Suspension setup for idiots?

[MattW]

i.e. me

Ok - just got myself a new rear Hyperpro shock, built for a 'loaded' configuration (me + missus + nominal 20kg luggage).

The manual says that 'static sag' is the most important base setting and that it should be 20-25mm.

So, trying not to sound like a complete numpty, is static sag just the bare bike or bike + load and where is it measured (I'd guess in line with the rear wheel spindle)?

I read in another thread that Hyperpro say that 'rider sag' should be 40-45mm at the rear (which leads me to believe that static sag is just the bare bike)...


A quick spin yesterday just after fitting the shock, (solo, unloaded) with just a little preload over minimum (and damping left at the factory setting) felt good and a massive improvement over my 19 year cold OEM shock but I'd like to try and set it up kind of properly.

I appreciate that solo unloaded use with this shock will always be a compromise and I may end up just having to set it up by 'best feel' but I'd like to try and get it right for a loaded configuration.

Any advice for a suspension novice much appreciated

 

[Flipfly]

Others I'm sure will be more learned than me on this, but I'd read static sag as the difference between the bike unloaded and sat on it's wheels (just the plain bike).

The rider sag would be adjusted to get 45mm with the preload adjuster depending on the weight of the load being carried. So you on your own = 1 turn of preload for example, but you and your Mrs + luggage = 3 turns of preload.

Rider sag seems more in tune with whats required as it relates to the load being carried. Static sag is fine when the load is contant and the spring is exact to the riders weight. For our type of stuff this doesn't seem partcularly effective imho.

That's what makes sense to me anyway

 

[earthmover]

Static sag is the difference between two points (I use axle bolt and seat bolt on a dirt bike) measured first with the back wheel off the ground, and then with the bike sat on its own with no rider. Subtract the second measurement from the first and you have the static sag.
Mark

 

[MarkShelley]

Here is some useful info on static sag

http://www.youtube.com/watch?v=UbWsfR1_YEU

 

[(RIP) Tunneruk]

*Sorry*
I don't know any of the info you're after ......... I just saw "idiots" in the title and was naturally drawn in

 

[Deleted account 211025001]

Re setting up the suspension (once sag is set), a good base to start from is to start with everything wound off too soft and adjust one thing at a time until it feels too hard, then just wind back a tadge. That gives a good base setting and after that you can tweak to get it spot on (or leave as is which is what I normally end up doing).

Andres

 

[cookie]

Re setting up the suspension (once sag is set), a good base to start from is to start with everything wound off too soft and adjust one thing at a time until it feels too hard, then just wind back a tadge. That gives a good base setting and after that you can tweak to get it spot on (or leave as is which is what I normally end up doing).

Andres

that is more or less what maxtons told me years ago, and it works well. i've never bothered with this new fangled sag business - seat of the pants all the way

 

[MattW]

Thanks all

After having a mess around this afternoon, I soon realised that trying to set static sag on half a ton of GS with any degree of accuracy on my own was never going to happen

So, I set the shock just off fully soft and went for a ride using the seat of the pants method. I think I've now got the preload at about the right compromise for solo use - just need to do the same with damping

 

[sycomoto]

Mat

Static is the weight of the bike on its wheels. So measure the shock fully unloaded then put it on its wheels and measure again. The difference between those two measurements is static sag. Dynamic sag is the difference between unloaded and rider sitting on the bike.
Just make sure you measure the same point each time

 

[ChasF]

Just make sure you measure the same point each time

Vertically through the rear wheel spindle/centre.

I think the seat of the pants method is much more useful for road touring bikes where the load changes.

More important than rear sag would be to try to get the bike to stay level - this is probably quite difficult when the bike is 2 up and loaded as most of the extra weight is way behind the centre of mass.

I've set my bike up for the best compromise between one up and 2 up riding so I don't have to adjust the preload (which would involve spanners in my case) but I turn the compression damping up a couple of clicks when 2 up.

 

[MattW]

Static is the weight of the bike on its wheels. So measure the shock fully unloaded then put it on its wheels and measure again. The difference between those two measurements is static sag. Dynamic sag is the difference between unloaded and rider sitting on the bike.
Just make sure you measure the same point each time

Vertically through the rear wheel spindle/centre.

I think the seat of the pants method is much more useful for road touring bikes where the load changes.

More important than rear sag would be to try to get the bike to stay level - this is probably quite difficult when the bike is 2 up and loaded as most of the extra weight is way behind the centre of mass.

I've set my bike up for the best compromise between one up and 2 up riding so I don't have to adjust the preload (which would involve spanners in my case) but I turn the compression damping up a couple of clicks when 2 up.

Thanks chaps

 

[(RIP) Kaister]

its all here

http://www.suspensionshop.org/tech_suspension_setup.php

http://www.motorcyclistonline.com/howto/122_0508_motorcycle_suspension_setup/


and :

Measuring sag is very simple, and should be the first job when ever buying a new bike. You see, it won’t just tell you whether the measurement is right but it will also indicate whether you have got the correct springs installed for your weight. All you need is a tape measure and a couple of mates.

On the end of the swing arm and tailpiece or rear guard make a reference mark to measure between. Get one of your mates to stand in front of the bike and hold it upright while you lift the bike from the tail end taking all the load off the shock so the swingarm is fully extended. Take a measurement at this point. For this example we’ll say its 500mm. Now while your mate is holding the bike upright sit on it with your feet on the pegs bounce up a down a couple of times and return to your natural riding position. Get your other mate to take a measurement from the same reference point as before, this measurement should be 25-30 mm less than the 1st measurement, i.e. 470-475 mm, or about one third of the total shock travel

 

[Tsiklonaut]

If you want the sag (spring preloads) correct, the most idiot-proof is the 1/3-law. Don't bother measuring the overall height of the bike - too much messing and you need a lot of help from a lot of people to get enough weight to push both shocks to the bottom to know where the actual "end" is.


When new, the Hyperpro's have the rubber o-ring on the shock shaft. That's actually very neat and elegant way of doing it:

• Put your shocks preloads into factory recommended settings per the needs you have for the particular setup - this will be your approximate staring point.
• Put your bike on the centerstand - the shocks are on their maximum. With some soft plastic detail (not to scratch the shaft surface) or with a textile band push the o-rings up agains the shock (you need to work through the spring "ribs" to do this)
• Now slowly push the bike off the centerstand (without the huge bump - use breaks if you need to "smoothen" the final "landing") and smoothly sit on the bike with the settings you have in mind, solo, two-up, luggage etc and plant those on the bike (SLOWLY, without any "bumps"). The shocks must smoothly obtain their nominal position like this without pushing them over the limit with inertia (with big bumps, i.e. fast coming off the centerstand or you jump on the bike - don't do this).
• Put the bike back to the centerstand and with some simple measurement tool measure the location of the o-ring on the overall scale of the shock-travel on the shaft.
• It must be around 1/3rd of the way from up to down (2/3 left to take bumps from the rear, 1/3 left for the other way). It doesn't have to be that precise, just approximately. If it's way off (i.e. 0-ring comes in the middle or just 1/5th of the travel then adjust), preload your springs accordingly, with more or less preload depending where the o-ring came (less than 1/3 - less preload, more than 1/3 - add more preload)
• (measure again to obtain the "1/3" on both shocks with this method)
• Do it separately for the all other settings to save your time in the future - solo, 2-up, solo-luggage, 2-up luggage. And REMEMBER or write down your preload settings whether it's a hydraulic preloader (write down the scale position from the preloader knob) or if it's simple c-spanner spring preload adjustments (write down the measurements from top thread start to down to the c-spanner adjuster in millimeters for each setting)
• Yer done and now every time you exacly now know where to tune your shocks per settings you require (solo, luggage, 2-up). Basically you've "mapped" your shocks for your personal settings.

Now I made a super-easy procedure look complicated

Anyways, this is how I did it without confusing myself with all the excessivly overloaded literature about the static and dynamic sag. With Hyperpros you can do all this ... with an utterly simple but a bloody brilliant o-ring on the shaft!

Once you have those fundamentals put right, the next step is the sweeter science - the dampening and rebound adjustments, and this also depends on your settings. But that's the next step.

Margus