slim4511

Need a little help. Not real knowledgeable so any help is appreciated.
The 2012 Cannondale Quick SL 1 has made a couple of changes from the 2011 model.
Went from Shimano R770 10/30 shifters (I believe Deore XT) to Shimano Tiagra 4600.
Also went from Shimano 105, 12-27 COGS to Tiagra 4600, 12-28.
I know the Tiagra 4600 groupset is new but are these changes downgrades from the 2011 components?

Talldog

That's a tough question. The easy answer would be to say "yes". However, Shimano has a history of trickle down technology. In plain terms the, the Tiagra of today may be better than the 105 group of last year ... and so on. It is never a good idea to obsess about component quality as long as you are at least in the middle of the "quality" range. The absolute top line stuff is more durable and a little lighter but it benefits racers the most. Most of the modern gruppos in the mid range work very well and are quite durable. In the end, there are more important things to worry about when deciding on a particular bike.

A10K

Normally I would agree with this, but in my experience there is a very large gap between even old 105 and modern Tiagra. Granted, my experience here is drawn from road bikes/STI shifters, but Tiagra components/shifting feel plastic-y and cheap; I'm comparing Tiagra 4500 here, which a few of my friends have vs 105 5500, which is the 9-speed group from the late 90's. I actually much prefer old RX100 components (which Tiagra replaced as the group beneath 105) to modern Tiagra. On the other hand, the flat bar shifters may alleviate some of these shortcomings. My experience with Deore XT is limited to their M750 series, which is great (I prefer SRAM, but that's another discussion).
On the other hand, if you don't have experience with either group, you may not have as strong a preference. The number of teeth on the cassette is the same way; it'll take a good bit of riding to determine a preference, and even then it'll probably be valid only for a specific bike/configuration. Its hard to feel 1 tooth starting out.

ALWAYS ALWAYS ALWAYS go in to the store and test ride the different options; this will help give you a sense of what is important to YOU. You might find a change of tires, or a different crankset, or a different handlebar width make your ride more or less pleasant than your drivetrain.

AdelaaR

I had never seen those Tiagra 4600 flatbar shifters before.
Apparantly Shimano want a group for the flatbar roadbikes and this is it.
I suspect it'll be comparable to the old R440 shifters but the 10 speed edition.

What Talldog said is true ... it's hard to compare old components to new ones.
Between 105 and Tiagra the main difference is weight ... you can look up the weight and compare it.