BrewCrewzz

I recently bought a 2013 Giant TCR SL 1. The bike is glorious, fast, and goes up hills easily. When I bought it the seller stated it had dura ace upgraded components from ultegra. That's mostly true. Ultegra shifters, ultegra chain, dura ace crank-front derailleur and rear derailleur. I just looked at the cassette and its a shimano 105. I believe it's all a 10-speed and seems to work well together but I can't help but think that I should upgrade the 105 cassette to at least ultegra if not dura ace. I'm still somewhat of a newbie when it comes to the different sizes/teeth/sizes of the cogs, etc. so I am looking for advice here. Should I leave the 105 as it seems to work fine or find a dura ace or ultegra cassette?
thanks
It's a dura ace 7800 for what it matters and the cassette is a cs-5700.

WhyFi

It's a wear item and the only thing to gain from upgrading is dropping some grams (possibly at the expense of longevity). Ride the 105 'til you need a new cassette. By the time you wear it out, you'll have a better idea of whether or not you want to change the gearing, too.

cb400bill

This.

datlas 

exmechanic89

Pointless to change it out. As said above, ride it until you need a replacement.

topflightpro

I concur with everyone so far.

StanSeven

deex

Seattle Forrest

Exactly this. Plus isn't a DA cassette like $300? Some people like a wider range of gears, some people like tight spacing, some people need climbing gears and some don't. Don't buy a cassette until the one you have wears out, or starts to annoy you while you ride.

69chevy

*seems to be

Cyclist0108

It may be that the 105 cassette offers different (likely lower) gearing than does the Dura Ace. I use Ultegra, but I am not at all convinced it is any better than 105, and at the rate I go through them, the 105 might make more sense.

FlashBazbo

I certainly would not go with a Dura Ace cassette. They are ungodly expensive and they do not last as long as Ultegra cassettes. There is no performance difference. 105 is perfectly fine and it would take a very sharp and knowledgeable eye to tell it from an Ultegra. If anything, the 105 cassette will last longer.

Litespud

IMO, unless you're a pro (ie, someone else is picking up the tab) and/or gram-counting is really important to you, get the lowest-grade cassette that works with your system. High-end Chorus- or Record-level cassettes for my ride can cost $200-300, or I can buy an all-steel Veloce cassette for ~$40. Completely compatible with my group, and costs me maybe an ounce of extra weight, and since it's right at the hub, it's the least consequential of rotating mass. Cassettes are wear items, so I can happily replace the cassette and a triplet of chains for half the cost of a Chorus cassette.