compact crank?
 

hey everyone. im in the process of doing a triple to double switch and had some questions on the compact cranks. right now i have a 30/42/52 - 12/26 set-up which im very comfortable with and im trying to decide if a 30/50 is the right choice. there were instances during downhill runs that i would be maxing out at over 100 cadence in my 50/12 rings. im just worried that a 30/50 wont be enough. i should mention that im tackling this with very limited experience but i love taking things apart and am excited about the build-up. any advice is appreciated. thanks for looking. cheers.

You could always put an 11-23 cassette on the rear to give you some higher gearing. I have a 50/34 compact double, and there have only been a few times where I would have liked higher gears, so overall I've been happy with it.

I don't really think anybody makes a 50/30 compact double. I could be wrong, but I think the 110 bolt circle diameter is too small for a 30 tooth cog. I believe that 34 is the smallest that compact doubles go. A 34/26 gearing is pretty good, unless you're constantly using your 30 chainring right now.

^^^agree the 11-23 on a triple is nice...and if I were you I would do this first. If you don't like it then you have the 11-23 for the compact....

http://www.bikeforums.net/showthread.php?t=123238 for info....

...p.s. do what you will but you going to get some slack from some BFs here b/c:

1. Your looking for a 30/50 ring set. Most CC are 34/50 or 36/50 and are run with an 11-23 or 25. So the CC is set for those who want a lower gear but most of the time not as low as your talking here...for the low gear that your talking about the set up you have has got what you want.
2. 50/11 > 52/12 so don't stress about spin out...
3. your talking about gears...

I don't think anyone make a front D that would do a 20t jump.

http://www.sheldonbrown.com/harris/french-cranks.html

50/28...


:eek: :eek: :eek: :eek: :eek:

I stand corrected. However, I think Sheldon and Harris should make an 87/11 UltraMegaCompact...

Hell, just put a 10-speed cogset on the front crank. 100 gears!

I just dropped off my jalopy to have a Gossamer compact installed in time for the Solvang ride next weekend. I'll be the first to admit I have no use for a 50x11. While I was there I saw a carbon K-Force MegaEXO. That was some nice eye candy.

To add to the confusion.....how about a trekking/touring crankset 48/36/26 with a straight block 11-21 cogset....:D
Actually, that would be my ideal triple setup as I have absolutely no use for a 52 or 53 big ring.....I think... :)

what**********? [ggg300 = confused] touring crank on road bike!!! :p

nice ride....have you done it before?

Nope, first time. I'm only doing 50. I haven't ridden much since I moved here but I wanted to do this ride even when I lived in Atlanta.

Actually, if you think about it, a typical touring crankset (or most older mtb crankset) uses 110 BCD cranks.......get rid of the granny ring and you essentially end up with a compact double....:D

I'd advise plotting all of the gear inches and thinking through your shifting pattern first.

A loooong time ago I built a triple with a 14/18 straight block. There weren't any duplicated gears so you'd run through the entire rear block in one chainring then make a big double shift and do it all over again. The problem had to do with where you happened to be when it came time for the double shift. Downhills weren't too bad but you'd lose all of your momentum trying to make that shift on an uphill.

Actually the 50/28 crank shown doesn't have the 110bcd of the typical compact cranks today.
About 2/3rds of the way down the page of the URL you posted, a table shows the BCD and smallest chainring that will fit that bolt pattern.

50/11 is over 36mph at 100 rpm. Unless your David Zabriskie with tailwind that's plenty of gear.

like i said, i was going down hill so it was over 30 mph ;) . anyway, i bid on a fsa carbon pro team issue with bb and won! im really excited as my previous truativ triple flexed a lot. the rings are 53/39 so we'll see how that works out. plus ill be doing some triathlons this summer so the bigger ring may help. cheers.

http://secure15.nexternal.com/repart...eam-issue1.gif

I have a 50-34 and 11-23. And I accelerated past 33 MPH by pedaling. So yeah, it's good.

yup...that crank is not a typical CC...the typical CC 110bcd can only get down to 33t...and the 50/28 is really set up as a single ring with a small range to bail out on as that crank was matched with a short bb...