This year's event aims to raise funds for Think, the head injury network for Kiwis, with McCauley its flagship rider.
"I competed in this event back in 1991 and 1992 when it was the NZ Post Challenge and finished last both times," McCauley reflected yesterday.
"I was asked to step in for Think this year after their original fundraising guy was injured and I was more than happy to do it. I felt great on the ride today winning stage 5 this morning and then was happy just to keep the other guys in my sight in stage 6. I didn't need to do much today and have still got the yellow jersey," McCauley said yesterday.
The competitor list includes two from Wanganui, David Luff racing in the 60-69 age group in group one and David Collins in the 40-49 age group in group two. They were both racing well.
The field also includes Beryl Billington from Cambridge who celebrated her 69th birthday on Monday.
Think spokeswoman Elizabeth Charleston said it was great to have someone of McCauley's stature on board, although nine or 10 other riders were also helping to raise funds through sponsorship.
Stage 7 began this morning from the velodrome in staggered starts to Kakatahi, while stage 8 sets off in the afternoon to Ohakune via Fields Track.
On this leg former Kiwi Olympian Stephen Cox has dusted off his bike after 20-odd years to help raise funds. Part of that fundraising exercise will include having his legs shaved for charity.
Charleston said funds raised so far were nearing the $10,000 mark and a fundraising evening was planned in Ohakune tonight.
The Challenge ends with stage 13 between Glen Murray and Pukekohe on Saturday afternoon.