FREE Suspension Setup advice from an expert

Will it be the same extension as when you pop a wheelie? I doubt it.

The difference may be a few millimeters but I’m quite sure will be there. As much as we’d like to think that our suspension moves freely there’s a significant amount of stiction, hence the continuing development of friction reducing coatings.

As I said earlier, leaning on the stand could give a good enough reading for most but wouldn’t satisfy my attention to detail.


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If the wheel if off of the ground while balanced on a side stand vs a triple clamp stand, its off of the ground.

A wheelie isn't a magical extension of the forks. Weight is transferred to the rear, the fork springs act and extend the forks.

I really don't get what you are putting down...

What I’m suggesting is that the angle of the bike on a side stand will not offer a true reading as opposed to a triple clamp stand… the wheelie is an example of vertical extension.


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Alkhater said:

What I’m suggesting is that the angle of the bike on a side stand will not offer a true reading as opposed to a triple clamp stand… the wheelie is an example of vertical extension.


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What you are suggesting is not possible.

Once the wheel is off the ground, the force of the spring/s is so great the suspension is absolutely at full extension. You could turn the bike upside down and suspension would be at full extension.

I’ve had three cycles get the sag set to my weight by experts at WCW in NJ, and each time one guy tilted the bike while the other measured with a tape. Pull out your stands if it makes you feel better, but, assuming you measure from the exact same location, the reading on a stand is the exact same reading tilted on the side stand.

AmpForE said:

What you are suggesting is not possible.

Once the wheel is off the ground, the force of the spring/s is so great the suspension is absolutely at full extension. You could turn the bike upside down and suspension would be at full extension.

I’ve had three cycles get the sag set to my weight by experts at WCW in NJ, and each time one guy tilted the bike while the other measured with a tape. Pull out your stands if it makes you feel better, but, assuming you measure from the exact same location, the reading on a stand is the exact same reading tilted on the side stand.

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That would be the case if the spring is longer than the fork body… is it?

Anyways, no need to get riled up about the subject. You perform your measurements the way you see fit.


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Yes! Please do it they way that makes you most comfortable.

Just do it. People don’t realize how much a properly set up suspension impacts their control and ability to point the motorcycle in the intended direction.

Full extension actually requires the bike to be lifted from the bottom of the triple clamp and pegstands so you can force the suspension down to full extension. There are top out springs.

roadracerx said:

Full extension actually requires the bike to be lifted from the bottom of the triple clamp and pegstands so you can force the suspension down to full extension. There are top out springs.

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Thanks. This confirms my thoughts exactly.

I assume this would not be the case with gas or spring pressurized forks?


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I still don't get what you're talking about. If the wheel is off of the ground it is off of the ground. I get the exact same measurement if the bike is in a stand off of the triple clamp or if I leverage the front wheel off of the ground on the kickstand. This measurement doesn't change with either method.

This is in the stand. I couldn't get a pick of the kickstand method since I didn't have anyone to take the pic. Its hard to hold the bike up, measure and use a camera phone.

bp_SFV4 said:

I still don't get what you're talking about. If the wheel is off of the ground it is off of the ground. I get the exact same measurement if the bike is in a stand off of the triple clamp or if I leverage the front wheel off of the ground on the kickstand. This measurement doesn't change with either method.

This is in the stand. I couldn't get a pick of the kickstand method since I didn't have anyone to take the pic. Its hard to hold the bike up, measure and use a camera phone.

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I don’t get it either.

bp_SFV4 said:

I still don't get what you're talking about. If the wheel is off of the ground it is off of the ground. I get the exact same measurement if the bike is in a stand off of the triple clamp or if I leverage the front wheel off of the ground on the kickstand. This measurement doesn't change with either method.

This is in the stand. I couldn't get a pick of the kickstand method since I didn't have anyone to take the pic. Its hard to hold the bike up, measure and use a camera phone.

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What I’m talking about is essentially a design deficiency in the factory suspension. Ideally, if there is 0 stiction in a properly designed suspension then it would fully extend… not only if the bike was at an angle but even if it was upside down.

What’s happening in the case in point is…

1st: the spring is shorter than the fork body so is unable to push the inner tube out to it’s extent.

2nd: there’s stiction between the fork seal and the inner tube… so when the spring fully extends the inner tube still has the ability to extend further but is hindered by the fork seal.

What this will look like in the real word, out on track and if logged on a linear potentiometer is that most of the time yes… you’d get the same fork droop when accelerating because the movement would be gentle but sometimes it isn’t gentle and the fork would extend further. This could be due to a sudden fork extension because of a bump or the fork seal heating up or god knows…

The point is that the stock fork design means that the movement isn’t fully controlled throughout its potential stroke. Some of it is controlled by the spring and the rest of its movement is controlled by friction.

One could argue that it won’t make much of a difference but… things add up, especially when considering lap times.

I’ve come to know that not only in setup but even in life… datum’s (absolute references) are salvation.


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IDK, goes against my direct observation. Front wheel off of the ground fully extends the fork. If you have stiction, then you have a problem which needs to be corrected. A properly functioning fork will fully extend when unloaded. I think you are way down a rabbit hole of minutia.

bp_SFV4 said:

IDK, goes against my direct observation. Front wheel off of the ground fully extends the fork. If you have stiction, then you have a problem which needs to be corrected. A properly functioning fork will fully extend when unloaded. I think you are way down a rabbit hole of minutia.

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All suspension has stiction, you can minimize it but can't avoid it completely.

Roadracer just confirmed that your fork will extend further when pulled, even if the wheel is off the ground.

I'm not denying that this is minutiae but this is no rabbit hole. Race teams go to greater lengths to eliminate doubt.

Alkhater said:

Roadracer just confirmed that your fork will extend further when pulled, even if the wheel is off the ground.

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Measure the forks off of the stand and on a triple clamp stand and circle back. Try to pull down on a wheel which is off of the ground. Post your results.

I will when i have a triple clamp stand.

Have you tried to pull a wheel down and take a measurement while on a TC stand?

Yeah, it didn't move.

Let’s move on then [emoji23]


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It can change slightly but it doesn't always happen. Both wheels can be slightly extended, maybe 2-3 mm. You have to push down with some force to overcome the top out springs. I guess it takes experience, not a big deal but it certainly is possible. I do this with every bike I measure.

Another small thing that makes a difference is making sure the bike is level when measuring the bike under just its own weight and with the rider. Usually this is done with the bike on a rear stand and a 2" piece of wood under the front tire.

Also a slight misunderstanding of stiction here guys....

When I take measurements for sag I actually take one fully extended pushing down on the wheel to get full travel, I call this F1.

Next I set the bike level on the ground gently and lift up and release gently and measure from the same two points, I call this F2; next I push down on both ends and release gently and measure from the same two points, I call this F3.

The DIFFERENCE between those two measurements IS stiction. Old or dirty fork seals or not properly lubed seals or even running both inner and outer fork seals contribute to stiction at the fork. This is why you see race bike not running the outer seal.

Shock stiction is more a function of pivot point lubrication including the linkage (if it has one); these are generally ALWAYS dry when I do a setup so of course I lube these with something like RaceTech suspension grease.

It is common for the fork to have 5-10 mm of stiction and the shock 2-3 mm.

At this point I average these two measurements (F2 and F3) and subtract that number from my initial measurement (F1) with no weight on the bike (fully extended) to get BIKE SAG.

To measure RIDER sag I do the same as measurements 2 and 3 with the rider on the bike and average those as well, then subtract that from the first measurement.

This is done by having the rider get on the bike gently for measurement F4 and then having them bounce on the bike a couple times for the final measurement F5.

At this point you should have 5 measurements front and rear.

For example a fork found on the V4R has 125 mm of fork travel, I like to measure from the bottom of the outer dust seal to the bottom of the slider.

F1 = 125 mm
F2 = 100 mm
F3 = 95 mm
F4 = 85 mm
F5 = 83 mm

F1 - ((F2+F3)/2) == 27.5 mm (bike sag)

F1 - ((F4+F5)/2) == 41 mm (rider sag)

Hope this makes things more clear.

That makes sense and confirms my initial thoughts.

This procedure is common in the RC car world.


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0260n25 said:

@roadracerx I thought I was getting my head around much of this, but I got confused by your post. Did you mean the opposite in your example? If a spring is too soft then to get proper rider sag you would have to crank up the preload, which would give you too little free sag. If the spring is too stiff, you would take out most/all of the preload to get the correct rider sag, which would give you too much free sag.

My OEM V2 rear spring is giving me 39 rider sag and 11 static sag. When I add more preload to get 30 rider sag, then I have almost no static sag. Isn't that spring too soft?

Thanks for your time with all of us. I installed a Ducabike adjustable link (to correct for chain adjustments and sprocket size changes) and will order the Kyle Racing ride height tool today.

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Roadracerx, what 0260n25 is saying sounds logical to me, I was thinking the same. Can you please explain again how you decide if the spring is too soft or too hard because this is confusing.
Thanks.