Originally Posted by HillRider

The reason for the spacer above the steerer is to assure the stem is completely supported by the steerer with no overhang. That spacer serves no structural purpose so you could use a 1-1/8" spacer if you wish. You will want to keep it centered as you adjust the headset preload but after the stem clamp bolts are torqued properly it won't matter. If it shifts around while riding you could use a thin shim to keep it centered.