compact cranks

[debdownunder]

i am an older rider (54) and have a felt 35 racing bike. i am having a bit of trouble keeping up on hills....any hill, i seem to fall behind the group.
all the girls seem to have compact cranks, apart from myself. a friend who is a top triathlete says a compact crank would help me, but the local bloke from the bike shop says it wouldnt make much difference.
dont know what to think....we generally ride about about 150k+ per week, covering a range of hilly, undulating and flat terrain.

[Andrea]

A compact won't necessarily make you faster, it will just make it a little easier to "spin" up hills, which is easier. It's actually a little slower, but won't give you quite the leg burn that turning a harder gear would.

[bounceswoosh]

i am an older rider (54) and have a felt 35 racing bike. i am having a bit of trouble keeping up on hills....any hill, i seem to fall behind the group.
all the girls seem to have compact cranks, apart from myself. a friend who is a top triathlete says a compact crank would help me, but the local bloke from the bike shop says it wouldnt make much difference.
dont know what to think....we generally ride about about 150k+ per week, covering a range of hilly, undulating and flat terrain.

I'm assuming you have a double now -- what about trying a triple? A lot of people use them around here.

[alpinerabbit]

It's usually easier to switch to a compact than a triple.

I did it on my first bike. No, it will not make you faster, as Andrea says, but +1 to what she said: it may preserve your strength on hills so you last longer. And it will save your knees (I hurt a ligament grinding up hills in my first year).

Folks call the regular double the "hero crank" and that's what it's for. I don't see how amateurs should have much use for it unless they live in a flat area. I see how shops sell them because it is "the standard" of old times.

[mimitabby]

I may not be right here, but I believe we're talking about leverage. The bigger the lever, the less work to get it to move.
If you get a compact crank, you're not going to have to turn it as far to move the same distance, but you're going to have to work harder.


to illustrate to yourself the difference between what you have and a compact
just put your bike in a higher gear next time you're going up a hill. you won't have to pedal as much, but IT WILL BE HARDER.

tell me if i'm wrong guys, but i just checked Sheldon Brown's website and from what it said, I believe I understand the concept.

I agree, get a triple if you want to have more options going up a hill.

[bounceswoosh]

I may not be right here, but I believe we're talking about leverage. The bigger the lever, the less work to get it to move.
If you get a compact crank, you're not going to have to turn it as far to move the same distance, but you're going to have to work harder.


to illustrate to yourself the difference between what you have and a compact
just put your bike in a higher gear next time you're going up a hill. you won't have to pedal as much, but IT WILL BE HARDER.

tell me if i'm wrong guys, but i just checked Sheldon Brown's website and from what it said, I believe I understand the concept.

I agree, get a triple if you want to have more options going up a hill.

I looked up the term, too, but I got a different description --

http://www.chainreaction.com/triples.htm

(search "compact")

"Just when you thought you had it all figured out, along comes the "Compact" crank. A new way (actually it's been around for some time, but forgotten) to get lower gears without a triple. Instead of the classic 53/39 front chainrings, you have a 50/36 (sometimes 50/34) combination that gets you quite a bit lower gears, while giving up a very small amount from the high end... all using standard double-compatible shifters & derailleurs. A high-quality compact setup is actually lighter weight than a standard double! The downside? You don't get as low a gear as a triple will offer, and you lose just a bit off your high end (the gears you'd be drafting trucks downhill in, but nothing you'd ever miss in day-to-day riding)."

[bounceswoosh]

It's usually easier to switch to a compact than a triple.

Is that because of the adjustment to shifting across three rings?

[mimitabby]

I looked up the term, too, but I got a different description --

http://www.chainreaction.com/triples.htm

(search "compact")

"Just when you thought you had it all figured out, along comes the "Compact" crank. A new way (actually it's been around for some time, but forgotten) to get lower gears without a triple. Instead of the classic 53/39 front chainrings, you have a 50/36 (sometimes 50/34) combination that gets you quite a bit lower gears, while giving up a very small amount from the high end... all using standard double-compatible shifters & derailleurs. A high-quality compact setup is actually lighter weight than a standard double! The downside? You don't get as low a gear as a triple will offer, and you lose just a bit off your high end (the gears you'd be drafting trucks downhill in, but nothing you'd ever miss in day-to-day riding)."

thanks Monique, that's better than what Sheldon said about it.
The compact isn't going to help you up harder hills, it doesn't have the gearing options of the triple. sounds nice for moderate riding; for folks that don't want to go too fast and don't have a lot of hills to climb.

[alpinerabbit]

Bounceswoosh: it's easier to switch because you may not have to change the front derailleur.

The compact isn't going to help you up harder hills, it doesn't have the gearing options of the triple. sounds nice for moderate riding; for folks that don't want to go too fast and don't have a lot of hills to climb.
I climbed Stelvio with a campy compact and 12-29 cassette.... and I did 20% hills with it*. That good enuff? What's in a name?

Yeah you can't draft the truck DOWN Stelvio. But I can crank it at 36+ kph in the flat. Wait till I get stronger.

The bigger the lever, the less work to get it to move.
If you get a compact crank, you're not going to have to turn it as far to move the same distance, but you're going to have to work harder.
No - IMHO, exactly the opposite. With the compact, you will have to spin more often to cover the same distance, but at less resistance. But I have never been intuitive at physics (although I wasn't outright bad).
To put it simply: Compared to the regular double, you have an overall set of easier gears. Yes not the amount of options of a triple, or the easiest possible granny gear, but a cheaper remodel, lighter weight and IMHO more precise shifting.

*new bike: Ultegra compact/11-27 - going to switch to an SRAM 12-28 cassette - and have not yet attempted either 20% or a major alpine pass. So the verdict is not in yet.

[mimitabby]

No - IMHO, exactly the opposite. With the compact, you will have to spin more often to cover the same distance, but at less resistance. But I have never been intuitive at physics (although I wasn't outright bad).
To put it simply: Compared to the regular double, you have an overall set of easier gears. Yes not the amount of options of a triple, or the easiest possible granny gear, but a cheaper remodel, lighter weight and IMHO more precise shifting.
.

I was comparing to a bike with bigger gears, not smaller. So we're both right.
my triple has bigger granny gears than your compact.

remember, just because you can go up a 20% grade hill without dropping into a granny gear doesn't mean someone who is already having trouble is going to want to do that. (or be physically able to!)

[alpinerabbit]

Oh absolutely. I was just saying the compact will help you up harder hills than a regular double which is what the original poster seems to have, and it's a viable option even in hilly, mountainous, alpine :eek: terrain.

Yes the Triple is even better ... except for the technical concerns. it's like strawberry, vanilla and chocolate.

my triple has bigger granny gears than your compact.
My daddy is stronger than your daddy :D:D:D j/k

[DebW]

I may not be right here, but I believe we're talking about leverage. The bigger the lever, the less work to get it to move.
If you get a compact crank, you're not going to have to turn it as far to move the same distance, but you're going to have to work harder.


Mimi, the term leverage would apply to the length of the crank arms. Longer crank arms would in theory make it easier to grind up a hill in too big a gear. The first consideration on crank length is leg (femur) length. But a spinner would tend to prefer a shorter crank while a rider who favors lower rpms may prefer a longer crank length for the leverage.

In the discussion of compact vs regular double vs triple, gear ratio is the appropriate concept, ie how far the bike travels for one revolution of the cranks. This is the ratio of the chainring size (# of teeth) to the rear sprocket size (# of teeth) multiplied by wheel circumference.

Traditional doubles were 42-52 because a bigger spread produced a very slow and awkward shift. With modern ramped and pinned chainrings, you can get a good shift over a wider range. You also want a front derailleur designed for the chainring spread and size of the largest chainring. A triple front needs extra travel in the front derailleur, and a design to maximize shifts for the given chainrings. Note that the rear derailleur has a maximum capacity (tooth difference of cassette plus tooth difference of chainrings) because it need to keep tension on the chain at all times. Sometimes swapping the cassette to a wider range can give the same low gear as going to a compact double, but for less money. Depends on what gears the bike currently has and how much extra capacity the rear derailleur has.

[7rider]

My daddy is stronger than your daddy :D:D:D j/k

Ooooo, boy!!! Time to pull up a chair, grab a tub o' popcorn, and watch the fur start to fly in the great "compact vs. triple" debate. This is gonna be fun!! :D

[Mr. SR500]

What cassette are you running? If you don't already a 12-27, it would give you some lower gears.

[aicabsolut]

Mimi, the term leverage would apply to the length of the crank arms. Longer crank arms would in theory make it easier to grind up a hill in too big a gear. The first consideration on crank length is leg (femur) length. But a spinner would tend to prefer a shorter crank while a rider who favors lower rpms may prefer a longer crank length for the leverage.

In the discussion of compact vs regular double vs triple, gear ratio is the appropriate concept, ie how far the bike travels for one revolution of the cranks. This is the ratio of the chainring size (# of teeth) to the rear sprocket size (# of teeth) multiplied by wheel circumference.

Traditional doubles were 42-52 because a bigger spread produced a very slow and awkward shift. With modern ramped and pinned chainrings, you can get a good shift over a wider range. You also want a front derailleur designed for the chainring spread and size of the largest chainring. A triple front needs extra travel in the front derailleur, and a design to maximize shifts for the given chainrings. Note that the rear derailleur has a maximum capacity (tooth difference of cassette plus tooth difference of chainrings) because it need to keep tension on the chain at all times. Sometimes swapping the cassette to a wider range can give the same low gear as going to a compact double, but for less money. Depends on what gears the bike currently has and how much extra capacity the rear derailleur has.

Correct.

There are generally 2 options for going with a compact: 50/36 (harder to find, and you must use a 110BCD), or 50/34 (often available with the more standard 130BCD--meaning you wouldn't have to buy new crank arms necessarily, just rings). Most double front derailleurs can handle the 50-34 tooth drop. One thing to keep in mind is your chain position on the rear cog when making shifts in a compact. You will also have to be very very precise with your front derailleur adjustments. Index shifters that give you the ability to move the FD half a click will help with cross-chain issues, but when making full shifts in the front (esp large to small), it can be easier to drop your chain if you are in the wrong rear cog.

I believe that compact cranksets are much nicer than triples. For one, you have many more usable rear gears per front ring. SEcond, you can really tweak a compact to suit your style of riding and terrain. I like a 36T small ring, because I ride a lot on flat ground in traffic when I don't really want to be in the big ring. It also gives me all the gears I need to climb pretty long steep hills that I encounter. If I were to build a climbing rig for more serious climbing, I would go with a 34T small ring. My next move will be to get a cassette with an 11 cog instead of a 12, for sprinting and descending.

Look up a good gear inches calculator. I believe Sheldon Brown's site has one. The reason I'd want an 11 cog for races instead of getting a regular double? A 50-11 is bigger than a 53-12. It also lets me see what kind of cassette I might want with a 34T ring or how I might change things up with my current crankset.

The ladies are right that the compact won't necessarily make you faster, at least at first. It depends on your fitness. Obviously, the best thing is to be able to "spin" a BIG gear. It definitely helps to start out spinning small gears and saving some muscle power on the climbs. Then just work on climbing. Do it a lot. Then you'll be able to do it as easily in harder gears. You aren't really going to lose much by switching to a compact. You may spin out easier while descending, but you can compensate for that some with a new cassette. But then, if you rarely ever use your hardest gear, you may be just fine with the cassette you have. You can always just try to spin like crazy or get as aero as possible on descents that are too steep in the compact. In my races, I tend to attack on descents. If I can do that in a compact, then it shows they aren't so wussy, even though I want an 11 cog.

You will save weight by going with a compact over a triple, and you will have to change fewer components--no need for a different derailleur or shifters.

[alpinerabbit]

Ooooo, boy!!! Time to pull up a chair, grab a tub o' popcorn, and watch the fur start to fly in the great "compact vs. triple" debate. This is gonna be fun!! :D

I was gonna say just the same.

[IFjane]

Just the voice of experience here. I took physics and remember little or nothing. And no, I did not stay in a Holiday Inn Express last night.

BUT - In January I switched from my Shimano Ultregra triple I had been using since I started road riding (6 years ago), to a Campy compact double. I am not some young hammerhead-ess. I am 54, carrying about 20+ pounds more than I would like, and live at the foot of the Blue Ridge Mountains. I do not and never have been a fast climber - uphill is my weakness - but for some reason the double is in most instances easier, and in a few, no harder than the triple. My theory is the weight savings by not having the extra chainring. :confused: The gearing is similar - my triple was a standard 52-42-30 with a 12/27 cassette. Now I have a 50-34 with an 11/27 cassette. I love it and have no plans to ever go back.

Good luck!

[debdownunder]

What cassette are you running? If you don't already a 12-27, it would give you some lower gears.

i have a 12-27 rear cassette...maybe i just need a lot more practice.
my friend, the triathlete says she wouldnt have anything else but a compact crank, and it seems to be the way older riders are going...obviously a very debatable topic.
ta

[debdownunder]

thanks,
finally a sort of, positive response.
i just want to make it easier on my old legs, which burn, baby burn!!!!when i try and go hard up some hills.

[PinkBike]

add me to the (small) group that advocates the compact double. i just switched (ultegra 10-speed) this year and i'm real glad i did. it is easier to go up hills without the leg burn if you have a smaller chain ring. and i'm having fun finding i spend more time in the big chain ring than i ever did before because of the lower gearing. i'd hate to think of a situation where i'd need more than the 34-25 gear ratio - what a climb that would be!

i'm also in my 50's and carrying about 10 extra pounds. when i lose that weight - lookout!!

[Beane]

I went from a triple (52/39/30 I think) x 12-26 to a compact double (50/34) x 13-29 and have found little difference between the 30x26 and 34x29. I've noticed it only on the worst of the worst hills. For the ease of transition, I would definitely say go with the compact double and get the biggest rear cassette you can. (which is 27 or 28 for shimano, I think)

[SadieKate]

I went from a triple (52/39/30 I think) x 12-26 to a compact double (50/34) x 13-29 and have found little difference between the 30x26 and 34x29. I've noticed it only on the worst of the worst hills. Wow, and I thought I was a princess. :p I'm amazed that you notice it at all as the gear inches are 31.15 and 31.66 respectively.

If you had stayed with the triple and just changed to a cassette with a 29 cog (30x29) you'd have 27.93 gear inches which is definitely noticeable.

Now, if you'd changed your inner ring to a 28 (entirely possible), you'd have a low gear of 26.07 with 28x29.

You can always get a wider range of gears with a triple. Whether you need/want them is an individual thang.


IFor the ease of transition, I would definitely say go with the compact double and get the biggest rear cassette you can. (which is 27 or 28 for shimano, I think)That would be the biggest cassette your rear derailleur can handle. You can always change the rear derailleur to a longer cage model and put on a cassette with a 34 cog.

[OakLeaf]

For you gals with compacts, how many gears do you actually use?

With my triple, it's the bottom 3 on the small ring, all 10 on the middle ring, and the top 4 on the big ring.

It's not just the range that counts, but also how many different gear choices you have within that range, that will allow you to spin your desired cadence. Even one tooth on the cassette makes a huge difference in cadence and comfort.

I've never actually done a spreadsheet to see how much overlap I have in the gearing, but those are the ones I actually use.

[Bikenow]

Try it you will love a compact. I have been riding since 1984 and in 2005 I got a new Bianchi with a carbon compact. I'll never go back. Everyone has really given a lot of good advice. Something to think about is the crank arms should be as close to what you have been riding, other wise it will take your
legs time to adjust to the new spin and new gears. Also the pedels may be wider or closer together than what you have been riding. This is called the Q factor. You might what to wait and change at the first of next year's riding season. Just try it, what do you have to lose. I'm 55 and love the spin, no mashing anymore.

[debdownunder]

forgot to mention that i dont have a triple...just the regular double...
and trying to make my riding even more enjoyable:)
playing catch ups is really hard work.

[debdownunder]

Great! another positive comment for comp/cranks.
i think i just need to be talked into it.
when i do it, i'll let you know what i think.
but...then again, i dont want to spend money for the sake of it.

[mimitabby]

you need to find one of those chain rings and hold it in your hand (if you're trying to decide which would be better a triple or a compact)
they weigh about the same as 3 ounces of water. I doubt that the extra weight of a triple is going to slow you down.
However, further back, i heard someone say it would be easier mechanically speaking for you to switch from what you have to a compact than it would be to a triple.

[Andrea]

SRAM is making an 11-28 now for all you "big range" junkies :D

Oh yeah, and I had a compact double last year, and it was fine unless I was in a race situation where I needed to go very fast downhill. That's the only reason why I switched to a standard when I upgraded parts, because otherwise, I loved it for hills & long climbs.

[aicabsolut]

SRAM is making an 11-28 now for all you "big range" junkies :D

Oh yeah, and I had a compact double last year, and it was fine unless I was in a race situation where I needed to go very fast downhill. That's the only reason why I switched to a standard when I upgraded parts, because otherwise, I loved it for hills & long climbs.


For you gals with compacts, how many gears do you actually use?

With my triple, it's the bottom 3 on the small ring, all 10 on the middle ring, and the top 4 on the big ring.

It's not just the range that counts, but also how many different gear choices you have within that range, that will allow you to spin your desired cadence. Even one tooth on the cassette makes a huge difference in cadence and comfort.

I've never actually done a spreadsheet to see how much overlap I have in the gearing, but those are the ones I actually use.

Remember, a 50-11 is bigger than a 53-12. How often do you really need a 53-11? If you love the compact, you can make it work for racing.

I use every rear cog with my compact. It's quite nice for racing overall. The compact lets me spin up big hills (I don't think I'd ever need a 34 for the races I do--the 36 is enough), but the best part is that a greater range of hills are now "big ring climbs" for me with the 50T. So the less I have to shift up front the less I risk dropping my chain, which is nice. Plus, shifting back up is faster when you don't have to jump rings. One thing I really like about the 36-27 is the ability to get started from a stop light on a hill. I appreciate that (which I encounter more often) than the ability to keep going when I really need that gear to get up a hill.

[Andrea]

How often do you really need a 53-11?

Not very often, but last season, I spun uncomfortably in the 50x11 a few times when chasing someone downhill and in a couple of sprints- one with a perfect leadout and one that was downhill. I am much more fond of my 53x39 with an 11x26 rear.

[OakLeaf]

So I had to do a little spreadsheet just to see. Told you I'm a data geek.

With my standard Shimano 30/39/50 triple and a 12-25 cassette, I have three gears on the puppy gear that are lower than anything I get on the middle ring, and four gears on the big ring that are higher than the highest gear on the middle ring, for a usable 17 speeds. Exactly what I posted earlier that I've been using...

With a standard Shimano 50/34 compact and the same cassette, one would have five speeds on the small ring that are lower than the lowest gear on the big ring, for a usable 15 speeds.

With a standard Campy 53/39 compact and the same cassette, one would have five speeds on the big ring that are taller than the highest gear on the small ring, for a usable 15 speeds if you go at it from the other direction.

Low gear on a 30x25 with a tire rollout of 2091 mm and an effective diameter of 26.2" is 31.44 GI. Low on a 34x25 would be 35.63, low on a 39x25 is 40.87.

High gear on a 50x12 with the same rollout is 108.99 GI, high gear on a 53x12 is 115.80.

TMI yet? :p;) Bottom line is, with 21% grades like our club climbed last night (the ride leader's Garmin said it was 24%) I NEED those low gears to get up the hills and the high ones to get down them; and the more close-ratio gears I have in between, the more comfortable my knees and muscles are on the flats. So I'm even more confident than before that I made the right decision in going with the triple.

[katluvr]

Ok, no physics here, nor do I race. I recently went from triple to a compact cassette. I live in the flat world of Flordia--so hills are not my fortey--or they used to not be. We do have some hilly areas that I train in.
Nor do I race.
I was very afraid to lose my "granny gear" for when I did ride the hills.
I LOVE my compact cassette. I think it allows me more range while in my "small ring". SO I can hill climb and then handle the flats. With a triple I was always having to then get out of my small ring to my middle chain ring and also dropping back down again. AND dropping my chain. So for me it was a good deal! And I climb much better!
:)

[Beane]

That would be the biggest cassette your rear derailleur can handle. You can always change the rear derailleur to a longer cage model and put on a cassette with a 34 cog.

Oh duh. Not sure why I didn't think of that...


With a triple I was always having to then get out of my small ring to my middle chain ring and also dropping back down again. AND dropping my chain.

I agree. I've been dropping the chain much less with the compact double than the triple.

[SadieKate]

Dang, I got it right the first time So do you feel all powerful? Ready to go rip some pavement?

[Scarlet]

add me to the (small) group that advocates the compact double. i just switched (ultegra 10-speed) this year and i'm real glad i did. it is easier to go up hills without the leg burn if you have a smaller chain ring. and i'm having fun finding i spend more time in the big chain ring than i ever did before because of the lower gearing. i'd hate to think of a situation where i'd need more than the 34-25 gear ratio - what a climb that would be!

i'm also in my 50's and carrying about 10 extra pounds. when i lose that weight - lookout!!


AGree totally (apart from being 46 )I do carry about 10lbs too much maybe more if i get on the scales
just changed from triple to compact Shimano 600 Hollowtech 2 'compact' 34/50 chainset.
and there is just no stopping me ... well almost :D

Scarlet