Try refreshing the page to ensure you are enjoying the latest version. I tend to make endless edits and corrections over time. Forgive the sometimes off-topic nature of my blog these days. Walking and enjoying the countryside are vital to my physical and psychological fitness and sense of well-being. They combine to undo the damage caused by an occasional excess of cycling. And, may even stave off another rant! Though I can't promise anything.


4 May 2015

4th May 2015 Cuckoo-cuckoo!

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Monday 4th 51F, 11C, a mild, windy and wet night. The rain is supposed to peter out early. Giving way to sunny periods. Grey and breezy but dry for my walk. My right Salomon boot was soon wet inside. Disturbed a buzzard within yards of leaving home. Lots of warblers, Chiffchaffs and my first cuckoo call of the year. I think. My wife "The Head Gardener" thinks she remembers a cuckoo during an early heat wave back in March.

I stuffed the Camper Longflap before taking these pictures. The Carradice is quoted as 24litres too. Judge for yourselves.

I have yet another bird identity crisis. Back speckled like a sparrow, clear buff moustache and plain metallic green chest, no crest. At first glance I was trying to make it into a lark, bunting, pipit or warbler. There is a Greenish warbler but its back is plain and its has no moustache. So it's not that. Nothing in my bird books or Google image search jumps out at me. The Cirl bunting is the closest so far. I only caught a glimpse in my binoculars before it moved further away to show its speckled back.

Just in case you were worrying I'd forgotten my cycling roots: I harp on a lot about the constant wind here in Denmark and the probable effects of bike bags on drag. A saddlebag is much better sheltered by the rider, than a front bag, but the front bag is actually more aerodynamic. Don't ask how badly my drag is affected by my 'Goth' rear wardrobe which sits much lower than most saddle-hung bags. I can't say I noticed much difference when I had the large bag on-board instead of the Carradice Camper. I used the Junior saddlebag sans rack as a saddle-hung, bum-bag yesterday and soon forgot the supposed saving in weight or drag.

I have noticed the wind on my morning walks too. It doesn't take much forward motion to really notice a light headwind. Turn round and walk the other way and the wind is neutralised. Since drag rises as the cube of velocity it doesn't take much to set the absolute limit on cycle speed even for Alex Dowsett: Nearly 53km /33mph in one hour, indoors on an ultra-smooth track at Manchester. The hour record has been broken several times recently but all the increases have been fairly modest. So the air drag limitation on maximum, solo, cycling speed certainly seems to hold true. Otherwise the UCI would not set rules for the maximum height of socks for record attempts! Socks are faster than bare skin apparently. Cloth bags over the rider's shoes are also banned. Requiring a redesign of normal track racing shoes into a form of slippers.

I think a lot of the drag and weight reduction in road cycling is rather mental. Unless you are actually accelerating or climbing the weight hardly matters. I have ridden past clubmen on their carbon fibre bikes up steep hills. With 10kg of shopping aboard my 38lb road-ready and "winterised" Higgins. Mudguards, lights etc.

Meanwhile, a real leather saddlebag fetishist might want to shield the Trykit rack from the wind to improve airflow. A bit of thick polythene stapled on would probably do. Luckily I'm not that way inclined. Though masochism is definitely mentioned somewhere in the small print index of cycling as a sport.

My choice of tri-bars is now well proven and they have saved me considerable extra effort in strong headwinds recently. Always guaranteed to provide an extra 2mph, over resting on the hoods, I wish it was as effortless to go even faster. As soon as I get into the aero position I immediately want to be doing 20-22mph on the flat. Silly old devil! A couple of younger chaps rode past me yesterday [on the hoods] at a steady 22mph, side by side, straight into exactly the same wind, when I was really struggling to do 18 on the tri-bars. I chased  like hell but couldn't close the gap as they got further and further away. I want legs like those! The same lungs as well. My chest seems to be constantly full of thick liquid.<spit!>

Apparently, wheel/tyre width hardly matters except [perhaps] for TT. The trend is towards wider tyres for much more comfort and lower rolling resistance. Let's hope it doesn't take years for the tyre labellers to catch up. I already have to buy my 25mm Duranos online because no bike shop sells anything but 23mm in klinchers. 

A brief summary of wind tunnel tests which you might find interesting: Aerodynamics of Real-World Bicycles | Off The Beaten Path

The crosswind was blowing from about 10 degrees behind me on the way out. Allowing me to cruise at 20mph+ on the hoods. Coming back it was 10 degrees ahead of me and I was doing only 10-14mph.

Handle reinforcing strap in galvanized steel. I drilled out the rivets from this side to release the handle and metal strip without causing damage. A weight saving of nearly 3/4lb! Though the new stiffening dowel does have some weight there is probably still a reduction of half a pound.

It was going there that I experienced a weirdness probably not normally found outside of a mescaline overdose. The traffic in the main road villages was keeping to the speed limit! I kid you not! Does not compute! Twilight zone alert! Send for the X-files team! Make a documentary for Fox News!

They were going so slowly, it felt as if I could have sprinted up and stayed with them. I've seen most Danish hearses travelling faster! Later I passed a police camera van parked up on the grass verge. But how did they all know in advance? I saw no placards beside the road to warn them that they should knock their usual speed in half. No blue bunting was strung across the road between lampposts. No flashing blue lights. Nor was there any sign of some secret headlight flashing code known only to the locals.

The bag was carefully marked with a pencil and two tiny square cut out of the leather to allow the straps to reach through to the new stiffening dowel from the rack's top crossbar. I thought it important not to make the holes too high because the dowel would never be used to physically hang the bag from the saddle. So I drew horizontal lines above and below the crossbar with the bag resting on the rack. The squares were easily cut out between the lines with a small, sharp, craft knife working carefully to avoid slitting the weather and making it weaker.

It felt just as if I had been transported to another dimension. Perhaps I should have pinched myself to see if I was really dreaming? Well, if the claimed idea was traffic calming, rather than milking easy prey, then today was 110% successful. But what about tomorrow and all the other tomorrows when they are ALL back driving at 55-60mph? Buses, artics, dustbin lorries, vans and cars. What then? Only 13, very weird miles! Whoohoo! Quack-quack! Cuckoo! ;ø]

Tuesday 5th 58-70F, 15-21C, mild, gales, overcast with rain. A warm low is passing over with "busy" weather fronts. The forecast is morning rain turning to thundery showers later. Followed by thundery rain possibly with cloudbursts. As I write this at 11am the sun has just come out! Meanwhile the wind is expected to turn from east to west. It is supposed to calm and clear tonight so I could try and find my lights. Rest day.
  
With all this rest time on my hands I might convert my 'Goth' bag to a real saddlebag with a dowel and short straps to hold the bag to the Trykit rack's, top crossbar. Getting rid of the massive, layered leather handle and associated "ironmongery" should be good for a half pound saving, at the very least.

Bag without handle for a sleeker and lighter look.  The Head Gardener did not agree! Said it spoilt the original, antique, "Doctor's bag" look. While I still think the handle made it look like a toolbag used as a saddlebag as an afterthought.

It might would be rather silly to hang the new bag from a B17's bag loops. If the bag started swaying back and forth to my pedalling cadence, as the Junior did the other day despite being strapped to the seat post, I might actually start bunny hopping! Or even pulling involuntary wheelies! And that would never do. I'll keep you posted. Me obsessed? Surely not? ;ø]

It stayed warm, dry and windy for a couple of hours. Allowing me to work outside. See attached images for the work involved in adapting the toolbag to a 'proper' saddlebag. Unlike Carradice I do actually own a tape measure [6 of them actually] and steel rule [several] to make the bag central on the rack. [Or saddle loops if desired.]

The Carradice hanging straps are the wrong colour but will be replaced if I can find some black ones. 

The Trykit rack now properly supports the bag all over. With the slightly oversized dowel helping to stiffen the bag and hold it tight against the face of the rack for stability and to maintain the boxy shape. The alloy, handle-fixing rivets have yet to be reset in their original holes. I ought to find some stainless steel or alloy washers to avoid them being pulled out again. Note how the "hanging" straps buckles are hidden inside the bag for security, weather protection, neatness and 'minimalist' appearance.

The stand-off, rack crossbar spacers were specially made by Trykit's Geoff Booker to allow more leg clearance. This is not normally a problem when pedalling but I like to straighten my legs to stretch my calf muscles occasionally. I find it helps to loosen up tired muscles on longer rides. Another rest day.

The air drag/turbulence caused by such a large rear bag will depend to some extent on the angle of incidence of the solid body to the airflow. Unfortunately the airflow passing over the riders legs and between them is highly disturbed. Not to mention the vastly greater complexity afforded by rapid leg movements from pedalling with both legs 180 degrees out of phase. It is no wonder the top cycling teams spend so  much time in wind tunnels! I have [crudely] drawn the major angles and dimensions of the bag and its slopes relative to the nominally horizontal airflow. The bag probably behaves like a crude, very thick and very short aerofoil but with much greater turbulence due to the squareness of all its edges. While the Carradice Camper is more rounded but has pockets sticking out into the airflow on either side of the rider. It is almost certain that the airflow separation behind both bags is rather dire. Greatly increasing air drag compared with a "clean" tricycle frame with rider. Testing bare bicycles or tricycles alone in a wind tunnel without the rider aboard is likely to be rather pointless.

Only lifting such a "squarish" bag to rest against the rider's lower back, as a continuation without any air gap, is likely to help to reduce drag. Then, probably only a little depending on the rider's forward lean. Not to mention the difficulty of actually "throwing a leg over" such a raised bag.

Chopped-off tails were once much in vogue and are still seen in the latest high performance cars. The fully formed, 'streamlined' tear drop shape is no longer considered the perfect form for low air drag. Many recumbent racing bicycles sport a rear fairing. Though exactly how well they perform  in practice is probably unknown outside a wind tunnel test. Adding the inevitable weight of a rear fairing to a road going machine may not pay the dividends which were hoped for. For steady racing speeds on a flat "oval" circuit improved lap times may give a better clue. I can't imagine that adding anything, except tri-bars, to an upright trike would be an improvement.

Click on any image for an enlargement.
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