Stock fork sag

[Soarezito]

Wonder if anyone has the correct number for sag without rider, and for an 80kg rider.

Thanks.

 

[MZ5]

Correct sag is ~1/3 of total travel.

 

[BerndM]

My bike is a 2013 NX700X-D version with about 3/4 full of gas.
With the forks fully extended, I measured 180mm of chromed shock showing.
With the shocks compressed by the bike with NO RIDER, the visible chromed section was now 150mm.
So 30mm of sag without a rider.

 

[MZ5]

I should elaborate on how I mean for a person to measure sag, to get to that ~1/3 of total travel. I mean for it to be what I call 'race sag,' which is with the rider aboard. Actually, I'm going to let Race Tech elaborate further for me.
RaceTech FAQ #3

Here are a couple more references for how to measure from their site:
Sag
Suspension and Springs

 

[dduelin]

It's probably in the Race Tech link...but I didn't look... to make sense of sag for the individual you really need to measure free sag (without rider) and rider sag (with rider). Rider sag should fall in a range of 34 to 45 mm which is .25 to .33% of fork travel.

 

[Cigar Mike]

Static sag and race sag together helps identify if your spring is to light or to stiff for your weight. If after setting your race sag you have no static sag your spring is to soft. With the correct spring rate once race sag is set your static sag should be in the ball park.

There is no preload adjustment that can compensate for the wrong spring rate. Many riders make there suspensions too stiff and never use the travel their bikes suspensions provide. I saw this time and time again with dirt bikes. The bikes would provide 12" of travel but the setup would only use 8" of it. No reason to have that much travel if you don't use. If I bottom out on the biggest bumps my suspension is doing what it is designed to do.

These settings provide a bench mark but personal riding style and terrain to be ridden is also a factor in setting the bike up for you. I like the suspension softer for pavement but it would be set up stiffer if I rode more in the dirt.

 

[dduelin]

Static sag and race sag together helps identify if your spring is to light or to stiff for your weight. If after setting your race sag you have no static sag your spring is to soft. With the correct spring rate once race sag is set your static sag should be in the ball park.

There is no preload adjustment that can compensate for the wrong spring rate...........

This is true but because it is not intuitive I will unpack it if I may. Say the measured rider sag is 55mm and the target is 40mm. I crank on a bunch of preload and reach the target of 40mm by adding compression on the spring before the rider gets on the bike. After adding preload the rider sag is now 40mm but the free sag is less than 5mm. The suspension is almost topped out, at the top of the travel with just the weight if the bike on the suspension. The weight of the rider blows right through the preload on the spring so the spring was too soft for the rider weight and target sag was achieved only by excessive preload.

 

[Cigar Mike]

This is true but because it is not intuitive I will unpack it if I may. Say the measured rider sag is 55mm and the target is 40mm. I crank on a bunch of preload and reach the target of 40mm by adding compression on the spring before the rider gets on the bike. After adding preload the rider sag is now 40mm but the free sag is less than 5mm. The suspension is almost topped out, at the top of the travel with just the weight if the bike on the suspension. The weight of the rider blows right through the preload on the spring so the spring was too soft for the rider weight and target sag was achieved only by excessive preload.

I agree, there is no way to achieve both settings if you have to soft of a spring. But if once the preload is set for the riders weight and you never bottom out, static sag is not very important. The spring then would not be too soft for your riding style and terrain.

 

[dduelin]

I agree, there is no way to achieve both settings if you have to soft of a spring. But if once the preload is set for the riders weight and you never bottom out, static sag is not very important. The spring then would not be too soft for your riding style and terrain.

This is actually not true if the spring is too hard. It would also be impossible to get both settings. If the spring is too hard then little to no preload is required to set rider sag but the shock or fork will still top out or nearly top out under free sag.

The spring rate is in the ball park if preload can set target rider sag and have

 

[MZ5]

Rider sag should fall in a range of 34 to 45 mm which is .25 to .33% of fork travel.

I'm thinking you meant either .25 to .33, or else 25% - 33%. 1/4 - 1/3 of 1% is too little.

Yes, the Race Tech pages I linked specify 28 - 33% front, 28 - 35% rear. I try to make it easy on myself and just say 1/3 at each end.

 

[Cigar Mike]

This is actually not true if the spring is too hard. It would also be impossible to get both settings. If the spring is too hard then little to no preload is required to set rider sag but the shock or fork will still top out or nearly top out under free sag.

The spring rate is in the ball park if preload can set target rider sag and have

It would require a very stiff spring for that to be the case. With very little rider preload the weight of the bike would work on compressing the spring sooner since there is little preload to overcome. I don't believe I have ever bought a bike that had to stiff a spring stock. But I am not a 160 pound rider which most bikes seem to be set up for. I do agree if the spring is in the ballpark you should get very close.