Compact Crankset for going fast

[rugbysecondrow]

I flirted with a compact on a century I just did and I must say, I enjoyed it. I have since switched back to a standard crankset and it has been hard adjusting to a standard size again. With the compact, I was able to spend more time in the big chainring and thus less shifting from big to little chain and back again. Also, I was able to (the obvious statement) spin more up hills and expend less energy. SInce being in the standard again, the gears feel ackward.

My Bedford is the bike I use for triathlons and I am thinking of permanantly putting a compact on there. From what I have read, including from some triathlon perspective, many people are moving to a compact even for racing. I would lose that top gear (53:12 for me) but I never push that gear so I am losing something I never actually usse. Also, I live where it is hilly so many of the tri's I do have hilly rides. Being able to spin more up hill would save me some for the run plus I think the higher cadence of spinning vs. the lower up out of the saddle mashing would result in an overall faster climbing time.

I have done some searches and it seems that the questions typically revolve around compact vs. Triple, or using a compact to take it easier due to age or knees, but I am thinking the compact might actually be better for racing and going fast. Could that be true? Is there a reason to stick with the standard? Am I being being a sissy by going compact? The only downside I see is having easier gears that I don't have now and relying on them too much.

Any thoughts?

Thanks,

Paul

[gone]

I've got compacts, triples and standard cranks on my bikes. For me, the answer to the question is very terrain dependent. A compact in the 50x11 spinning a moderate cadence (90 rpm) yields about 32 MPH. A standard crank at the same cadence yields a couple more MPH so the difference isn't that huge. Depending on the terrain, you might find yourself cross chaining more with a compact staying on the big ring but if you're not concerned about that (and you're looking for fast times, not maximum drivetrain longevity in a race so why would you be?) a compact is certainly a reasonable choice.

[Bob Ross]

I would lose that top gear (53:12 for me) but I never push that gear

Just fyi, a 50-tooth compact chainring combined with an 11-tooth cog yields a bigger top gear than a standard 53:12.

[Ray]

There are absolutely no rules. You know the ratios you most like to use in the terrain you ride. Whatever setup provides the most convenient access to those ratios is the right one to use. Whether your goal is to go fast or to go slow...

-Ray

[malcolm]

I live in a area that has lots of steep short hills and I use compacts quite a bit. I've found the opposite of you however. I find myself shifting the front considerably more with the compact than I did with the 53/39 or winding up cross chained. Many of the hills are too steep for me on the 50 but I really don't need the 34 or 36. Unless I was powering down hill, I could just leave it in the 39 for the hills and short flats inbetween but I feel compelled to shift back to the 50 with a compact. I've gotten used to over the years, but I considered going back to 53/39 at one point.

[bobswire]

More important than MPH is how long are you able to maintain speed.

I'm now using a 48/34 Sugino Alpina 800 chainset and 11-28 cassette and have no problems with less strain maintaining speed and climbing than I did with a standard set.
Where I was climbing maybe 6-7 MPH on a long sustained 6- 7% grade I'm now doing 9-10 mph.*
On the flats without wind I'm able to maintain in the low to mid 20's.*





*Taken into account I'm 65. :rolleyes:
* Data: Garmin Edge

[AndrewS]

The only thing that compacts actually do is provide a lower gear ratios on the SMALL RING than a normal double can. On the big ring the relative change of gearing per rear shift is exactly the same - it's just that for a particular gear position, like the fourth cog in (53x16 vs. 50x14), the compact will be between .5 and 1.3 mph higher for the same rpm (this assumes you are comparing a 12 vs. 11 for the first position, as most compacts are set up). So while every combination in a compact is a little different than its normal equivalent, the ratios between shifts haven't changed and your perception of how long you can stay in the big ring is an illusion.

All 50x34 compacts really do is provide around 14% of additional gear ratio between high and low cogs over a traditional 53x39. Aside from the slight difference in final drive ratios mentioned in the first paragraph, that is the only important difference between them, and a compact will not change the way you ride, spin up, or use your gears on the big ring.

BTW, if you want your compact to have nearly identical gears to your 53, use a 49 instead of a 50. That puts them really close on a 12-23 vs. 11-21.

Don't take my word on it - use this calculator to view the gear ratios and how they change:
http://www.sheldonbrown.com/gears/

[bobswire]

The only thing that compacts actually do is provide a lower gear ratios on the SMALL RING than a normal double can. On the big ring the relative change of gearing per rear shift is exactly the same - it's just that for a particular gear position, like the fourth cog in (53x16 vs. 50x14), the compact will be between .5 and 1.3 mph higher for the same rpm (this assumes you are comparing a 12 vs. 11 for the first position, as most compacts are set up). So while every combination in a compact is a little different than its normal equivalent, the ratios between shifts haven't changed and your perception of how long you can stay in the big ring is an illusion.

All 50x34 compacts really do is provide around 14% of additional gear ratio between high and low cogs over a traditional 53x39. Aside from the slight difference in final drive ratios mentioned in the first paragraph, that is the only important difference between them, and a compact will not change the way you ride, spin up, or use your gears on the big ring.

BTW, if you want your compact to have nearly identical gears to your 53, use a 49 instead of a 50. That puts them really close on a 12-23 vs. 11-21.

Don't take my word on it - use this calculator to view the gear ratios and how they change:
http://www.sheldonbrown.com/gears/

True but I like the Illusion of not having to drop down into my small ring but for only the steeper grades. I live in San Francisco where just going across town you average 800-1100 elevation gain ( http://connect.garmin.com/activity/47870147 ) and being able to do it in the 48 tooth ring without dropping down to the smaller ring is more satisfying to me mentally than cold based calculator equations. Then again I don't limit myself to 12-23 or 11-21, I use 11-30 IRD cassette,the sky is the limit.
:rolleyes:

[AndrewS]

It is an illusion, Bob. If you were using a 53 with a 12 or 13-34 cassette you wouldn't shift any more often then you do now. The size of the big ring, by itself, doesn't have anything to do with how long you can remain in it. If the cassette cogs get larger in proportion to the front, your gearing is exactly the same.

[bobswire]

It is an illusion, Bob. If you were using a 53 with a 12 or 13-34 cassette you wouldn't shift any more often then you do now. The size of the big ring, by itself, doesn't have anything to do with how long you can remain in it. If the cassette cogs get larger in proportion to the front, your gearing is exactly the same.

Aha, but its the perception not the reality that rules the heart and mind,isn't thus? Kinda like having a shiny new bike as opposed to rusty old one when in reality they both perform the same service.
Now I'm out for a ride. :beer:

[AndrewS]

I suppose, but only as long as no one tells you about reality.

[fourflys]

It is an illusion, Bob. If you were using a 53 with a 12 or 13-34 cassette you wouldn't shift any more often then you do now. The size of the big ring, by itself, doesn't have anything to do with how long you can remain in it. If the cassette cogs get larger in proportion to the front, your gearing is exactly the same.

the mental aspect accounts for more than any other aspect so if that makes a difference, the compact does make a difference IMHO...

Besides, typically the legs don't lie... I agree a compact "feels" easier and more efficient to spin at times than a standard....

[rugbysecondrow]

I might have to try it this weekend. I have a race this that is social (all you can eat, drink and live band after the race) so I can see how it does. It is a flatter race, but the wind can be wicked, so it might be an interesting test.

I ride on hills often, varying degrees of incline and length, and so the spinning benefit would likely help take it easier on the legs while also allowing for maybe faster times due to the higher cadence.

I like this discussion though, so let me know your thoughts. I am on the fence about this one...not a typical position for me. :)

[fourflys]

I might have to try it this weekend. I have a race this that is social (all you can eat, drink and live band after the race) so I can see how it does. It is a flatter race, but the wind can be wicked, so it might be an interesting test.

I ride on hills often, varying degrees of incline and length, and so the spinning benefit would likely help take it easier on the legs while also allowing for maybe faster times due to the higher cadence.

I like this discussion though, so let me know your thoughts. I am on the fence about this one...not a typical position for me. :)

Rugby,
I felt I was in the big ring more with a compact than my standard... I have no doubt the ratios don't lie as Andrew said above, but all I can say is that I'm able to ride up more hills in my 50 tooth than I ever could in my 53... is it all in my head? maybe, but as I said above my legs say it makes a difference...

good luck with the race and let us know what you thought about it..

Chris

[Bob Loblaw]

The advantage of the compact is NOT that the 34 is smaller than the 39. If you want a smaller gear, you could easily get a 28 (or 30 or 32) tooth cog on your cassette and achieve the same result.

The advantage of the compact crank is that the difference between the sizes of chainrings is greater than on a standard crank. That means you get a wider spread of gears using a compact.

IOW, a compact crank running an 11-23 has a higher high gear AND a lower low gear than a standard crank running a 12-25.

This chart lays it all out:
http://home.i1.net/~dwolfe/gerz/index.html

BL

[AndrewS]

Right, the 14% difference I mentioned.

[fourflys]

I think we have to remember a compact was initially designed (as far as I know anyway) to replace the triple and NOT the standard... as the compact did away with most of the duplicate gear ratios on a triple and was lighter and simpler to boot...

at least that's what I'd always read....

[AndrewS]

It was conceived to give triple-like gear ratios AND lower weight than a double while retaining the shifting and derailleur advantages of double. It manages that to a large degree, but doesn't go as low as a triple and has slightly increased cog and chain wear over a normal double.

If you think 50-34 is great, think about how a 9-18 cassette would let you go to a 40-26 crank. What "spin up" that would have, eh? ;)

[MattTuck]

I like my triple.

Yes, it has some duplicate gears, but it gets me up virtually any hill I've encountered.

My next bike will probably be a compact, but I'll miss some of those very lower gears. As far as spinning out the top of a compact, that just isn't a problem for me. ;)

[dave thompson]

I've coupled a compact crank with an SRAM Apex 11-32 cassette (using a 6700 short cage rear derailleur!) to climb the hill and mountains that surround us. I like my combo better than the triple that I ran a few years ago.

[malcolm]

I think we have to remember a compact was initially designed (as far as I know anyway) to replace the triple and NOT the standard... as the compact did away with most of the duplicate gear ratios on a triple and was lighter and simpler to boot...

at least that's what I'd always read....

I don't think this is true, I think it has essentially happened but I believe compacts also at one time known as alpine gearing was made for mere mortals to use in the alpine passes. They do however seem to have supplanted triples.

[nahtnoj]

Paul,

It sounds like what you like about the compact is the 50. I agree the 50 is great. I can't stand a 34 inner ring though, switch that to a 36 or 38 and I can get down with a compact on almost all terrain.

[AndrewS]

If you like that gearing you can do it on a normal crank. 130BCD cranks will handle from 38 to 60 tooth cogs. Stiffer crank, too.

50-40s used to be somewhat common on sport bikes.

[Ti Designs]

My Bedford is the bike I use for triathlons and I am thinking of permanantly putting a compact on there. From what I have read, including from some triathlon perspective, many people are moving to a compact even for racing.

The advice I would give is based on info that's not here - is the bike set up in a traditional road position or with tri bars?

If it's a traditional road position, I think too many people have gone to compact cranks as a solution to learning how to climb. This from someone who runs a 44/55 up front and an 11-21 in back...

If you're doing triathlons, the number that counts is the elapsed time when you finish the run, so getting off the bike and being able to run counts for something. Tri bars don't allow the rider to leverage body weight on the pedals, so it's either gearing or pure leg strength, which will take it's toll on the run. I've worked with a couple of triathletes, the trick is have them test in bricks (ride/run workouts), increasing the cadence and keeping track of total elapsed time.

[Blue Jays]

"...This from someone who runs a 44/55 up front and an 11-21 in back..."Spinning that 55 x 11 must result in a fast ride!

[rugbysecondrow]

The advice I would give is based on info that's not here - is the bike set up in a traditional road position or with tri bars?

If it's a traditional road position, I think too many people have gone to compact cranks as a solution to learning how to climb. This from someone who runs a 44/55 up front and an 11-21 in back...

If you're doing triathlons, the number that counts is the elapsed time when you finish the run, so getting off the bike and being able to run counts for something. Tri bars don't allow the rider to leverage body weight on the pedals, so it's either gearing or pure leg strength, which will take it's toll on the run. I've worked with a couple of triathletes, the trick is have them test in bricks (ride/run workouts), increasing the cadence and keeping track of total elapsed time.

It is setup as a road bike with drop bars. I race triathlons recreationally and I don't feel the need for a tri bike.
I use this bike for not just races but recreational and group rides as well.
I can ride all the hills where I live, but thought that the compact might add some without detracting much.

Thanks

[AndrewS]

Spinning that 55 x 11 must result in a fast ride!
36.1 mph at 90rpm.


Reading these posts I think, like the majority of gear topics on this forum, that this is more an emotional, "feel" issue than a discussion of real world equipment performance. The acceleration of your bike depends as much on the crank configuration as it does on the frame color.

If the answer is always going to be "whatever makes the rider feel that they are riding better", then having a discussion about it becomes no more than an exercise in reinforcing bias.

Compacts are a solution to making little rear derailleurs handle wider gear ratios. Everything you want to know about their road "performance" can be found in a gear chart. Everything else is hocus-pocus, and I think somebody needs to say it. The king is naked.

[malcolm]

36.1 mph at 90rpm.


Reading these post I think, like the majority of gear topics on this forum, that this is more an emotional, "feel" issue than a discussion of real world equipment performance. The acceleration of your bike depends as much on the crank configuration as it does on the frame color.

If the answer is always "whatever makes the rider feel that they are riding better" is the only valid answer, then having a discussion about it becomes no more than an exercise in reinforcing bias.

Compacts are a solution to making little rear derailleurs handle wider gear ratios. Everything you want to know about their "performance" can be found in a gear chart. Everything else is hocus-pocus, and it shouldn't be rude to point that out.


Everyone knows red is faster and blue is stronger, jesus man read a book.

[dauwhe]

If you think 50-34 is great, think about how a 9-18 cassette would let you go to a 40-26 crank. What "spin up" that would have, eh? ;)

40/26 sounds perfect for me, with a 12-30 cassette!

As you can see, gearing is a VERY individual thing...

Dave

[Ti Designs]

It is setup as a road bike with drop bars. I race triathlons recreationally and I don't feel the need for a tri bike.


Well, if you race recreationally, you should test the same way. Do two ride/run workouts, one in a lower gear at a higher cadence, the other pushing your standard gear. Make note of how you feel as you start the run. My guess is you'll feel far better having pushed the cadence over pushing a larger gear. If it's about recreation, you have to go with what feels better...


Spinning that 55 x 11 must result in a fast ride!

Oddly, it's something I use 'cause I don't race any more - it's a stupid gear, but great for fooling around. If they let me open a gap before a downhill town line, I win. That said, it's not something I would let my racers use. The amount of energy it takes to go from 37 to 38 MPH is so great and so short lived that it can't be worth the effort over time - you're better off allowing your heart rate to drop and making up the distance by increasing average speed.

Years ago in the Killington stage race I started a minute ahead of the national champion in the time trial. It was a long downhill followed by an even longer uphill to the ski lodge. He took a minute out of me on the downhill section - I was stunned when he passed me at the bottom of the hill. I then took 63 seconds out of him on the uphill...

[false_Aest]

Uhm.

When I rode a compact I seemed to favor a front/rear ratio of 1:3.125

Now that I ride a "standard" crank I favor ratio of 1:3.117

Similarly, I didn't know I needed compact gearing until I bought compact gearing.

----

I'm gonna assume that my riding is very much like a bell curve.

I'm also gonna assume that the reason Tyler rode a compact is because his mechanic said, "Dude, if you make me throw on a triple I'm gonna tell the press that you're doping."

Everything else has to do with Maury Povich the putz that wrote the first copy using "laterally stiff/vertically compliant."

[rugbysecondrow]

Well, if you race recreationally, you should test the same way. Do two ride/run workouts, one in a lower gear at a higher cadence, the other pushing your standard gear. Make note of how you feel as you start the run. My guess is you'll feel far better having pushed the cadence over pushing a larger gear. If it's about recreation, you have to go with what feels better...


...

I did a brick today with the standard crankset, I will try another one with the compact. I have a cheaper Veloce that I can put on to test out in the brick format.

Thanks for all the advice. It is hard, at least for me, because mentally it feels like I am giving in a bit to the compact, but logically and based on the gear ratios it seems to make more sense. Since I ride hilly and rolling terrain typically, it might make more sense. I will have to do a test and report. Feel is part of it, but speed counts as well. If I can keep my times while decreasing the recovery time on the run, that would be great.

[dd74]

I've used a compact with a 12-27, and worked no less than I would have if I had a standard. In fact, I've felt less fresh at the end of a climb with a compact.

These days, for very hilly rides, I have an 11-30 with a standard, which is only two teeth less than a 34-27.

In short, the compact never really did anything for me. It didn't feel too advantageous in the hills than when I used a 39/53.

I believe I fall on the side of Ti Designs. I feel I am faster in the hills with a 39/27, 24 or 21, than spinning in a compact. Spinning actually wears me out faster than a strong pull to the top.

The 11-30, so far, has added some climbing help, but usually it's the 24 and 27 gear I still find myself in.

[MattTuck]

So, as I was huffing and puffing my way up a hill today on my triple, I was thinking about this thread...

I came to the conclusion that a discussion of compact vs. traditional is useless without a discussion of weight (and I'm talking weight of the rider, not of the crank).

So, yes, if you're 5-9, and 140 pounds, it might not make sense to have a compact crank. If you're 5-9 and 200 pounds, even if you produce the same wattage, or even more wattage than the 140 pound rider, you're probably better off with a compact.

I don't think it has anything to do with "knowing" how to climb... although I'm sure that can help. I think the question has less to do with the amount of power you can generate and more to do with the amount of power it takes to carry you up the hill which is derivative on the bike's weight plus your weight.

For some folks that need the lower gears, there just isn't another way to get up the hill.

[jbrainin]

I feel that the choice of compact vs. standard cranks is an issue that is largely dependent on your cadence. If you pedal at an average cadence of 90rpm or more, than a compact is likely just fine for you. if you pedal at a slower average cadence, then you may feel more comfortable with standard cranks.

[1centaur]

I went to compact for chain line. When I was starting out I ended up getting close to 39/14 as a typical gear, and around here I don't need to shift much. Sometimes I wanted one cog harder, sometimes 2 cogs easier. One cog harder was more likely to give me chain rub, and using the FD was slow and therefore annoying.

So I used that Sheldon Brown gear calculator and thought about the gear inches I really use and figured out that a compact would give me good chain line in the big ring and easy RD access to one harder or 2 easier, plus bailout gears for something really steep. I actually went with 48/38 on several bikes to get the chain line even better and a shorter jump on the FD.

[zap]

snip

....., but I am thinking the compact might actually be better for racing and going fast. Could that be true?

No.

[AndrewS]

I feel that the choice of compact vs. standard cranks is an issue that is largely dependent on your cadence. If you pedal at an average cadence of 90rpm or more, than a compact is likely just fine for you. if you pedal at a slower average cadence, then you may feel more comfortable with standard cranks.
Why? What has cadence got to do with it?

[thegunner]

Why? What has cadence got to do with it?

because the range of available gear ratios tends to be lower on a compact vs. standard assuming you don't make changes to the rear cassette. some people prefer riding >100 RPMs at steady state, and some prefer 80. for the sake of the argument, to achieve same speed, the latter would prefer the standard.

i think that's what he meant?

[AndrewS]

The gear ratios per cassette position may be lower or higher, but that's not the point. If you don't like the gear your in; shift. 10 cogs means that there is one that is the right ratio for the speed and cadence you want to ride.

The difference between a 53 and 50 at 90rpm is 1.5-2 mph. That is nearly identical to the difference between a 12 and 13 cog, or a 16 and 17. So if you want to pretend you have a 50 on your 53x39 crankset, shift one cog down on your cassette. Same-same.

I think there are some very good reasons for using a compact, but cadence isn't one. The size of your large ring was more important in the days of 6 speed freewheels that had large ratio jumps between cogs. But a cassette that is 12, 13, 14, 15, 16, 17, 18, 19, 21, 23 offers such fine gradiations that screwing around with the chainrings is redundant.

[GuyGadois]

snip


Quote:
Originally Posted by rugbysecondrow
....., but I am thinking the compact might actually be better for racing and going fast. Could that be true?



No.

An answer like that really doesn't hold true all the time. It would depend on the race. For a race like Cat's Hill Crit with a large short hill I find the compact great as you can stay in the large chain ring while everyone else is dropping their chain or having to shift front and back. There is no room for error in that race. I raced my compact in almost all the races this year and really never found myself in trouble spinning out (50x11). There have been a couple of times I noted I was spinning a little fast but it was nothing that sitting a wheel for a minute couldn't fix. So, the answer to your question is - it depends on the race and what your legs are used to.

-GG-

[jblande]

You can reach almost all the same gear ratios with both cranksets. One thing you cannot do, but that is important to me, is to be able to run 50/11 and 34/25. One for going up and one for going down. With 50/11 I am just as fast going down as my friends with 53/12, but I can ride a more comfortable cadence going up with 34/25 than they do with 39/25. That is just me, YMMV

[AndrewS]

You could also use a 12-28 with a 53x39. That produces a low gear that is pretty close to a 34/25.

[bobswire]

You could also use a 12-28 with a 53x39. That produces a low gear that is pretty close to a 34/25.

I run a 11/ 30 tooth cassette with 48/34 chainset. What size cassette would you need for 53/39 to be comparable. Simple answer you can't.
I live in very hilly country so I set my bike accordingly (along with my age).

[thegunner]

I think there are some very good reasons for using a compact, but cadence isn't one.

maybe not, but the factor does exist on climbs. there are gradients in which a 39 can't spin the rear cog at the cadence you want.

[AndrewS]

I run a 11/ 30 tooth cassette with 48/34 chainset. What size cassette would you need for 53/39 to be comparable. Simple answer you can't.
I live in very hilly country so I set my bike accordingly (along with my age).
12-34

Give me another!

[Ralph]

I'm old, not as stong as I used to be, don't race, sometimes ride where hills are steep and long, and have used a compact.

I think some of you are making too big a deal out of this. Too me....you race with a compact when you need/want the inner ring to be less than 39. Then you work out your top gear by using a teeny tiny small rear cog. That's about it.

This wasn't part of the question, but for casual riding in extreme hilly or mountainous terrain, not racing, I still prefer a triple when I need low gears. But that's me. I need all the mechanical advantage I can get on some of those long steep hills that seem to go on forever. I even like a 1-1 low gear, something one of you strong racers would never need. A compact is ideal for you strong riders where you mostly big ring it, just using a 34 for steep climbs.

[Chuck Hammer]

OMG.... have I made a mistake?

I just ordered a 7950 Dura-Ace Compact Crank and the 7900-12/25 Cassette for the new bike. I have been riding an Ultegra triple for years. My thoughts were to go to the compact since the triple is not available. I also agree with the comment that the object is to get the mass 190# up the hill the fastest so I can go down the other side with those that went up faster.

[AndrewS]

The only mistake you could have made is if you didn't get the right gear ratios for what you want to do. Did you get them?

[Chuck Hammer]

crank 50/34 - cassette 12/25

[AndrewS]

Does that combination give you the high and low gears you want?

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

Plug in gearing you are used to, then check them against your new gearing.

The combination you have there is roughly equivalent to a 53x39 with 13-28. That good for you?

[Chuck Hammer]

Will do... thanks

[christian]

This discussion is hopeless, so long as you don't specify exactly where and how you're riding.

I ride a 110 bcd crankset (compact, if you will) on my Pegoretti. I use a 50t outer ring and a 39t inner ring, with a 12-25 10sp cassette. I picked this for a couple of reasons:

1) a 50x12 lets me go 30 mph at 100 rpm. I can't sustain a long 30 mph sprint on the flats, so that's high enough for me.
2) a 39x25 gets me up any hill in the tri-state area at a reasonable pace
3) the combination makes for convenient shifting -- there is a big jump between the 17 and 19 cog in a 12-25 cassette, and this combination allows me to use 39x25 through 39x14 and then shift directly to the 50x17, avoiding the big jump from 50x19 to 50x17.

But the only reason this works for me is because of where I live -- NY has few grades >7% and few grades >2 miles. In different geographies, my gearing choices might be totally different.

Now, this could be achieved by either a 130mm bcd or 110mm bcd crankset, but I use the compact because inner rings are cheaper than outer rings, and the compact will allow me to switch to a 36t or 34t inner on Alpine vacations.

[bobswire]

12-34

Give me another!

53-39 x 12-34 ?!? No thanks. I'm not talking mountain bike fugly in the rear w/ road bike chainset.
Crunching numbers is fine if you're just trying to prove it can be done but
I'll stick within road bike spec that I find comfortable and aesthetically pleasing.

[AndrewS]

Well, that's the difference between "can't" and won't.

As I said early on in this thread, compacts are a great way to get a wider range of gears using a road rear derailleur AND lose some weight. Any claims about compacts producing gearing or riding performance that can't be duplicated with other systems is simply incorrect.

BTW, anyone who wants to exactly duplicate the gear ratio difference of a 50x34 with a 130 or 135 BCD crank can do it with a 55x39 set up. AND, a 55x12 high gear is the same as a 50x11. The down side is derailleur capacity, which is why we have compacts in the first place, going all the way back to Suntour Microdrive and XCPro medium cage derailleur.

[bobswire]

Well, that's the difference between "can't" and won't.

As I said early on in this thread, compacts are a great way to get a wider range of gears using a road rear derailleur AND lose some weight. Any claims about compacts producing gearing or riding performance that can't be duplicated with other systems is simply incorrect.

BTW, anyone who wants to exactly duplicate the gear ratio difference of a 50x34 with a 130 or 135 BCD crank can do it with a 55x39 set up. AND, a 55x12 high gear is the same as a 50x11. The down side is derailleur capacity, which is why we have compacts in the first place, going all the way back to Suntour Microdrive and XCPro medium cage derailleur.

Hey Andrew,you should have seen some of the "franken" bikes I've built just to see if I could,yikes!

[dd74]

http://forums.thepaceline.net/attachment.php?attachmentid=74388&stc=1
Good looking crank. What brand is that?

[AndrewS]

Controltech?

[bobswire]

http://forums.thepaceline.net/attachment.php?attachmentid=74388&stc=1
Good looking crank. What brand is that?

ControlTech Shield, I'm very pleased with it but then again I'm no masher. :rolleyes:
I see they are going for a pretty cheap price now... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=380265269579&rvr_id=144121821381&crlp=1_263602_263622&UA=M*F%3F&GUID=2d7b198911b0a0b583d3d563ffd4129b&itemid=380265269579&ff4=263602_263622

[dd74]

Haven't heard of Controltech. Any flex to them? How do they compare to Shimano Compacts? I'm sure they're lighter if they are carbon.

[RPS]

As I said early on in this thread, compacts are a great way to get a wider range of gears using a road rear derailleur AND lose some weight. Any claims about compacts producing gearing or riding performance that can't be duplicated with other systems is simply incorrect.
One minor advantage of using a compact crank in combination with a smaller cassette to replicate standard larger-ring gearing is that the rider normally picks up one extra cog before the jumps become larger when measured in tooth count. For example, if we compare an 11-23 to a 12-25, there is one more cog with a 1-tooth jump before the jumps go up by 2 teeth. Since this normally occurs near the middle of the cassette where it gets a lot of use, the effective tighter gearing in the mid range is a nice bonus. It’s a small one but one I’d take if there are no penalties.

Having said that, the main advantage I see to compacts is gearing flexibility. It’s a lot easier to install larger rings on a compact than small rings on standard cranks.

[AndrewS]

What's funny about all this is that the only piece of technology that had to be developed for "road compacts" was the 11 tooth cog. 110 BCD double cranks have been around for ages. When you pair a 110 crank with a fairly normal gear range, like 12-25, you end up with something that came on mid-priced "Sport" road bikes of the '80s. But, newly repackaged with a downhill gear, Compacts are the hot new thing.

What no one talks about now, but did then, was that 130 or 135 BCD cranks are stiffer than 110s. No one "serious" would ride such a little, flexy crank back then. So when I see people buying compact cranks to hang big rings on, it's kind of funny.

I guess "light, stiff" compact frames with huge seatposts is the same kind of silly.

[brownm68]

I've been using compact cranks for almost two years. I've found that they're just as effective as standard cranks. They also add a wider range of gears. Lastly, they've been less stressful on my knees.

[AndrewS]

I've been using compact cranks for almost two years. I've found that they're just as effective as standard cranks. They also add a wider range of gears. Lastly, they've been less stressful on my knees.
How has the compact been better for your knees?

[RPS]

What's funny about all this is that the only piece of technology that had to be developed for "road compacts" was the 11 tooth cog. 110 BCD double cranks have been around for ages. When you pair a 110 crank with a fairly normal gear range, like 12-25, you end up with something that came on mid-priced "Sport" road bikes of the '80s. But, newly repackaged with a downhill gear, Compacts are the hot new thing.

What no one talks about now, but did then, was that 130 or 135 BCD cranks are stiffer than 110s. No one "serious" would ride such a little, flexy crank back then. So when I see people buying compact cranks to hang big rings on, it's kind of funny.

I guess "light, stiff" compact frames with huge seatposts is the same kind of silly.
Isn’t that like comparing apples and oranges? Back then isn't today.

There is no practical limit to how “stiff” a crank with 110 BC can be made, nor is there a practical limit for large chainrings. Only a little extra weight may be required to make them equally stiff; and I’m not sure of that. The 110 BC stuff that came on cheap bikes was, after all, cheaply designed and made. Maybe they don’t discuss this issue of stiffness any more because we’ve come to realize that it’s not an issue worth worrying about. I expect there is greater variation in stiffness due to manufacturers and models than inherently due to the bolt pattern being smaller.

Regardless, since I wouldn’t flex either enough to care about it’s not even on my radar.

[palincss]

When people talked about how flexy chain rings were, they were comparing the 50.4 BCD TA Pro 5 Vis with the 144mm BCD Campagnolo Nuovo Record.

[AndrewS]

Hey, it was talk then and it's just talk now. I was just Andy Rooneying it about the things that cyclists get fascinated on in different eras. I just remember people talking about Campy's 5mm bolt circle advantage over Shimano and Suntour. :rolleyes:

If I needed lower gearing, I would definitely go to a compact crank. I recently put a Rival crank on a friends 7410 Dura Ace bike so she could charge up all the hills in southern WI. It's cool.