I've seen a lot of random posts on this, so I thought about it and I figured I’d outline the actual differences I see.

1. Shifter difference. This is the most obvious and should probably decide which grouppo you get. I personally prefer campy’s thumb shifter system. It’s great for sprints because you can shift up quickly and separating the up and down shifting is smart in my opinion. I personally also hated the shape of the old shimano levers, but the new DA 10 levers I actually like, in fact I like how they feel more than campy. But the thumb shifters still have me hooked. In any case, those are the differences between the two and it’s purely a personal thing

2. Shimano DA 10 crank. I’ve heard from people that ride it that it is noticeably stiffer. Whether or not added stiffness actually makes a performance advantage is up for debate, but one thing is for sure: stiffer feels faster, and for most people, when you feel faster, you go faster.

3. Availability of parts. This is especially a problem in the US. Shimano parts are just plain easier to find when your bike breaks in a random town the night before a race. Not so much of a difference in Europe but its still there

4. Chain. The new DA 10 chain just plain sucks in my opinion. It’s a new special super-thin width, even thinner than the campy 10 chain. It's just screaming "break me! torque me!". Now I also think the campy 10 chain sucks, I torqued mine after only 2 months, but at least you can replace it with a wipperman chain that will last a LONG time. You can’t do that with the DA 10 chain because of the special width you need to accomodate the super-close DA 10 cogs.

5. Price. Less of a difference now with DA 10 being so expensive, but in general, campy is a bit more expensive than Shimano.

6. Coolness. Campy is cooler. Admit it. Lol well actually I think the new DA 10 crank looks cool but Campy still has an Italian artistic flair. Plus it has carbon, which automatically makes it 10 times cooler. lol. Shimano is so mechanical. But this isn’t a difference like the others in the list, just me flaming lol.

My personal opinion? I’m sticking with campy cuz I like the shifting and hate the DA 10 chain. But my opinion doesn’t, or shouldn't, matter to anyone else. Anyways, I figured I’d outline the actual differences for the hell of it.

I think the availability in Europe is for both good.

debating among the two is silly IMO

some folks just can't keep their own grouppo and let the other guy have his.... talk about insecurity after purchasing, not only do they need to feel good about their won choice (which they should feel fine about) they need to try to convince the other guy that he himself made the right choice...

pick the one that fits your hands best - the rest with proper adjustment all work well enough. Not going to stop you from winning anything and certainly not going to stop you from riding.

I think they are as good as each other. The new Shimano 10 speed levers are definitely better than Campag. But, I prefer the thumbshift of the C. Also, C is cooler with the carbon. I run both. One bike with Poo-Race, another with Record. My chainset of choice is neither, I use FSA. Also have a Record cassette on both bikes (13-29). With the FSA 50-34 it gives nme a very nice low gear. Campag are introducing a compact chainset later in the year.

I love my Record although I would still be on my Dura Ace if I didn't have a problem with numbness of the hands that plagued me for several years on the bike. Just a matter of a couple of miles on the ShimaNO and my hands would go numb. I road a friends bike with Campy and my hands felt great. I switched to Campy about a year and a half ago and no numb hands since. Plus, everyone would say how that previously Shimano made sense, even though it's not rebuildable, you used to be able to buy three rear Dura Ace derailleurs for the cost of a Record rear derailleur. Now that they both cost about the same you can keep the desposable, I'll spend my money on what can be rebuilt.

Friends don't let friends ride ShimaNo!

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my bike came with 10 speed dura ace.

i sold it and bought campy record 10 speed with the carbon cranks.

i dont like the splines with the shimano setup, especially the new 10 speed spline on an old spline hub (ksyrium) they improved it for a reson but if you want the improvment you need the shimano wheels.

also i didnt like the smaller size of the new dura-ace shifters, and all this pro lance crap, i dont want my shifters smaller because hes a little guy.