This is my first post on BikeForums. Thanks in advance for any help you can offer.

When trying to shift to my big chainring, my chain spins endlessly on the small chainring, trying to ramp up, but rarely ever catching.

I have:

FSA Gossamer MegaEXO, External Bearing Bottom Bracket, CNC'D 36/46T Chainrings, 110BCD
SRAM Rival Front Derailleur
SRAM Rival, 10-speed Shifters
KMC DX-10SC, 10 Speed chain

These components all came standard on my bike which I purchased ~6 months ago - a complete list of my bike's specs can be found here: http://www.bikesdirect.com/products/..._pro_rival.htm

I took it to my LBS today and they tried tweaking it for 45 minutes, adjusting the height of the front derailleur, fiddling with the limit screws, making sure the ft derailleur cage was parallel, with me taking it out for test spins in between each adjustment. Occasionally, it catches the big ring, but usually only going down hills. But even this doesn't always prove to work either.

Sadly, it was working fine yesterday before I brought it in. Today, I brought it in for other adjustments & the LBS cleaned & lubed my drivetrain - now it won't catch the big ring at all. Can lube cause this problem?

Incidentally, I've been suspect of the front derailleur since purchasing my bike as it's always been a bit shifty (excuse the pun) - yet it almost self-fixes itself most times which is why I've blown it off until now.

LBS mechanic said the derailleur is perfectly adjusted - he has the same SRAM Rival and his has never caused any problems.

As absurd as these theories might sound...

1. LBS mechanic could only surmise that possibly I need new chainrings as it appears that my chain simply is not catching the ramps to switch up to the big ring. Is this plausible? I really don't want to spend money on new chainrings & a new chain, only to find out this wasn't the problem afterall.

2. The two times we've lubed the chain (I know, I should be more diligent with lubing), it has sent the shifting into a frenzy. One day, after I rode bike in the rain, I lubed it up & the chain started popping off every time I tried shifting up. The next day, I rode 38 miles & I was able to shift flawlessly.

Please help! I have a 25 mile charity ride through a real hilly community tomorrow morning so it would suck to not have both rings available.

Thanks!
dB