Spring rate help YZ250

[jim7411]

I have an '05 YZ250 and I weigh 213 lbs. I ride motocross mostly on a sand track. I put a 5.2 rear spring on it as per Race Techs spring calculator and when I set my race sag to 95mm I only have about 6mm of free sag. First of all do I really need to go to a stiffer spring to get the free sag better? Also, how do I know what Spring to buy next in order to get it in the proper range? Would 5.4 be sufficient or do I need to go stiffer? If the calculator said go to 5.2 and that didn't work it's only a guess to know where to go next. At $109.00 a pop, you would think that the spring rate calculator would be a little better.
I had the race sag set at 105mm and I had 18mm of free sag. I went to the track and let a couple more experienced riders try it out and they said the front was to light. They told me to go to 95mm of free sag and lower the forks in the clamps. They told me to make those adjustments then they would help me set the clickers this weekend. So when I went to 95mm of race sag that's when I only ended up with the 6mm of free sag. I ordered a 5.4 from Race Tech today so if any body has experience with this bike I would welcome the input.

 

[bclapham]

did you buy the 5.2 spring from RT??? if the numbers are off, i would ask them to exchange it.

that said, i am sure they will use the excuse that those spring numbers are designed to work with their valving and try to sell you more stuff, LOL!!!

 

[jim7411]

Yes, I bought the spring from Race Tech. Then I ordered a 5.4 this morning before I called them. When I did call them the guy I spoke to was very helpful and said that they 5.2 was the proper spring rate for me and that 5.4 was going the wrong direction anyway. So he canceled my order. He also said to set the sag at 100 to 105 and as long as I Have some Free sag then I am good to go. I think that I will put it at 100mm and raise the fork tubes in the triples and see how that works.

 

[marcusgunby]

something sounds wrong to me, i would look for a secondhand spring as there are loads going but i would want 100mm and 25mm freesag.

 

[SpDyKen]

You might want to consider patronizing MX-Tech; did you notice that Jeremy Wilkey hosts this forum? He also has a spring generator, click on the link to the left. Just a thought.

 

[jim7411]

You might want to consider patronizing MX-Tech; did you notice that Jeremy Wilkey hosts this forum? He also has a spring generator, click on the link to the left. Just a thought.

I have tried the spring calculator on MX-techs site but I always get this message when I try to get the answer -

ADODB.Field error '800a0bcd'

Either BOF or EOF is True, or the current record has been deleted. Requested operation requires a current record.

/sbw/springlist.asp, line 17

I would be real interested in what MX-Tech has to say that's one of the reasons I posted here.

 

[marcusgunby]

yes says the same for me.

 

[jcdawson5]

jim7411.

I have that exact same problem. I have a 2005 yz250 with a 5.4kg race tech spring and practically no static sag even though the spring length is within adjustment limits (9.42-10.18in). The service manual says to let the new spring break in and reevaluate. I emailed race tech but have not recieved a response. I dont feel so bad now that I see you are having the same problem. My buddy said to run comp and reb on the soft side. I read your post that said to move the forks up in the triple clamps. What negative effects will that have for Hare Scramble riding?

 

[jim7411]

jim7411.

I have that exact same problem. I have a 2005 yz250 with a 5.4kg race tech spring and practically no static sag even though the spring length is within adjustment limits (9.42-10.18in). The service manual says to let the new spring break in and reevaluate. I emailed race tech but have not recieved a response. I dont feel so bad now that I see you are having the same problem. My buddy said to run comp and reb on the soft side. I read your post that said to move the forks up in the triple clamps. What negative effects will that have for Hare Scramble riding?

I ordered a 5.0 spring from Race tech and I will be recieving it today. I will throw it on late tonight and set it up and see where we land with the free sag. I will post the results as soon as I have them. All i can figure is even if they tell me the 5.2 is the correct spring but my free sag is way off, I need a lighter spring. So that's what I did. If it doesn't work then I will throw the 5.2 back on.
I ride on a sand track and the guys have told me to set my sag at 95mm and raise the forks up in the triples. But being a hard head I am going to set it at 100mm and raise the forks. This is all supposed to make it turn quicker and put more weight on the front end so that it sticks in the corners better. As it is, I was having trouble missing the rut. After the other guys rode the bike they said the front end was way to light ad made they recommendations to me. Tomorrow they are supposed to come out to the track and work with me on the clicker settings. I'll post back soon.

 

[jcdawson5]

jim7411,
If that 5.0 spring works for you maybe I could buy the 5.2 from you. I wonder if I lower the forks first then set the sag if that will change any numbers?
Jeremy ( jcdawson5@aol.com)

 

[jim7411]

jim7411,
If that 5.0 spring works for you maybe I could buy the 5.2 from you. I wonder if I lower the forks first then set the sag if that will change any numbers?
Jeremy ( jcdawson5@aol.com)

Okay here is a little update. By the way, it's obvious I am NO suspension tuner, I am only going by what those in the know tell me. With that said - I just recieved the 5.0 spring and I read the paper that came with it. It said that if you set the race sag first and then you have not enough free sag then you need a HEAVIER spring. If you read back in my other posts I had a 5.4 on order but the guy at Race Tech told me I was going in the wrong direction. So I cancelled that order and ordered a 5.0. Well after reading the Race Tech paper I called them and another guy tells me that "no, I need a 5.4" so I have to return that one and they are shipping me a 5.4. They were very nice but I tore my bike down last night in preparation for the new spring so that I could go to the track Saturday and I paid 30.00 something bucks for 2 day air so that I had it in time. Now I have to put it all back together to ride this weekend and then take it apart again to put the 5.4 on when it come. :(
How much do you weigh? If you already have a 5.4 on yours and you are getting to little free sag then it appears that you would need a heavier spring not a lighter spring like I said in my previous post. I know this is like the blind leading the blind but I asked "professionals" and I am working off of their recommendations. Makes me wonder if I should be asking anyone how to clear that big triple! :yikes:
Same old story, when I get the new spring in nd put it on I will let you know how it comes out. Sorry for the confusion but that is what the internet is all about. :laugh:

 

[russ17]

Here is some insight on some of the manufactures spring rates. you might need to be aware of.

[ Quote: ]The spring rate tester is very unique as it compresses the spring up to 7" then releases it to its' free length. As it does this it samples over 1000 different rate readings giving a dynamic graph of rate of the spring through its normal travel." This has opened up a huge can of worms as we are seeing rates completely different than what the manufactures are stating. The largest culprit has been the WP PDS spring. These tested rates are much higher than what is advertised on the spring."

 

[jcdawson5]

jim7411, I weigh 230#. I am confused about something else. In the manual (pg3-30 "spring length installed") it gives "extent of adjustment" figures of 9.47(less sag) to 10.18(more sag). With the 5.4 spring and sag set at 100mm (4 inch) my spring is compressed to 10 inches. This leads me to believe that this is the correct spring. Given this measurement, if I go to a stiffer spring I doubt it will be compressed enough to be in the adjustment range, hence, the shock will not operate in the correct part of the stroke. What are your thoughts.

 

[jim7411]

jim7411, I weigh 230#. I am confused about something else. In the manual (pg3-30 "spring length installed") it gives "extent of adjustment" figures of 9.47(less sag) to 10.18(more sag). With the 5.4 spring and sag set at 100mm (4 inch) my spring is compressed to 10 inches. This leads me to believe that this is the correct spring. Given this measurement, if I go to a stiffer spring I doubt it will be compressed enough to be in the adjustment range, hence, the shock will not operate in the correct part of the stroke. What are your thoughts.

Again, I am no suspension guru but if you have a heavier spring you have to crank less preload into it to get your race sag correct. Since you have to put less initial tension on the spring, it is easier for it to sag under the bikes own weight (free sag). In the manual they are talking about the stock spring and standard preload 90-100mm so they give you the length of the spring to achieve those settings using that 4.9 stock spring. But that part I am not positive about. I am just somewhat guessing. That would be a good question from someone who really knows.
It get's harder and harder to comress the spring the more you push down on it. So if you have to crank in alot of preload to get to your race sag for your weight then the spring is compressed so much that it pushes the bike up and holds it there. Therefore you end up with no free sag or very little. The more preload you have the less free sag you have.
I hope this helps and I hope that I have not made any false statements here. Maybe somebody that really knows could chime in and help out.

 

[marcusgunby]

If you have no free sag you need a stiffer spring. What are your numbers now free sag and race sag? i wouldnt look at the book for the max and min amount of tension to put on the spring as then you have 4 numbers to think about, if you are in the range 20-40 free sag and 95-105 race sag then just set it up as best you can with that spring.