Rake and Trail – your Harley is not a shopping cart

The look of a Harley-Davidson may be a decisive factor in deciding a purchase, but most of us take the candidate of our dreams for a test ride. Chrome and colour suddenly becomes secondary, the right ride feeling is important. The handling of a bike is depending on dozens of factors, the colour clearly not being one of them.

If you are interested in technical details, it is important to understand the basics of front suspension geometry, as these are the major factor in how your bike will handle on a straight line, under braking and in corners, under speed or very slowly. This geometry is primarily defined by six variables, which I want to analyse more closely. At the end, it boils down to 2 headline numbers: rake and trail. Other secondary factors which I will not analyse here in detail are hight adjustments and, sorry to point it out, your very own weight.

First lets look at the primary 6 variables on a bike:

1) The Offset – This is from the centreline of top of steering neck to the centreline of top of fork tubes pic offset

2) Rake – This is the angle in degrees of the steering neck from the vertical

3) Fork Length – This is the distance between the top of the fork tubes to the centreline of the axle.

4) Diameter of the front (and back) tire – this is… the Diameter of the front and back  tire

5) Trail – the most important number, a result of other factos, its the distance defined by vertical line from axle to ground and intersect of centreline of steering neck and ground

6) Raked Triple Trees (not shown above) – Making things complex, and in order to bring trail figures back into line, triple trees with raked steering stems can be used. Expressed in degrees, usually adjustable in 3, 5, and 7 degrees of rake, this number should be added to the Steering Head rake.

Uhh, new technical term, and no, its not Xmas, this is what is called a Triple Tree:

You could consider the Triple Tree as 2 plates, to which the steering neck and the front fork are attached. As shown above, the Offset is defined for the upper plate. If the lover plate has the same offset, both steering neck lne and fork line are parralel. If however the offset is increased on the lower plate of the triple tree, additional rake is introduced, increasing the total rake.

Now lets look at some Harley-Davidson data, collected from the official website (*) and other internet sources (**), not sure they are all correct, as sometimes marketing managers tweak data for a more pleasant look,  and not everything published on the internet is certified to be correct.

Lots of remaining question marks, lots of other influencing factors, but the trail is clearly the number to watch. For example the big difference in trail for the 883R and 883L (low rider) comes mainly from different wheel diameter. The Road King however gets its long trail primarily from a negative offset.

From experience, I ride a Road King and a 883R regularly, above numbers are butt tested and prove to me that a bike with lots of trail will be directionally more stable. It will tend to go straight and be easy to ride hands-off (never do that!!), it will not have its direction changed by every tiny bump in the road. But such a bike will take more physical effort to steer than a bike with less trail, that is also why bikes with long trail have wider handlebars. A bike with lesser trail like sport bikes will be livelier, it will take little effort to change its direction, whether that effort comes from your hands on the bars or (bad!) from a bump in the road. However, too much or too little trail will make your bike undrivable, and chopper builders go to great length to control rake and trail, check out this front special axle, designed not just to please the eye, but also to reduce the trail.

Trail causes the front wheel to act like a caster, and the greater the trail, the more forcefully the wheel tries to align itself with the direction of travel. But only few wants a bike so stable it can not be turned but prefer a bike that can be ridden no-handed for at least a few seconds without going out of control at the tiniest bump. Twisted City Roads vs a straight highway to the horizon, these extremes define your trail needs.

The above numbers however also show one thing very clearly: there is no golden solution, the mix is important, as well as drivers preference. Other external factors also play a role, as the weight of the driver influences the trail (heavy dude lowers the bike and reduces the trail), and the trail actually changes constantly, because under breaking the fork length reduces. Thus entering a corner under breaking (or not) changes the behaviour of the bike, and for a 20-stone dude its again different then for the slim lady on the same bike.

We do not need a PhD in geometry to evaluate a bike, our butt will do that, but to understand the influencing factors will help to formulate preferences. Harley-Davidson website only provides some geometrical data, but rake and trail is disclosed, giving a first hint on how the bike could handle. Then you can more consciously test ride different bikes and customise your own with more then just chrome covers for the back footrests, but maybe a new Raked Triple Tree for Xmas. And you may understand that using raked triple trees on a stock Harley front may not be the best idea, as it may shorten the trail too much and lead at instability at higher speeds. You do not want your bike to handle like a TESCO shopping cart.

Disclaimer: above are my personal research and thoughts. This is just to explain the principles, not to serve as instructions or recommendation, and worse of all, it could be wrong. Happy to receive your comments and corrections.

24,673 shots in a year

When Nikon announced its new flagship D4 camera last week, they advertised that its carbon fiber shutter was rated to 400,000 actuations.

The web community is not clear on what exactly this means, but one does not need to worry that after 400,000 pictures the D4 breaks down. The camera however may start to show signs of age, and a speed of 1/250th second may then be 1/257th or 1/242th of a second. Does it matter? A little.

Fact is, our car breaks down after hundreds of thousands of miles, or less, every product has a life-span, light bulbs, washing machines, and SLR cameras.

The next question is: are 400,000 shutter releases a lot, or not. And if this is the number for the brand new top of the line D4, what is the expected life for a Nikon D700 shutter, my somewhat older camera model first announced in July 2008. Searching the web, the number most often mentioned is 150,000 actuations for the D700, less then half as for a D4, but then the D4 is nearly 3x the price. Should I worry?

First I have to find out how many pictures I take during the year.

My D700 is now exactly 1 year old, and with the help of a RAW file and Apple’s Preview Inspector I found out that in the last year I pressed the shutter button 24,673 times. Wow! That is about 475 pictures every week, or 65 pictures every single day. It sounds even worse when you realise that in 2011 I took about one picture every 20 minutes.

If I continue like this, the shutter of my D700 could start to deteriorite in 6 years, by then in todays fast moving digital world the D700 can be considered a antique and ripe for the museum anyway.

So my very personal conclusion is: Skrew it, lets shot the ride!

The icing on the HOG cake

A great HOG seasons ends for me on very high notes. The first one came via Royal Mail, in form of the Winter 2011 HOG magazine. There on page 15 one of my many photographs of the season was printed:

The picture was taken some time back in May, while we visited the Hawk Conservancy Trust in Andover.

Some days later, the prize arrived, not money, not coupons, but a pin. I think you need to be a keen photographer to enjoy the moment, and I enjoyed it very much.

As if this would not have been enough, I received a heart warming Thank You from my Hogsback Chapter UK during the End of Season Party, in form of a big metal badge, for the photographic work of the last season:

What a ride, I have to say Thank You, as it was great fun for me to share many miles with my fellow members.

Intrigued by the building on the front, I found out that it is the Harley-Davidson offices in Milwaukee, 3700 West Juneau Avenue, USA. Never been there, but riding on Google Street View I took the next left…, and yes, thats the same building.

Have a safe winter.

I wear a helmet because I want to, not because I have to…

Hyperventilating Health and Safety bureaucrats rule the world, and we let them hijack day in day out our own responsibilities. As a citizen, I do not need a brain any longer, all I need to do is following the ever increasing rules and regulations issued by a army of nerds. And if anything goes wrong, we hire a lawyer to sue the shit out of somebody close.

This is a very dangerous development.

I am very worried by recent announcements, where people, sitting in dark back-rooms in Brussels or Westminster, are trying to force us bikers to wear HiVis day glow vests. I am not against HiVis clothing, I own one myself, but I want to decide when and where to wear it, and not be ordered by some public servant who is paid to invent new regulations. The point is: they do not have these ideas because they want to save the world, no, they just want to save their job and be important.

We live in a overly regulated world, where any kind of personal responsibility is discouraged. All what our children learn is to wait for the little green man, and they do not know anymore how to cross a street in safety once the traffic lights break down. This is very wrong, and dangerous. Some communities start to realise this and dismantle traffic lights altogether, leaving it to few simple rules, common sense and the observation skills of its citizens to organise their movements. In principle, we are all willing to respect a set of rules and values, but if our own intelligence gets questioned by politicians piling regulations on regulations, we start to loose the respect of rules, and worse, we start to break them. And it becomes fatal, when we start to break the wrong ones.

Me in yellow at a 4am start John O’Groats – Lands End Iron Butt run to

I wear a HiVis on occasions, when I ride in dark foggy winter conditions, but on a sunny day, my black leathers or even T-shirt for the short dash to TESCO will do just fine. You may consider this risky, yes, but it’s a risk I take, you are not put at risk at all. So let me live my life, if you want to spend yours sweating in a Ronald MacDonald costume, fine with me.

I do not want to ride my bike looking like a clown, I want to decide when I wear a HisVis and when not. The point is: all I endanger is my own life, so please step back and let me decide what to do with it. If some cool dude want to ride without helmet, gloves and in his flippers, let him, its his choice to turn his life at a much too early stage into that of a rotting tomato.

The thing with these health and safety bureaucrats is that they never stop being creative. Today its HiVis for all bikers, tomorrow all cars have to be painted in either bright yellow and orange. Seriously, if I have to ride along in a yellow or orange clowns costume to be seen, I expect every pedestrian to wear the same garbage men’s HiVis vest, so we all can see us during daydreaming. And then we all will suddenly ride faster, and walk with even less attention, as -hurray- we can expect to be seen!! A fatally wrong development, as all our attentions will reduce dramatically. The first to die will be cats and dogs, ah no, wait, stupid me, they will also have to wear Hi-Vis vests.

In a sea of yellow and orange, black becomes the new HiVis colour. Leave Hi-Vis vests for those who actually need them: traffic obstacles. A broken down car driver, the road workers, RAC, AA and ambulance or police, and many others, as they are all temporary sudden obstacles that deserve a special high level of recognition and protection. But normal traffic participants like cars and bikes are not a obstacle.

If we follow the bureaucrats misguided inspirations, we will drown in a bright sea of hi-vis colours, not recognising anymore what is a traffic obstacle and what a normal participant. That is when serious accidents will start to happen.

Harley-Davidson recalls 300.000 Touring models 2009-2012

Since some days it is official, Harley-Davidson recalls over 300.000 bikes, to fix a switch problem that can cause failure of the brake lights and possibly even the rear brakes themselves. The HD eecall ID is 0145.

The problem affects Touring, CVO Touring and Trike motorcycles from the 2009 through 2012 model years. They were built between June 6, 2008 and Sept. 16, 2011.

Now, in the next days or weeks, I expect to receive a nice letter from my dealer to schedule a repair, but what happen until then, how serious is this defect, and what exactly is broken. Its all about this little switch:

Here in more details:

A – is the rear brake fluid line leading to the switch
B – is the switch, which is activated by pressure in the brake fluid line
C – is the electrical cable for the rear brake light

As all this is very close to the exhaust, its getting hot, and heat can break the switch. 3 things can happen:

1) rear brake light fails to work
2) rear brake light works all the time
3) brake fluid leaks from the switch, compromising brake pressure and eventually the rear brake will fail

Am I getting nervous? No, not at all. If the brake light fails or works all the time, bad luck, I check it prior to each ride, but I do not consider this critical, if you know its broken, drive more defensively and check your rear mirrors closer. Having no rear braking power is not very nice, but if you know it, one can still limping home, as over 70% of all braking is usually done via the front brakes. Just be careful in corners and do not push too hard.

Until I get the recall notice or the all clear from my dealer, I will check this switch for leaks prior to each ride, and test occasionally that the rear brake light works. Otherwise, I will continue to enjoy every sunny mile in these last days of the riding season.

Disclaimer: This is not a recommendation, this is what I do, and it may damage my health.

For a list of all included in the recall, see:

http://www-odi.nhtsa.dot.gov/recalls/results.cfm?rcl_id=11V506000&searchtype=quicksearch&summary=true&refurl=rss.