Coil spring assembly for the Marzocchi Bomber Z1 Coil fork. Use this spring to change the spring rate of your Marzocchi Bomber Z1 Coil fork to be more stiff or more soft. Or, used it in conjunction with the Z1 Coil Conversion Kit to convert your Bomber Z1 air fork to coil. Bomber Z1 Coil Recommended Spring Rate Rider Weight in lbs Recommended Spring 120-150 Purple/Soft 150-180 Blue/Medium 180-210 Green/Firm 210-250 Yellow/X-Firm