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Re: Trip report - Faro to Porto

CTC Forum - Touring & Expedition - 20 October 2015 - 12:59pm
Last October we just wheeled our bikes onto trains ond nobody said a thing. We also took them on the Metro in Porto and Lisbon. For the bus we wrapped them in clingfilm and the driver took them on problem. At Lisbon bus station the ticket clerk said we could not take them. We went to inquiries and asked. We were told it was no problem. She phoned the driver and told him to expect the bikes. We just then went back to the ticket counter and bought two tickets not mentioning the bikes.

Re: Evil cyclists attack innocent babies

CTC Forum - On the road - 20 October 2015 - 12:49pm
beardy wrote:It is a pity that they didnt have a video camera fitted to show just how unprovoked the attack was.


I do wonder slightly about the L plate line.

"There were L plates on the car and my partner was driving. As we passed him again I said out the window we have L plates, have consideration."

One would assume on the balance of probabilities, and based on the wording used, that the new mother is the one learning to drive, and the L plates were therefore irrelevant to the (presumably) bad driving, since the boyfriend is the one who was driving.

Re: Headwind/Incline Equivalence

CTC Forum - On the road - 20 October 2015 - 12:48pm
BrianFox wrote:...there is lower air resistance at altitude, and also in hot weather. Even at ground level, air pressure can vary by +/- 5%
Is that so? I often feel that the air is somehow 'thicker' on hot days, and imagined that it was something to do with air currents rising from the hot asphalt. Is that wrong?

Perhaps it's the tyres sticking to the road.

Re: Headwind/Incline Equivalence

CTC Forum - On the road - 20 October 2015 - 12:42pm
iviehoff wrote:I have often wondered whether there was materially lower air resistance at altitude

Formally, air resistance is proportional to density multiplied by velocity squared in fully turbulent flow.

Density is proportional to air pressure, and inversely to (absolute) temperature; air pressure falls with altitude.

So yes, there is lower air resistance at altitude, and also in hot weather. Even at ground level, air pressure can vary by +/- 5%

Which is why Bradley Wiggins had the velodrome heated for his hour record attempt, and cursed the high air pressure on the day.

For mortals like myself, however, a bit more effort and a few less cakes is what really matters...

Re: Cycle touring insurance

CTC Forum - Touring & Expedition - 20 October 2015 - 12:37pm
Tesco travel insurance covers you when you are cycling as transport, but not racing. I read it carefully and it is pretty clear on that point. So my interpretation is that it covers touring. I'm not sure which countries it is valid for.

Re: Evil cyclists attack innocent babies

CTC Forum - On the road - 20 October 2015 - 12:35pm
Oh dear! Yet another DM-inspired rant (and just look at the comments - if you dare - my eye caught on one threatening to put the cyclist "in hospital - if he's lucky" ).

The cyclist was obviously very much in the wrong to do criminal damage to a vehicle - unless he was so much endangered, that breaking a window was the only way of drawing the motorist's attention to his presence. Unlikely, but that sort of thing has happened. Probably we'll never know the truth.

Incidentally, car windows are made of a type of glass that is supposed to shatter into rounded pieces of gravel, less likely to injure anyone it hits. Having said that, not something I'd want flung at a small child.

Re: 2 weeks cycling hollidays with 4 kids in Europe

CTC Forum - Touring & Expedition - 20 October 2015 - 12:34pm
Thanks to this thread we have decided to squeeze an extra week in to do the St Malo to Roscoff trip on that link!

Not camping though, we have two beautiful tents and usually camp for a couple of months a year but they are heavy (a DeWaard and a Tentipi) and there is no way that we want to add a similar quality biking tent to our stash right now. It would involve new sleeping mats and bags as well as a tent. So we are going to stay in B&Bs instead in 2016.

Brittany Ferries don't have a problem with the tandem which is a relief as we have only had it a month and are completely new to taking it anywhere, we haven't bought a rack yet so our rides are all from home. We just pay for three bikes for three people. Shame the winter is approaching really, mind you it is going for a respray in the worst months.

Re: Cycle touring insurance

CTC Forum - Touring & Expedition - 20 October 2015 - 12:30pm
The company is called JS Insurance. Came up on a Google search. I've had a bit of correspondence with them and they've been quick to respond. There's £100 excess on a few bits of the policy which I can live with. I'm hoping that this policy is the only thing I've bought for this tour that I don't use

Re: Evil cyclists attack innocent babies

CTC Forum - On the road - 20 October 2015 - 12:28pm
It is a pity that they didnt have a video camera fitted to show just how unprovoked the attack was.

Re: Headwind/Incline Equivalence

CTC Forum - On the road - 20 October 2015 - 12:24pm
gaz wrote:Brucey wrote:using this calculator
http://bikecalculator.com/veloMetricNum.html
on its default settings, it suggests that every 1% gradient is roughly equivalent to 10kph of headwind. It feels worse than that to me.....
I do not pretend to understand the calculator, however I've ridden up a 25% gradient but I don't fancy my chances into a 250kph headwind .
As was pointed out above, the resistance of headwinds rises with the square of windspeed, but gravity is linear. Naively that suggests to meif you relate 1% to 10kph, then a 25-fold increase in gradient should relate to a 5-fold increase in windspeed (square root of 25). I have read the rubrics to the calculator, which suggests that it is using a squared relation for windspeed, but we do not see actually see a simple square relationship like that, especially not at lower gradients and windspeeds. Indeed at lower gradients and windspeeds, we initially see a roughly linear relationship, at least in the area of 1% to 3% and 10kph to 30kph. The windspeed becomes more significant rather above that, it tells us a 10% slope is equivalent to about 63 kph wind, and a 20% slope a 95kph wind. At those higher slopes and speeds, the square relationship is more nearly approximately satisfied, though not quite. I suspect that in part this is because there is a substantial aerodynamic resistance even at a 0kph wind, and aerodynamics is more complicated than just this one relationship.

Now I have encountered winds I couldn't cycle in, and hills I couldn't cycle up. But trying to use that to get a relationship is tricky. I have got up Hardknott with its 33% sign, but only because the 33% sections are very short. There are 20% hills I have failed to get up, at least in one go, because the 20% section went on for a long time. Winds, on the other hand, tend to be more persistent than steep hills. They also tend to be more variable, and it is probably the gusts that had me off the bike, not the averages. It is pretty clear to me that I can't cycle in a 95kph wind, and I should probably acknowledge that I can't cycle up a 20% hill for more than a pretty short distance.

I remember days in Patagonia and Iceland where I grovelled along at about 8kph in a strong wind. If I said that the wind was probably of the order of 60kph, and it was a bit like going up a 10% hill all day, that wouldn't be far wrong. In fact a 10% hill all day would probably have been a bit worse. I am making myself comfortable with the relationships of this calculator, remembering the shortcomings of approximating real gusty winds to constant windspeeds the calculator uses.

I have often wondered whether there was materially lower air resistance at altitude and this calculator answers the question. Being at 4000m is equivalent to a tailwind of 8 or 9kph. Though there are other issues in relation to being at 4000m which make riding there much harder. Also, it is often very windy at such altitudes.

Evil cyclists attack innocent babies

CTC Forum - On the road - 20 October 2015 - 12:16pm
More proof that cyclists are a menace to society

http://www.dailymail.co.uk/news/article ... e-row.html

(NB. same logic should NEVER be applied to rogue motorists, who are not representative of their genus as a whole, this logic only applies to cyclists, who when they are not covering babies in glass, are probably eating them for breakfast.)

Re: Good Samaritan...Guy In Island

CTC Forum - On the road - 20 October 2015 - 12:12pm
I still haven't been able to thank the two ladies who tended to me, ten years ago, when I had an 'off' on a quiet country lane and knocked myself unconscious with a bit of amnesia. I was a bit stupid even after coming round: I didn't get their names or their car reg., I don't even remember whether they were in the same car or two separate ones. One of them called the ambulance, waited till its arrival, then they went their way. If by the remotest chance you're reading this, ladies, belated thanks!

Re: Cycle touring insurance

CTC Forum - Touring & Expedition - 20 October 2015 - 11:55am
b1ke wrote:I contacted the company and they've added a cycle touring endorsement to the policy.
That's good news. The devil is in the fine print with all policies. Can you say who you are with?

Re: Roundabouts or traffic lights?

CTC Forum - On the road - 20 October 2015 - 11:51am
DaveP wrote:Gosh! You've surprised me with that one...
There are a couple near me. Fair enough, they are pretty big specimens, but I find them stress inducing even in the car.Hmmm... perhaps you've caught me out there - I'm trying without success to recall whether I've recently negotiated a RAB of that type, by bike. My line of reasoning was, it reduces the risk of motorists cutting across you when joining the RAB, because they'll be stopped from doing so by the T/Ls. OK it seems there are other factors...

Regarding the matter of RABs in the USA: from my brief visit last year (by car: no cycling ), I recall that the only RABs we passed were on relatively minor roads, single carriageway roads with not much traffic. The busier S/Cs mostly had US-style intersections with T/Ls (and the 'turn right on red' rule which in itself could be a hazard to cyclists!). On the Freeways (dual carriageways), the junctions were invariably motorway-style with flyovers. But possibly things are changing over there. I think much of the USA is very cycling-unfriendly for those who want to cycle on roads.

Re: Safety design research - any help greatly appreciated!

CTC Forum - On the road - 20 October 2015 - 11:36am
mjr wrote:Survey doesn't work on android mbrowser.
or my old ie browser!

Re: Cycle touring insurance

CTC Forum - Touring & Expedition - 20 October 2015 - 10:53am
I contacted the company and they've added a cycle touring endorsement to the policy.

Re: BBC R4 depressing item

CTC Forum - On the road - 20 October 2015 - 10:20am
I came across a psychiatrists interpretation of this behaviour recently, in a different context but her behaviour fits the explanation perfectly:

People doing this start from a position of perceived self interest then create a back story to justify it, and then try to reinforce it by pushing it around as if it were fact. The less credible the back story is, the more effort needed to reinforce it. i think it's interesting to read this stuff with that in mind - not just about cycling but lots of things.

I said perceived self interest because most of these things - road tax for cycling, waiting for red lights, compulsory insurance etc work against the interests of motorists if you follow them through to a likely conclusion. (That's not true for everyone of course and several journos do well out of spinning these stories).
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