Yes. Someone has already gone through of work of doing this very thing by extending the gauge series: http://www.sencha.com/forum/showthread.php?159879-KPI-Gauge
There is a .zip you can download and add to your library. Then you can essentially just do:
{
xtype: 'chart',
style: 'background:#fff',
animate: {
easing: 'elasticIn',
duration: 1000
},
store: store1,
insetPadding: 50,
flex: 1,
axes: [{
type: 'kpigauge',
position: 'left',
minimum: 0,
maximum: 100,
steps: 10,
margin: 0,
label: {
fill: '#333',
font: '12px Heveltica, sans-serif'
}
}],
series: [{
type: 'kpigauge',
field: 'data1',
needle: {
width: 2,
pivotFill: '#000',
pivotRadius: 5
},
ranges: [{
from: 0,
to: 70,
color: '#FF0000'
}, {
from: 70,
to: 90,
color: '#FFFF00'
}, {
from: 90,
to: 100,
color: '#00FF00'
}],
donut: 70
}]