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Jon-D

10-13 YZF 450 stock spring vs steel?

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Kind of an odd question, but does anyone feel any difference between the stock ti spring and an aftermarket steel spring?

The reason I ask is I am looking for a 10-13 YZF 450 stock 5.5 spring to put into my bike. have not found a ti spring yet, but am looking.

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With any elastic material such as spring steel, the real "spring rate" of the material itself is progressive, not linear. Even when you wind a single rate spring and call it linear, there is some small amount of progression nevertheless. If you think about it in terms of how the spring really works, it makes sense.

Understand that a coil spring is nothing more that a way to make a torsion bar more compact and convenient. When a coil spring is compressed, the spring wire is not being bent, it's being twisted, and looking at any cross section of the wire you will see that.

It's also easy to both understand and demonstrate that a torsion bar has, at some point, an elastic limit, and if that's exceeded, the spring will break. Coils will usually bind on themselves before the limit is reached, but the closer the material gets to its elastic limit, the more it resists being twisted farther. So, it is, then, progressive.

Steel springs and Ti springs have slightly different levels of progression because of the characteristics of the two materials. IMO, it's pretty small, but it could be significant.

Read more: http://www.thumpertalk.com/topic/272196-2006-yz250-shock-unfolded/#entry2291038

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There you are. If you were thinking of finding a spring for the '06-'09 shock, forget it. They don't interchange.

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interesting....i thought the stock springs for the 10-13 are titanium?

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I don't think that the OEM Ti spring thing went past the '07 models.

09 was the last year, but the YZ 250 smoker may very well have Ti springs still......

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http://motocrossactionmag.com/Yamaha/News/MXAS-2012-YAMAHA-YZ250-MOTOCROSS-TEST-NOT-EVERYONE-8839.aspx

According to that, the 2012 YZ250 still has a Ti spring. In case anyone is wondering, I just so happen to have a YZ250 Ti spring and a 2010 YZ450 stock spring to weigh on my bench.

According to my hops scale (for beer making)

YZ250 Ti = 38.8oz

YZ450 Steel = 58.7oz

So the Ti spring is almost 1.25 pounds lighter.

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the weigh savings of Ti is nice, but i really like the way they react compaired to steel, if you can understand what i am saying. i have allways ran Ti on my KTM (PDS), which is much more sensitive to changes than a traditional shock. if i can gain that same improved feeling (improved for me anyway) than it would be worth it.

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