compact gearing recomendations

[Climb01742]

i'm thinking about trying a FSA compact crank, probably a 50/34. any recommendations on what a good rear cluster should be? since i've never, not even going downhill, ever used my 53-11, seems like a 12 is a good place to start, yes? how high to go, a 25? any suggestions appreciated greatly.

[JohnS]

A 34:25 would be equivalent to a 28 or 29 tooth rear with a 39. Is that enough for you?

[Bruce K]

Climb;

FSA has a small chart of roll-outs for compact gearing available on their website.

If you want a more extensive version, contact me via private e-mail and I will send you my more extensive list (too much time on my hands one day).

I just ordered those cranks and plan to use an 11-21 for everyday riding/training, an 11-25 for sligthly hilly rides, and a 12-25 for big hills and probably the Open House.

BK

[victoryfactory]

I matched up an FSA 50/34 with a 12/27 (shimano) to try to get the most climbing gears possible without resorting to a triple. It shifts great, but I think the downside with a 12/25 or 12/27 is that you don't get a 16, you just get a 15 and 17. And I have found that (in my own case) The gear I want for the flats seems to be somewhere in between the 50 and the 34, so sometimes I have to choose to work harder or less hard than I want to.

I guess I could find the right gear if I was willing to ride with the chain on more of an angle, this may just be a hangup on my part, but when I look down and see the chain at a big angle, it seems wrong, maybe I'm just stuck in the 70's when we had 5 cogs back there.

Bottom line, the FSA for octalink works great.

Victory Factory

[Climb01742]

bruce, i'll check out the FSA site. thanks.

john, so far, i've never had to go to my 39-25. not at least around here. so a 34-25 should be enough (i think/hope) for most mountains i might encounter in travels.

[flydhest]

climb,

If you've never needed anything smaller than the 39/25 why change? If you don't need a 53-12, you could get a 13-29 (assuming Campy) and you'd be golden.

Another reason to stick with what you have or swap cassettes is that larger cogs wear longer than smaller. All else equal (e.g. gear inch, speed, cadence, maintenance) a 13 will wear out faster than a 17 so if all you're doing is working your way down the cassette to smaller cogs by getting smaller rings, you might be wearing things out faster.

A small bit of insight from a fixed-gear rider.

I think smaller rings are good if you need the gearing, as it gives you the gears you need and the ability to stay with a double, etc. but sounds like you have what you need.

Bruce, I don't understand the distinction between the 11-25 for slightly hilly and 12-25 for very hilly. Did you mean 11-23? I would have thought that all that mattered much is the biggest cog.

[Bruce K]

Fly and company;

I mis-typed.

It will be a 11-23 for slightly hilly.

BK

[Climb01742]

fly,
many thanks for your comments. maybe i jumped to a solution, when there are other ways to solve my "problem". which is: i don't ride my 53 very much. my body seems to like spinning smaller gears better than pushing bigger ones. so on the flats i often find myself riding my 39-11, which is way bad, of course. i really only use my 53 on 23, 21, and 19, very rarely even my 17. so i'm looking for more big ring options. since i find so few useable 53 gearings, i tend just to stay (and abuse) my 39 by angling the chain radically too much, too often. that's why a 50 "seemed" to solve my issue. is there a better way? thanks again.
climb.

[JohnS]

I bought a Stronglight 48t for my Chorus crank. I haven't had a chance to install it yet. I had the same problem as you, I was never in the 53t.

[Climb01742]

john, why a 48, rather than, say, a 50?

[JohnS]

There's really not enough change between a 50 and a 53. You only pick up one cassette cog. With the 48t, you pick up around 1.5. Here are the approximate gear ratios:
53-12 4.42 50-12 4.17 48-12 4
53-13 4.08 50-13 3.84 48-13 3.69
53-14 3.79 50-14 3.57 48-14 3.43

[Climb01742]

john, so if a 48 is your big ring, what's your small? and what's your rear cassette? thx.

[jeffg]

Climb --

Question #1 -- Campy or Shimano?

Campy -- Due to cassette choices (i.e. nothing lower than a 25 without dropping the 12), I would be tempted to stick to a 53-39, 13-29 setup unless you need a real triple equivalent. Without modifying the cassette, you will spin out of any decent downhill in a 50-13. Considering that a 53-39, 13-29 provides a slightly lower bottom gear than a 34X25, the 16 tooth jump seems not worth it if you use a 12-25, IMHO. You get better spaced gears and an adequate top end with the normal Campy crank and can use a Phil BB.

Now, you could use the "Tyler option" and get a 52-36 w/ FSA and then a 13-29 would be great for mountains and a 12-25 would be fine for most other riding.


Shimano --

With Shimano's cassette choices a 48/34 seems a better option since you always have a 12 cog. You can steer clear of composite cranks and stick to low Q/square taper alternatives like TA, PMP, etc.

As for gearing, 11-23 is like a 12-26, 12-25 a 13-29, and 12-27 like a 13-31 for the steeps. The 52/36, 13-29 and 48/34, 12-27 provide almost identical gear ranges, so I would opt for the 14 tooth difference any time.


Good luck!


Jeff

[JohnS]

39. With Campy, you can't go any smaller. I run a 12-25 in back. Since I live in Southeast MI, I don't have to worry about spinning out on any downhills. By the way, what's a hill?

[Ozz]

Climb,

You might find this useful in your quest:

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

[Climb01742]

thanks, ozz. one thing about learning--it shows you how much you have to learn. :crap:

[Ginger]

I just found out why I'm so dang slow even when I'm spinning my brains out and why I can spin out on my road bike and mtb, but not my cyclocross bike.

Something else to think about...

[PaulE]

that give you some information on gear inches you may or may not find useful/interesting:

http://danenet.wicip.org/bcp/gearing.html

http://www.jbarrm.com/cycal/cycal.html

I think I got these from a post in the old forum.

[Peter]

Get yourself a 40-48 double setup and a 12x23.

Of course, I'm making some assumptions-I assume you don't race and I'm guessing about your fitness and the terrain.

I ride an 8 tooth difference in chainrings and it's great-here's why: I ignore the charts and possible "duplicate" gears. The 8 tooth difference, combined with any cassette setup, makes the bike a "crossover" geared bike, called that because at any point along your cassette you "cross over" to the other ring for the next gear up or down.

Crossover geared bikes have very simple shift patterns-no double shifts to reach the next highest/lowest gear. The trade off is some duplicate gear ratios but with 9/10 speeds in back that's no longer an issue.

Here's how it works: start in your lowest gear, and as you shift across your cog set, at ANY time you can choose to shift to the large ring and it will be as if you merely chose the next highest gear. Same thing when heading in the opposite direction.

To set up a crossover geared bike, merely choose your lowest gear via picking the large cog/small ring you need, then pick a large ring that goes with the smallest cog on the cassette to give you the highest gear you need.
Simple gear selection, simple shift pattern, plenty of useful gears. And the shift between the rings is smooth, as well and the change in gears from small to large as enjoyable as a shift in back.

The 48x12 is equivalent to a 52x13, and the 40x23 should get you up anything. If not, you can pick a 25 or 27 and still have a great crossover set up.

[BigMac]

I think Flydhest has your best advice. Save money and get a shorter geared rear cluster rather than a new crankset/BB.

If you were already using a very short-geared rear cluster, then the 110BCD setup makes sense rather than resorting to a triple with all of its associated compromises. I personally do not like the 50/34 combo, for most setups a 48/34 or 50/36 generally results in more evenly spaced ratios with fewer duplicates. I would suggest you run a gear-inch chart on all 18 or 20 available ratios to determine the best spacing and fewest overlapping ratios.

Ride on!

[Bruce K]

Leanard Zinn has just responded to a question about compact cranks and gearing in Velonews.com

In his answer he posted a very nice/easy to read gear chart.

BK

[MallyG]

I'm really interested in this thread because I have signed up to ride L'Etape this year and have been thinking hard about gearing. I am reluctant to change to a triple (I currently use Campag Record 10 speed) because the cost to alter everything for one day is huge. My bike shop suggested the FSA compact (either 50 or 48 large ring) with a 13/27 or 29 rear cassette. Looking at the distance I'm going to be covering (150 miles) as well as the climbs, I reckon a 53 may waste my legs. What do you think?

[jeffg]

Originally posted by MallyG
I'm really interested in this thread because I have signed up to ride L'Etape this year and have been thinking hard about gearing. I am reluctant to change to a triple (I currently use Campag Record 10 speed) because the cost to alter everything for one day is huge. My bike shop suggested the FSA compact (either 50 or 48 large ring) with a 13/27 or 29 rear cassette. Looking at the distance I'm going to be covering (150 miles) as well as the climbs, I reckon a 53 may waste my legs. What do you think?


Mally --

This may seem crazy, but think about descents as well. I remember flying down the Dolomites on the last section of the Dolomite Marathon and spinning the 53X12 at 100-110 the whole way down once the hairpins on the Valparola gave way to some wide open downhill. It would have been a bummer to spin out. I try to keep at least a 52X13 equivalent at the ready. A 48-12 works just fine here. That being said, the 34X27 or 39X29 is more important than the 12 cog. Taking the Giau in a 39X27 after 10,000 feet of climbing taught me that (50-55 rpm for an hour).

So, what about a 48/34 with a custom 12-29 rear cluster? If a standard double with a 13-29 won't cut it, here's my suggestion: For one day, get a Centaur 13-29 cassette, drop 13, 16 cogs and add first position 12 and 2nd position 13. Get a TA or PMP alloy crank with 48/34 TA Syrius rings amd voila! A 52X13 equivalent for going down, a 30-26 (ok, a 25.5) for going up, and plenty of well spaced gears in between with little to no overlap. You might just decide to keep that crank on and use a 12-25 back in the UK!

best,

Jeff

[Climb01742]

jeff, whenever i read a post like yours, or one from bigmac, or 11.4's on track bikes, or a host of others, all i can think is, whoa, i'm such a newbie. dang, there are some darn smart, experienced riders here. thanks for sharing your knowledge, and what i lack in quality posts, i endeavor to make up for in sheer quantity. :p

[jeffg]

Originally posted by Climb01742
jeff, whenever i read a post like yours, or one from bigmac, or 11.4's on track bikes, or a host of others, all i can think is, whoa, i'm such a newbie. dang, there are some darn smart, experienced riders here. thanks for sharing your knowledge, and what i lack in quality posts, i endeavor to make up for in sheer quantity. :p

but I am no BigMac, Climb! Thanks for the kind words, though. I am just hoping he doesn't stomp my candy-East coast-resident self too badly this spring out in CA. I find if you just pay attention on this board then lots of tidbits come your way that the Conventional Wisdom out there tends to disregard or simply be ignorant of. For instance, I couldn't help chuckling when Velonews referred to a 110 BCD crank as an "innovation" just about a year ago. Glad I have the Serotta-board folks to set me straight! :D

best,

Jeff

[MallyG]

Jeff
Thanks for the post. I'm going to print it out and take it into my bike shop. Of course, I will give you full credit for your wisdom.

[Too Tall]

If anyone has a line on an FSA 175 compact ISIS tell me! That's what I've promised Mrs. Too Tall. Apparently this is a popular item as it is not to be had.

[Oaklandhills]

All,

I was about to start a similar post. I am not as familiar as you all about gearing, but I have some of the same issues. I just went from a bike with a 12-25 to one with a 11-23 and it seems considerably tougher on the bigger hills. I belive the chain rings are the same size. Am I reading this correctly that the 12-25 is better for hilly areas?

I understnad "hills" are based on ones ability, but what is generally considered a bigger hill - 8%+ or in the 11% + range?

Thanks

[Bruce K]

Too Tall;

A couple of weeks ago, the Isis drive FSA comapcts were on sale all over the place. We beat it to death on the forum but could only guess it was overstock.

I think it was Alfred E Bike that had the best price out there at the time.

There seems to be a shortage of the Octalink compacts at the moment. My LBS is having trouble locating a set of 172.5's for me.

Oakland - the higher the number of teeth on the rear cassette the easier the climbing will be - or the lower the number of teeth on the chainrings = same deal.

BK

[Climb01742]

oakland--also consider cadence. there are two very distinct climbing styles: spinning high revs (see lance) or pushing big gears slowly (see jan). your gearing should reflect your style.

[JohnS]

OaklandHills,
If you have a standard double on the front, the only difference in climbing would be if you climb in your biggest cog in the rear.