09 wr450 with 08 yz spring?

Hello Guys,

 

 I am hoping you can confirm something for me regarding a rear spring:

 

I have a 09 WR450.

I weigh about 175 lbs (190 w/ gear).

I think I need a rear spring with a rate of about 5.5 (sound right?)

I think the stock spring on a 08 YZ450 is 5.5 (sound right?).

If all that is fact, I am thinking I can put the stock YZ spring on my WR and I should be good to go as far as getting my rear sag set up properly.

 

Am I missing something?

 

I got the spring from a friend, from when he had his suspension done on the YZ. I do not see any marks or color codes on the spring itself.

Well, if you use a really used spring, it will no longer be the same as it was stock. They sag.

As they get shorter, they get stiffer.

Go into bikebandit.com or similar to find out spring rates via parts listings.

 

Do not change the rear without changing the front at the same time.

Use Racetech.com's spring calculator to estimate your needed spring rates

I have looked at the calculators, just wanted to see if that sounded right before I took it apart.

Is having only the rear properly sprung much worse then the entire bike under sprung? Like crazy to ride it like that?

My plan was to start with the rear and get the sag set properly and then move to the front as cash allowed. I guess just buying new springs that I know are correct is going to be cheaper in the end anyway.

Thanks for the reply.

I think you know the answer already

 

You are much better being in balance and under sprung than out of balance

Well, if you use a really used spring, it will no longer be the same as it was stock. They sag.

As they get shorter, they get stiffer.

 

Not true.  Shortening a spring by cutting makes it stiffer because it shortens the total wire length of the spring.  Springs that have sagged still have the same wire length they always did, and the rate doesn't change.  It's also true that springs of any respectable level of quality actually sag very little over time.

 

Another spring myth is that if you keep them compressed for long periods that it causes them to loose free length ("sag").  That's also false.  What sags a spring is cycling it; compress, release, compress, etc.

Not true.  Shortening a spring by cutting makes it stiffer because it shortens the total wire length of the spring.  Springs that have sagged still have the same wire length they always did, and the rate doesn't change.  It's also true that springs of any respectable level of quality actually sag very little over time.

 

Another spring myth is that if you keep them compressed for long periods that it causes them to loose free length ("sag").  That's also false.  What sags a spring is cycling it; compress, release, compress, etc.

 

Dang, you are right about the length.

I have found all stock Honda springs, and Diverse racing springs to sag pretty quickly.  Not a ft/lbs issue, but a sag issue.

Pre-load on a brand new one is apt to change a little, yes, but they don't get very much worse than the initial set over time.  Depends on their use, obviously.  As I said cycling the springs is what eventually "wears" them until they sag.

I think the titanium YZ spring seems to hold up well to sag.

Thanks for the replies guys.

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