Fork Springs - How can I identify them?

Joined
Oct 11, 2004
Messages
46
Likes
0
#1
I have a 2001 KDX200. I am not the 1st owner.
I really like the bike. Everyone says the best mod you can do is to set up the suspension properly for you riding style and weight.

I weigh 200 pounds so what side fork springs would I need?

Secondly, how can I tell what is already in there. For all I know they may be the heavier springs. Is there a way to ID the springs?
 
Joined
May 7, 2007
Messages
57
Likes
0
#2
I've changed springs out on other bikes and so far I have not seen stampings or other labelling on the springs that would help you identify them. Some suspension shops have a strain gauge that will can measure the spring rate.

Stock the KDX's come with relativley wimpy springs. The local Kawi dealer tells me that the stock springs on my 99 220 are .32kg units. I had a cursory look around and the only folks I could find with shippable stock on aftermarket springs was Fredette Racing Products. There are links to thier site in the FAQ, and thier site has reccomendations for spring rates. I am 200 (ish) plus gear and I opted for the .40kg springs for riding in the woods.
 

blackduc98

Damn Yankees
Joined
Dec 19, 2005
Messages
193
Likes
0
#3
If you have an accurate bathroom scale (digital scale is better) then you can measure it yourself.

1) Remove the spring from the forks (obviously).

2) Get a rod which will fit inside the spring, and which is longer than the uncompressed spring. Any material will work, I used a piece of pvc pipe.

3) Stand the spring on the workbench, and slide the rod inside the spring till it stands on the workbench too. Now put a pencil mark on the rod which lines up with the top of the spring.

4) Remove the rod, and use a ruler to put a second mark some known distance from the first mark. 100 mm works well, but 50 mm will be easier to compress.

5) Slide the rod inside the spring, and stand them up on the bathroom scale. Now compress the spring (don't touch the rod) until it lines up with your 2-nd mark. Read the scale.

6) Now you know how many pounds it takes to compress your spring a known distance. Multiply that number by 0.45359237 to convert it to kilograms, and then divide by the distance between marks. For example, if your scale showed 39 kg, and your marks are 100mm apart, then your spring rate is 39kg / 100mm = 0.39 kg/mm