New Rear Shock Spring - KDX220

I weigh 220lbs without gear.

What rate and brand shock spring should I be replacing my OEM shock spring on my KDX220?

What other internal changes could also be made within the shock itself to better suit handling and also to complement my kx250f front end?


I weigh 210lbs, and went with Race Tech's recommendation of a 5.2kg/mm. Stock is 5.0kg/mm, and you wouldn't think .2kg/mm could make such a difference, but it does. To get 3.25" of race sag, the adjuster collar is a full 1/2" higher on the threads than it was at 3.50" with the stock spring. Haven't checked the free sag yet, but since I'm running it 1/4" or so higher in the stroke than normally recommended, I figure it will be a little short.

Shock internals are just good condition stock. You could Gold Valve it I guess, but I'm finding with a little adjustment of the clickers, the stock valving is working very well.

The ride if I'm setting is almost MX harsh on both ends, but standing, it's smooth as silk, and tracks perfectly straight through all normal hack. Big hits aren't big anymore, and it jumps/lands (within reason, it's still not an '11 KX250F) like a dream. I'm lovin' it.

Go to Race Tech's site ( and see what they say for you.:thumbsup:

Edit: I see the MX Tech site David_L6 posted recommends the same fork & shock springs for me as Race Tech does (same price too). Looks like the common theory, go with whichever company you like the looks of best.:blah:

You may want to look at a 5.2, 5.3 or 5.4 rate spring. Try a new (correct for your weight) shock spring before doing anything to the shock internally. Since you have been riding on a too soft spring this whole time, every idea you have about improvement is based on poor information from using the wrong spring.

Shoot for 100mm of sag on a KDX, then check the bike's static sag.

Mnay thanks.

I di dthe online test at mx-tech and it comes out at 5.4 rate spring.

THis bike is going to be great when finished :-)


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