This is giving me punctures every 2 days or so - which makes a change from my ride from England to China, 20,000 km without a puncture.

(Or, one puncture, but it didn't count because it came from a spoke-hole, and my wheel didn't have any rim tape in it....)


  1. Ed,

    20,000km without a what's the secret?

    I had a Japanese guy the other day try to talk me into the resin tyre treatment trick where they inject an elastic resin into your tyre, meaning that your tyre is a solid resin no puncture machine. Sounded like a good idea apart from the extra 3 or 4 kilos it adds to the bike.

    So, what's your secret? Just pure luck?

    (If you don't mind telling the story for the 100th time).

    - Rob

  2. How many revolutions of the wheel is 20,000 KM cos you could then work out the odds against a puncture.

    That would be a wicked complex bit of maths to do.

  3. RT -

    You can get this green stuff called Slime, which you inject into the tube and it self-seals small punctures.

    But I didn't have that. I had a set of Schwalbe Marathon Smartguard tyres, which have a built-in layer of something blue. The blue stuff seems to stop anything sharp and pointy going through.

    Anyone from Schwalbe reading, can you pay me for saying this, please?


    LOIQ -

    Sometimes when the going is boring, I sit there pedalling away and work out how many revs I have left between wherever I am and England.

    Invariably, though, I forget the answer. Which is quite useful, because it means I can do all the sums again the next day, too.

    Keeps the brain ticking over while the legs are pumping....

  4. Thanks Ed. I got me some of those smarty pants Schwalbe tyres a while back, so it looks like I'm on the right track...

    All I need to do now is......

    Argh. The list is too long.

    First of all it looks like I need to get Loiq working on some certain odds so that I can start taking bets.

    - Rob

  5. oh well it was just a question I must say as I've just cleaned the bike I was seeing how far it was to the pub. I feel much better now for having cycled "hick!" but coming back along the canal was really very suspect.

  6. Wheel revolutions in 20,000km

    Using 700c wheels with 28mm tyre (typical wheel + tyre diameter of 680mm)

    680mm x p (3.14) = 2,135.2mm

    20,000km = 20,000,000m = 20,000,000,000mm

    Therefore 20,000,000,000mm divided by wheel circumference (2,135.2mm) = revs in 20,000km

    = 9,366,804 revs

    Using 26” wheels with 1.75” tyre (typical wheel + tyre diameter of 643mm)

    643mm x p (3.14) = 2,019mm

    20,000km = 20,000,000m = 20,000,000,000mm

    Therefore 20,000,000,000mm divided by wheel circumference (2,019mm) = revs in 20,000km

    = 9,905,894 revs

    So using 700’s saves you about half a million revs in 20,000km, maybe the penny farthing wasn’t such a bad idea after all!


    Albert Einstein

  7. Ok that clears that! however why does it seem further too the pub and closer once I've been at a few pints of wife beater? aka stella artois, kronenburg 1664, Lowenbrew, Tennants Super or Special Brew in one big glass with a straw.

    So leave the drink alone kids! It's not big nor clever to look all messed up and go shopping in your local 7-11 around mid-night.

  8. Albert,

    Thank you for your great knowledge that you have bestowed upon us.


    What's the odds of getting a puncture?

    - Rob

  9. Hi Albert -

    I did the sums the other day from a less theoretical, more hands-on (or should I say feet-on?) perspective.

    I counted 294 pedal-revs in one fairly average kilometre bobbing along in a fairly average sort of gear at a fairly average sort of 15 k/h.

    Which makes about 29,400 revs in an average-ish 100 km day; say 2,940,000 revs from here to Exeter (say another 10,000 km), and around 12 million revs UK-China-UK (something around 40,000 km).

    I am trying to work out whether that sounds like a lot, or a little.

    You reckoned on about 10 million revs for 20,000 kilometres, which is not far off double my count.

    But I don't plan on counting all the way home, to establish which of us is right.


  10. Odds for punctures well this is even more complex. I've looked at both Al's and Ed's figures and am currently thinking right hard about it.

    will let you know

  11. Edward, I was talking wheel revs not pedal revs!

    Pedal revs would depend on the gear you were pushing and would constantly vary on a multi-geared bike and stop when free wheeling. The only way you could sort out number of pedal revs over a given distance would be to ride fixed wheel, or count them. Don't suppose you'd fancy that though, fixed would be misery and imagine losing count and having to go back and start all over again!

    Best wishes from the grave

    Albert E

  12. Right I'm going to start my master piece.

    The theory of punctures and the probability there of for a journey of approximatley 1000 meters.

    I have measured the road ouside our studio/ office it's close to 3m wide (bit hard to measure when there's loads of car snotting past)

    On my road bike the contact patch is approx 1.8cm x 1.2cm x2 as there's two wheels on my mountain bike the contact patch is slightly larger at 3.2cm x 2.6 cm x2 as this also has 2 wheels.

    to make things fair I added 2 control points each was a 2m x 2m marked area into each I put 20 drawing pins (this represents chance) the bike history

    racer has done about 300 kilometres (bit new but has had a puncture, when valve stem became detached from inner tube think it was faulty from manufacturer) mountain bike has done about 10,000 kilometres hard to judge mainly used as down hilling and cross country so no real ability to judge distance just pain value.

    So to the test

    2 runs per bike
    1996m road riding with normal hazzards per run
    2x 2m high risk areas with a total of 40 drawing pins (this area has to be negotiated with eyes closed to avoid trying to weave through the pins)

    Data is still coming in but I believe the results to be disappointing. So we're going to the pub to work on our findings in more productive surroundings.

    The only thing this test did prove that it was friday today, sunny and we did no real work at all afternoon. BRILLIANT!

    results to follow

  13. loiq,


    I look forward to the results.

    - Rob

  14. Got a have hangover and data still inconclusive but the pub raised a number of other interesting points. Till the lager ran out and maths got some complex we all had to go for a curry to continue the thinking process.

    Our findings all material's hazzardous to tyres will sooner or later end up on the edge of the road, Subject to voulmes of traffic. So cycling in the middle is better for tyres as you'll get less punctures.

    You'll probably get run over before you get a puncture. Maths to follow once I piece my life back together and head ache goes away abit

  15. New hangover! only went out for a quick beer, somehow turned into another beer marathon. shaking, skin all cardboardy, lips all dried up and cracked up, eyes all sunken in, feel sick, got a headache and de-hydrated I guess. Going back to bed!

    still can't give proper answer re punctures but we developed the theory a bit further hope I can still mkake sense of it when it's complete should have tried this while at uni might have gotten better results.

  16. hangover was so bad wnet owt for a drink to settle the old tum. toally arsefaced! crpa more later

    data still inconclusive appart from we got no flats on test.

  17. Loiq,

    When it comes down to it, really it is only a simple matter of two-dimensional kinetics. You know, where the positive-y velocity is offset by gravity in the negative-y direction.

    However the more that one contemplates the concepts of this two-dimensional rotational space, the more one feels the neccessity of a three-dimentional kinetic component...Something simple like |p| = f = sqrt (vx2 + vy2), where p indicates punctures, and f indicates frictional forces of the tyre (could also be replaced with r, indicating rolling resistance).

    However, this poses some issues when we start talking about universal gravitation. Now, I know what you're thinking. You're thinking "Rob, get real - the only issues would be with the m1 and mE variables". Maybe, but only if punctures and revolutions of the wheel were affected by integral turns, rather than by just multiplication of integration. Quite simple when spelled out like this, aye?

    In any case, this is more just something to think about as you ponder the issues at hand. I'm sure the stuff I've written would make much more sense after a few Fuzzy Einsteins and Newton Gins.

    Ever supportive,


  18. Erm no... to be honest I now have the answer and it's far simpler than that.

    Going to get a coffee, water, orange juice, toast and some headache tablets.

    Will then unveil the answer!

  19. Once again, the 2wheels blog is gripped in suspense.

    - Rob

  20. Rob, aren't you the smarty pants then!!!

    |p| = f = sqrt (vx2 + vy2) eh?

    Trying to bullshit Albert Einstein, really. I think you've been riding around with your head too close to the ground; such proximity of the brain to the Earth's core is bound to make you delusional. You'll be suggesting recumbent cycling's a good idea next!

    I believe all this proves the theory that blog bullshit content is directly proportional to length of subject string.


    Albert E

  21. #@%&. I should have known that Albert could have been watching...

    My sham talk has been uncovered...

    I do think though that Fuzzy Einstein and Newton Gin are good names for coktails. They could come with ice in the shape of subscript or superscript numbers.

    - Rob

  22. Still drinking coffee

  23. need biscuits will be back

  24. Well here we go, taking into account I'm now sober and might become a tea totaller. The following is factual during our test we got no punctures! we covered slightly over 4Km and exposed the tyres to over a 160 objects that could cause punctures.

    This sets the "form" in racing speak so the odds are now dependant on the over all mileage of the trip. size of tyre contact patch and size of earth. Considering the miles Ed's already covered and his puncture appears to be mechanical failure and so won't count.

    Rob - The idea that gravity can cause punctures can I guess be discounted as you'd have to really pedal some to get enough G built up to draw objects into your path.

    Quoting Albert Einstein

    "All this proves the theory that blog bullshit content is directly proportional to length of subject string." So will try to pad this out somemore.

    I therefore believe punctures are caused by "Karma" rather than physical forces which affect all of us and the odds can not be directly calculated. As Karmic forces that protect you from punctures are transient and changes on a daily, hourly rate Blah blah ... So to avoid punctures be nice to other people, animals and stuff, I would add this caviat that objects end up at the edge of the road. This I believe is a fact and so try cycling where possible in the cleanest part of the carriage way. As well as avoiding wobbling around as this put the wheels out of line and so increases the risk of said afore mention punctures.

    I would also add having a friday afternoon in the office carpark in the sun. Trying to calculate something so stupid as the chance of punctures. Then going on a 2-3 day drinking session has cleared the air here. I would recommed it as perhaps a managment exercise.

    So punctures is down to "Karma" man, we might run this test again in the rain after a storming row at the office with some clients to see if we get punctures then.

    The end.

    PS. I feel ill looking at empty beer bottles, but like the sound of a Fuzzy Einstein! It sound refreshing perhaps even a thinking mans cocktail.

  25. My Dearest Ioiq

    Don't be breaking any of those empty beer bottles and throwing them in the road. That wouldn't be good for your Karma, and as you state in your theory would probably then result in a puncture or two.


    His Holiness the 14th Dali Lama of Tibet

  26. Dear His Holiness the 14th Dali Lama of Tibet,

    Or can I call you Your Grace? or Dali? for short, as i feel I know you from your cheerful smile, snappy dress sense and the bloody brilliant interview with Parkinson a few years back. Made me want to rush out to Tibet and kick some commie butts "Rambo" style. Not very peace loving and tree hugging but you know what I mean. They (the ones I'm not supposed to mention incase Ed gets hoovered up and put in the pocky for my slanderous comments. Them that's it!) should give that whole place right back to you and all your other goodselves for sure. Although I never really got why hung aroud with that Nazi fella (who was not a german I might add bit like Big H himself)in the old days whe you where only an itzy, bitsy weenie dali.

    Well anyway thanks again for your insight, you have a good point and thanks for stepping in as I was thinking of. Only for the scientific interest you understand not for the plain urge to smash and destroy stuff. I wanted to smash a few bottles to see how many average bit's of glass you could get and how big the spread pattern could be. Also what danger they'ed pose to cyclists and other road users. As I believe this to be the final piece in this mighty puzzle. On which I have been working ever so hard these past few days. Unfortunatley due to a rather disturbing incident over the weekend in the local winery, a local Nepalese Specialty Cusine Dining Establishment (which is rather good! if you like that sort of stuff) and several other houses which offer fine and delicate ales to taste only (not to slug down like it's the end of the earth) and a chinese centre for culinary delights (the chikin is very rubbery). I find myself unable to look at, let alone touch bottles or be near bottles of beer at present. I was thinking that this could be a sign from your all good selfless self. To stop me slipping down that ever so slippery path to being a durty wee stained dosser. Having to sleep in affordable housing made from recycled carboard boxes.

    Rather than living in the overpriced box made from bricks and mortar which I'm desperatly trying to pay for every month.

    Anyway thanks again for making an appearance and helping me out in this complex world in which we transiently live.

    Till the next time!

    yours affectionatley

    loiq the 3rd

  27. So Edward, how long is the longest thread of at least semi-legitimate comments you've had on this blog so far?

    - Rob

  28. hold on! atleast mine was a properly conducted experiment, with a structured aim. Yours was suspect maths, also Ed's blog has turned me away from the evil demon drink (for now anyway)

  29. loiq,

    I really should have made myself more clear. I was not at all suggesting that this thread of comments was semi-legitimate. I believe that this is indeed compelling evidence for the inner workings of the odds of getting a puncture.

    Your hands on evidence is indeed impressive. A work of art in fact. Maybe you could contact Carl and see if you can't get your findings set up as a art exhibition even. By the looks of the kinds of artworks he has to deal with on a daily basis, your setup could be a winner. Just make sure you serve some Fuzzy Einsteins with subscript number shaped ice at your launch.

    And I will have you know that my maths is very legitimate. All the big words and random equations were taken directly and legitimately from's page on two-dimensional kinetics and stuff on universal gravity.

    I do admit at this juncture however that I have not even so much as touched a science or maths text book since fifth-form. I honestly couldn't tell you what eight multilpied by seven is without the aid of a calculator.

    You must understand that one such as myself who grdauated from uni with an arts degree must rely on my own powers of spinning crap in order to stay at least semi-legitimate in this world of science and technologimical advancements.

    Your theory of karma is much more understandable to a common layman like myself.

    - Rob

  30. Rob

    Don't put your lack of maths ability down to the fact you've not touched a maths book since school.

    I was considered to be a slow learner at school. I got all the menial tasks to do such as sharpening pencils, cleaning the blackboard, oh, and mending the punctures in the maths teacher’s bike tyres. Some little bastard spent his days drinking Stella and throwing the empty bottles into the playground.

    Your two-dimensional kinetics and universal gravity bull shit was great. I was convinced, it was me old pal Isaac Newton who spotted the BS factor. Now there’s a clever man, managed to get a research grant to help finance his cider making business!

    I’ve given this puncture probability thing a bit more thought and I’ve noticed puncture frequency increases during spells of high solar activity. Maybe it’s just coincidence though. Isaac seems to think Edward’s problem probably relates to the huge amount of tinned dace he crammed into his panniers the other day. Something to do with gravity he says. Could have been Asmund though; he’s taken up Voodoo, I saw him the other day with a little bearded doll on a bike, he was sticking pins in the bikes tyres. I believe he punctured one of his beloved pink rubber gloves by accident at the same time. Oh well they say what goes around comes around.


    Albert E.

  31. Have you seen the short list of pieces for this years turner prize?

    changing the subject slightly.

    Erm hang on.................

    right back..............!

    Nope! Still no good can't open the beer bottle still feel sick at the idea of lager.

  32. Sounds like you've been innoculated right and proper, loiq.

    For those who can't be bothered Googling the Turner Prize:

    Turner Prize 2006

    Must admit, that's the first I've ever heard of the Turner Prize.

    - Rob

  33. Rob, you've never heard of the Turner prize!

    Shame on you, I thought you said you had an arts degree as well. What kind of art did you study exactly?

    Love & Stuf

    Tracy Emin xxx

  34. Hope your finger is better? and your leaving the cooking sherry alone.

  35. That Rob fella is a foreigner! He might talk the englishe but he aint no englishe! I think? no self respecting english "tommy" would ride a suspect looking push bike like that!

    tried some red wine aawwwghh!

    Question for Ed how much of your diet is lager based? as it's good for Carbs I guess.

  36. Rob,

    A language eh?

    Ummmmm, let me think.

    Is it BULLSHIT?

    Einstein seems to think so.

    If it is you could find yourself very well qualified to enter the Turner Prize. It worked a treat for me. That silly bugger Charles Saatchi was well taken in by it. Sold the old fool a ropey old tent I'd had in the loft for years for thousands.

    One of those ridiculous bikes you ride could be just the ticket. Just spred jam on it or something and write a bit of BS. Watch out for that old bugger Brian Sewell though. He can smell bullshit from halfway round the World. Oh what a coincidence, that's just where you are!

    Bye for now.

    Tracy E xxx

  37. Yeah! I got right seen off by that old fake Tracey E. She done me right proper! So bad in fact I had to burn the lot and get me dosh back from the insurance. What a palava mate! Talk about the emperor's new clothes.

    I was a right MUG!

    What was worse that other fake bloke got all the ashes and made a packet saying even the ashes was art like. Sold the lot and never gave me nothin.!

    So don't get taken in by all that rubbish and put your money into lard it's new and happening. I would be interested in having a gander at the bike and jam sounds very new wave! Is it a statment about being able to avoid jams by using pedal power? It's a all green wave, it's gonna be huge.

  38. Rob,
    Just watched your video bloody good, however I wanna see some offroad action! only bit you did was what 6-10m and the whole thing shook like mental

    Get out there get some downhill rough as you like cross country, cos I think something will drop off! for sure!

    I need a drink!

  39. Rob,

    it's not perfect but shows how roadtraffic clears two central channels on gravel roads.

    If by the way you end up in iceland you've gone too far.


    close but no cigar


    double crap let's try this!

  42. loiq, thanks for the link. I will check it out when I get back from this country of suicide drivers (China) to the land of civilised driving (Japan). Just spent two hours in a car on the China freeway south of Shanghai. Madness, complete and utter madness.

    Re the shaky camera, check out my suspect atatchment method, and you'll know why.

    - Rob

  43. very suspect attachment indeed, but not bad for a fews bits of string an aboriginal dart gun, elastic bands and camera. Very A-Team. but a fine looking washing rack.... will you be bringing it along on your trip?



  44. The washing rack is a bit too cumbersome to fit on the bike, so no, I won't be taking it along ;)

    The camera pole however, I will be. I have some ideas in mind for some 'quick release' attachments so that I can attach the pole to different parts of the bike at different angles. Hopefully they'll end up being a bit more sturdy!

    - Rob

  45. to be honest I've filmed stuff on bikes, paragliders, ski's and skateboards etc. You need a really wide angle lens looks like your already getting vignette from wide angle adaptor? so you'll probably have to live with the vibration aspect.

    due to weight of camera/ head at end of pole or make a gimble arm as counter balance.



  46. CW, first time I have ever heard of a gimble arm but after a quick search, looks like it'd be a fun project to work on if I had time.

    The vignette is from the cheap little semi fisheye lense that I have. I could zoom it out, but it all gets a bit tricky. You see, the lense attachment is magnetic. But the magnet is not strong enough to hold when it gets bumpy. Therefore, I have a very sophisticated set up consisting of narrow strips of duct tape to hold the lense on. In any case, if I were to try to use the zoom with this setup, I'd burn the zoom servos out.

    But it does the trick...


  47. Everydays a school day.

    Try gaffa taping the camera to your head you get some right mad look footage if you increase the speed in post.

    Whats' black and white holds the world together?

    duct tape is fine and then just be happy with getting footage as it will have a value which can not be calculated by others.

  48. loiq, that how to drive in Iceland video is good fun. It brings back memories of the old 1978 Toyota Starlet I had when I was in uni. Twas good fun to take the old bomb down out of town and slide around the gravel roads...

    - Rob

  49. toyota starlet you devil!

    I too have bombed down tracks like those in a crapped out mini very Italien Job.

    Great days! I might go on ebay and buy a mini this afternoon to cause havoc next week.

  50. Puncture lore is a complex thing- there are so many deities getting a look in that you really can never tell which species of small furry animal you should be sarificing to which, when and in what way.

    At the top of the pile, pantheon-wise there's Lord Puncturro, a Baron Samedi character, fearsomely vengeful. He's the one responsible for the nastier punctures- nothing he like better than sending an actolyte to position a tyre slashing bit of glass or flint just where you'll ride over it, in the mud five miles from anywhere on a wet windy off road route. When you've already punctured at least once already, naturally.

    More minor punctures are the work of the puncture fairy. She moonlights for Puncturro occasionally, specialising in hawthorn caltrops

  51. Now that's what I call an undeniably solid theory.

    - Rob