Archive for Cycling

SRAMs’ wireless bicycle gear shifting: Protocol analysis

It’s pretty rare that I get to blog about both cycling and networking. Hard to see how those two topics share any common ground. That’s about to change as SRAM, the American bicycle component maker, appear to have a wireless gear shifting system in advanced testing.

The system was seen at the Tour of California earlier this year, though disguised with decoy wires to make it seem like a wired, electronic system. It was also spotted recently at the USA Pro Cycling Challenge, now without the decoy wires.

You may ask, why on earth would bicycles need radio-controlled gear shifting? Which is a good question. One benefit seems to be that the wireless shifting weighs slightly less than either a conventional mechanically actuated system, or even a wired electrical one. However, that benefit surely will be very marginal. The lack of cabling may make installation and maintenance easier too. Perhaps. Another possibility is that SRAM were behind Shimano and Campagnolo in delivering an electronically controlled shifting system, and SRAM decided that going wireless would help differentiate their product from the other two. Who knows!

As someone who specialises in network protocols, I’m curious to know how it might work in terms of the messages sent, logical layers of the radio protocol, and how the different components communicate to co-ordinate shifting.

There are obvious questions: Is it secure? Are there any limitations? Will it be reliable? The brief answers to which are, yes it should be secure; yes, there seem to be some limitations over traditional shifting systems; and probably it should be quite reliable, however when it isn’t there could be quite strange behaviour.

The rest of this blog will go into the details of how this system works at a network protocol level, as gleaned from SRAMs’ patent on electronic shifting. It will look at the ramifications of the design decisions made, and also how this could affect the operation of the system in extreme circumstances where messages are lost due to, e.g., radio noise.

The quick summary:

The SRAM system, at least as described in their patent, has a number of limitations that are a consequence of the network protocol:

  • It can not support more than two front chain rings
  • It can not support intentional simultaneous shifting of front and rear dérailleurs

While radio noise is unlikely to be a significant problem, outside of deliberate interference or some unusual locations, should the system be affected by continued noise it may manifest itself as:

  • Missed rear shifts followed by an overshift of the rear
  • Overshifting rear shift, after an apparently normal front shift
  • Combined unintentional shift of both dérailleurs, on an intended front shift

The system should though be relatively robust against interference, due to its use of a low-bitrate network layer. It should be secure, due to use of strong encryption, so that only those with physical access to the bicycle (e.g. the rider) can control the gear system.

The system that goes into production may differ from the system described in SRAMs’ patent, and some or all of of these limitations may not apply to it. We won’t know till it is released.

Update 20150213: I’ve just noticed the very bottom of the SRAM patent mentions that the dérailleurs can transmit their current gear position. The patent mentions this might be used to allow the front mech to adjust its trim according to which gear the rear dérailleur is in. The patent does not mention this being used in the control protocol though, e.g. to have the dérailleurs ACK the shifter messages which could make the protocol more robust to missed messages. However, the hardware described in the patent is at least capable of this, and production systems could be enhanced this way. There may still be issues left in how the system appears to allow for shifting to be distributed over two shifters, I’d need to go back and re-check.

Read the rest of this entry »

Comments (10)

Transport Scotland and its attitude to active transport spending

Transport Scotland had planned to spend £27m on low-carbon, sustainable and active transport, of which cycling is but a part, over  3 years (I presume roughly from 2013 to 2015?). Which makes the annual budget be £9m.

Now, if you were about to hand out £424k of that £9m – just about 5% of the entire annual budget for low-carbon, sustainable, and active transport – you’d do your homework on it, wouldn’t you? You might want a detailed proposal, with goals and metrics, perhaps? You’d want to see some detailed proposals for what the campaign might cover, no? You’d possibly need some back and forth to give feedback and work out the details, which’d generate minutes and emails, right? Surely?

Not if you’re Transport Scotland. No. Transport Scotland, it seems, will hand out £424k – again that’s pretty much 5% of the entire annual, active transport budget – based on nothing more than barely 2-pages of a proposal. A proposal with the scantest of details, and which couldn’t have taken more than 30 minutes to write up. That’s all it takes to get £424k from Transport Scotland, at least in terms of anything that leaves a record, apparently.

This is Transport Scotland’s official stance, made in response to my Freedom of Information request about the commissioning of the Nice Way Code, which they re-iterated to the Scottish Information Commissioner, after I appealed on grounds of incredulity.

I think this stinks of a somewhat cavalier, uncaring, and dismissive attitude both to public money, and to active transport policy in Scotland. I would expect Transport Scotland to be a lot more careful with 5% of their budget for active transport.

I think that’s fairly scandalous.

Leave a Comment

UK Cycling Culture

There’s things I find fascinatingly perverse about cycling culture in the UK, having experienced cycling in the Netherlands as a child. By cycling culture I mean both the culture and norms amongst those who regularly cycle in the UK (and the various sub-cultures), as well as in the general culture.

It struck me most the other week, when I cycled out of Glasgow early on the morning of the Pedal For Scotland event, out along the road leading back to Glasgow Green, where that event starts. There was a little more traffic than normal for a Sunday morning, because of the cars heading to PFS. It hit me that the UK is a country where, every weekend, people drive to cycle. They drive out to parks, country lanes, and sportives. They drive along roads they dislike cycling on, out to those roads to cycle on that are least quiet, if not free of cars. They drive out to sportives on open roads,  looking for a feeling of safety in numbers.

Clearly there is a great demand for cycling. Those ferrying their bicycles on their cars are just the tip of the iceberg – there are surely many more potential, casual cyclists who don’t care enough to invest in cycle racks, etc. Yet, the cycling culture, nay, the entire transport culture is so perverse here.

  • The letter of the law is that children must cycle in with 50 km/h (30 mph), even 65 km/h (40 mph), motor traffic on many roads, because there is no cycle-path provision and it is illegal for them to cycle on the footpath. Only children under the age of criminal responsibility can safely get away with this, as they will not be prosecuted. However, legally, little children are supposed to cycle in amongst fast motor traffic on such roads!
  • Even adults can feel uncomfortable cycling on these roads, and will cycle on the footpaths. The Scottish governments’ answer to this problem of a clear lack of safe cycling infrastructure? Run an ad campaign to tell such adults to grow up.
  • There is never any room for dedicated cycle paths, even though most towns and cities are criss-crossed by multi-lane roads.
  • At best, the cyclist gets either a useless little lane painted on the road that does nothing to protect them from motor traffic, but does bring them through the dangerous door-zone of parked cars; or the footpath gets designated “shared use”, bringing the cyclists into conflict with pedestrians instead, and having to cede priority at every little junction and property exit. The more experienced cyclists often ignore such useless infrastructure, with good reason.
  • A sub-culture of cyclists are derisory of any attempt to argue for quality dedicated cycling infrastructure.
  • A sub-culture of cyclists are afflicted by Stockholm Syndrome and believe in mandatory helmets for cyclists, even mandatory HiViz.
  • Organisers of low-risk cycling events often impose a requirement to wear helmets on participants, typically by justifying it as a requirement of their insurer (even when false, e.g. British Cycling non-race event insurance does not require helmet use), thus condoning the ongoing “dangerising” and de-normalisation of cycling in the UK.
  • Motorists who injure or kill cyclists are given derisory sentences, if they are even prosecuted and found guilty. Even motorists who deliberately knock down cyclists do not go to jail. If you want to murder someone in this country, use a car and claim “the sun was in my eyes” or “a bee came into my car”.

I could go on and on. It’s almost enough to make me despair.

Comments (3)

De Tour van Bauke: English subs

If you’re into bicycle racing, you might enjoy the “De Tour van Bauke” (“Bauke’s Tour”), a behind the scenes look at Team Belkin’s 2013 Tour de France campaign, by Kees Jongkind of the dutch NOS public service broadcaster.

It has a few fascinating insights, such as into the echelon stage where Saxo, OPQS and Belkin managed to split the field; managing egos within a team with several top riders; and generally some of the dynamics within a top WorldTour team. The film doesn’t spend much time on explaining the background, and does sort of assume you’re fairly familiar with how the TdF ’13 played out, and perhaps how the team had had to scramble over the winter before to find a new sponsor after Rabobank pulled out, succeeding in finding Belkin as title sponsor. If those assumptions are met, the documentary is very enjoyable.

I obviously can’t remove the original dutch sub-titles that are embedded in the video. So I’ve had to position the sub titles above, which means I’ve had to use the “Alpha Sub-Station” format, rather than the more common SRT format, as SRT does not support positioning. Ideally, NOS would prepare an English subtitle version, with the subtitles professionally rendered. I did contact someone at NOS to see if they’d be interested – they apparently have their own plans for further releases to non-Netherlands markets, but I didn’t get any specifics. I’d be more than glad to licence the subs back to NOS for web use for free, to say thanks for making “De Tour van Bauke” available on the web.

As some of the Belkin DSes have strong regional accents, I’ve sometimes used regional english words. E.g. in my mind, the english subtitles for Nico should be read with a strong Irish accent – think Sean Kelly 🙂 crossed with Mrs Doyle from Father Ted (“Go on, go on..”). I’ve also snuck in one or two Liggettisms for the TV commentary subtitles!

In order to use these subtitles you need a video player that supports “Alpha Sub-Station” format subtitles, such as VLC 

To watch it with VLC:

  1. Download the documentary from NOS. You have to save one of the following links to your computer, so you can watch it in VLC – watching in your browser probably wont work:
  2. Rename the downloaded video file to, e.g., tour_van_bauke.mp4
  3. Download the subtitles file from OpenSubtitles, and save it as, e.g., tour_van_bauke.ass to the same folder as the video.
  4. Open the video in VLC.

VLC should then automatically play the sub-titles. If it doesn’t go to the “Video” menu, then “Subtitles track”, then choose “Open file…” and manually locate and open the sub-titles file.

Feedback/corrections would be appreciated!


Comments (2)

Why not let the dopers dope?

A not uncommon reaction, in the wake of the Armstrong USADA revelations is to say “well, why not make doping legal? Then at least it’d be fair.”. There’s a number of arguments against this, from vague ones about sporting fairness. However, the most compelling argument, to me, is about protecting the health of athletes.

First though, it’s important to note that those who want doping to be legal can go set up their own “Doped-Cycling Federation” and setup races. There’s nothing stopping them, at least in countries like the UK and USA. E.g. Lance Armstrong can still compete in bike races and tri-athlons that don’t sign up to anti-doping, and which don’t care about the USADA ban, and he has in fact done so. Arguing that doping should be legalised therefore is a redundant argument, because it is already the case, and there are competitions for people who think this way. Body-building has doping tolerant (and intolerant) factions apparently; baseball in the US seems to tolerate doping; there are cycling races without doping controls; etc. etc. Dopers are more or less perfectly free to to dope away in those competitions!

However, many other athletes would prefer not to dope. It can have serious health risks. Both high-consequence risks, such as death (blood thickening from too much EPO; bad blood transfusions; aggressive, accelerated cancers from abusing hormones such as EPO, testosterone, etc), as well as more insidious and higher-probability health problems that can arise from continuous abuse of steroids and hormones, such as calcium-depletion in bones leading to premature osteoporosis, suppressed adrenal and immune system function leading to a wide variety of possible problems (e.g. otherwise fit people being completely floored for months by normally harmless viruses that we nearly all carry without much harm; auto-immune disorders; degeneration of connective tissue; etc).

The list goes on and on, it’s literally as long as the side-effects lists in the advice sheets that come with the substances being abused.

Many people, in and around sport, feel that we shouldn’t be forcing our young sports-people into having to dope in order to pursue their dreams and make use of their talent. They feel athletes should have the option to compete clean. That means you need to provide sports with incentives and measures to discourage unhealthy, unnecessary, risky medical intervention – so that those who want to compete clean have a venue where they can have a decent chance. This is why many sports bodies, including ALL that are affiliated with the IOC (directly or indirectly), are signed up to the WADA Code.

Maybe those measures are imperfect. Maybe they need to be improved. Maybe more needs to be done (e.g. there are credible allegations that some major sports like football and tennis are ignoring their own PED doping problems). However, protecting the health of athletes is a compelling reason as to why we should try to provide doping-free sporting venues, to give them a credible way to compete without having to use risky medical procedures and products.

Leave a Comment

Delayed justice for Lance Armstrong

It’s been over 13 years since Lance Armstrong tested positive for corticosteroids in the ’99 TdF. It’s been over 7 years since L’Equipe revealed that a WADA accredited lab in ’04 had found EPO in 6 samples taken from Armstrong in the ’99 tour. It’s been over 6 years since David Walsh and Pierre Ballester published “L.A. Confidentiel” which included eye-witness testimony that Lance doped, and that his back-dated doctor’s note for the ’99 corticosteroid positive had been a sham. It’s been more than 2 years since Floyd Landis came out with detailed allegations of Land Armstrong doping, including a revelation that UCI made a ’01 EPO positive result go away – a result which the head of the lab concerned, Dr Martial Saugy, has since described as a “suspicious” result which he notified the UCI of, and an allegation corroborated by at least Tyler Hamilton. etc., etc., etc..

There’s more than a decades worth of allegations against Armstrong. None of these allegations had been properly investigated before by a body with sanctioning power. The governing body UCI instead had ignored, even dismissed allegations out of hand or, worst of all, attacked and even sued those making allegations, anti-doping crusading journalists and officials. It’s possible that this investigation came about only because Floyd Landis emailed USADA. The testimony about jurisdiction in the Federal lawsuit suggests that that email may have been key in ensuring that the allegations against Lance Armstrong could finally be investigated by a body with authority to sanction Armstrong but not run by officials cosy with him. USADA reportedly have further analytical results against Armstrong showing evidence of blood manipulation, from his ’08-’11 come-back years.

Regardless of the result of an investigation, it is right that allegations be properly investigated. Indeed, it is crucial for the integrity of the sport. USADA ultimately found against Lance Armstrong, but had he been innocent, it would have been just as important to investigate, so as to clear him. It is important to note that, as a result of Armstrong’s attempt to block USADA, we have the word of a Texan judge to believe USADAs’ processes are fair, and sufficiently robust to satisfy the requirements of due process.

Yet, according to some, the greatest injustice in all this is that USADA is taking 2 months to write up the report on this? A report on one of the longest running doping cases in sport? A case where USADA were sued by Armstrong immediately before giving a finding, then receiving nastygrammes from McQuaid effectively backing up Armstrong, in his attempts to block USADA from issuing its finding. Which likely means the report requires an extra level of legal argument added to it, and double and triple-checking, so as to ensure its reasoning is water-tight against UCIs’ jurisdiction claims. Note that should USADA deliver the report mid-October – the current ETA – then it’ll have taken just 1½ months (not quite “months”), as their finding was issued August 24th.

It is not USADA which has delayed this investigation, or delayed the results.

It is the UCI which has delayed justice. The UCI are corrupt.

Further sources: partial index of Lance Armstrong doping allegation stories.

Edits: Re-arrangement of structure of text, to better flow.

Leave a Comment

Does Cycling Scotland promote cycling as dangerous?

Letter to cycling I sent to Cycling Scotland via their website recently, after noticing how many of the images there “dangerise” cycling. I wonder if their efforts, however well-intentioned, may actually be counter-productive.


In your “About Us” you state a number of goals for your organisation, including goal 4:

Show that cycling is a safe, effective and economical transport option that’s better for the people of Scotland, and for their environment

Every picture on your website appears to show cyclists wearing safety equipment. The section on “bikeability” training – targeted at children – has pictures of children in hi-viz vests along with helmets. Further, though I have not yet looked at your training materials, I assume from the visual message on your website that you also strongly promote safety equipment to any potential cyclists or parents.

I am curious how you reconcile goal 4 with the message you seem to have deliberately created that cycling is so dangerous that it requires safety equipment? A message which is course not grounded in reality, as cycling is little more dangerous than other normal, daily activities such as walking beside the road.

I note that in the Netherlands, which has the best cycling safety in the western world along with the highest cycling rates, there is almost no use of safety equipment. Thus, it is an undeniable fact that helmets and hi-viz are not a pre-requisite for safe cycling. Are you perhaps working against real safe cycling by helping promulgate a false sense of cycling danger, and thus perhaps turning off more people from cycling than you encourage?


Paul Jakma

Comments (2)

Most of your body is not protected by a bicycle helmet

This was a comment on, but they never published it and then closed comments.

First off, I’m really sorry to hear you had such a terrible accident, and I’m very glad to hear you’ve managed to recover from it. Please don’t misunderstand me on that, in what I’m about to write.

I have to say, it sounds like you suffered quite a number of very serious and potentially life-changing, even life-threatening, injuries across your body – the spinal injury in particular. The recovery time and process for several of these injuries would have made quite an impact on your life. The important thing to note is these are injuries for which a helmet gives no protection. To think that the major lesson to take away from your accident is “wear a helmet” is, I’m sorry, dangerous. The real lesson is:

Helmets are not magic and will not protect you from major injury, even death, generally. If you want to be safe, slow down!

Indeed, it is actually possible that the helmet contributed to your accident and hence your injuries, by making you over-confident and taking more risks on a fast downhill descent than you might have if not wearing helmet . A well-known effect, called “risk compensation” or “risk homœostasis“.

I often don’t wear a helmet. I’ve had other cyclists comment on this, and question why I dare to take such a risk. Then I see these same cyclists fly past on downhill descents, barrelling through corners and taking far more risk than I would. They are surely far more likely to have an accident because of this, and their skin, limbs, torso, major organs and face are no more protected than mine are! Further, there is clear evidence that helmets, while helping protect the cranium (but to a lesser extent than is often thought), increase other injuries. Particularly neck and facial injuries.

So, again, I am baffled that the life lesson you drew from your accident was that helmets are uber-important. The real lesson surely should be “Slow down! Take less risk!“. In the unfortunate event of a crash, the lower the speed, the better the outcome!

Comments (1)

Letter to Biffa about close pass

Sent over a month ago, on the 19th of  February. No reply from Biffa to date.

Yesterday morning, at about 0910, I was cycling along Archerhill Road, in the West End of Glasgow. As I came to a constriction in the road (parked cars on my side, road works on the other side), one of your Biffa garbage disposal trucks decided to pass me. Given the constriction, they had to pass very close to me – far too close. I don’t believe there was any maliciousness on the part of the driver. I just don’t think they realised what they were doing.

I’d be very grateful if you could issue a reminder to your drivers about rule 163 of the Highway Code, and that cyclists need to be given as much clearance when passing as they are tall. This is needed in case something happens that makes them fall to their side (such as unexpected potholes, parked cars opening doors, mechanical failures, etc), to ensure they are not seriously injured by passing vehicles.

I’m sure you’re as anxious as I am that your drivers are mindful of the safety of more vulnerable road users. I look forward your reply.


Paul Jakma.

Leave a Comment

Comparing cycling in the Netherlands to Scotland

The following thoughts on comparing cycling between Scotland and the Netherlands are intended to be anecdotal, from my impressions of having been a cyclist in the Netherlands as a child and adult visitor; and as a commuter & recreational cyclist in Glasgow, Scotland for a year & ½. For more evidence based perspectives, please see blogs such as “A view from the cycle path” and “At War With The Motorist“. 

Read the rest of this entry »

Comments (1)

Older Posts »
%d bloggers like this: