Wheel alignment

Friday 26 March 2010

Wheel alignment - improve your handling at no cost

About 7 years ago, thinking about the impact of good wheel alignment stirred what Jennie laughingly refers to as my brain!  I'd had some new tyres fitted and wasn't happy with the handling.  New tyres always feel a bit odd until you get used to them anyway but in this instance, the turn-in to corners felt different depending on whether I was going into left or right-handers.  It bothered me enough to use the time-honoured string line method of checking and sure enough, the rear wheel was significantly out of alignment.  The improvement was noticeable when properly aligned.

Moral of the story: Correct wheel alignment makes a big difference to the handling if it's accurate. You shouldn’t rely on a new rear tyre being correctly aligned when fitted at a tyre shop unless they have good gear and maker's graduations on the swing arm are not necessarily to be trusted either. There can be enough play in the components to throw alignment out.  In addition, each time the chain is adjusted, you run the risk of shifting the alignment. Using string lines works just fine, but is time-consuming to set up and care is required to take the actual measurements (Not to mention tripping over them at regular intervals or having the cat decide that the string is there for entertainment purposes!)

After this episode, I got to wondering about using the same principle as string line alignment but substituting the string for a laser instead. No cumbersome setting up and hopefully nothing for the cat to attack. The prototype rig was constructed in 2004 and intentionally made from materials which I already had at home and it has been so successful that I've never got round to making a fully adjustable one to cater for a range of tyre widths. There are multiple permutations on the design shown, and also variations in the way it can be used. However, let's go through the principles with a few photos and you can decide whether it's worthwhile building one and if so, whether you want to improve on the design. Click on the photos to enlarge them.

Rig construction:
The rig is constructed in two parts: the laser beam emitter/support bracket (blue) and the laser light target (white).  The laser emitter is a cheap laser pointer combined with a pen, but single purpose laser pointers can be obtained cheaply from electronics and office supplies shops etc.

The support bracket is constructed from MDF. It should be recessed in the top to provide stability to the laser pointer. In this case, two 3mm pieces of MDF were sandwiched to a wider piece of MDF. The pointer is held in place with elastic. A spring clothes peg is used to keep the laser switched on. The centre line of the laser is 90mm above datum, which is close to the maximum height that can be used for a Honda Blackbird on its centre stand with a 6mm ride height spacer under the shock absorber without interfering with the laser beam. (You can use a bit of wood under the centre stand to get better clearances if this is an issue).

The laser target is constructed from a piece of straight dressed timber painted white, with Perspex end-pieces. The overall length is 500 mm, the height above datum of the timber surface is 80 mm and the height of the Perspex end-pieces is 130mm. The timber is 58mm wide with a centre line marked on it. The centre line of 29mm equates to half the difference between the widths of the front and rear tyres I use. If this is different for other tyre combinations, it doesn’t really matter as a steel rule can be used to measure how far away the laser beam is from the edge of the front tyre.

Both end-pieces have a vertical line scored in them with a scriber. The score lines are on the inside faces of the Perspex. This helps to slightly scatter the laser light on the line and make alignment easier (much like a rifle sight). The target end piece has a strip of black insulating tape behind it to make the laser easier to see.  The second and third photos show the target being struck by the laser beam.

How to use the rig:
The first photo in this section simply shows the general arrangement of the rig.

Prior to commencing the alignment process, spin the front and rear tyres to look for any significant oscillation on the widest part of the tyre wall. The laser beam can be helpful for this purpose. If the rims are in good order and the tyre has been fitted properly, it will be negligible. If any movement is >1-2mm, then position the wheel so that the laser is roughly at mid-point of the oscillation.

Align the front wheel as close as possible to the centre line of the bike by eye. The target part of the rig is then pushed up against the front tyre. It can be held in place with light elastic if there is any concern over possible movement. The laser emitter and support assembly are placed at the back of the rear tyre so that the beam just kisses the widest part of the tyre front and aft.  This will take a bit of practice with a small diameter beam to make the fine adjustments, but isn't difficult. The photo shows shows the inner part of the beam just touching front and aft rear at maximum tyre width.

Turn the forks until the laser beam lines up with the lines on the Perspex end plates, or runs parallel with it. This is shown in the next photo. In the latter case, measure the distance from the beam to the widest part of the tyre.

Move both parts of the alignment rig to the other side of the bike without disturbing the front wheel . If the distance of the laser beam from the widest part of the tyre is identical to the measurement on the other side of the front wheel, then it is properly aligned.  This is shown in the following 2 photos which show the laser beam striking the centre line of the target on both sides of the bike.  If not, then tweak one of the adjusters and re-check alignment.  Just a reminder, the centre line of this prototype is half the difference of the maximum (inflated) widths of a 180 section rear tyre and a 120 front.  It wouldn't be hard to make an adjustable one or simply measure any variation with a steel rule provided that alignment on both sides of the bike is identical.

Re-check the alignment when tightening the rear axle to ensure that nothing has moved. A suggestion to increase the interval between full alignments is to scratch some small alignment marks on the swing arm and adjusters if the stock ones are inaccurate. Eccentric adjusters for chain tension require a slightly different approach but the principle is identical.

Well there we are - a simple (and cheap) device which will allow you to check and set wheel alignment accurately.  My instructions are probably as clear as mud but if you have any doubts, build a simple 2-dimensional model from a bit of card to sort out the principles.  They are straightforward, but visualising them and having something in your hands at the same time might be even easier.

If all else fails, you'll find my email address near the top of the blog. I'll do my best to help if you get stuck!

When I sold the Blackbird and bought a Street Triple which had different width tyres, I experimented with a different approach to the front wheel "target".  Instead of a piece of straight wood with "gunsights", I simply used a tape measure which was placed at the maximum width of the front tyre, both at the rear and front to make sure the front and rear tyres were parallel.  This is is repeated on both sides of the bike to determine the degree of misalignment and/or offset.  As with the methodology listed above, it's simply a matter of subtracting the difference between front and rear tyre maximum widths and halving the result to get the calculated offset on one side.  The photo and sketch below show the methodology for the Michelin PR3 tyre which I was using at the time.

Monday 22 March 2010

No riding this weekend, something even more important!

This blog is unashamedly about motorcycling but this post has nothing whatsoever to do with bikes apart from the event which prevented me from riding this weekend, haha!

Our younger son Kerryn and his fiancée Becky returned to NZ a few weeks ago after 5 years working in the UK. It's been a wonderful week. On Thursday, he heard that he landed a senior job with a food company in Auckland and Becky is short-listed for 2 top property management jobs. However, the most wonderful bit was that they got married on Friday and Jennie and I couldn't be more proud of two fabulous kids who are absolutely devoted to each other. It was also the first time that Kerryn, his sister Victoria and brother Lyndon had all been together for 6 years and that was very moving. Also very moving is that a number of the Merton Rugby Football Club in London that Kerryn played socially for also came half way round the world for the wedding! This crusty old biker must be going completely soft as I filled as many handkerchiefs as Jennie!

The ceremony was at a natural geothermal hot spring on the Coromandel Peninsula where we live and Becky walked in to the song "Growing up Beside You" by Paolo Nutini. I'd never heard it before and it triggered more waterworks - just lovely. It's on YouTube if you've never heard it either.

With all the troubles in the world, it's the best feeling in the world to see two young people who are bright, funny and possessing strong personal values making such a great start.

Our 3 kids: Lyndon, Victoria and Kerryn.  Enormously proud of their achievements.  Lyndon is an Occupational Therapist, Victoria is a Psychologist and Kerryn is a Food Technologist.

Sunday 14 March 2010

Death of a Triumph engine

I've just been sorting through some old photos and the one that's attached here still makes me wince!  In my early motorcycling career, I had a pre-unit construction Tiger 100 500cc twin . (See: The passion really starts to get hold)  The previous owner had lavished a lot of care on tuning the engine, with 10.5:1 compression pistons, E3134 sports cams, tuned exhaust and so on.  After owning it for a couple of years, I discovered a small crack at the bottom of one of the cylinder liners.  The crack didn't look recent but to be safe, I decided to have a new pair of liners fitted and a local company undertook the work.

Carefully put it all back together and commenced carefully running it in.  A week or two after the rebuild, I was going up a steep hill a few miles from home and it felt sluggish so decided to pull over and have a quick check.  Peeked in my rear view mirror before stopping and saw an awful lot of smoke - oh sh*t!  Got towed home, stripped the motor and holy heck.....

The resolution of the photo isn't all that good (you can enlarge it by clicking on the photo) but the arrows mark the obvious damage - it's an excellent example of cause and effect.

The cause is that the new steel liners had gradually rotated in the alloy block.  Each liner has 2 cut-outs at the bottom to give clearance to the con-rods when the crankshaft and rods are at half-stroke.  As the liners rotated, they gently shaved the con-rods, depositing fine alloy powder throughout the lubrication system until the motor seized (the effect!).  The broken piston is testament to that!!

I wasn't confident that I'd be able to get every trace of the powdered alloy out of the oil galleries and wasn't about to have it happen again, so gave the motor away for basic parts and got an inexpensive bog standard second hand replacement which ran perfectly until I sold the bike a few years later.

Putting new liners in an alloy block involves chilling the liners and heating the block to ensure a good interference fit.  I've got no proof, but did wonder if the people undertaking the work perhaps skimmed the bore in the alloy block to make fitting a little easier.  Of course, this was denied and I had to wear the problem.  

However, it's incidents like these that ultimately give us a better understanding of things mechanical, even though we don't see it like that at the time!

Friday 5 March 2010

Global driving standards or the lack of 'em...... grrrr

I need to get something off my chest with a bit of a rant so bear with me!

The Coromandel Peninsula where we live is a motorcycling Mecca - around 300-odd km of loop road comprising of twisties, sweepers and stuff-all straights; running by the coast and over a mountain range.  A technical, challenging road if ever there was one, particularly as a lot of it is relatively narrow with more than a few blind bends.  It's what every experienced rider craves and it doesn't disappoint.  On the downside, it has breathtaking scenery which means that it draws tourists both domestic and international to add to the local population.  Even then, it can hardly be described as overcrowded on most occasions.

Me, decking everything on the Blackbird!

Idyllic you might say and to a large extent, it's true but there's one big blot on the landscape.  The big blot is the motoring public on 4 wheels trying to kill me at every opportunity!  I take a dim view of that and am known to get a mite testy.  All I can say is that I'm forever grateful that my advanced rider training instructor spent an inordinate amount of time on situational  awareness or I might not be writing this!

Tourist vans, rental cars, 4x4's towing boats (but only if the driver has a baseball cap and moustache - why is that???) - they're all out to get me but how, you may ask?  The favourite form of assassination is by straight-lining/offsiding corners, that's how!  Doesn't matter if you're closing on them from behind or they're coming towards you, show the knuckle-draggers a corner or a sequence of bends and they'll cut it, irrespective of what else is on the road.  Even better if a corner is completely blind. The look of complete surprise on their faces when they discover someone else occupying the correct lane on a collision course beggars belief - INCOMPETENT BASTARDS!  Sorry, built up quite a head of steam there!

Let's have a think about the business of straight-lining. In the UK for example, straight-lining (or whatever local term fits) is taught as an advanced riding technique to improve sight lines, less risk of binning it in adverse conditions and a whole heap of other advantages.  There's a critical word I've left out and that word is BUT! The BUT comes in association with the words ADVANCED and JUDICIOUS  in knowing when to apply the straight-lining technique.  In other words, let the average member of the motoring public go straight-lining and you have the potential for serious injury or death through poor situational awareness.

In NZ, you risk a hefty fine and demerit points on your license for straight-lining -  "failing to keep in your lane".  Given the propensity for straight-lining being used by people who are simply lazy or terminally stupid, perhaps staying well in your lane is good insurance.  I must admit that I use the technique a lot less than I used to although I do still shift position all over the road to get the best possible view when preparing to overtake or get a good forward sighting of conditions.  The debate about whether to straight line or not ran to 11 pages or so in the Kiwi Biker forum thread: Straight-lining corners or not? with good points raised by both sides, plus the normal amount of crap by people who can't be bothered to think deeply enough to put a good argument together.

I don't think there is a completely watertight argument on either side of the debate but do think there's something upon which we can all agree. The level and quality of instruction received when first learning to drive a car or motorcycle is woefully inadequate, at least in NZ and probably elsewhere.  This translates into putting other members of the public at risk as well as the perpetrators, especially you and me as more vulnerable motorcyclists. There are situational awareness techniques plus some others which are only taught at an advanced level, yet are simple enough to be taught to learners so why don't we do it to reduce the road toll?

Handling potentially dangerous industrial equipment usually requires high level training to operate it and yet operating a road vehicle where the consequences and high cost of accidents are beyond dispute only requires pretty basic instruction to get rolling.  Sounds crazy when you put it like that, doesn't it?

Anyway, rant now over and I feel better for it, especially as Jennie and I went out in the boat this morning and caught 9 snapper (6 for Jennie, 3 for me which is par for the course but who's complaining when there is great seafood going into the pan!).

Catch you later.....

Tuesday 2 March 2010

New bookcase triggers a nostalgic bike episode!!!

Well, the title of this post sounds a bit preposterous but it's absolutely true!! Jennie and I recently commissioned a local craftsman to make us a 1.8 metre high oiled solid macrocarpa bookcase (the first picture shows it freshly unloaded from the trailer today!).  In anticipation of its arrival, I started sorting through a few old boxes of books that haven't been opened since I don't know when and looking on storage shelves to see what should go in the new bookcase and what can go to the local charity shop.
Rustic macrocarpa bookcase

Sorting through old books wasn't exactly a riveting prospect but then Karma stepped in as it sometimes does in times of need!  Within a minute or so of starting rummaging, what should pop up but two Triumph maintenance manuals which haven't seen daylight for decades.  Not any old Triumph manuals, but one for the second bike I owned back in the 60's - a 3TA 350 (plus the T90, T100 and Speed Twin).  The other manual covers all Triumph twins manufactured from 1945 to 1962.  This latter manual says 10 shillings and sixpence in the flyleaf so I'm assuming that this was a 60's purchase too!  What's more, they're in pristine condition - not an oily thumbprint to be seen on any of the pages which is a bloody miracle!  (The handful of scanned pages I've posted here can be enlarged by double-clicking on them).  Also see HERE for a link to the fun to be had with the oil pressure relief valve!

As you might imagine, sorting books stopped immediately and has yet to re-commence as I leaf through these wonderful documents which have triggered so many memories.

This brings back memories

An even older manual

The first thought was how few special tools were required to completely strip the engines, which was just as well for an impoverished trainee mechanical engineer  who's bike was his only form of transport!  However, reading how to replace the tappet shafts brought a wry smile. The manual exhorts owners to buy a special tool (an overpriced skinny bit of split pipe with a chamfered bore if I remember correctly) to stop the O ring seals on the shafts being damaged on re-fitting and causing oil leaks.  To be honest, I think the Triumph Marketing Department had their collective tongues firmly planted in their cheeks when selling this tool.  Despite every care, mine still liberally dribbled oil all over the cooling fins.  However,  the wonderful smell from the weekly application of Gunk brand degreaser to remove it did offset the annoying effects of the leak to some extent!

Beware the unwary!

Although sprung hub Triumphs were a little before my time, I've heard chilling tales regarding the maintenance of these hubs and have posted a picture from the manual to show how they went together (err... or were abandoned in this state).  At the heart of this frightening device were blocks of rubber held in place by wicked springs under compression which would have taken the weight of a main battle tank.  I wonder how many owners on-sold their bike to some unwitting sucker rather than face rogue springs ricocheting round the shed destroying the contents and causing severe bodily harm.  Looking at it in a dispassionate manner, I suspect that military scientists used the Triumph Sprung Hub as the basis for modern anti-personnel weapons like the Claymore.

Modest horsepower - an understatement

The other photo is part of the tech data sheet from the Triumph 350cc 3TA which I owned after selling my Suzuki 50.  The data sheet records a mere 18.5 bhp and allowing for Marketing Department hype, it might have been rather less.  Anyone reading my earlier account of being given a hiding by a newly-released Yamaha 100 twin would have seen the writing on the wall for the British bike industry and it was mainly that incident which caused me to sell it and buy a Tiger 100.  More power, but just as many oil leaks despite my best efforts!  Thank God it wasn't a Tiger 100A though.  Joe Lucas wasn't called the Prince of Darkness without good reason but the Energy Transfer ignition system fitted to the T100A was a triumph (no pun intended) of poor design and had owners spending more time running alongside the darned things than actually riding them.  Still, I suppose that fitness levels increased dramatically.

Before we finish these musings,  I also noticed that the headlight bulb was a 6 volt 30/24 watt Lucas item.  How we found our way anywhere in the dark without colliding with large, solid objects is probably testament to the ummmmm... modest performance of the bike and comparative lack of traffic rather than the headlight actually being effective.  Still, we lived through it all and are wiser (a debatable proposition) for having owned early British bikes!

Wonder what else I'll find in these fabulous books with their charmingly optimistic instructions?