compact crank, gear compatability (noob)
 

My question is I got a Rival comapact crank; 50/34T and a Shimano Ultegra 12-25T cassette. (as i have heard many times that shimano cassettes are a little more quiet.) Is this setup good? did i lose too much top end or with my gearing did i completely negate my compact? i researched to compact part but i guess i just trusted the guy at the bikeshop to know what cassette would go well with it.
i do climb alot though and i want to make sure that my cassette compliments my Compact crank. thank you for your time and patience.

No way to answer that question. Put it on your bike and try it out. I use 11-23 with my compact crank.

11-23 is the one i see most commonly. i just wanted to make sure that my 12-25 is good. i know there are some gear heads out there.

You probably made the best choice.

Al

This takes some simple math to analyze. Your 50/12 is a bit higher gear than a 53/13, so you've lost most of the top gear that a lot of bikes have. The lowest gear is just abit higher than a 39/29, so you've got more low gear than a typical 39/27.

12/50 x 53 = 12.7

25/34 x 39 = 28.7

Using a 50/34 with an 11-23 doesn't do a thing for the gearing range, compared to a 53/39 with a 12-27, but it does reduce the big cog jumps at 21-24-27.

So essentially with the setup that I have, I lost a little top end speed but I did gain a little extra for climbing. Since I wont be sprinting for stage wins I'm sure I wont miss the top end.

Thanks DaveSSS and Al1943 for your input.

^ Correct.

Should you feel the need to change anything in the future, this is a great resource.

http://www.sheldonbrown.com/gears/