'09 CRF450R fork misinformation

Ok first off I don't claim to be a suspension expert. However..........I just got my '09 about a month ago and I'm just now learning more about the suspension setup on this bike, but the more I look the more I see a common trend of people confusing the n/mm rating with the kg/mm rating; people incorrectly equate for example a 4.6 n/mm spring with being .46 kg/mm, which it is definately not (the n/mm to kg/mm conversion is .102 I believe which would make that spring a .47 kg/mm). This is driving me crazy because it seems like an important piece of info to get right if you're trying to dial in with stiffer fork springs, especially with all the hoopla over this bike's forks. I see MXA claiming all over the place you need to go from .46's to .48's and I seriously think they may actually mean 4.8 n/mm which is more like a .49 kg/mm spring. See the same mistake here on TT too. Makes it tough to know who's advice to take.

they have fitted 0.46nm thats 0.47kg as you say, but they test at closer to 0.48kg(ie one rate higher than specified) it is confusing...

Use the oem's parts fiche. That's the most accurate source. Magazine and suspension calculator websites have a few errors so you have to be careful.

It's right in the owners manual. Not that difficult. .47kg is stock (4.6nm)

Edited by The Captain

0.47 kg = 4.6 N not 0.46 N:p

0.47 kg = 4.6 N not 0.46 N:p

That's what I meant!


To make things even more entertaining, Yamaha lists the springs in kg/mm in their service manuals, and N/mm in the parts catalog. :thumbsup:

MoreCow - you are exactly right. I've seen the same thing here and actually had to edit one of my posts to double check myself on the subject. Someone had posted ".46kg/mm" in reference to the CRF fork spring and I was going to make the point that it's not - but then I had to edit to make sure I wasn't stepping on myself.

I was right. As are you. It is indeed critical information - especially on the 09/10 CRF450 - because getting the forks up, the weight back, and the back lowered is very important on this machine.

I don't doubt - because of posts that I've seen here - that a lot of well known suspension companies don't realize the spring rate is stated in Newtons.

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