Friday, 22 June 2012

Are you fatigued?

The eagle eyed may notice something a little wrong in this picture, the handlebars have taken sick. As this bike is only just over a year old, and probably not much more than 6,000 miles on the clock it came as a bit of a surprise to me. In fact, quite a lot of a surprise at 6:30 in the morning shortly after I set off. What happened was that, when I was spinning along at around 20 - 25 mph (I don't use a computer) the left hand bar just went. I wasn't stressing it at the time, I got no warning, as a result I had a coming together of me and a parked car. Fortunately I was not seriously hurt, a bit of bruising, my helmet stopped by head being hurt as I gave the car's rear spoiler a Glasgow kiss. Frankly, just about anywhere else on my commute the result could have been unthinkable; anywhere on the main route would have been bad, I sometimes touch 40-ish on the 1 Km descent along Holland Park Avenue, mostly in close proximity to traffic [shudder].

This failure has concentrated my mind around metal fatigue, to try to work out how to avoid and survive it. After all, it's not the first time. Back in February my four year old Marin Point Reyes succumbed:

I noticed that crack around the seatpost, given that all that would happen would be the seat swinging around I rode home out the saddle for most of it. That ended up well, as Marin provide a lifetime warranty on their frames, and this was clearly DED. They supplied the current version, which is a 29er, which I sold and found an old model being sold at reduced price, everyone happy.

But now, I've been trying to find out what it is that causes the aluminium to fail (bearing in mind that the frame of the On-One is steel). The bars themselves were 3T Mutant such as these:

I contacted them to ask what alloy they were made from and discovered that they predate the relaunch of 3T four years ago. But, after a little more fossicking on the Internet, I discover that they are made from 6068 T6 Alloy. This is important, as it describes the characteristics; the first part is the alloy - 6061, 7075 are common - which provides its base characteristic of strength and weight and the second is the temper, which provides the added capability to better withstand age, flex, corrosion. This bar also has a 26mm clamp section.

So what is the difference between the different alloys? This is where I poke around the dark corners of the Internet and try to sound as if I have some idea; I don't. If someone turns up who does, I would be grateful for their opinion.

First 6061-T6. This is the most common alloy used. My Marin has 6061 bars. Wikipedia tells me that " the fatigue limit under cyclic load as 14,000 psi (100 MPa) for 500,000,000 completely reversed cycles using a standard RR Moore test", in contrast 7075 (the other common alloy is "159 MPa 23000 psi 500,000,000 cycles completely reversed stress; RR Moore machine/specimen" So, almost half as good again, right? The trouble is I know that most bike manufacturers have the weight weenie marketing inthe back of their mind. So, if something is half again as strong, they will only use two thirds the thickness, or some such. Can't find much about 6068, I assume it falls between the two.

So where does that leave me? Frankly, I don't know. I do know the rigours of my commute are rather harsh on bikes. I do know that I want to get the strongest bar which means the most fatigue resistant alloy and the largest diameter clamp. After that, I don't know how to translate that into real life, any ideas?

Tuesday, 24 April 2012

Are Addison Lee on a Downward Cycle?

Addison Lee were the rising stars of the London Minicab market, the largest in town. They have thousands of cars on the road, and they brand most of them, so they are visible.

It all kicked off a few days ago when their outspoken chairman decided that he could change the law, and told his drivers to drive in bus lanes and he would pay any fines (read more here or many other places). The subtext to this is that he wants to make as much money as he can during the Olympics, and probably thought he could get away with it. However, he misjudged and found himself at the center of a backlash: A direct instruction from TfL not to contravene the law, and opened up the potential for TfL to revoke his license to operate. After all, someone who publicly advocates the breaking of the law can't be a fit person to run a company of this size and standing. In a rare moment, cyclists and cabbies found themselves with common ground to oppose this move.

It then transpired that he had also written an article in his in house magazine, read by customers and people in his cabs which effectively said "It's the cyclists own fault if they have an accident, don't blame yourself if you run into one, it is inevitable" Loads of other crap too ( for more).

As a result there was a "Die In" organised in front of Addison Lee's offices, which I went along to. A wonderfully diverse range of cyclist numbering about 300 turned up despite the poor weather and "died" in front of him. To be fair to John Griffin he did face the crowd - and then mostly spouted the same old crap. His valid point is that training would be good for all cyclists. That is wrapped up in a wrapper of so many misconceptions and ill conceived notions that it is barely discernible. Plus, while he is welcome to an opinion on this or any other matter the only thing he has CONTROL over to any extent is the behaviour of his drivers. He could doubtless make a real contribution to cycle safety if he trained his drivers to behave better and then put measures in place to make sure they did.

So where do I stand on the whole issue? Actually, I can't get as wound up as many do. John Griffin is just another ignorant motorist who fails to understand the value of the cycle on London streets: if more people used cars (as he seems to advocate London would grind to a halt. He does happen to be in charge of a substantial cab operation, though, and as such it is entirely inappropriate for him to voice these inflammatory views where they can influence the attitudes of those drivers negatively and potentially result in injury or even death. Addison Lee in my view are no worse than any other mini cab drivers, probably better than the majority of outer London ones, but they do have the misfortune of having the brand emblazoned on their cars. If John Griffin wants to build the value of his brand, then he needs to grasp the nettle of that branding and make sure his drivers are better than others - ambassadors for his company. You don't do that by breaking the law or barging cyclists off the road.

I can't see their license being revoked, and given the distress it would cause to thousands of the drivers who have done little more wrong than any other and the undoubted need for the service I am not certain that it would be valuable, however appealing the image of the schadenfreude is.

I'll share the road with anyone, I have as much right to it as any car. All I ask is that drivers do their bit and try to avoid me.

This photo courtesy of David Firn, set here I'm not in any, other photos in which I also appear here, I'm easy to recognise as I am the only one is short sleeves and shorts.