Suspension part 4

Measuring the travel

The final part of setting the springing (as weíve been discussing the last two issues) on the suspension is to measure the amount of travel used while riding. Itís important to do this final step rather than rely on how the bike feels. Often our perception of what the motorcycle is doing is quite different from what is really happening.

This final step is probably the most simple of all. To measure how much travel the suspension is using itís just a matter of putting a cable tie (sometimes referred to as a zip tie) on the shaft of the forks and the shock. In this way you can see how much of the available travel is being used by the location of your cable tie after the bike has been ridden.

To ensure accurate results, you should only measure the amount of travel being used after riding in your normal environment. Meaning that if you do mostly ride days and sport riding, just going around the block isnít going to give you a very accurate idea of what the suspension is actually doing!

If you find your cable tie is pushed up against the end of the shaft, chances are your suspension is too soft. On the other hand, if your cable tie is only half way along the suspensions travel, chances are your suspension is now too hard. The ideal scene is to have the swept area (the total amount of travel used) to be only slightly smaller than the total travel available.

By using the three measurements we have discussed over the last two issues of AMCT, you now have the tools to set the springing correctly. As you change the preload to suit one of the settings, you may find that it makes the suspension fall out of the ideal range in the other areas. This tells you that your spring may not be the right one for your application. For example. Lets say you did everything right in setting the sag and the one G test, but your suspension is bottoming out (using too much of its available travel).

This would tell me that your style of riding requires a harder spring set with less preload. This spring would require more force to use all itís travel, but less to start it moving. Meaning that you can still get the sag figures correct, while using the right amount of available travel.

There are far too many possible variations for us to cover in this short amount of time, but at least now you should be able to recognise whether or not your suspension is working within the range it was designed to work.

Next issue: damping controlling the movement of the spring...

Good luck with your riding.