102mm cranks on a 29er...good idea?

[Rubix]

OK, I had 127mm cranks on my 29er. The left one went kaput, so I decided to go a size smaller. I ordered some 102mm cranks. Looking at them side by side, there doesn't seem to be much of a size difference. I mean, how much can 1 inch throw it off? Well, come to find out, ALOT!!!

I got them put on thru the LBS. Got home, aired up the tire, and tried unsuccessfully 4 times to do a static mount. Normally, on my old cranks, I'd nail it each time. Not so much with these. First thing I noticed, leverage. Or should I say, the lack there of. When I would get up and in the neutral position to start going, there wasn't much to get me going, takes a little more umphf to get going. I rode down the street and back, and it felt a little wobbly, but fast. I came in for a stop, tried my usual maneuver, but the uni wanted to keep moving forward. I hop off, and the uni keeps going for about 15 ft. Hmmm, seems like all I've learned with my 127s is now out the door. I'm not sure if or when I will tackle a hill or two with this thing, how it will perform.

Now, was it worth it for me to move down a size to 102? Or should I have kept it at 127? I know it will take me a bit to relearn mounting and stopping with the 102, I just wanted to progress to the next step.