Suspension Setup recommendations.

I have come up with a formula that I use for setting the suspension up on my bikes. This info was collected the past few years from several different tuners and applied. I have broken this down into a formula using percentages of available travel so this will work on most any bike. (KTM PDS is slightly different but close). I thought I would share this knowledge with you.
Your shock spring preload should be less than 10mm on linkage suspension but not less than 5mm. You don't want to over preload a weak spring as you will just get a harsh ride that still will allow hard bottoming. I usually shoot for about 5mm preload on fork springs. If you have the right spring.
You can figure your correct sag numbers by using percentages. That way you can get the correct springs for you and your bike. Base these percentages on the available travel front and rear with a variance of + - 3 mm.
Front suspension static sag should be 14% ( available travel in mm X .14 = static sag in mm)
Front suspension rider sag should be 25% (X .25 = Rider sag)
Rear suspension static sag should be 11% of available travel (X .11 = static sag)
Rear suspension rider sag should be 34% of available travel (X .34 = rider sag)
Using these principles you can figure the correct sags for any bike and thus the correct springs without guessing and compromising.
Once you get the springs set correct you can get the forks and shock revalved if need be. I usually like to take 20-25% of the high speed compression out with the correct spring rates.
I usually leave rebound stock or change according to the replacement springs. I usually will change rebound one click per .2 kg. on rear shock. If I go up on spring rate say from a 5kg to a 5.8kg , I will go in 4 clicks. That is a good place to start. After setting rebound and spring sags (and getting correct spring rate installed). I find a G out or a ditch that I can jump into and expect to bottom front and rear at same time. I will back off compression till I am bottom softly front and rear. NOT DRIVING FOOTPEGS THROUGH YOUR FEET OR METAL TO METAL BOTTOMING.. Just bottoming softly. Then I go back in about 2 clicks to compensate for heated suspension. I then will ride extensively to see if I need to go in or out slightly to fine tune. Damping I find is a very personal thing it you take the time to dial it in. I like a plush and compliant suspension but not wallowy. Many times lately I find that I have to go down on fork springs and up on shock spring rates. I weigh 180-185lbs and ride a 2011 WR150. It came with .42kg fork springs. That is what my KTM 525 / 530 had in the front forks. For sure there is a big difference in weights. I tried .44kg on my 525 and the bike would not turn. The bike should settle into the corner front and rear when turning. My bike would not settle. The forks were way off static and rider sag. I was on the cusp whether to go to a .38kg or .40kg. If I were 10lbs lighter I could have used a .38kg. But as it stands the .40kg allowed my sag numbers to work perfectly. 40mm static and 75mm rider. I had Hall's Cycles take out 20% of my compression on front. I am using 5wt Maxima Racing fluid. I am 10 clicks in from full out. My WR150 came with a 5kg on the rear. When I had the correct rider sag , I had NO STATIC SAG. I kept going up on my spring rate till I was at 6kg. A huge difference. A full Kg or 5 sizes heavier spring. But I had to do this to get the needed 30mm static sag with 101mm rider sag. With the correct sag rates the bike is not nearly as tall feeling. Much easier to throw a leg across. Turns perfectly and is very stable on straights. I had Hall's Cycles take 25% of my compression out of the rear shock. I am very happy with the results. Use the formula and you can get the perfect spring rates for you and your bike. Don't ride the bike till you are satisfied you have the correct spring rates as most shops will exchange unused springs for different rates. If you ride with them they will look used and can't be sold as new. I think you will be very happy with the results if you don't compromise.

Thanks for sharing Dwight!
if memory serves I think I am at 105mm rider and 35 static and liking it- I'll check again with spring prep.
Related to set up- but not focused on springs/ preload, I am going to change fork oil and am happy with my forks right now- to a point that I am afraid to have anything change drasticaly.

I have a 09TE450 which has the stock AGIP 7.5weight fork oil. With all the reported varience in viscosities compared to what's on the lable I was curious if anyone knew if AGIP 7.5 is closer to MOtorex 10, 7.5, 5, or 2.5? or if it mattered too much. I know thicker = slower dampening. But with all the reported varience in actual visosities versus labled... I am wondering. I do have 2 liters of Motrex 2.5 and was going to try some till I got something else-just cause I have time and want the old stuff out now, but wondered if that was a complete waste of time. I spose the easy answer is try to find Agip 7.5 since I like my fork action now.

I have spring fever mainenence with 2 feet of snow remaining on the trails so that might be why I ponder such things... forgive me.

I'm wondering if some of those figures would need minor adjustments to account for rider speed; ie. slower trail plonker vs expert level racer...........

Thanks, I need to stay away from those spring rate calculators, they never seem to work well for me, I will try this instead.

Should not. If anything I would er toward the + 3mm side if a slower rider and the -3mm side if a faster rider. The main difference is how you adjust your compression damping.

Here's my numbers punched in with Vinduro's figuring on my 09TE450.
fork travel per spec sheet= 300mm
shock travel per spec sheet=296mm
Front suspension static sag should be 14% ( available travel in mm X .14 = static sag in mm)
300mm X .14= 42mm
Front suspension rider sag should be 25% (X .25 = Rider sag)
300mm X .25= 75mm
Rear suspension static sag should be 11% of available travel (X .11 = static sag)
296mm X .11=32.56mm
Rear suspension rider sag should be 34% of available travel (X .34 = rider sag)
296mm X .34= 100.64mm
I am a bit suprised by the sag numbers on the forks- I haven't measured but I know I am not near the static or rider sag on forks- probably half that. I am no Mx'er so I am curious why I have been so pleased... I will have to see where my numbers actually are I am curious.
For the shock- I run a tad less preload than I could but I am no expert- I don't think I am too far off with my numbers- I think they were 35mm and 105... guess I am pushing that +3 a little.

Overall I have been happy- but will check out my fork sag and maybe try some different fork springs and sags...

Thanks again Dwight.

You could decrease your sag a tad by going with a bit more preload on the rear getting the sags inside the 2-3mm leeway rule. I agree that your rear spring is probably OK. Check those fork sag numbers. I think you would be really pleased with how the correct spring rate would work for you.

Thanks! I'll check that out and see what I have. We got a bunch more snow this week: actually the biggest here in 120 years... guess I get a few more weeks to snowshoe

From this table in the manual it appears the TE 2009 forks have 4.5 springs. So if I went a step lighter- I'd go to a .44...
COSTANT K (N/mm) CODE
4,5 (TE) 8000 B1713
5,0 (SMR) 8000 A7608

I weigh about 180lbs. I had .42kg springs in my KTM520EXC / 530XCWF . The main thing is to check those static and rider sags in the forks after you adjust your shock sags to the correct numbers. (Be sure to recheck after you get the right fork springs). Spray fork tubes with some silicone lube to minimize stiction. Check at least 3 times. Use the 2 measurements that are the same.

Good stuff here Vinduro.

Thanks for all this info and starting later this week, I should be back home and have the time too see how these numbers work when applied to my 08 TXC 250 ... I'm pretty happy with what I have now but I'd like too see if I am off somewhere on the sag stuff ...

Thats great info... I wish i had it before i bounced into the tree last friday night...

Could someone with more posting privilges that I have , please move this to the Technical forum ? Several have asked me about that.

What do you think would work on a 09 125 for 200 pounds? On the old model a 5.4 worked so that is what I bought but the new frame appears to have a much higher leverage ratio.

I weigh about 180lbs neked. I am using a .40kg fork spring and a 6.0kg shock spring. That is on my 2011 WR150. Stock fork springs are .42kg.
Stock shock spring is 5.0kg. Hall's installed a 5.4 spring when they serviced my bike. It wasn't close. I had little to NO static sag. Hall's was great about working with me and exchanging springs ( I didn't ride with them till I had the correct one). My fork sag stock wasn't nearly enough. I went down to a .40 and got 40mm static and 75mm rider sag.... PERFECT ! On the rear I was baffled as I kept going up. Jay Hall did take out about 25% of the high speed compression valving. Barely enough. Jay weighs 215lbs and says he uses a 6.8kg. spring. I think that maybe a bit much but I don't know what his sags are. When I got up to 6kg my sags worked out perfect. 30mm static and 101mm rider sag. I don't know what the leverage ratio is on the old frame vs the new frame. But my bike handles SO good, I can hardly believe it. Turns on a dime. Is stable and the front end sticks like glue. You may need to cut a new preload spacer for the forks . It is BELOW the spring. I used a paint stir stick to get it out. Get a PVC Heavy wall to cut new spacer out of if needed.

Checked my sag today- albeit not fully geared- but not in shorts either and I still have my winter fat.

Fork: Static sag 34mm, Race 70mm
Shock: Static sag 36mm, Race 101mm

I guess I know why I have been happy with my suspension- I am pretty darn close to your recommendations Dwight. Close enough to say I fully support your formula

Your shock is great. As for the fork. I would reduce my preload a bit. You need a bit more static fork sag and rider sag. Your spring is probably good if you get the static sag right. Try shortening preload spacer 5mm . Best bet is to make another from PVC pipe so it you need to go back you can.

You have an interesting theory, i am going to try it. The questions i would have would be how does the leverage ratio created by the husky linkage affect it as opposed to the Husaberg or KTM linkless? There would have to be a percent of load factor incurred in the change. I think this would be overly harsh for a link less setup because of the difference caused by the multipliers created by linkage. I am not able to explain the equation by typing it, but you know what i am saying. Just as leading link transfers energy so would the difference in shock location relative to shock preload and spring rate. The front end is a great example for this math, no worries. Also how does rider use play into it? Fast or slower, tech or wide open. Anyway i printed it off for use just cause it shows a great deal of thought with good results. Great post.