Need help with my girlfriend's Dahon Ciao D5
Hi everyone. This is my first post but i've been lurking for a pretty long time. Need some help and I'm hoping someone can help me finally comprehend what i'm actually trying to accomplish. My gf and I have had folding bikes for a while and have slowly upgraded. Finally, she's settled on a Dahon Ciao D5 mostly because of the looks. This is the look of the bike she's always wanted but after some time, she's gotten stronger and wants it to go much faster. Just to set the context, I have a Dahon Vector P8 and I'm doing various upgrades and seeing this, she's becoming frustrated how slow her bike is compared to mine. Now, i've done research on gearing and it seems pretty clear to me at times but I just want to confirm, with her 5 speed sturmy archer and her tiny 38t chainring, she spins out on the 5th gear pretty easily. 1 through 3 gears are virtually useless yet she's unwilling to give up the bike, itself. Where should I start to begin upgrading the speed on her bike? Keep in mind, she doesn't want to give up the frame itself. She likes the position...she just wants a lot more top end speed and even the very steep hills seem to be something she can conquer on 2nd through 4th gears. Should I increase her chainring size and associated parts or should I think about replacing her wheels and get rid of that internal hub? A normal RD is definitely a consideration but i'm just looking to you guys--Where should I start?