Snap and SK are right.

I've been a coach for TNT since 2001, and have been involved w/the Leukemia/Lymphoma society in various roles since 1999. They figure the fundraising minimum by taking your expenses (hotel, airfare, event entry, costs for supported rides for X number of months), and multiply it by 4 to get the fundraising minimum amount. That way they guarantee that at least 75% of the money raised goes to leukemia research and patient services. Generally, the % is more because people actually raise well over the minimum.

Events like the AIDS ride and MS rides (which I am doing in 2 weeks), will often have lower $ minimums. The MS rides do not offer any coaching, there's no real sense of "team" besides what you bring to it with your friends (not to be underestimated ) and the organization leaves a lot to be desired in some ways, but of course the cause is good so I am wholeheartedly excited about my upcoming event. I know some events do not have a guaranteed percentage that goes to the cause. Historically, TNT's 75+% is the highest of any of these sorts of venture, just because they insist on a high amount.

So you can certainly be confident that the $ you raise will be going to a good cause - and I hope you have a wonderful time in the process!