Sapience

Would a standard or compact crank be more appropriate for a 5'4 rider? Or does it not matter? The only con I know of for compact cranks is that the top-end speed is lower than standard cranks, but honestly, how many people (especially shorter people) can maintain a top-end speed that a compact crank can't reach? And, what would the optimum cassette choice be (if I run a 34x50 crank, 11x?? casette?)?

Flatballer

oh boy, we haven't discussed this in at least two days.

dauphin

Your height is irrelevant. If you have a 50 chain ring already then nothing changes unless you switch from say a 12-27 to an 11-28...but the difference is hard to detect for most people. Cassette choice is totally dependent on your ability, condition, and the terrain you normally ride on.

kimconyc

Needing/wanting a compact crank has nothing to do with your height.

Cassette gearing depends on your fitness level, terrain you ride in, and whether or not you like to spin at a higher cadence on a lower gear to get the same speed you would by spinning slower on a higher gear.

For reference, I have 2 bikes with standard gearing (53x39) and the following cassettes (11-25 and 11-23). I also have a bike that I specifically built for climbing that uses a 50x34 crank and 11-25 cassette.

"Fred"

I love my compact with a 12-24.

Sapience

Reasoned I mentioned height is because my weight will be significantly lower than the average cyclist, so I didn't know if it would be easier to push the weight with a compact crank rather than a standard crank. I'm fairly new to cycling and really have no clue how to find out which I actually want?

daxr

You'd be fairly safe to get a compact then. Its nothing to do with height or weight, but you probably won't miss the 3 or 4 mph you give up on the top end of a descent or a sprint.

jbhowat

Yeah, because that couple-mph difference occurs in the 40mph range. As much as people would like to believe it, very very very few people on BF could hit 42mph in a sprint after a race. Even fewer would have any reason to have the gearing to hit 45.

MrMojoJoJo

I agree. I just switched to a Dura-Ace Compact and the only thing I noticed is that I will spin out the crank at about 40mph the down hills.

RoboCheme

I'd go with a compact. If you'll be riding in the hills a lot, get a 12-27 or a 11-28.

oldbobcat

I'm a fairly large rider and I could never utlilize a 53/11 unless I was going downhill with a stiff wind at my back. The 50/11 that I used on my Felt, just like the 53/12 I currently use, only come into play when I'm traveling at least 32 mph, and they are pretty much spun out at about 39. Any faster than that and I'm usually coasting through corners. Remember that in the 1980s very few pros ran anything higher than a 53/13. Claude Criquelion escaped from the peloton in one Belgian classic because he knew the route and took advantage of a stiff tailwind and a 12-tooth cog that he machined himself.

If you're strong an 11-23 cassette should get you up just about anything. If you want to fine-tune the system get an 11-21 for flat days or an 11-25 for long or especially steep, long mountain days.

Bah Humbug

Same here (though I'm weaker than many here). My high gear is 50x12, and frankly, on the downhills that I can spin that out on (probably a lower cadence than what others would consider "spun out") I'm better served focusing on steering and preparing for the following climb. Having the gearing to push a bit faster on those few big downhills is not important to me.

umd

There are things called downhills...

jmpsmash

compact. i am not worthy of a standard.

rollin

If you can max out a compact, even downhill, you probably don't need a compact

scirocco

No it isn't. 50x11 is higher than 53x12. Of course you can trump everything with a 53x11, but why would you bother?

RoboChrist

Topography is the biggest factor in what you should be using.

Bah Humbug

Yes, but not everyone feels the need to have gearing that allows them to lay down the power at top speed on a downhill. I'm not saying people who want to shouldn't, mind you, but people who aren't racing might prefer gearing that's optimized for the majority of their rides that aren't high-speed downhills. I know that on my 2-3 hour rides, I spend less than a minute unable to put power down in top gear. I'll live with that for gearing that works for the rest of my ride.

Sapience

I guess another question relating to cranks is does crank arm length matter too much? My inseam is 29in so I'm apparently supposed to be using a 155mm crank, but most cranks don't go that low (165mm or 170mm is the lowest for most I'm finding)

carpediemracing 

I wear 30" jeans, have closer to a 29" inseam (28.x?), and ride, depending on the upcoming ride/event/s.

170s for track or flatter summer races. Best for top speed, some sacrifice on rolling gears up hills.

175s for uphill finishes or more hilly terrain (typically winter training camp type stuff). Sacrifice top speed and suppleness for more power on short climbs (under 400 meter). Longer ones don't matter.

I last used 167.5s about 14 years ago, then went to 170s. I tried 165s, got dropped pretty quickly using them.

I tend to spin but can push when it's necessary.

Big gears help if you have lots of downhills. I spin out a 53x12 in the tame CT hills. 53x11 is nice, you can still pedal at a reasonable rate on faster sections of a ride. Big gears also help when moving up in a group, or when responding to other riders' attacks and such.

True, it's "possible" to turn smaller gears over, but why spin like mad? Would you drive in 3rd gear on the highway if you could cruise in 5th? It's good to have a flexible rpm range but I find it less than ideal if I have to spin up to 120-140 rpm all the time because of gear limitations.

Compact only refers to bolt circle diameter (BCD). Ritchey sold, for a long time (10 years?) a 110 mm BCD crank that came with 53x39 rings. BCD limits the minimum chainring size, but it doesn't necessarily limit the maximum chainring size.

A 110 mm BCD allows you to use a 34T ring. A 130 mm BCD (standard Shimano road BCD) limits you to 38T, a 135 mm (Campy) to 39T. Minimums, all of them. You can get enormous rings for all of them (biggest I've seen stocked is a 59T 144 mm, old Campy).

Use what feels right for you. If you don't know, ride what you have and then see if you can't swap or borrow stuff from other riders. Inevitably there will be those that have experimented and have a few cranks (or whatever - brakes, derailleurs, etc) laying around.

hope this helps,
cdr

roadiejorge 

Good post. I have a two bikes: one standard with a 170mm crank, the other a compact with 172.5mm crank and I find that I like the shorter crank as I spin more comfortably. Having the compact is nice for the hills but being that we don't have anything massive around these parts I've been contemplating switching and replicating the set up on my other bike.

bretgross

+1!

umd

These discussions are always so silly. Yeah, use the gearing that works for you. I would never try to convince somebody to use a particular kind of gearing, and I find it funny when others do. I'm just pointing out that there is a time to use a high gear other than in a sprint.

Basil Moss

I use a 12-23 cassette with a 42 and a 53 chainring. I have 175mm cranks, and race mostly in the UK Eastern region- all very flat. I put a 12-25 cassette on for the hilliest races, and used a 39 chainring in the Ras de Cymru. Wales has more hills than Cambridge! Generally I find the gap from 53 to 39 way too big, can't imagine what it's like from a 50 to a 34.

I do think compact is maybe too often reccomended to new riders- I see a lot on our clubruns, never using the small ring, cross chaining and ruining their shiny new DA chains. If you are a casual rider in a very hilly area, by all means use it, but if you live somewhere flat, why bother?

BikerPoe

I was just wondering the difference. Now, I have no idea about the gears. Or anything about them. At least I kinda know about compacts.

Thanks!