You have several options. If you are mostly concerned with the spikes leaving marks on the floor you can place something under the spikes. A coin is fine, a knockout from an AC box, a piece of metal shim or some companies sell specific "footers" to go under spikes. You can also use a T-nut (the item which has teeth to grab into wood and threads inside). You place the T-nut on the floor facing up and the spike sits in the threaded portion of the T-nut. Buy a small T- nut that will allow the spike to reach not quite to the floor. Any of these devices should be PlastiTak'd to the floor for security. (You can buy PlastiTak at The Container Store or use photo mounting plastic from an office supply store. Both are essentially the same as BluTak but less expensive and easier to find. BluTak can be purchased from Audio Advisors.) If you want to avoid spikes all together you can use ball bearings. Since the ball bearing is round the contact with the floor will be along its tangent and will provide the same type of mass loading that a spike does. These can be PlatiTak'd to the speaker if you do not plan to move the speaker. You can find metal and nylon ball bearings mounted in a captured housing which will allow you to move the speakers without marring the floor. I use a hard nylon ball that I found in an auto supply house. It was threaded to accept a piece of all-thread with the same thread pattern as the spikes. A few nuts to secure the two pieces together and the speaker is loaded to the floor but I can slide it out of the way on my hardwoods and not mark the floor. These nylon balls were meant to be replacement knobs on generic automobiles. Depending on the size you want they will run a few dollars each. Take one of your spikes with you to check the threads.