For the time being you can use the following workaround:

        <script>
            var pointerSize = 35;

            function pageLoad() {
                var gauge = $find("<%=rgEpmScorecard.ClientID%>");
                gauge._gaugeObject.options.scale.rangeSize = 25;
                gauge.repaint();
            }

        </script>
        <telerik:RadRadialGauge ID="rgEpmScorecard" runat="server" Skin="Metro" Height="99px" Width="100px">
            <Pointer Value="50" Color="Black">
                <Cap Size="0.5" Color="Black" />
            </Pointer>
            <Scale MajorUnit="10" Max="100" Labels-Visible="false" StartAngle="-45" EndAngle="225">
                <MajorTicks Visible="false" />
                <MinorTicks Visible="false" />
                <Ranges>
                    <telerik:GaugeRange Color="#ac1d23" From="0" To="16.67" />
                    <telerik:GaugeRange Color="#c26522" From="16.7" To="33.33" />
                    <telerik:GaugeRange Color="#d2b408" From="33.5" To="50" />
                    <telerik:GaugeRange Color="#b5be25" From="50.04" To="66.66" />
                    <telerik:GaugeRange Color="#0c833f" From="66.8" To="83.33" />
                    <telerik:GaugeRange Color="#0b6cb3" From="83.38" To="100" />
                </Ranges>
            </Scale>
        </telerik:RadRadialGauge>
        <script>

            var dataviz = kendo.dataviz,
                draw = dataviz.drawing,
                Path = draw.Path,
                DEFAULT_LINE_WIDTH = 0.5;

            kendo.dataviz.RadialPointer.fn._renderNeedle = function () {
                var that = this;
                var options = that.options;
                var minorTickSize = that.scale.options.minorTicks.size;
                var center = that.center;
                var needleColor = options.color;

                var needlePath = new Path({
                    fill: { color: needleColor },
                    stroke: { color: needleColor, width: DEFAULT_LINE_WIDTH }
                });

                needlePath.moveTo(center.x + that.radius - minorTickSize + pointerSize, center.y)
                          .lineTo(center.x, center.y - (that.capSize / 2))
                          .lineTo(center.x, center.y + (that.capSize / 2))
                          .close();

                return needlePath;
            }
        </script>