Vaughters was however wary of his motives for accepting an invitation from fellow cancer survivor Geoff Thomas to join him in a charity ride .
Vaughters rode with Armstrong in the US Postal Service team in 1998 and 1999 .
Vaughters , who rode with Armstrong in the US Postal Service team in 1998 and 1999 , was however wary of his motives for accepting an invitation from fellow cancer survivor Geoff Thomas to join him in a charity ride .