24 Sep 2012

Losing weight.

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Another (long) rant: Nothing to see here. Move along, please! 

Much effort goes into the endless discussion of reducing weight on pedal driven transport. Usually meaning bicycles. Carbon fibre has largely passed by the humble trike as a frame material. The poorer cousin does not warrant the expensive research which is necessary to make a safe, but lighter trike. So we are stuck with high tensile steel tubing and steel bars for axles. So how do we try to reduce tricycle weight effectively enough to warrant the design exercise?

I have a recurring anxiety about trikes not progressing much over the last 50 or more years. Dragging the Longstaff conversion out of the shed (still fitted to its last donor road frame) was a real shock! It seemed to weigh a ton compared with the Higgins. Even without the rear wheels fitted! Together they must add an extra 7lbs. At least! I certainly wouldn't want to carry it far. And didn't! Longstaff is/was a highly respected maker of bespoke tricycles. What went wrong over the years that the trike didn't ever develop? Not even postwar?

The rear axles of a trike are the major area of weight increase over a bike. Apart from the extra wheel of course. Light, racing, trike wheels probably weigh about 3 lbs each complete with tyre and tube. (from failing memory) There is no escaping this extra wheel of course. Otherwise a trike would be a lopsided bike. Which would be absolutely no fun at all! :-)

Most existing trikes still use solid drive axles. The Longstaff axle is larger in all respects than the Higgins. Though "waisting" obviously helps, steel axles are almost impossible to make much lighter. Not without them becoming too thin and weak. The alternative is to make them much larger but hollow. (ie.tubular) Most of the middle of a metal bar is just excess weight. It contributes very little to the stiffness of the rod. The bare 1WD Higgins axles weigh 1.5 lbs without the cones. I can't remember how much the Longstaff axles weigh but it must be well over 2lbs. You can buy a complete bike frame that weighs under 4lbs!

If the axle diameter is made any larger then the axle casings must obviously be made much larger too. Though the axle casings can probably use modern, frame building, thin wall, steel tubing. Adding very little extra weight themselves. Tubing is available in a range of sizes suitable for road and MTB frame building. If the drive axles are larger throughout then the hubs must be made much larger too. As must their supporting, journal bearings.

Would much larger, thin-wall tubing make lighter and stronger axles than the present, relatively skinny, solid ones? I'm not sure much research has been done into larger diameter, tubular, trike axles. Smaller diameter stub axles could still be used for the lengths inside the hubs and 2WD double freehub. With only the length between the axle bearings increased in diameter to allow thinner-wall tubing to be used for this section. Larger, tubular hubs could use small, drive splines and a screwed ring (a là old-fashioned bottom brackets) to lock themselves safely in place. Flange size could still be kept quite modest. Hubs, being alloy, don't increase in weight too much due to having larger flanges. (within reason)

The short section, outboard of the outer bearing, is the most highly stressed area on a trike axle. Yet high performance motorcycles seem to be able to use a tubular axle and a one sided hub. The loads on those components, compared with a humble, pedal-driven trike, are simply enormous! Perhaps it would help to make the hub closer to the outer bearing? Perhaps with some compressive pre-loading against an axle flange inboard of the outer journal bearing? This would relieve the loads on the short, cantilevered section of axle between the bearing and hub. The bearing itself would be in lateral compression. As this would only involve the inner race I can't see any obvious problems with this. The bearings already sit on a step in a solid axle to resist side thrust during cornering.

Suitably narrow, journal bearings might be thin enough, laterally, not to increase weight too much. With the rider's weight and road shocks spread over a much larger ball bearing surface area they should cope. Asymmetric bearing sizes are also possible. The outer bearings carry the full weight of the rider. Plus road shock loads from the wheels. The inner bearings must resist only chain tension, drive loads. The rider's weight is a much reduced just here thanks to advantageous leverage. Weight could be saved by using smaller balls for the journal bearings themselves. Ball diameter being an important factor in overall bearing race dimensions.

The question is how best to size a tubular axle. One which can tolerate several hundred thousand miles, or more, without risk of early metal fatigue failure. Whether this balancing act between diameter, wall thickness and weight reduction, without loss of strength, is worth the effort, who knows? Something must surely be done to try and rid the trike of its present, rear axle, weight handicap.

There is a tendency towards using carbon fibre road frames with added trike conversion axles on the back. The problem I see with this is that the main frame section is not where the weight saving is required. It is with the rear axle. A conversion still needs the bike's rear stay triangles. So there is some material and weight redundancy here.

Modern conversion axles are now designed to increase the wheelbase. Rather than the classical conversion set which threaded through the rear stay triangles. Which much shortened the wheelbase. Leading, in some unfortunate cases, to heel strike on the axle casing. I fell foul of this problem myself with my Longstaff conversion on a short wheelbase road bike. I have large feet so other users may have more leeway in chain stay length. Crank length will also play a much smaller part in ensuring clearance for the rider's heels. My heels can also strike my Higgins' widely splayed seat stays.

But now I have digressed: Carbon fibre frames are designed for bikes. Not for trikes. The carbon chainstays are meant to resist vertical loads primarily at the junction of the stays and rear drop-outs. The trike conversion throws loads onto the centre section of the chainstays which were never part of the design brief. I'm not sure how long the chainstays would cope with such localised stressing in the long term. Paralympic riders may not ride the high training mileages typical of competitive time trialists and tourists. They seem to favour conversion sets more than other riders. Perhaps in the hope of weight advantages with their slightly lower power input?

As I said before: The weight of the main triangle of a bike (and trike) is really not where the weight problem lies. Suitable choices of frame tubing in the best modern steels will not mean a serious handicap in increased weight. Not over a carbon fibre, aluminium or titanium bike frame. Admittedly the splayed rear seat stays of a conversion will help to resist lateral loads on the donor frame. Mass produced,  carbon fibre frames have dropped in price. So a conversion can save money over a fully fledged racing trike. Though probably by not very much.

Carbon fibre is not proving to be a long-lived material. The Internet is full of images and complaints of permanently damaged frames from simple mistakes. Forks and wheels in particular seem to be even more fragile. They are also very flexible under side loading from cornering on a trike. Which they were never designed to encounter! Crashes are usually fatal. For the machine. If not for the rider. New machines are two a penny to a sponsored pro. The weekend warrior may have to buy a whole new bike! But at least curvy, carbon bikes look really sexy. So that's all that really matters.

Even wheels need careful consideration for their ability to withstand the sideways forces endured through repeated cornering on a trike. Remember that every corner taken on a trike throws heavy side loads onto the entire frame, fork and wheels. Many R531 trike frames are reaching the official retirement age for humans. Yet most continue cheerfully on their way without visible complaint. I find it interesting that the most successful  trike time trialists are still using "classic" steel frames. Albeit with fragile carbon forks in some cases. Rider weight is another important issue. Of which; much more later.

I doubt that exotic materials like carbon fibre or titanium can provide the strength and longevity required in the actual axle assembly. The dangers associated with the loss of a trike wheel, on the road, in traffic, are too catastrophic to warrant clumsy road tests to destruction. Probably leading to the destruction of the rider!

There is now CAD software which can illustrate the local stresses on a component like a trike axle and frame through the use of colour change. All we need now is a 'tame' CAD designer/engineer to balance tubing diameter against wall thickness and the, hoped for, weight reduction.

A final thought is the obsession with weight saving on bicycle components despite the weight handicap of the rider. The forums are full of 20 stone riders asking for a 100g lighter saddle or brake suggestion. Or which expensive (Big Name) carbon or titanium frameset is the very lightest? Why does it even matter?  I usually liken being overweight to carrying a rucksack full of bricks. One which the owner dons the moment they climb out of bed in the morning. And only put back down when the rucksack owner finally climbs back into bed. A typical brick weighs somewhere between 5 and 6 lbs. How many bricks are you carrying everywhere? How many more bricks can you actually manage?

I managed to reach about 13.5 stones at my maximum weight. That's about 190lbs in New World parlance. Let's say I was carrying  at least 40lbs of excess weight compared to the optimum for my 5'9" height. Or 8 extra house bricks. How far can you carry 8 house bricks? I carried them from dawn to dusk every single day. Strangely, it didn't make me any fitter.

I was enjoying a steady diet of Danish pastries at work and drinking litres of milk instead of the industrial grade coffee from the machine in the cantine. I loved coffee but it upset my stomach. I felt constantly full! I had heartburn most of the time and blamed it on the works coffee. I would complain to my wife that she was making our meals far too large. I could not even lie down on my right side without regurgitating my dinner. Or having a horrible burning sensation in my throat, if I was more lucky. My colleagues began to jokingly point at my "beer belly." The fact that I wasn't getting much beer (at all) only made the jibes worse. Though I laughed it off. As you do when you are weak and fat.

Despite all of this I was in denial that I was remotely fat. Like a smoker addicted to the weed I could find all the excuses imaginable for being the shape I was in. Even the medical profession said that being well-padded was better than being underweight. So that's all right then. I checked my BMA and found I was borderline clinically obese. I look at the pictures of myself taken at the time and I didn't look particularly fat. Though my arms and legs were much larger they were still quite obviously muscular. At least they were to my eyes.

I was finally saved by two pivotal events. I suddenly rediscovered my passion for trikes. My brother kindly found me a Longstaff conversion and sent it over. Later, I was made redundant. Like many others in Denmark, as production was moved abroad. That meant no more free Danish pastries. Nor milk waiting in the canteen 'fridge. It also meant a lot less exercise. Unless I bothered to exercise myself.

So started the routine of riding my trike every single day. Forcing myself to go out even when I didn't feel like it. Even when it was bitterly cold or wet. Forcing myself to publish my pathetic daily mileages on my blog. Pretending anyone else cared if I could actually manage a ride to the nearest town or village. Suffering daily saddle discomfort for literally years on end as I fought to increase my range. Suffering constant leg pain and endless tiredness. And they say this is good for you? Ouch!

I had to learn which modern cycling clothes were most comfortable in different weathers. On a fixed income I could no longer afford to experiment. Not at bike shop prices for Chinese made cycling gear! So I collected older "racing" bikes and MTBs for a fiver each from flea-markets and recycling centres. To strip them for spares or as donor bikes for my Longstaff conversion.

I bought my entire cycling wardrobe from charity shops. Except for gloves. They came from local supermarkets. Most of the latter were a complete waste of money. Though not all. The flimsy road mitts in the bike shops were certainly no better. As I have said before: They remind me of Edwardian lady's gloves for a visit to the opera. And, just about as useful for palming off the gravel in a fall. I only fell off three times. (from rapidly failing memory) Always after coming to a sudden standstill on sloping ground. Nothing more serious than very sore hands and a bad shoulder or arm ache for several days. Not enough to put me off riding.

I was required to seek employment (of course) as a condition of receiving a fairly generous income from the government and my union. I used this as another string to my tricycling bow. Every day I would ride out to find a new business where I would ask about the chance of employment. Heaven knows what they thought of a properly dressed "racing" cyclist turning up on a trike in all weathers. Most of my cold calling interviewers were rather sympathetic. Gently amused and polite, but they never had anything suitable for me.

I was close to retirement age, English and had dreadful Danish grammar and pronunciation. With a rather limited vocabulary. I was also a tricyclist. One almost alone in Denmark. Where only the disabled and elderly ride trikes. I probably looked and acted like a walking time bomb. More trouble than was worth the risk of further investigation of the package. So I would smile, thank them very politely, get back onto the trike and continue my journey. Being able to smile at yourself is wonderful therapy. It helps not having to defend oneself daily against wild accusations of eccentricity. Or the abject silliness of daring to ride a racing trike in Denmark! :-)

Shopping used to be a strictly car-driven affair. Without the need to commute I wouldn't pass any shops with the car's enormous carrying capacity. So I developed the habit of attaching a sports bag to the rear stays of my trike. The bags came from charity shops too and usually enjoyed a short, but active life. Often dangling dangerously and loosely from the Higgins rear end. Not unlike the dog's wotsits in retrospect. The trike obviously had limited carrying capacity despite the size of some of my sports bags. Shopping gave me another valid and meaningful excuse to ride every day. It gave me a purpose in life when nobody else needed me to have one. The car cast a deep shadow and the grass eventually died where it stood unused. Often for weeks, or a month, at a time. The insurance company even gave me a discount for light use!

My trike mileages increased slowly but surely. My weight came down about as slowly. After three years of being a hapless job seeker and terminally forgetful shopper I was told to retire. For some reason this gave me a reason to ride further. I was free at last. Of what, I am still slightly unsure. My increasing fitness also allowed me greater range. Usually that range is still set solely by the level of comfort offered by the saddle.

There is a moral to this (endless) saga. Weep no tears for me. Except in laughter. Let's get right to the point: Being overweight is a personal choice. Being unfit is a personal choice. (medical problems aside) Though carrying a rucksack full of house bricks surely can't help any condition to improve! Being made redundant is not the end of the world. One adapts and one makes more beneficial life choices. All thanks to the greater freedom suddenly on offer. It is not something ending for good. It is another branch of opportunities opening up.

One has to try anything to improve the quality of life. Particularly when one has so much potential spare time on one's hands. Remarkably many people die off soon after compulsory retirement. I found that writing about it on my blog brought the self-discipline which was often lacking in the past. Even if only one or two other people read your blog it still demands some serious responsibility. When the numbers increase you had better perform!

Who cares if nobody else reads it if it makes you think for yourself? Few do. Most only regurgitate what they heard on the news. Or mumble the same tired, over-rehearsed comments about the latest sports result. Or nod approvingly at the neighbour's latest car purchase. Only the latest in the endless string of commuter boxes before the very last commuter box finally claims its owner. Did you see that programme on the telly last night? Sorry, I didn't. Don't elaborate though. You're not allowed to say you don't watch TV. It would be like making offensive comments about the enquirer's wife!

I was once addicted to Danish pastries without ever having to buy them. (One day at a time) I drank milk because I thought it was healthier than industrial strength coffee. Now, as I sink ever closer to 11 stones, 70kg or 155lbs I can stand up on the pedals for hundreds of yards on a climb. I can climb our 60 degree cottage stairs without becoming breathless. Back then I could only manage three miles, riding flat out around the block, before having a lie down to recover. And, the crazy thing is, I still thought I was fit!!

Now I eat all day and still feel hungry for the first time in decades. Feeling hungry is a wonderful feeling after years of feeling full! My weight is still dropping slowly. I feel more positive about life than I ever have. They said that dementia could be held off by exercise. I have the worst short term memory on the planet but I don't think it has actually got worse. As far as I can remember.

I give life greater meaning by deliberately giving routine tasks a multiple purpose: Greater fitness, greater range, money saving, avoiding depression, reducing the risk of heart disease, diabetes and skeletal problems. Fending off dementia, increasing skills or knowledge base. Or, just saving the planet. By leaving the car where it is for emergencies. Even giving myself something to think about in the absence of problem solving at work which no longer exists. For anybody at the present rate of industrial decline.

My wife used to call me Toffee Boy. In a kindly, bemused sort of way. Because I always walked like I was up to my knees in treacle! So, thanks to her kindness, I now choose to walk briskly when off the trike. Despite the racket from my MTB shoes clattering about in the supermarket aisles! Most people don't even walk. They amble on their slow motion visits to the supermarket. Rolling, often quite literally, from their cars to the trolley parking. Then rolling into the shop to buy their 55 gallon drum(s) of Coke for their daily fix. The wheelbarrow loads of fat-laden, semi-toxic, processed crap which is always sold in decorative boxes. Like aunty's Xmas presents from under the tree. Always so full of promise. Always ending in unmentionable disappointment. Nuts! (are filling and quite good for you)

Many shoppers are now so weak, from permanently carrying their personal loads of house bricks, that they lean heavily on the supermarket trolley handles. Rehearsing endlessly for their allotted Zimmer frames awaiting their twilight years. If they even last that long!

You can't change the colour of your skin. But you can certainly change how big it needs to be to house your inflated ego. They say that junk always grows to fill the space available. How many house bricks are you carrying today? How many more can you possibly manage?

Hi. I'm Chris. I'm a greedy pig. I am addicted to chocolate and biscuits and cakes. I am (still) carrying two extra house bricks. One day at a time. ;-)

/rant
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