SV650.org - SV650 & Gladius 650 Forum - View Single Post

Bibio · 10-10-12, 08:55 PM

Part 3. Dampening
Now that you have set your sag it’s time to start turning those clickers. If you have basic suspension your pretty stuck and will find it difficult to dial in compression or rebound but it can be done using thinner/thicker oils and opening/closing the bleed holes in your front suspension. If you have a basic rear shock with no dampening adjusters then your well and truly stuck and the only thing you can do is upgrade your shock to a better one. I’m not going to go into describing how to modify your damper rod suspension forks and will leave that to those suspension guru’s out there to advise you better.

Dampening rate can either be Hard (slow) or Soft (fast) or anywhere in between. Do not confuse this with making your suspension hard or soft as it’s a method of controlling the rate at which the spring is controlled in its movement and nothing more.

I’m not going to even attempt to explain the shim stacks and valves in cartridge type forks and rear shocks but mention that there are two types of dampening within them which are Fast and Slow rates the fast rates control sudden bumps and let more fluid pass by valves at a higher rate while the slow rate controls chassis movement.

Rebound.
Rebound dampening is the control of the spring in a downwards motion. Too much dampening will stop the spring from returning quick enough and too little will make it return too fast. Your looking to set the dampening just enough that the spring is controlled so there is no over shoot but still allow the spring to return quick enough to stop packing down.

Turn both rebound adjusters (if you have two) to full hard so they are lightly seated at there full travel then mark that position with a marker pen adjacent to and as well as the slot on the adjuster this way it gives you a indicator then back them off 1 full turn towards soft or if you have the clicker kind count the clicks and note them down.

Sit on the bike and grab the bars then pull up on the bars then push down with as much force as you can then allow the forks to come back up without pressure on them, it takes a bit of practise to get right but patience will reward.

Your looking for the motion of your front forks as they rise back up. If they come up slowly and stop abruptly then decrease the rebound adjusters (go softer) by 1 full turn. Remember to do both adjusters if you have one on each leg that control rebound. Then repeat the bounce test. Your looking to set the rebound just at the point where the forks rise up then stay there and just after the point of overshoot. So you bounce till your forks come up then go down again then add (1/8th of a turn) 1 click towards hard till they stop going down again after the bounce so they come up quick enough but without overshoot.

The rear is slightly harder to judge but is the same principle as the front but to make it easier get someone to sit on the bike while you bounce the back and watch for the point of overshoot then wind back till gone.

Compression.
Compression dampening is the control of the spring in an upwards motion. Too much dampening will stop the spring from compressing quick enough and too little will let it compress too fast. Your looking to set the dampening just enough that the spring is controlled so there is no undue movement while compressing. For instance your wheel hits a bump in the road and you don’t have enough compression dampening, it will continue to compress after it has hit the bump as there is nothing controlling the force on the spring so your wheel ends up leaving the road surface till your rebound takes over and returns it back on the road surface.

I personally find compression adjustment a nightmare to set statically so i resort in riding the bike to get it somewhere I like.

Fortunately there is help at hand in the form of your tyres. Compression and rebound problems can manifest themselves in very telltale signs in the tread pattern of your tyres. I will admit that this is where I’m still learning the art of reading tyres but from the information I have gathered it seems that there are distinctive wear patterns that emerge to help us diagnose problems. I’m going to leave cold and hot tear out of this and concentrate on just the basics of suspension signs in tyres.

The picture below is of an Avon Storm Ultra 2 tyre and is taken off the internet via Google images. The red arrow indicates the direction of travel, the green curved line indicates what I’m going to call the leading edge of the tread pattern and the blue curved line is indicating what I’m going to call the trialling edge of the tread pattern.

There are two distinct types of wear that arise from suspension problems the first is chamfering and the second is ridging. Chamfering looks like the edge has been worn away and ridging looks like a ridge sticking up on the edge.

I’m more than likely wrong with this but to much compression chamfers the leading edge. While to much rebound ridges the trialling edge. If this is correct then I would presume that these signs would disappear once the correct dampening is dialled in.

Fast compression adjustment or rear shocks is the dampening control when hitting sudden bumps. Its not to control how the shock acts at high mph speeds. So only adjust this if you find the rear a bit vicious hitting sudden bumps like raised and over painted rumble strips. Be careful of this though as it can cause your shock to blow by to much fluid resulting in loss of dampening.

10-10-12, 08:55 PM	#4
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,569	Re: Suspension Basics Part 3. Dampening Now that you have set your sag it’s time to start turning those clickers. If you have basic suspension your pretty stuck and will find it difficult to dial in compression or rebound but it can be done using thinner/thicker oils and opening/closing the bleed holes in your front suspension. If you have a basic rear shock with no dampening adjusters then your well and truly stuck and the only thing you can do is upgrade your shock to a better one. I’m not going to go into describing how to modify your damper rod suspension forks and will leave that to those suspension guru’s out there to advise you better. Dampening rate can either be Hard (slow) or Soft (fast) or anywhere in between. Do not confuse this with making your suspension hard or soft as it’s a method of controlling the rate at which the spring is controlled in its movement and nothing more. I’m not going to even attempt to explain the shim stacks and valves in cartridge type forks and rear shocks but mention that there are two types of dampening within them which are Fast and Slow rates the fast rates control sudden bumps and let more fluid pass by valves at a higher rate while the slow rate controls chassis movement. Rebound. Rebound dampening is the control of the spring in a downwards motion. Too much dampening will stop the spring from returning quick enough and too little will make it return too fast. Your looking to set the dampening just enough that the spring is controlled so there is no over shoot but still allow the spring to return quick enough to stop packing down. Turn both rebound adjusters (if you have two) to full hard so they are lightly seated at there full travel then mark that position with a marker pen adjacent to and as well as the slot on the adjuster this way it gives you a indicator then back them off 1 full turn towards soft or if you have the clicker kind count the clicks and note them down. Sit on the bike and grab the bars then pull up on the bars then push down with as much force as you can then allow the forks to come back up without pressure on them, it takes a bit of practise to get right but patience will reward. Your looking for the motion of your front forks as they rise back up. If they come up slowly and stop abruptly then decrease the rebound adjusters (go softer) by 1 full turn. Remember to do both adjusters if you have one on each leg that control rebound. Then repeat the bounce test. Your looking to set the rebound just at the point where the forks rise up then stay there and just after the point of overshoot. So you bounce till your forks come up then go down again then add (1/8th of a turn) 1 click towards hard till they stop going down again after the bounce so they come up quick enough but without overshoot. The rear is slightly harder to judge but is the same principle as the front but to make it easier get someone to sit on the bike while you bounce the back and watch for the point of overshoot then wind back till gone. Compression. Compression dampening is the control of the spring in an upwards motion. Too much dampening will stop the spring from compressing quick enough and too little will let it compress too fast. Your looking to set the dampening just enough that the spring is controlled so there is no undue movement while compressing. For instance your wheel hits a bump in the road and you don’t have enough compression dampening, it will continue to compress after it has hit the bump as there is nothing controlling the force on the spring so your wheel ends up leaving the road surface till your rebound takes over and returns it back on the road surface. I personally find compression adjustment a nightmare to set statically so i resort in riding the bike to get it somewhere I like. Fortunately there is help at hand in the form of your tyres. Compression and rebound problems can manifest themselves in very telltale signs in the tread pattern of your tyres. I will admit that this is where I’m still learning the art of reading tyres but from the information I have gathered it seems that there are distinctive wear patterns that emerge to help us diagnose problems. I’m going to leave cold and hot tear out of this and concentrate on just the basics of suspension signs in tyres. The picture below is of an Avon Storm Ultra 2 tyre and is taken off the internet via Google images. The red arrow indicates the direction of travel, the green curved line indicates what I’m going to call the leading edge of the tread pattern and the blue curved line is indicating what I’m going to call the trialling edge of the tread pattern. There are two distinct types of wear that arise from suspension problems the first is chamfering and the second is ridging. Chamfering looks like the edge has been worn away and ridging looks like a ridge sticking up on the edge. I’m more than likely wrong with this but to much compression chamfers the leading edge. While to much rebound ridges the trialling edge. If this is correct then I would presume that these signs would disappear once the correct dampening is dialled in. Fast compression adjustment or rear shocks is the dampening control when hitting sudden bumps. Its not to control how the shock acts at high mph speeds. So only adjust this if you find the rear a bit vicious hitting sudden bumps like raised and over painted rumble strips. Be careful of this though as it can cause your shock to blow by to much fluid resulting in loss of dampening. Last edited by Bibio; 12-10-12 at 10:54 AM.