Worth checking your wheel bearings are ok first then invest in something like
http://www.ebay.co.uk/itm/Quality-0-10mm-Dial-Test-Indicator-DTI-Gauge-Magnetic-Base-Stand-Clock-Gauge/141324088660?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20141212152715%26meid%3Dfc32812b07e34b4d9c7d69d9949d1ac4%26pid%3D100338%26rk%3D2%26rkt%3D29%26mehot%3Dpp%26sd%3D221394427355
http://www.ebay.co.uk/itm/Quality-0-10mm-Dial-Test-Indicator-DTI-Gauge-Magnetic-Base-Stand-Clock-Gauge/141324088660?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20141212152715%26meid%3Dfc32812b07e34b4d9c7d69d9949d1ac4%26pid%3D100338%26rk%3D2%26rkt%3D29%26mehot%3Dpp%26sd%3D221394427355