ORIGINAL: VENOMOUS Yes no problem use a 2S 7.4V pack and as soon as you detect it slowing down pull it off and change/charge the pack.
Glad you put that, I just shoved a Lipo on and forgot whether I should have checked about it first!
Oh, didn't forget sboti74, couldn't find a video showing me what I was trying to explain, then a certain Edi from Austria posted this today. It's a 1/5 bike but still applies, showing how much the forks of a bike move even when leaned over in a corner.
http://www.youtube.com/watch?v=wOJWB_kILk0