When should one choose a compact crank?
At what level should you steer clear of the normal 53/39 gig? I’m just wondering if I should swap it out for a compact. Would it benefit my cycling?
I’m not the strongest cyclist around, averaging 19~20mph (+/-) on my training rides.
From what I can tell, compact cranks make sense if you live in a very hilly area, you race on hilly terrain frequently and you ride for the most part on your own or with one or two others and don’t do much drafting. If this is what you do then a compact crank set up makes sense. More gear options in the mid to low end of the range which is where you will be riding most of the time.
if you ride a lot of varied terrain and you have difficulty maintaining a consistent cadence …
if you find yourself on the inner half of the cluster (larger cogs) most of the time when you’re in the big ring …
if you only use the big ring/small cog combo on the occasional fast downhill …
if you run out of gears and your cadence slows on climbing …
…these would all be good reasons to try a compact set-up.
I’m not the strongest cyclist around, averaging 19~20mph (+/-) on my training rides.
Go compact. Or, maybe just replace your outer 53 with a 50 (or even 48) ring. If you ride mostly flat terrain, you probably don’t need a 34 or 36 inner ring, so you can save some cash by only changing the outer ring instead of the whole BB/crankset.
FWIW, I ride pancake-flat terrain & trained and raced IMFL using a 48T outer ring on a 12-23 cassette - worked out perfectly. I averaged just under 20mph at the time as well.
I definitely recognize myself on some of these points.
I do most (all) of my biking alone.
I do stay in bigring medium cog alot on the flats, and use small cog primarily on downhill.
There are “couple” of mountains. But everyones cadence drops when the gradient is 10%.
I’ll probably pick one up and try it out, maybe a q-ring 
Go compact for triathlon and here is why
Triathlon is not the same as TTing and certainly not the same as road racing, so why use the same gears. For road racing you need big gears to make, counter and keep up with the attacks and high speeds. Time trialing is a single event where a cyclist is giving 100% of his effort to complete a course as fast as possible. So he is going to “attack” hills, sprint to the finish and not worry about saving anything at the end. Not that you need to be told this but in a triathlon you gotta run after the bike. So do you really want to sprint and attack and worry about a fast top end, I say no. You want an even consistent effort across the entire race. Now some will argue “well Macca uses, or Norman rides” but most people on here arent a pro, so why are you trying to ride the same gears. If you run a 50/34 with a 11-23 or even a 12-23 you will see that you are still able to achieve high speeds going down hill, but when you are on flat terrain you are able to ride in the big ring, at the small end of your cassette, but still have plenty of low end gears for a hill allowing you to maintain a good cadence. I think Dan addressed this in an article a few years ago, talking about how Tri bikes should be specd with compact cranks…if you think about it, it makes sense.
Another question to ask is are you a spinner or a grinder ?
If you spin at high cadences (90+rpm) then consider a compact for all but the flattest of courses.
I have a 50/34 and a choice of cassettes 11-23 and 12-27
i recently got one to make climbing more efficient. also, i was mashing on flats, and didn’t want to continue to that, as it’s not ideal for endurance.
as a result, i climb a hell of alot better, my bike is lighter, and have a more ideal cadence in the flats, but still crank out the same type of speeds. was def a good move for me; i had “outgrown” my triple; but needed something that could address big hills.
Personally i think its a nobrainer for anywhere but kansas. Im convinced almost all AG triathletes are overgeared for all but the pancake courses.
Ive been riding my compact with a 27 tooth rear, and its brilliant- i can keep 90rpm cadence up almost any hill, and while everyone else is standing up and mashing away, im still sitting down and spinning. If I really want to piss them off ill stay in my aero bars and drink from my profile.
The best way to summarize a compact for a given rear cluster is that you lose your highest gear, and gain two more lower gears. Personally, i find that i almost never was using the highest gear, and im very often in the lowest…the highest gear was only useful at >36mph, when im rarely pedaling anyway.
Additionally, testing with other riders, holding a constant HR and alternating between standing in my middle gears (the non-compacts low gears) and spinning in my lowest gears, i am dramatically faster sitting and spinning, and my back hurts less.
Ive been thrilled with mine. the guys at guru thought i was nuts specifying a 180mm compact crankset, but its fantastic.
For me it was an easy choice. I was always switching back and forth from the large chainring to the small chainring (and riding in the 3 smallest cogs (12/13/14) on the small ring…and the 19-21-23 on the big ring). Once I switched to the 50/34…I rarely change into the small ring. I train on flat to rolling roads. I am “straight chained” in the 15/16/17 cogs a greater % of the time. I race flat courses to hilly courses. I find them ideal for both cases. I am very curious as to why people think they are not good for flat courses?? I averaged ~24mph for an OLY yesterday on a pretty flat course…never shifted out of the big ring. I used a tight geared cassette and was able to completely control my cadence. I train around 85-95 rpm and race around 90-100 rpm.
FWIW- I averaged ~19mph last year at IMWI and used every gear I had! I also have them on my road bike and have no trouble keeping up with my Cat 4 buddies!
For me, it’s a no-brainer. I do most of my training in the small chainring usually on somewhere between a 14 and a 15 on the flats, and shifting up to the 21 or 23 on the hills. (I use a 12-23 99% of the time). If I have a strong tailwind, then I’ll shift up to the big ring.
A compact setup would mean that I have to shift on the front more often than I do now, so I’d rather stick with a conventional 53/39, 12-23 combo.
My vote goes to which ever setup allows you to not use your 12-14 or 15 cogs most of the time. Using those cogs a lot wears out the cogset in about half the time. The logic is simple 12 teeth get twice as much work as 24 teeth going the same distance, and maybe more since a higher % of teeth are wrapped at one time. I don’t pretend to know the physics, folks. . I am a cheap kind of guy that used to ride 90% of the time in the 39 /13,14,15 and I was wearing cogs out way too fast. So I switched to riding in the 53 and using the midrange cogs and get almost twice the milage on my cogsets.
Also if you live and race in Florida,Illinois,Louisiana or the other pancake states the regular 53/39 set up is plenty. If you have 2-5 k foot climbs you do on a regular basis I would think you might really think about a compact set up. I have both and sort of pick my bike based on the rid that day. In Hawaii we have climbs on most every ride including the Sunday fixie, so lots of people like the compact. I get laughed at when I ride with my Louisiana homies and my travel bike has a 48/36.
Its seems that I’m going compact.
I’ll swap out the 53 for a 50, and next time I’m out I’ll check where on the cog I usually am on the big ring.
This should maybe be on separate thread, but are Q-rings worth it?
This should maybe be on separate thread, but are Q-rings worth it?
Yes
.
Always, flat or hilly. I have 50/34 12/27. I never run out on the flats with my 50/12. (Now if one is a bike stud, then forget my inputs).
And, if you bike in the hills, the 34/27 will let me spin up anything.
I have never missed a gear combo I wish I had.
Dave