Suspension setup.

[Saint aka ML]

Ok so it is not for Monster, yet, but rather for my hyper but I can later on apply same rule to Monster.


So I have unloaded front suspension of 22cm
Under bike load it is 21.5cm

Unloaded back of 40cm
Under bike load 39.5cm

Bike with rider on front 17cm (sag of 4.5cm)
Rear 35cm (sag of 4.5cm)

Front suspension is fully adjustable wit plenty left.
Rear semi but plenty left.

Where do I start to eliminate the sag and by how much should I eliminate it?

I know on rear I need to wind down the spring till I get desired effect.
Apparently Hyper 821 has fully adjustable rear shock (**** but is adjustable) so after doing above I play with rebound and if possible compression.

Front is confusing.

What do I need to adjust?

[rollo22]

Have a look at the Ohlins web site they have a section on setup

[Darren69]

I seem to recall reading somewhere that desired sag is around 25mm, but I don't know if t hats a universal figure or not and you need to adjust the pre-load (increase in your case) to reduce the sag. Nothing else will have any affect on the sag, that's a static adjustment. the rebound and compression are dynamic I would say that you need to get the static setting right first then tune in the dynamic adjustements to fine tune things.

[Saint aka ML]

Ok will start with static sag

[Dirty]

I prefer sag aloo and never have any trouble eliminating it...

[Darren69]

Oh, I think your confusing saag with sag. Saag will make you turbo powered not your bike! Then you need to find a loo:)

[Dirty]

Aloo gobi :mand:

[BigOz]

Set the rider sag first 1/3 of travel is not an uncommon soft road setting, not sure how the sag measurements given as mm of travel translate to a Hyper as the suspension is long travel.
Then "bounce" each end of the the bike and adjust the rebound so it does not drop into a second downward stroke after recovering to the top of the stroke finally adjust compression as required to tune the rate at which the suspension compresses.
At the end both ends should be in balance and fall and rise together.

Take a look at some of the Dave Moss videos on Youtube https://www.youtube.com/watch?v=bNn2Y0QlhgM is a good video on the bounce technique.

This Video (https://youtu.be/LGoQ32iKVMw) might contain some numbers that would help.

[utopia]

After you've set the front preload, it might be worth fitting one of those plastic rings around the fork leg to measure maximum travel.
Then, after riding it for a while (which should include some extreme bumpiness) you can see at a glance whether you are using nearly the full stroke of the suspension at max deflection (the ideal situation) or not.
Then the preload can be fine tuned to suit.

Pedantic point ... Oz is clearly referring to compression and rebound DAMPING (as I know he knows) but has used the common abbreviation.
This only leads to confusion amongst the unaware.
Sorry to be picky mate ... no offence, its just that I'm on a bit of a crusade about this.

[slob]

http://www.thelasturl.net/img/sag.jpg

http://www.thelasturl.net/img/damping.jpg

[BigOz]

After you've set the front preload, it might be worth fitting one of those plastic rings around the fork leg to measure maximum travel.
Then, after riding it for a while (which should include some extreme bumpiness) you can see at a glance whether you are using nearly the full stroke of the suspension at max deflection (the ideal situation) or not.
Then the preload can be fine tuned to suit.

Pedantic point ... Oz is clearly referring to compression and rebound DAMPING (as I know he knows) but has used the common abbreviation.
This only leads to confusion amongst the unaware.
Sorry to be picky mate ... no offence, its just that I'm on a bit of a crusade about this.

You are quite right, I was being a bit slack with my terminology.

Ignoring changing the spring rate which is really the first thing that needs to be correctly chosen.
Spring preload is the for gross adjustment of ride height.
Hydraulic rebound damping is to control the extension stroke of the suspension.
Hydraulic compression damping is to provide fine control the compression stroke.
Another factor that affected the suspension that is easily adjustable is the air spring effect of the air above the oil in the fork.

With the travel you never want to use all of the travel in normal operation. If you run out of travel the tyre will no longer track the surface correctly and grip will be affected. The rider will feel a physical knock though the handlebars, worth noting this can happen when the forks hit their mechanical bottom and also if they hit a hydraulic bottom if the fork oil fill is high.

[Drumnagorrach]

Thanks for the post Slob, ( seems very disrespectful to refer to you so ,and I mean no offense by it )
I think my set up is O.K. seems to follow the figures quoted , Just thought I would post a pic of the fork deflection I saw with this mornings "spirited" ride to work on dry and bumpy roads ,looks like I am getting over two thirds compression ( see tie wrap ).
Should I reduce the spring preload a bit ? the front does feel to patter a bit on bad roadsurface corners ,http://i241.photobucket.com/albums/ff171/gasaxephoto/IMG_0901.jpg (http://s241.photobucket.com/user/gasaxephoto/media/IMG_0901.jpg.html)

[utopia]

The indicator does look a little higher than I'm used to seeing the one on my 750 ...with non-adjustable Showas and 11st rider.
And I think mine is oversprung if anything.
But I'm no expert.

[BigOz]

You would need to know where the forks bottom as the dust seal does not always reach the casting, my 1098 Showa do but for example a Triumph 675 bottoms 17mm up from the casting.

Assuming your forks bottom at the casting you could afford to remove a little preload, on a track with a predictable surface every lap I'd try to get much more of the stroke working for me but on the potholed roads of the UK I'd keep some travel in reserve.

Don't forget to check the rebound damping afterwards as it may be a little slow with the spring tension removed.

Thanks for the post Slob, ( seems very disrespectful to refer to you so ,and I mean no offense by it )
I think my set up is O.K. seems to follow the figures quoted , Just thought I would post a pic of the fork deflection I saw with this mornings "spirited" ride to work on dry and bumpy roads ,looks like I am getting over two thirds compression ( see tie wrap ).
Should I reduce the spring preload a bit ? the front does feel to patter a bit on bad roadsurface corners ,http://i241.photobucket.com/albums/ff171/gasaxephoto/IMG_0901.jpg (http://s241.photobucket.com/user/gasaxephoto/media/IMG_0901.jpg.html)

[slob]

It could be the spring rate is a little high. I don't know what you weigh and you need to remember the stock setup is a substantial compromise, not only on production cost but it needs to be usable for an 8st rider or a 16st rider, sometimes with passenger and/or luggage. So on top of Oz's advice, you may never use all the travel.
As ever check your tyre pressures are correct first, and then make a note of you current suspension settings. Once you've done that try changing one setting at a time (and keep taking notes). Also remember the front may be reacting to what the rear shock is (or isn't) doing.

[slob]

It could be the spring rate is a little high. I don't know what you weigh and you need to remember the stock setup is a substantial compromise, not only on production cost but it needs to be usable for an 8st rider or a 16st rider, sometimes with passenger and/or luggage. So on top of Oz's advice, you may never use all the travel.
As ever check your tyre pressures are correct first, and then make a note of you current suspension settings. Once you've done that try changing one setting at a time (and keep taking notes). Also remember the front may be reacting to what the rear shock is (or isn't) doing.

[slob]

all that said (and I'm not a suspension expert) first I'd try two clicks softer (out) on the front compression damping and see what it feels like.

[utopia]

Ha.
My post had originally included both Oz's and Rob's points, but I edited it for simplicity.
And I would also have said that less front preload will lower the front ride height a little and make the steering sharper, unless you raise the yokes a tad.
But I was assuming you knew all that stuff.
After all, anyone with an oil cooler muff obviously knows a thing or two. :cool:
... spotted and applauded.

[Drumnagorrach]

Thanks for the advice,been out and checked the settings . Compression was 6 clicks out ,which is factory settings ,rebound was screwed in to 4 . My combined sag was 45 ,so I will leave that alone, it could be O.K. for my 11 stone .
Reset compression to 7 clicks out and rebound to 6 clicks ,the forks now can be moved by bouncing the handlebars down ,the forks feel like most bike forks that I have had .
Starting to look promising , too much rebound damping could have been preventing the tire from following the undulations .
Cheers Jeff , my low temp oil warning is going off after 7 miles with the muff ,and should my oil temp get to high I can rollit up and put it in my pocket ( hasn't happened yet )

[Saint aka ML]

Ok so I have adjusted the settings to be within ball park figure suggested (roughly in middle).

Front I have about 25mm sag.
Rear about 22mm sag.

Went for a ride much more stable under acceleration and tips in easier. Now need to experiment with Compression/Damping front.

Now Ducati website says stock 821 Sachs is fully adjustable but I can only see two adjustments.

1. Spring
2. At the bottom of shock S to H I get that is compression right?
How would preload look like?


Also started reading more on the Static sag settings and some say it should be calculated % wise from suspension travel. It is suggested to be 25 to 30%

If that is the case then at 25% front on hyper should be 46.25mm sag and rear 43.75 (185/175 travel if I found the right figures).

Now that sounds on high side for me! Those figures are for 821 SP so even if stock 821 sachs has slightly different travel it can not me much different.

What do you think?

[slob]

spring (preload), correct
screw at the bottom 'S-H' is rebound Soft - Hard

as ever, if you don't have one already, download the owners manual here: http://www.ducati.com/services/maintenance/index.do
eg for 2014 Hypermotard (not SP or 'strada) rear shock: see p145

[Saint aka ML]

Thx Slob preferred to ask as there is no clicks on my adjuster and now found on net many do not have clicks. So far for me good setting is half turn from fully closed.

Now would love to confirm the static sag malarkey.

As per Shazam guy (he is reliable) static sag should be between 20 and 30% of total travel. 20 being more track while 30 more Road.

What ya think as so far rear based on your post feels good, front I will see after few days.

[stopintime]

Sag numbers on a bike with progressive springs should not be compared to linear springs numbers.

If you have enough and suitable compression damping, the sign of correct spring rate is how far down it compresses at your chosen riding and road conditions.

[Saint aka ML]

That is very vague stopintime.

Compression dampening will be affected by spring rate.
To do good setup on anything you need to have the least one constant or one default setting. No?

[utopia]

The spring rate is the "constant" and is determined by rider/bike combined weight.
If correct, it should result in the suspension deflecting to about 90/95% of its travel under the most extreme riding conditions.
I think this is what Stopintime is saying.
Its also what I was getting at with the rubber ring thing.
Compression damping will not have any significant effect on how FAR the suspension deflects. It only affects how FAST it deflects.
Unless it is set to such an extreme level that it masks the action of the springs.

Or at least, that's my analysis of the physics, but I'm not a suspension guru.

Interesting about the progressive springs.
I hadn't had cause to consider it before but its a good point.

[stopintime]

Progressive springs are softer at the beginning of the stroke and stiffer towards the end (compared to linear springs). One of the results is that sag will be greater.

The damping gets more difficult to set because it doesn't quite match the beginning or the end of the stroke (since the spring resistance range is greater on a progressive spring than on a linear).

The ill effects of compromise is more evident on a 'progressive' bike and it's not possible to adjust away from that. Everyone should make the best of what they've got, but my point is that we should not compare numbers with, or expect to achieve sport bike linear behaviour.

[Saint aka ML]

For sure I am not comparing bikes I want my setup and I like my setup to be on harder side. I never had a bike with such long suspension travel so is all new to me. 749 and monster I always setup on 30mm sag me so about 28-27mm with my gear on for front, back about 25mm. Done same here but this one has huge travel so question is what the sag values should be on bike that has almost 30% extra travel

[DrD]

Across on http://www.ducati.org/forums/hypermotard/64122-setting-suspension-sag.html they say about 25% Front and 30% rear of travel for sag.
For 185mm Front Travel that is 46.25mm

[Saint aka ML]

DrD seen that but it's kind off high if you ask me. Will test on sport bike setting now and can always soften it. So far like rear.

[BigOz]

The spring rate is the "constant" and is determined by rider/bike combined weight.
If correct, it should result in the suspension deflecting to about 90/95% of its travel under the most extreme riding conditions.
I think this is what Stopintime is saying.
Its also what I was getting at with the rubber ring thing.
Compression damping will not have any significant effect on how FAR the suspension deflects. It only affects how FAST it deflects.
Unless it is set to such an extreme level that it masks the action of the springs.

Or at least, that's my analysis of the physics, but I'm not a suspension guru.

Interesting about the progressive springs.
I hadn't had cause to consider it before but its a good point.

My understanding totally agrees with what you say on the hydraulic damping.

In many, but not all forks the adjustment for the damping is a tapered needle in a seat and is on one of two possible paths for the oil, it can go through the path with the needle or though the piston and past the shim stack. So the effect of the adjustable path has less effect when the forces involved are enough to open the shim stack which tends to be the situation where the suspension suffers a lot of force and hence deflection.

The compression damping is often the finest of the adjustments in the fork and is mostly there for fine tuning to enable a balance to be found between front and rear or other ride quality tweaks to be made not as a gross adjustment or stroke control device.

Andy.

[utopia]

DrD seen that but it's kind off high if you ask me. Will test on sport bike setting now and can always soften it. So far like rear.

Oh no, you can't.
Adjusting preload has no affect on softness, it only affects ride height.
So with less sag, the bike will just sit higher on its springs.
The suspension will then tend to "top out" much too easily.

With 30% extra travel, the sag should be 30% more too.

[slob]

DrD seen that but it's kind off high if you ask me. Will test on sport bike setting now and can always soften it. So far like rear.

Hyper' is not a typical sportsbike

[Dirty]

Saint is not a typical rider :)

[Saint aka ML]

No i am not, I tend to be agreessive so get the bike out of line when to soft. We will see. I now have rough idea as to what senting at front I need to get sag of 45mm which is 4 turns. 28mm is 11 turns. From now till can easy let it go.