General Cycling Discussion - Building my first bike, Compact or Full Size crank?

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kman79
07-24-09, 10:11 AM
Hello,

Definitely new to the cycling world. Main intention for picking up cycling is to loose some weight and go on rides with my brother in law.

I saw the FC-R700 at a decent price and jumped on it, the Ultegra FC-6600 was a hundred dollars more at the cheapest price I saw. The Cassette i bought was the CS-6600 12-25.

I live in the Houston/Richmond Area, so there aren't many hills or inclines, if any! Would the Compact Crank plus the CS-6600 @12-25 be too short in gearing for flat riding? Should I return the compact and purchase the FC-6600?

Any help an input on this is greatly appreciated


Pat
07-24-09, 11:04 AM
It depends on your cadence (rpm) and how fast you ride and how strong you are. I think compact cranks have a 50 tooth big ring. A big ring that is that size will have 112 chain inches using the 12 tooth cog. At 100 rpm, that gear will push you down the road at 33 mph. Now some people have low cadences like 80 rpm in which case that gear would be more like a 25 mph gear.

It sounds like you are just starting out. Most people starting out have low cadences of 80 rpm or even slower. The good thing is that new riders are not strong enough to ride fast enough to be limited by their gearing. Most people starting out cruise at about 14 mph and in a burst might reach the twenties.

The added benefit of compact gearing is that it will give you lower gears for hills and that is always a good thing.

A comment on speed. Eddie Merckx was the first rider to average 30 mph for an hour. That was a really big deal when he did it. Thirty miles per hour is really moving on a bike when you are solo. If you were to take up racing, you can hit into the high thirties on the flats in a group but that is not your stated intention.

I think the compact gearing will do fine.

Hask12
07-24-09, 12:16 PM
No hills? Compact.


scattered73
07-24-09, 12:50 PM
I live in the houston area also and to be honest I have found neither perfect for me. 34/50 the 34 was just to small the 50 was ok. On the 39/53 the 53 was really over kill but the 39 was ok. So I recently put on a 36/46 and that really seems to be the sweet spot for me though I am running it with an 11-23 cassette. It is really rare that I go faster than 30+ mph in houston or surronding areas. I have also run cross specific cranks 38/48 which also love. If I lived in a hillier area I might fill different about my gearing though.

stapfam
07-24-09, 01:47 PM
On the flat and 50/36 will be fine. If you find the 50 is not big enough- go to a cassette with an 11t on it.

I am not a speed merchant- just prefer to get in milage and hills. I did have a 52 on one bike and found it just a bit too tall for me.Did most of my riding in the 42- so went compact with 50/34 and this is just right for me and my hills.

But You may find different.

Little Darwin
07-24-09, 02:44 PM
The typical rider might never need more than a 50 tooth chain ring.

A 52 or 53 might be useful for going very fast down hill, but unless you are racing, once you reach maximum speed on a 50 tooth, just coast, get into an aero position and let gravity do the work. ;)

clutchy
07-24-09, 06:41 PM
I started on a standard 53/39 12-25 and did all kinds of climbing with it and centuries and all that jazz. I just recently got a compact 50/34 and i love it. It makes going up hills so much more fun. I can keep my cadence up and i have more power. However i live the socal foothills so.... i wouldn't get a compact in houston.

I have family there and i don't know if i'd even be brave enough to ride out there. :(