Cycling UK Forum

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...

Brucey wrote:
that you (apparently) don't notice or care is not the same thing as it not happening...

Ahhh, Schrodinger's headwind.

I’m 6’4” so have similar problems. There are very few “fast” frames with mudguard clearance and rack fixings available in large sizes.

See discussion here

viewtopic.php?f=5&t=99469

in the end I could only find Kinesis and Ribble offering something off the shelf. I now have the Kinesis in a 63cm which I’m very happy with. I’d guess that with your extra inch in height it would probably also fit you. You can see the seatpost and bar heights on the pic. It’s an Alu frame. The Ribble one was cheaper. If you’re feeling flush and can wait, I’m told Van Nicholas are offering the titanium Yukon in 64cm next year. My very brief exploration of potential custom frames was prohibitively expensive.

I think your answer depends on how fast you ride.

First, a bit of basic fluid dynamics
To a first order, air resistance scales as the *square* of speed.
Gravity resistance, however is *constant* regardless of speed.
Power (what you put in on the bike) is resistance multiplied by speed.

So... if you double your speed going up a hill, you need double the power to defeat gravity. Going up at 10mph takes twice the effort of going 5mph. This assumes you’re going so slowly you have negligible wind resistance.

However, if you double relative airspeed – say ride at 10 mph on the flat into a 10mph headwind, you need *four* times the power vs no headwind – the *square* of the change.

Obviously it’s more complex than this in reality, but you get the gist. It also helps explain why it’s so much more wearing riding into the wind than up a hill – you get much less payback for your effort.

Elizabethsdad,

your statement about how "society as a whole these days" could be put into context against how that society was in earlier times.

Cartoon from CTC gazette, 1932:

https://html2-f.scribdassets.com/8p4lts ... f1150d.jpg

Extracted from

A Denial of Our Boasted Civilisation”: Cyclists’ Views on Conflicts over Road Use in Britain, 1926–1935

http://www.academia.edu/1976440/_A_Deni ... _1926_1935

In summary, it's far from clear that "society as a whole" has regressed from an earlier golden age!

In conflict situations with motorists I try and avoid hitting cars or giving the finger. I find blowing a kiss much more effective.

Ah - it's an older model with a 105 sticker on it. Makes sense. Not sure why that's a problem though, I can easily lock up the rear which suggests they're good enough...

I'm not sure I understand the issue with Shimano brakes. AFAIK they *do* now do at least 105 with long reach calipers, and I think ultegra too though I''ve not checked. But maybe I'm missing something.

I have 105 57mm reach on my lovely brand new Kinesis 4s bought for the purpose of mainly commuting and occasional light touring. Lovely bike and probably not too dissimilar from Etape, but available in a frame to suit my height.

Flite, wow, never heard of those. My experience of raynauds is very much the same as yours. Looks like I may need to go to the us to get a pair for drops.

Tony,

I look at it from the opposite point of view. Helmets are next to useless at providing protection in case of a collision, but constitute an excellent high level light mount.

Anecdotal evidence (me in a car) suggests that cyclists with helmet mounted lights significantly enhance their visibility.

Further anecdotal evidence (me being hit by cars, twice) shows that helmet performance is not impaired by light fixtures.

Warming: the value of anecdotal evidence may go down as well as up.

I use a small cateye light (now out of production) for exactly the same purpose.

This is the current equivalent I think

http://www.evanscycles.com/products/cat ... t-ec012554

Cateye also do a helmet mount, you'd need to buy that separately, it's changed since I bought mine so can't comment on how good it is.

http://www.evanscycles.com/products/cat ... 2-ec035704

The joystick recommended above is brilliant, but *much* more expensive - I use one on my bars.

I suffer from Raynauds:
http://www.nhs.uk/Conditions/Raynauds-p ... ction.aspx

and the best solution I've found is the specialised lobster claws linked above. They come with a separate inner, but I also add a thin liner too for properly cold days.

I also find wearing arm warmers down over the wrists overlapping the gloves helps.

What I struggle with is warm long sleeved tops which are long enough - I'm 6'4 and no-one does extra long sleeved cycling gear that I can find.

Ha!

Found the mark. It's a 2300 ie double.

That would explain everything.

Hassle time - need to get a refund...

Thanks for the pointer

Rehon2,

other than "SHIMANO" on the top, I can't find anything else printed on it

Brucey,

the mech has "Shimano Triple" on a sticker on it. Other than that, I'm not sure how to find out what exact model.

I'm afraid I don't know what you mean by "chainline". Neither chain nor mech has been changed since bought from new.

reohn2,

There are two clicks.

Setting up exactly how you describe, it changes fine from small to middle and middle to large, but in the large ring it's not quite far enough across to avoid rubbing.

If I then use the cable adjuster to put more tension on, that makes it OK in the large ring, and it changes down fine from large to middle, but won't change down from middle to small ring.

Is it possible this is a double shifter rather than a triple? How could I check? That's all I can think of.

Are these things adjustable in any way - it doesn't look like there's anything on the shifter that's changeable

I don't think it's an MTB mech - it came with the bike (Specialised Secteur) and worked fine until the shifter change.

Unless the mech took a bash and was damaged in some way at the same time the shifter was done for, I think it must be something else.

The mech doesn't look obviously bent or twisted. But I'm not sure I'd be able to tell if it was, I'm no expert.