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Bagstr

Yamaha WR 450 - Rider Sag

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  Hey Yamaha Experts,,,,  I have a friend that is setting up his bike for the first time.  Can you tell us the target front and rear Static and Rider Sag measurements, please.

          Thank You!!

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the magic number for 99.9% of linkage bikes is 100-105mm rear race sag. the following is a set up guide from an multi time ISDE rider that I have used on a couple of my machines with good results. Real world sometimes its a bit detailed with its requirements, but the guide is about the details for great balance. the most important are the numbers coming close. the rest is a lot of story line.

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.

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On tracks I run 102mm desert or high speed 95mm.

 

Make sure you set your sag with full gear on

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What year WR? The newer bikes ride a little different but the race sag window is within 5 mm of the older ones. Pretty much what has been posted. 95-110mm. Pretty much depends on terrain, rider pack, how many carnitas burritos you ate that week... 

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Thanks Guys - MotoPolo here- I'm the friend Bagstr is talking about.  It is a 2006 (steel frame) WR 450F with Safari tank.  I weight about 170 lbs and am 5'10".  Most of the time I'll be riding with a 10-15 lb. tank bag and a 10 lb tool kit on rear fender.  I am currently running 7 wt fork oil.

 

What is the best way to get available travel numbers - OK to use spec sheet?  [Front wheel travel is 300mm (11.8"), Rear wheel travel is 305mm (12").]

75mm front and 103.7mm rear?

Are the 95-110mm and 102mm numbers above just the rear rider (or race) sag?  What are you running up front?

 

When adjusting rear shock preload (5-10mm)  - Is that done by putting bike on stand with rear wheel off ground and backing off the spring  perch adjuster until you get some play between perch and spring, and then compressing  spring 5-10 mm?

thanks for the help!!

 

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So the sag off the stand is "race sag"  that is the 95-110mm.  Static sag or "free sag"  is measure wheel off the ground then the bike sitting on the ground at rest.  Static sag helps you determine whether or not you have the proper spring in the bike for you race sag setting.   You need to check with your bike's manual but I think its supposed to be between 20-30mm.

 

So if you set up race sag to 100mm, then static sag is 10mm, you cranked the spring too much and you need a stiffer spring.  if its 40mm, you have almost no preload and you have too heaving of a spring in there.

 

Race-tech has a spring calculator in their website, but my experience has been the calculated spring rate is 1-2 sizes too soft.

 

Now my only experience is motocross, 20+yrs and I am fairly new to dualsport.

 

I have a race tech sag tool you can borrow, I need to find it though.  It fits in your axel and mounts where a seat bolt is.  I makes it so 1 person can measure it.  I am in Ramona and I know it's at my buddies shop in Miramar somewhere.  I'll look for it tomorrow.

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    Or,,,It could be -   Set the bike on the stand, measure axle to a fixed point   =  A .

                                 Take the bike off the stand and bound suspension a few times and let settle. Measure same points  = B.

                                 With help,  mount the bike in riding gear, bounce suspension until settled, Measure same points  =  C.

                A minus B =  Static Sag.             A minus C =  Rider Sag.    A =  Total Travel

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I've got the Motool Slacker digital sag scale and am happy to set your race sag (and measure your static sag) if you'd like. 

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Thanks Guys I was able to measure it OK with the wifes' help.  Looks like I really need softer springs up front.  Race sag is like 50mm or about 18%

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99 .9 % of time front springs are sprung to the lighter side. you need balance. Most guides don't discuss fork springs. 

Static sag is the bike sitting unweighted on its own, your zero is on a stand with the suspension fully extended.

Race sag is fully weighted (with you all geared up- if you are going to carry/tote/rack 50 extra pounds all the time check your race sag with all that extra weight.  Don't get all wrapped up but I will say that the RaceTech weight charts will get you very close to where you want to be on spring rates (not for MX as stated above).

For me I err to the heavy side, even for off road enduro, for most folks go to the lighter side if the number does not match with the exact spring.......or you can go to one of our local suspension guys like S101 and have them dial you in.

 

http://racetech.com/ProductSearch/1/Yamaha/WR450F/2006

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