GT suspension improvements

[wordsmith]

GT suspension upgrade - September 4th 2019  

I'll have to be briefer than usual, for my supposedly-fixed PC is still sulking.

The work took Joe - owner of Ride Dynamics and suspension guru par excellence - some three and half hours of steady work, with no coffee or smoko breaks and no time-wasting Facebook chat.

As I had said before, his workshop is neat, clean, tidy, a place for everything and everything in its place, including the multitude of specialist tools required for this work.  I couldn't imagine an amateur like me working with cheap hand-tools in a home garage being successful. 

We again confirmed what I was looking for, we chatted briefly about my riding weight, whether pillion and/ or luggage is routinely carried, etc., and hi ho, hi ho!, it was off to work.   After I swore on a stack of Bibles that I wouldn't get in his way or want to chat constantly, Joe allowed me to stand by - not too close! - to observe and take pix.   It was a very interesting experience as calm, methodical work proceeded.

As the various parts emerged from the front fork legs Joe explained the function of the various bits - springs, pistons controlling oil-flow, and so on.   To my novice eyes, the new K-tech components looked as if they'd just come from a high-end Swiss watch manufacturer, beautifully finished as they were.

The rear shock was a more straightforward swap, and although I was surprised at the weight of the new Razor R shock with remote adjuster, the OE shock was much heavier.   The new unit has adjustable length, so about 10 or 12mm (half-an-inch) was wound out, lowering the bike's rear by that much after I said that I like to be able to fully flat-foot at rest, which is barely achievable with the OE unit.

Sag - which I had always believed to be what happens to a woman's breasts and a man's belly as they age (the latter has happened to me!) - was precisely measured with a cunning device as small incremental changes were made until the desired settings were reached.   Joe reckons that it's rare for an owner to need to return to him for further tweaking, but of course it's there as required.   After he had a short test-ride to check everything, it was my turn to ride home, with my thoughts already given after that short and brief 33km ride.

Yesterday's 181km outing along very familiar roads was intended to give me more time to evaluate things on terrain of widely-varying surfaces and conditions.   There is a distinct improvement in ride quality, best explained that the sharp reactions to road surface irregularities were ironed-out and a more compliant and composed and comfortable ride eventuated.   A very good example of what this means was quickly apparent, as I found that I was no longer constantly being bumped-up off the seat and inched forward until my gonads were crushed against the rear of tank: I was 'planted' more  firmly in the chosen spot.   Of course, larger irregularities in the road-surface - and there are plenty where I went - were still felt, and I don't want to try to convince members that this was a magic-carpet ride, but certainly it was a pleasing outcome for me.

Memories of subjective impressions are such that it would be fruitless for me to try to compare the new GT ride with that of my later BMW Boxer twins, which are much heavier bikes and with high-end OE components, including BMW's incomparable Telever front-end, but I am happy.

I now intend to take that planned ~1000km circuit some time in the next week or two (but not at next week's end, for it will be Friday the thirteenth!), by which time a couple of shorter outings will have put a few hundred kilometres on the new suspension and allowed everything to have bedded-down.

A very good question at this point might be - "was it worth the $2100 spent on the K-tech upgrade?".    I'm fortunate enough to have spare disposable income, so while not quite a no-brainer the matter of cost was not a great concern.   But others may prefer to take a different lower-cost approach, maybe getting specialists like Ride Dynamics to make changes to the OE components by simply changing oils, shims, springs, whatever, and tinkering with the adjustability of the ex-factory suspension.

The jury is still out as far as I'm concerned on whether or not I'll want/ need to buy a new BAGSTER seat to replace the GT's OE seat, which although light-years ahead of Gen1 seats is still only 'just' for me.   A new BAGSTER seat would cost $450 -$550 depending on specification, but from past experience I know that it would be the cherry on top of the icing on the cake.   I'll make that call after the 1000km outing in a few weeks time, but in any case they are not yet available.

Finally, big thanks to captainscarlet who introduced me on this Forum to K-tech and the whole shebang.   Pix follow...

 a place for everything...

 new Razor-R rear shock

 work under way...

 new (red) and old OE shocks.   

 spotless workshop..

 draining oil from fork legs..

 OE (right) and new oil-flow pistons 

 fork off...

 new K-tech oil-flow control pistons

 beautifully machined...

 new rear shock installed

 sag-o-meter

 job done!

Edited 2 minutes ago by wordsmith

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Wordsmith - a '39 model; bike - a 2019 Tracer 900 GT, Midnight Black and with many farklings.   Redland Bay, SE Queensland, Australia.

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[wordsmith]

A final update on impressions, which is part of my new post about 'a 1000km + circuit in SE Queensland...' under the 'Ride Reports' heading on this Forum.

 

My assessment of the suspension changes is positive without, I hope, being overly gushing and optimistic, which is often hard to avoid when one has spent up big on something like this.   The K-tech parts and guru Joe's setting-up have worked well, even very well.   The harshness and ultra-quick reactions to even minor road-surface irregularities are largely ironed-out, although major lumps and bumps do get through, though dampened out a lot, and there is no 'wallowing' on corrugated surfaces.

I do feel from earlier brief outings that the rear shock could be softened just a little, as I felt that was where most of the reactions were still being felt, so I'll be talking to Joe about this shortly - I'm sure it's only a matter of dialling-out a little compression on the shock remote (but I'll let him guide me!)   But at no time was I bounced up and off the seat, something that couldn't have been guaranteed with the OE suspension.

A caveat might be that anyone doing this sort of an upgrade and expecting a magic-carpet ride as if on a lawn-bowls or billiard-table surface might be a little disappointed - there is no magic, but I'm very satisfied with the outcome.   Would I do it again? - yes, definitely.   Do I also now need that cherry-on-top-of-the-icing-on-the-cake BAGSTER seat - yes, if considering future long multi-day rides, no if confining myself to shorter local outings. But I'll possibly get one anyway! 
 

 

 

Edited September 18, 2019 by wordsmith

[OLD DVB]

There is a danger of misunderstanding of the effects of adjusting fork and rear shock pre-loads.  This NEVER alters fork or shock hardness/softness, no matter that even Yamaha refer to it that way.  It ONLY changes the ride height or static sag.  Think about it.  The bike sinks on its springs until they support its weight.  Pre-load is what it says, it pre loads the springs to a greater or lesser extent but they still sink to the same spring compression point and thus act in exactly the same way every time.  It just happens at a different point in the suspension overall travel.  It is useful to increase preload if the suspension is using too much travel (bottoming) or the reverse if it not using enough.  The static sag has an effect on the attitude of the bike and its ground clearance and can effect the handling characteristics by changing the steering head angle, if that is what you want, as can moving the forks in the head clamps or changing the rear shock length.  The only way to change springing is with a different spring!

By the way, I envy the way you guys in the States seem to have lots of suspension specialists able to modify or swap fork internals.  That option is very uncommon here in the UK.  The last time I saw a respected suspensions specialist offering to "set up" forks he was just offering to twiddle the existing factory adjusters!  If someone manufactures replacement internals, they can be fitted, but changing shims and damper internals is not easy to get done.

By the way, I've just swapped my Aprilia Caponord 1200 for a Tracer 900 GT because at least the Yamaha has two way damping adjusters on the front and I can always fit an Ohlins on the rear if I don't like the original.  The Aprilia had active computer controlled suspension.  Sounds good but what you actually get is what some designer decided you should have, not what you may want or prefer and no adjustment possible.  So beware fully active suspension.  If you don't like it you're stuck with it!

Edited September 24, 2019 by OLD DVB

[chitown]

18 minutes ago, OLD DVB said:

There is a danger of misunderstanding of the effects of adjusting fork and rear shock pre-loads.  This NEVER alters fork or shock hardness/softness, no matter that even Yamaha refer to it that way.  It ONLY changes the ride height or static sag.  Think about it.  The bike sinks on its springs until they support its weight.  Pre-load is what it says, it pre loads the springs to a greater or lesser extent but they still sink to the same spring compression point and thus act in exactly the same way every time.  It just happens at a different point in the suspension overall travel.  It is useful to increase preload if the suspension is using too much travel (bottoming) or the reverse if it not using enough.  The static sag has an effect on the attitude of the bike and its ground clearance and can effect the handling characteristics by changing the steering head angle, if that is what you want, as can moving the forks in the head clamps or changing the rear shock length.  The only way to change springing is with a different spring!

Trying to convince the internet is a losing battle

Also, with progressive rate springs it's not altogether incorrect to say adjusting preload is making it harder/softer. But you're right with straight rate all you're doing by increasing preload beyond desired sag is giving away suspension travel you could enjoy if sprung properly. 

Edited September 24, 2019 by chitown

[OLD DVB]

Nope - the exact same reasoning applies with progressive springs too.  They also sink to exactly the same point till they support the bike weight even though it is tempting to think otherwise.

[chitown]

1 hour ago, OLD DVB said:

Nope - the exact same reasoning applies with progressive springs too.  They also sink to exactly the same point till they support the bike weight even though it is tempting to think otherwise.

This is a bit of a semantics issue but probably shouldn't pollute this thread any further. I'd just direct folks to Traxxion Dynamics "Suspension For Mortals"  video series on youtube for a good discussion of the topic from a reputable source that's also a vendor here.

Cheers!

Edited September 24, 2019 by chitown

[betoney]

2 hours ago, OLD DVB said:

 The Aprilia had active computer controlled suspension.  Sounds good but what you actually get is what some designer decided you should have, not what you may want or prefer and no adjustment possible.  So beware fully active suspension.  If you don't like it you're stuck with it!

First I have heard of semi-active or electronic suspension not having a manual mode to set damping to your liking. It must be unique to that Aprilia model?

[Therealal]

2 hours ago, chitown said:

Also, with progressive rate springs it's not altogether incorrect to say adjusting preload is making it harder/softer. But you're right with straight rate all you're doing by increasing preload beyond desired sag is giving away suspension travel you could enjoy if sprung properly. 

Monoshock rear suspensions generally have a linkage which decreases the mechanical advantage which the swingarm has over the shock as the swingarm travels. In this case, increasing preload would "soften" the suspension.

[OLD DVB]

Just about to see what I can achieve on my brand new Tracer GT using the factory adjusters.  Looking on my computer records, I found the following saved information.  I can't remember where it came from so my apologies and thanks to the original author who has done a great job clarifying the dark art of suspension set-up.  I have also included recommended sag figures in which you will see there is little absolute agreement despite them coming from various credible sources.  They do offer a guide though and are all in the same general area.  Hope it is some help.

SUSPENSION SETTINGS

 Static Sag Recommendations from various sources

 

OHLINS SOURCE 1	Without rider	With rider
Rear	5-10mm	35-40mm
Front	25-30mm	35-48mm

 

OHLINS SOURCE 2	Without rider	With rider
Rear	10-20mm	25-40mm
Front	15-30mm	35-50mm

 

SBK SCHOOL ROAD	Without rider	With rider
Rear	15-20mm	30-40mm
Front	30-40mm	35-55mm

 

SBK SCHOOL RACE	Without rider	With rider
Rear	5-10mm	20-25mm
Front	12-25mm	25-35mm

 

AUS SBK SCHOOL	Without rider	With rider
Rear	0-10mm	25-35mm
Front	20-30mm	25-35mm

 

• Preload (Spring tension, based on your weight)
• Damping (speed the spring squashes and returns to normal )
o Compression (advanced damping control, speed the spring squashes)
o Rebound (advanced damping control, speed the spring returns to normal after been squashed)
Note that compression and rebound are part of damping.

After I had established what I can adjust on my bike and how to adjust it, I got a pen and paper and wrote down my bikes current settings so that I can return the bike to it if I make a mess of things. On my bike, this meant counting “clicks” as I turned the screws for the compression and rebound clockwise or anti-clockwise. Preload is easier to note and record as you can see what “notch” the rear spring is on and what “ring” the front is on.

The manufacturer has spent a lot of time and money on research and development and they have a financial incentive to ensure that my bike handles well, therefore the manufacturers recommended suspension settings for your bike will not be that bad. Compare what your current settings are for your bike against the manufacturers setting. If they are different, and you think your bike could handle better, have a go at setting your bike to manufacturers recommended settings.

You should be able to fiddle with your suspension and bring it back to the settings recommended by the manufacturer or your original setting before you go any further. Do not read any further unless you are competent with the above and acknowledge that this whole article is purely for information only. Please do not fiddle with your bike, then injure yourself and then blame me.
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DAY 2 - SET UP BIKE TO YOUR WEIGHT (PRELOAD)
To set up your bike you will require the proper tools as recommended in your bikes handbook, usually a long screw driver, spanner for the front and a funny looking tool for the rear preload and tape measure!!. You will need patience and time. It is best to set the bike up where you are most likely to use it i.e. on the roads or race track.. Ensure your bike is in good working condition, including replacing dodgy fork seals, lubricating linkage, and changing fork or shock oil and you have correct tyre pressure.

Twiddling with setting randomly will not get you far. You suspension can be broken down to the following
• Front wheel
o Preload
o Damping Compression
o Damping Rebound
• Rear Wheel
o Preload
o Damping Compression
o Damping Rebound
If your bike does not have some of these setting then you will have to compromise on the setting of your bike or buy aftermarket suspension if necessary. You really should set up your bike in the right order. It is best to start with the preloads, front and rear as this is based on your weight and relatively easy to set up, then work your way down.

Rear Preload
Whatever your weight, when you sit on the bike, you want the bike to squat just a little bit (about 30mm) but not too much. You want to ensure that the bulk of your rear suspension travel is available for when you actually ride the bike as opposed to supporting your heavy frame. At the same time you should have a little bit of sag left. If the bike drops too much then increase preload and if you are very light and the bike barely moves under your weight, then soften the preload.
Below is a more detailed explanation. This is easy to set up but can be a bit confusing so just follow the steps one at a time.




Step 1 Step 2 Step 3
Step 1: First find the fully UNLOADED length of your rear suspension. Put your bike on its centre stand. If you do not have a centre stand find a means of lifting the rear wheel up under the engine so that there is no weight (including the weight of the bike) on the rear axle and wheel. Measure the distance between the rear axle and a fixed point directly above like a bolt or mark. Note this measure measurement. Do not use a rear wheel bike stand as there is still the weight of the bike on the swing arm.

Step 2: Find the NORMAL length of you rear suspension. This is amount the suspension drops under the weigh of the bike alone without the rider. Put the bike on level ground and bounce it up and down to free any stickiness. Measure between the same two points as above, i.e. the rear axle and the fixed point directly above.
Step 3: Find the fully LOADED length of your rear suspension. This is the length of the suspension with the rear wheel on level ground and the rider seated on it in his normal riding position in full biking garb. First bounce up and down on the seat to loosen the suspension then get into your normal riding position with all weight on the bike and both feet on the bike. To prevent yourself from falling of (if you have not already) lean the bike against a wall and get your mate to measure between the same two points as above i.e. rear axle and the fixed point directly above.

Next thing is to understand a couple of buzz words. “Static sag” and “Rider sag”.
RIDER SAG is the difference steps 1 and 3. This is the amount the bike drops when your heavy arse sits on the bike.
STATIC SAG is the difference between step 1 and step 2. It is how much the bikes weight acts on the rear suspension or how much you can lift the bike rear without the rider on it before it tops out.
A top racing suspension company suggest that rear wheel rider sag should be around 30-40mm and static sag should be around 5-10mm. However this many vary depending on your bike and manufacturer. The more rider sag you have, the softer the bike suspension will be. I personally use 35mm for road and a few track days use.
Therefore if your rider sag is less than 30 mm then your preload is too hard, if it is more than 40 mm, then it is a bit soft. Once you have set your rider sag as close as possible to 30-40 mm, next check your static sag. If you have more than 10mm then you may need stiffer springs. If however, if your static sag is less than 5mm or you have no static sag then your springs may be too hard for your weight.

If you have to compromise then try to have at least a bit of Static sag in order to stop the bike from topping out.
Note that books, videos, media and pub acquaintances will all have different opinions on the naming and figures quoted above (and below). I find that I get fewer complaints with the current labelling system than I would with other labelling systems.
Avoid being obsessed with numbers and naming systems. I will try to explain the underlying principles of setting up your own bike. There are too many scenarios and permutations surrounding the effects of tweaking each setting that it would take me forever to cover them all. Therefore I will only touch on a few of the more common effects.
Front Preload
some people set the front suspension based on rider sag and static sag. This is especially useful in determining if you need softer or stiffer springs. Use the same system as above to determine Rider sag (35-48mm) and Static sag (25-30mm). However I prefer the below method to optimise my current original front forks.
You want your bike to use as much front suspension "travel" as possible without "bottoming out" (no more travel) even in extreme conditions. So lets establish how much suspension travel you are currently using.
Wrap cable ties around the smooth part (stanchion) of front forks near the rubber seal to the forks. Ensure that it does not scratch the stanchion and it is not too tight as to damage the rubber seals.
With the cable ties in place ride your bike as normal using as many riding conditions (corners, braking, accelerating, wheelies and stopples) that you are likely to meet. Then increase or decrease your preload until the cable tie stops about 10 mm before “bottoming out”.
Reducing preload should give you more travel. If the forks bottoms out, reset the cable ties and increase preload until the cable tie stops around 10mm above the limit. You should always leave about 10mm travel for emergencies like slamming into uncharted potholes.
Done
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DAY 3 - FRONT DAMPING

The damping, both rebound and compression are best adjusted after riding your bike and feeling how it handles to you. You cannot use your mate’s settings. The reason why there is so much debate and controversy regarding suspension set up is because it is a personal experience and depends on how and where you ride your motorcycle.
Some people, media and websites will charge or tell you what they think is best for you whilst amongst top racers it is a closely guarded secret. You have to find your own settings that you are comfortable with and take notes as you experiment with different settings.

tyre profiles
Setting the right amount of damping depends on the type of bike, how you ride the bike of bike, and shape and pressure of tyres you use. Also it depends on your riding style and how much suspension travel you want at any particular moment. This article will try to explain what to look out for and how to tweak it.
If you can adjust the damping but cannot adjust the rebound and compression separately, then you will have to find a compromise between the two for your bike. If you run out of adjustment, then depending on if the damping, either rebound or compression, is too slow or too fast then you may need to change the damping oil to thinner or thicker suspension oil relatively.
Note that your suspension will handle differently under different conditions i.e. high or low speed, wet or dry conditions, therefore experiment with setting up your bike under the conditions you would like to use them.

To start with, set your bike damping rebound and compression to your manufacturers or your preferred setting.
I do not know the exact terminology used in your manufacturers owners manual but note that
Soft damping = little damping = decreased damping
Hard damping = excessive damping = increased damping




Nose Up Nose down

Front Compression
You need your front compression under braking and when riding over uneven humps. You want your front suspension to compress slowly and controlled when you break. As your bike “nose dives” under braking, it transfers more weight over the front wheel. This helps slow the bike quicker.
If the front suspension compresses too quickly (too soft) you risk the suspension bottoming out and then your bike will feel vague and since it nose dives too quickly the back wheel may loose contact with the road and move sideways. On the other hand when compression damping is too high the suspension can't react quickly enough to compress over bumps and will skip and chatter. You will have an uncomfortable ride and your braking is compromised, especially in the wet.

Another important aspect of front compression is when you brake just before a turn. As you brake before the corner, the bike will naturally “nose dive”, this will shorten the wheel base and alter the geometry of the bike making the bike turn quicker into the corner. It is important that your bike compresses predictably and safely in a corner/turn.
SOFT: If your compression is too soft, your bike will nose dive too quickly, then as you turn into the corner, the bike will collapse into it and you end up having to compensate.
HARD: On the other hand if you have too much front compression damping, do not get enough nose dive and the bike will be reluctant to turn and may drift wide on entry to the corner.

Go for a ride on your bike and try braking and turning into corners at different speeds. This will cause a bit of nose dive so try different setting. If your bike bottoms out, increase the front preload. See preload notes above. Keep notes.

Front Rebound
Front rebound damping is to control the rate the bike “sits up” after the front suspension has been compressed i.e. from nose down position. If it is too soft, the front end will pop up too quickly after any situation causing the front suspension to compress e.g. braking or cornering causing the bike to "see-saw". This may result in lack of traction If rebound damping is too high you may have lack of “feedback” and in extreme cases where the suspension can't react quickly enough to extend again it will pump down until it bottoms out which is simply dangerous,
An alternative to manufacturers setting for front rebound is to place your bike on level ground and have your mate or rear wheel stand support the back of the bike. Press hard on the top of the yoke without pressing the brakes and let go. The suspension should rebound to its original position within a second.
If it takes more than a second then you need softer rebound but if it takes less than a second or it rebounds past its original position then you should make your rebound harder. This method may work but really it is too simplistic for real world riding.
One critical area where you want your front rebound to work well is through them corners and turns. As you fly down the road and brake before or into the corner, the front suspension compresses, then as you let go of the brakes, the front wheel will rebound fully. You do not want your front end to sit up too quickly especially mid corner. It does not matter whether you brake before the turn but this is more critical if you brake into the turn.
SOFT: If it rebounds too quickly in the corner your bike will sit up very quickly creating a longer wheel base. The front wheel “shooting” out also causes the bike to drift wide or a feeling of the front end “washing out” If this happens, increase (harden) your rebound to slow the rate the front wheel rebounds.
HARD: On the other hand if the rebound is too hard, when you let go of the brakes and on to the throttle in a corner, because the wheel is compressed for longer you will have a shorter wheel base for longer. This may cause the bike to feel wooden in the corner and turn too quickly. Soften her up.

To set up your front rebound damping you are going to have to go through a few corners a few times and it is best that you have sorted out the preload and front compression first. Basically you want to be able to
1. brake hard either before the turn or up to the apex of the turn, (whichever suits you)
2. let go of the brakes
3. get on to the throttle without the bike “see-sawing” i.e. sit up or dive
by adjusting only the rebound damping only (remember that we have sorted the compression so don’t mess it up.)
NOTES
No advanced damping control
if you cannot adjust the rebound and compression separately but you can adjust the damping, then you will have to go for a compromise. Since most accidents happen in a turn, then I will suggest that you set it up for cornering. Try to get the bike to enter and exit a corner with minimal rocking or seesawing to the front end. These setting should be ok for bumpy tarmac.
Keep a record
Keep a note of the settings you are using as well as the make and pressure of your tyres. Different tyres shapes, sizes and pressure can affect your readings and therefore you may want to keep a record of all your setting especially if you are a track addict or racer. Also keep a note of the weather and cooler temperature will thicken the oil in your forks while on a hotter day, your fork oil may thin a bit. You do not want to go through all this again
Counting Clicks
If your bike uses clicks to adjust damping, and you want to adjust your damping settings, do not simply turn it a few clicks till you think you have the right new settings. Fully count the clicks in to ensure you were on the right old settings then count it out to the right new settings. Example you think your front compression is on 5 clicks out and you want to try 7 clicks out. Do not simply turn it 2 clicks out. Count the 5 click in, and then count the 7 clicks out.
Set Up
Do not adjust more than one setting at a time unless it is to a previously recorded set up as you will not know which setting cause the most effect. I commute to work and I used to make one small (a click) adjustment a day. Sometimes I would leave it for a week because the conditions where not right to feel the new settings in action. On the track, I would suggest one setting change per session, minimum.
Altering Bike Geometry
You can alter your bikes geometry by sliding your front forks up through your front yoke.. i.e. your forks will stick up through the yoke a bit more than standard thereby causing your bike to have a more nose down bias. This makes the bike turn in faster, it doesn't increase the corner speed and you will loose ground clearance
I will not recommend moving your front forks more than 5 mm
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DAY 4 - REAR DAMPING



Kick Up Squatting


Once you are done with the preload and front wheel damping let move onto the rear wheel. You can set it based on comfort and uneven road using the same methods as you would with the front wheel. Also you could try to do what’s called:

Suspension Balance
Take the bike off its stand onto level ground and stand next to it. While holding your motorcycle upright, put one foot on the foot peg next to you and press hard on it. The front and rear of the bike should squash down and raise at the same rate. If not adjust rear damping compression and rebound to compensate

Now you have a comfortable bike with adequate suspension balance. Now let’s fine tune it a bit. Again there are no tricks to setting up your rear wheel suspension, you have to understand what causes your rear suspension to work. Since rebound occurs after compression we will deal with compression first.

Rear Compression
Like with the front wheel; if your rear compression is too hard you will have an uncomfortable ride because the rear wheel simply bounces off bumps and ripples in the road also giving a vague “feel”. Conversely, if it is too soft, you may get excessive “squatting” under heavy acceleration causing the bike to feel lethargic or even “bottoming out” on those rough roads.
When you accelerate, you need a bit of rear end squatting to give the tyres a chance to get some traction and absorb excessive power to the back wheel. However, it is that squatting action under heavy acceleration that can cause problems when coming out of corners.

SOFT: Let’s imagine that you are exiting a corner on your motorcycle, and the bike is leant over and you start to accelerate smartly. If the compression damping is too soft, you will get too much rear end “squatting” causing a “nose up” situation. This will cause your bike to drift wide on exit of the corner. This is not the same as a too much of front compression damping which causes the bike to drift wide on entry to the corner.
HARD: On the other hand if your rear compression damping is too hard, you will not get enough “squatting” and therefore may not get enough traction. This will cause a bit of rear wheel spin, or the rear wheel suddenly “kicking up”. You can imagine what can happen in extreme circumstances.

To set your rear compression damping up properly, it is best to have the front end sorted out first. That way you know you that your entry into the corner is as smooth as possible. Then you want to be able to put on the gas as you exit the corner and your bike should hold its line and inspire confidence.


Rear Rebound
Nearly the end of this setting up drivel. You have exited the corner and the bike is now flying forward in a straight line. At this point you want the rear rebound damping to keep the rear wheel in contact with the road, thereby giving you maximum traction
SOFT: However if it is a long corner then your rear rebound will come into play mid-corner. If your rear wheel kicks up too quickly, it will unsettle the chassis of the bike making it “wallow” and “lurch” mid corner. A lot of people wrongly try to cure mid comer “wallowing” by increasing rear preload. This may "stiffen" the rear end but you may loose a bit of suspension travel. The cure is to increase (harden) rear rebound.
HARD: However if your rear suspension is too hard, your back wheel will not sit up quick enough. This will cause you the have the back end squatting causing a “nose up “situation for longer. This may cause you to drift wide similar to the effects of soft compression. Also since the rear shock does not extend quick enough, you may get a feeling of vagueness or loss of traction


If you have reached this point and found out that your original set up was the best then oops sorry. At least you have a few more buzz words to drop in the pub with other bike mates.
________________________________________
SUMMARY
First get your owner manual out and familiarise and compare your current suspension settings with the recommended settings in the manufactures hand book. Still not satisfied?
Then set-up your preload, front and rear, so that you can use as much suspension travel as possible when riding your bike. This is based on your weight, so if your weight fluctuates then keep an eye on it.
Next adjust your damping so that your suspension does not compress or rebound too fast or too slow to upset the bike and be uncomfortable. I believe that if you can get your bike suspension set up for cornering then it should be OK on a straight line.

1 - Front compression
This is when you want your front compression to control the "nose down" effects of braking so it turns in to corner properly
2 - Front rebound
You have let go of brakes, adjust front rebound so that the front forks extend at a controlled rate allowing you to keep your line.
3 - Rear Compression
You want the rear end to squat a bit as you apply the power.
Make sure that the rear rebound setting keeps the rear wheel in contact with the road.
Note: this image is only for illustration only. Your braking, turning and exit points and lines may vary, especially in the wet.
CONCLUSION
The point of this article is to educate you on how your suspension works so you can attempt to sort it out yourself. You should be able to feel the bike through the handle bars and the bike seat and be brave enough to note down the current settings and have a go at altering it to suit yourself.
I found that it is difficult to set up the bike for all condition. I recently changed my front brake pads and they were biting harder which made the bike nose down quicker. As summer approaches, I like to ride a bit faster. My weight is fluctuating. All these scenarios have caused me to change my setup. Top racers alter their setup at every track.
However if you are not competent with DIY, remember that if it isn't broke, don't fix it

[OLD DVB]

20 hours ago, betoney said:

First I have heard of semi-active or electronic suspension not having a manual mode to set damping to your liking. It must be unique to that Aprilia model?

Now I think about it, you're right.  Ducati's "skyhook" suspension is customisable and BMW's has various ride modes.  It's either Aprilia's "we know best" arrogance or their cheapskate approach just like their so-called cruise control which is  a simple button on the right that can't be reached with the throttle hand and just locks to the current speed - no adjustment.  Shame - lovely engine and gearbox and a very comfortable seat but luggage lids that are too flexible to seal.  That's why I've now got a Tracer!

[CumuloNimbus]

Thanks for the above info OLD DVB.  I have just fitted Nitron fully adjustable dampers and cartridge kit to my Triumph Speed Twin so I need lots of this advice while I make the various adjustments to suit.

Anyway the reason I mentioned this was that Nitron, who are in Eynsham, near Oxford are looking for a willing 900GT owner who  wants to improve their suspension, to leave their bike with them for a week or two, and they will fit their latest kit for a very reasonable discount.  They've just put up a request on FaceB.

I've just done this with my Triumph as they wanted to create a new fork kit to suit the new model and I didn't want to have Ohlins.  They asked me if I would be a willing Tracer GT owner too.  I am willing, but not so able at the moment, as the bike is in regular use. 

Maybe someone here might like to get in touch with them?

 

I also need to set up my GT which is new to me, so I'm gratefull you have shared your old records.  You may have/probably have come across Dave Moss Tuning.com.  He's a proper suspension guru and has just bought himself a Tracer GT which he has started to write about, detailing all the fine tuning he is doing to his bike.  Worth a read, but you might have to subscribe.  He has hundreds of YT videos too.  Definitely worth a look for anyone mildly interested in bike suspension set-up and ergonomics.

 

 

[leanangler]

Great info - suspension doesn't always have to be a black art..

 

[edgarjessop12]

I noticed that the standard rear shocker spring in the U.S.A is silver ? in the U.K. it is Black ?

Is that correct and is there a weight difference .

I have a 2018 Tracer 900 GT.  And I am in the U.K.  I am 87 kilos with all my bike gear on.

What is the standard Black spring rated at. Do I need to change it ..... playing with the suspension.

Got the front spot on for me now ,took a long while messing about doing small changes and lowering

the forks 7mm through yokes.  The answer for the rear is a K-Tec razor replacement. But just wondered

about the standard spring weight.

Cheers Edgar Jessop.

[Adreeuhn]

4 hours ago, edgarjessop12 said:

I noticed that the standard rear shocker spring in the U.S.A is silver ? in the U.K. it is Black ?

Is that correct and is there a weight difference .

I have a 2018 Tracer 900 GT.  And I am in the U.K.  I am 87 kilos with all my bike gear on.

What is the standard Black spring rated at. Do I need to change it ..... playing with the suspension.

Got the front spot on for me now ,took a long while messing about doing small changes and lowering

the forks 7mm through yokes.  The answer for the rear is a K-Tec razor replacement. But just wondered

about the standard spring weight.

Cheers Edgar Jessop.

Front 0.7kg/mm

Rear 10kg/mm

For 87 kilos rider. About 1kg/mm in the front and 11kg/mm in the rear.

[betoney]

4 hours ago, edgarjessop12 said:

The answer for the rear is a K-Tec razor replacement. But just wondered

about the standard spring weight.

When you order your shock, the suspension vendor will have that calculated for you.  Anytime you talk to a suspension shop, one of the first questions they will ask is your weight and type of riding, they will set it up with the correct spring.