When is a rising rate not a rising rate? when its at the wheel of course!
Today here at  ATG-Training during a Cytech Level 3 Suspension course, we delved into the quite complex world of full suspension bicycle design and talked about the ins and outs of what it takes to make a frame and rear shock that work in unison.

In the short space I have here it’s impossible to even scratch the surface of this topic, but one thing I’d like to share is about leverage rates.

These can be measured in two different ways. At the shock (which is the most accepted way in the industry at the moment) or at the rear wheel.

I think people use the rear shock as it is easier to understand the principles behind the theory. If I use the term ‘Rising rate’ this means that the shock will become stiffer the deeper the rear shock goes into its travel (which is a good thing as it will pevent harsh bottoming of the shock) you’ll hear the terms ‘ramping up’ and ‘progessive’ used as ways of describing this also.

If I use the term ‘falling rate’ this would mean that the rear shock would become softer the deeper it got into its travel, which of course would be undesirable as the shock would consistantly bottom out on harsh terrain (aswell as being almost impossible on an air shock which will naturally exhibit a rising rate) the term ‘digressive’ can also be used here.

So that’s the rear shock dealt with. Got it? most people will as this is something that you can ‘feel’ on the bike.

One thing that we can measure, but is difficult to feel is the wheel rates. We can’t discount them as they are n integral part of the frames design.

A ‘rising rate’ at the wheel will mean that the linkage will push more of the shock the deeper it goes into the travel (leading to the shock bottoming out more quickly) because the mechanical advantage of the linkage increases throughout the travel.

A ‘falling rate’ at the wheel will mean that the linkage will push less of the shock shaft throughout the travel, meaning that the mechanial advantage of the linkage becomes less and less the further you get into the travel. This would be better on a downhill bike for example as it would mean that the likelyhood of botoming the bike out would be reduced.

Understood? Well, things are rarely as straightforward as this in the world of bicycle design and there are a bunch of other factors that we would need to consider.

If you’d like to know more then get yourself booked on to one of our Level 3 Suspension courses and get ready for some head scratching!!