Understanding Dog Bones, and Leverage in your suspension

I know there`s a few on here that have changed their dog bones for desired affect, or to correct for a different shock installed from standard.

To be anally correct in setting up your rear suspension, there is more than just changing your dog bones, and the factors involved with the maths in doing so.

I can`t help but to be one of these people, to get the correct spring rate to suit the ratios of a given out come, from changing the geometry from a different shock, and dog bones to suit.

http://www.promecha.com.au/leverage_linkages.htm

Peter at Promecha is a man who knows his business inside out, he did my suspension.

I know a lot of suspension services, won`t always  take different length shocks, and different dog bones to suit as part of the equation. They will typically ask you your intensions of use, and the weights of the bike, yourself, and luggage on top of that, without considering the geometry difference and how that affects the total set up.

If your just upgrading your standard shock , or am putting on an after market, designed for your bike, than it is a basic equation of what is correct.

Just putting it out there, if you were to upgrade to a different "length shock, or altering dog bones" , that there is maths involved, and not just a text book set up, as the geometry has been altered.

Too much knowledge is dangerous .AS Ant West once said "I know nothing about suspension set up , I just ride the bloody thing "

I'm with Ant West. I wouldn't know what good suspension even feels like.

reddog wrote:I'm with Ant West. I wouldn't know what good suspension even feels like.

That's the funny thing about it.  
When everything is set up well, the bike goes around corners and over bumps, stops and changes direction without you even knowing that it's doing what it does well. 
When your suspension is not set up correctly for your weight and style of riding, then you will start to feel what bad suspension feels like.  Wallowing, running wide, harsh ride over bumps. All of the things that a bad handling bike does. 
A good suspension set up makes a good bike a great bike.
A bad set up can make a great bike feel terrible.

well this is part of the point I`m making.

I, along with others, have changed certain parts of their suspension, and if your going to the effort to change your shock or height, why not do it right?  unless of coarse you do what I did with my other Bandit, and buy a quality brand X shock, which is state of the art, designed for that bike, but costs an arm and a leg.

I`m not about to do the sums myself. I will go to a suspension dude, lay out what I`ve got and want, he should be able to do the sums, for the right spring, to suit a different length shock, with a given length link arm. I don`t see it as rocket science on his behalf, it`s his job, and if he can`t work it out, then he`s not the man for the job.

Only that way, will you know if your bike will handle correctly or not, but has to be in tune with your front. Once again, leave the maths to those that do it every day.

I'll preface this with - I know little about suspension and would have difficulty putting a pogo stick together    

I liken this suspension geometric accuracy to a lesson I learnt from an old college professor I had at RMIT when I was studying my electronics degree.  He'd set us a transistor problem to work out the gain of a circuit or something simular and 30 minutes to do it.  We had all these formulas and expensive reverse polish calculators that had multiple memories and could do calculus and simultaneous equation.  We'd work like trogons to solve the problem only just finishing the task in the time given.  At about 29 minutes in he'd whip out his trusty Wollies calculator (that I'm not even sure had a square root key) and solve the problem with half a dozen key strokes.  The thing was, it didn't matter how accurate we were, in the real world you can't get components to the exact tolerances we had calculated. Our professor used "rule of thumb" figures that would get you to as close as you could with available components, and even then the variations of mass produced component were such there was still a fair degree of flexibility.

And it seems to me that the variation in riding in day-to-day commuting or long distance touring, whether you are solo, two up (or three up), with or without sidebags/panniers, the road condition, weather, traffic and a gauntlet of other variables would mean the optimum suspension setup is only good for a small part of the time.

But then again I'm an old fart that still rides with a training wheel so I'm a little slower than the average canyon rocketees  

You might need to get that wobbly side-car wheel looked at Barry 
I suppose exact settings for suspension would be great , but unless you are riding on the edge on a set surface , compromise is all you can hope for or that is necessary  really .( what you just said I suppose   )