Somehow the topic has been beaten to death

[Mud]

Forums change, history changes. Conflict brings about change. Life goes on. Right now I need some technical experience.

I currently run a 13-29 cassette. I am very comfortible in the 39 ring about 98% of the time and after having hooked up with a group that said it was B* on a fast flat section we could keep the pace with no problem.

Unfortunately the 13 ring is not available to me in the 39 ring. I would like to change out the rings where the 9th and 10th ring are 11 and 12. Has anyone done this. I thought there was a thread a while back.

I am not interested in gear inches equivalents and while I very rarely if ever use the 3 largest cogs I am saving them for a couple of the local hills.

Any help will be most welcome.

Bruce

[ergott]

There is a company that makes an 11-30 for Campy hubs. I think it's Soma. Haven't used one yet.

[Birddog]

Forums change, history changes. Conflict brings about change. Life goes on. Right now I need some technical experience.

Agreed, the hand wringing is getting tiresome.

To possibly answer your question. I haven't done it, but I'm contemplating doing the same thing. I see no reason why you can't combine a Campy 12/25 with a 13/29 as long as the cogs or most of the cogs are loose like on Centaur or Veloce level. The only thing you would need is a Campy first position 12 w/lockring. I'm thinking of a 12,13,14,15,17,19,21,23,26,29. I'd primarily use it for rides with some serious steeps or long grades.

Birddog

[Dave]

The suggested combination of a 12-25 with a 13-29 looks great on paper, but the 15-17 shift is awful. I know, I tried it.

Yes, you can find an offbrand cassettes with a 12-28 range, but reports on the IRD cassette are mixed too. The 11-28 is close to what you need, but the lack of a 14T will definitely be felt.

http://www.interlocracing.com/cassettes_steel.html

Unless youlre running a 50/34, an 11T cog shouldn't be necessary and an 11-12-15 jump would not really suck.

When 11 speed is avaialble, you might get an 11-29, but Campy engineers don't seem to think like I do. I read rumors of initial cassette offering gear more toward racer. They'd add a 23 to an 11-21 and a 27 to a 12-25 and the 12-25 might become a 12-27. An 11-27 instead of the current 11-25 is a no brainer and a 11-29 only require the last cogs to be 26-29 instead of 25-27.

[gdw]

It would give you the gearing that you need and is available from TA and possibly Campagnolo. I know you're not into gear charts but a 49t and 13-29 cassettte would allow you to use your big ring for most of your flatter rides.

49 39
13 99.4 79.1

14 92.3 73.5

15 86.2 68.6

16 80.8 64.3

17 76.0 60.5

19 68.0 54.1

21 61.6 49.0

23 56.2 44.7

26 49.7 39.6

29 44.6 35.5

[Birddog]

but the 15-17 shift is awful. I know, I tried it.

Do you mean you don't like losing the 16, or do you mean mechanically it's lacking. I have for many years, from time to time used a Shimano 9 spd 12/27 (12,13,14,15,17,19,21,24,27). I had no problem getting used to it, although I know a lot of folks miss the 16. I've also used a Miche 12/28 (steel), but last year on the TBP my first position 12 broke and rendered the lock ring useless and me freewheeling. Fortunately I was only about a mile from our sag and I swapped out wheels (Shimano 10 no less) to finish. I have no idea why it broke (split right through from outer to inner circumference w about a 1/4" gap). The Miche shifting quality was so so. I wouldn't buy another one, instead I'd buy a Veloce for near the same $.

Birddog

[Mud]

Let me take a second to explain. I changed from a 50/34 to a 39/52 and rediscovered my Mojo on the bike. I am working very hard to get my cadence up. When I rode the 50/34 I would pound the 50. The cadence would be slower and the rides would not be faster or I would feel like I had been through a ringer.

I tried the other day to push the 52. The first half of the ride was faster, the second half slower with the net being .1 mph. Again, I was tired.

My theory about all of this can be picked apart but here goes. I believe in sweetspots. It is obvious in tennis, golf, baseball, etc but also believe it exists in cycling where a certain combination of gears-not gear inches-seems to work extemely well for someone. I am able to maintain cadence and speed far more easily in the 39 ring than in the 52. Plus I don't feel the least bit tired at the end of the ride. The rides are up 2 mph.

I think age may be a factor where I may not quite have the drive in the larger ring but my climbing is as good or better in the 39 over the 34. I also believe it is mental.

When I used an FSA SL-K 39/53 the spacing is a hair wider than the 2006 Campy 39/52. I had no trouble getting the 13 cog in the 39 gear. The Campy does measure slightly narrower so there is the tinging noise in the 39. That is why the second smallest cog becomes the key. If that were a 13 I would be in Phat City, I think.

Since there are still so many creative people on the forum I figured I would ask the question.

[thwart]

I have built a 12-26 Chorus 10 spd and a 12-29 Veloce 9 spd cassette. Both work well, with no problems---even with that wide range 9 spd. Out of the saddle shifts or elsewhere, no mechanical issues. Of course gearing gaps are another topic.

I also have a Wheels Manufacturing 12-27 10 spd cassette on a set of Heliums; it works very, very well also.

So... lots of options... I'd probably buy a 12-25 Veloce cassette (all are loose cogs) and mess around with the ones from the 13-29 you have now.

[TACSTS]

I know it's not feasible if you are using a 135mm bcd crank (Campy) but if you are on something 130mm bcd try switching your 39t to 38t. I didn't want to go to a compact crank so I tried this and it's perfect for my needs.

[Tobias]

My theory about all of this can be picked apart but here goes. I believe in sweetspots. It is obvious in tennis, golf, baseball, etc but also believe it exists in cycling where a certain combination of gears-not gear inches-seems to work extemely well for someone. I am able to maintain cadence and speed far more easily in the 39 ring than in the 52. Plus I don't feel the least bit tired at the end of the ride. The rides are up 2 mph.Mud, sounds to me like you are challenging someone here to pick your theory apart, so here it goes. ;)

The description of what you are trying to achieve is considerably different than most others because you are not running out of gears when you hit the 13T, you just don’t want to use your large chainring. And that’s quite a difference.

No one should be crossing their chain all the way from the 39T small chainring to the smallest cog – in this case the 13T. If you are riding on your preferred 39T chainring and the 14T cog (which you imply works just fine) and need more speed, the next gear you should hit is the 52T/17T. That’s practically as close as anyone “needs” to get to the 39T/13T you are looking for; and it’s already available. Additionally, the chain line will be much better and you will be close to the center of the cassette so you can go up or down as needed.

Your premise – or assumption – that gear sizes have a magical affect on your legs, power, and therefore speed is flawed. Sorry but its true -- it doesn’t work that way. It can only matter significantly in a person’s head. For each revolution of your cranks your rear wheel turns 3 revolutions when riding a 39/13. The same would occur if you rode a 51/17, or 54/18, or 42/14. Same is same. Differences can only exist due to variations in drivetrain efficiency and they are very minor (nothing in the range you describe).

The main advantage to you staying in the small ring is that you in essence end up riding a straight block most of the time. And that’s good; but going to the large ring once in a while to go faster (beyond the 14T cog) won’t keep that from happening often anyway.

If it were me I’d pat myself on the back for having gotten stronger and then I’d start using the big ring when appropriate instead of changing the cassette. When you get to the point of spinning out the 52/13, then consider changing the cassette.

By the way, to increase speed on a ride 2 MPH (and I’ll assume you mean average speed) an average rider would have to increase his power by 25 to 30 percent; and there is no way that can happen due to gearing. You’d never be able to measure variations in gearing efficiency by measuring average ride speed.

Now your turn to counter. :beer:

[Ken Robb]

If you don't want to look at gear inches neither do I :) . You might find gearing Nirvana with a triple. I spend a lot of time in the middle 42 ring when I have one. With 50-34 compacts I sometimes do multi cog shifts when I shift rings but that doesn't bother me much.

[RPS]

When 11 speed is avaialble, you might get an 11-29, but Campy engineers don't seem to think like I do. I read rumors of initial cassette offering gear more toward racer. They'd add a 23 to an 11-21 and a 27 to a 12-25 and the 12-25 might become a 12-27. An 11-27 instead of the current 11-25 is a no brainer and a 11-29 only require the last cogs to be 26-29 instead of 25-27.Granted most engineers are predictable if nothing else, but occasionally they may surprise us.

If we do reverse engineering on how they select gear spacing for a given cassette spread or range, occasionally they seem to insert a little logic beyond the normal even-spacing based purely on math.

Two examples that come to mind are the Shimano 12-27 and Sram 11-28 ten speed cassettes. Neither follows the exact math approach, but instead spread gears to that they are closer in the range we ride the most.

Maybe Campy will do the same with 11 speed cassettes.

[cadence90]

I don't know all the current Campa cassette ranges, or the various aftermarket options (IRD, Wheels Mfg., etc.) but I do know that when I built my bike I looked seriously into a compact crank as opposed to my standard 53-39.

I hung out on good old Sheldon Brown's gear ratio chart, and it turned out that my best ratios were with a 50-36 crankset and my old 11-23 and 12-25 cassettes, The roll-out is better at both the high and the low ends.

I used a 50-36 because I did not want the 16t jump of a 50-34 crankset. I just kept my standard Campa fd and rd. I'm usually in the 50 ring now.

I love it. This option may not appeal to you, and might be marginally more costly, but compact cranksets are available a dime a dozen now.

Just an alternate thought....

[MilanoTom]

I don't know all the current Campa cassette ranges, or the various aftermarket options (IRD, Wheels Mfg., etc.) but I do know that when I built my bike I looked seriously into a compact crank as opposed to my standard 53-39.

I hung out on good old Sheldon Brown's gear ratio chart, and it turned out that my best ratios were with a 50-36 crankset and my old 11-23 and 12-25 cassettes, The roll-out is better at both the high and the low ends.

I used a 50-36 because I did not want the 16t jump of a 50-34 crankset. I just kept my standard Campa fd and rd. I'm usually in the 50 ring now.

I love it. This option may not appeal to you, and might be marginally more costly, but compact cranksets are available a dime a dozen now.

Just an alternate thought....

I agree that a 50-36 crankset works great. I've got them on a couple of bikes, and they work well with 12-25, 13-26 and even (for long and hilly rides) 13-29, if you have a medium cage rear derailleur. I've also got a bike with a 48-34 crankset and 11-25 cassette. Like the 50-36, there's only a 14 tooth gap between the rings, and the 11-25 is pretty comparable to running a 50-36 crankset and a 13-26 cassette.

Regards.
Tom

[Dave]

Do you mean you don't like losing the 16, or do you mean mechanically it's lacking. I have for many years, from time to time used a Shimano 9 spd 12/27 (12,13,14,15,17,19,21,24,27). I had no problem getting used to it, although I know a lot of folks miss the 16. I've also used a Miche 12/28 (steel), but last year on the TBP my first position 12 broke and rendered the lock ring useless and me freewheeling. Fortunately I was only about a mile from our sag and I swapped out wheels (Shimano 10 no less) to finish. I have no idea why it broke (split right through from outer to inner circumference w about a 1/4" gap). The Miche shifting quality was so so. I wouldn't buy another one, instead I'd buy a Veloce for near the same $.

Birddog

The 15-17 shift hesitates and jumps, if the cogs are not properly timed relative to one another. When you mix cassettes, the 15 and 17 do not have the same timing that the 15-17 has in my 11-25 cassette.

The 15-17 jump is also large at 13% compared to the average 8-9%. That can give it a clunky feel, even if it shifts correctly (which my 11-25 does).

[benb]

HTFU, Stick it in the big ring, and put the hammer down.

You're halfway down the cluster in the big ring at the point you are using the 39x13 with your gearing..

If you're on flat you should be in the big ring.. you'll have 2-3 bailout gears for slight hills before you go back to the little ring, and you'll have less drivetrain resistance... as 39x13 is a horrible gear in terms of chainline and the equivalent in the big ring is going to be almost a straight shot.

Not really any HTFU required other then pushing the gearshift though.

You're basically between 53x17 and 53x19 with 39x13. If the 2-cog jumps at that point in the cassette bother you the right thing to do is probably to start thinking about moving to a tighter cassette rather then trying to avoid using the big ring, especially if you're never using the 23/26/29 cogs!

[fiamme red]

If you're only using the big ring 2% of the time, you need a smaller big ring. Change it to a 50t or 49t or 48t.

[Dave]

I have to agree with others who find the OP's logic flawed. I've read other posts about some "sweet" gear ratio that they could not live without. Makes NO sense to me. Even riding the exact same route over and over, I don't use the same gear ratio on the same section of road, on every ride, because some days I've got a headwind, others a tailwind or some sort of crosswind. Each one might require a different ratio.

If you use a compact and want similar gearing with the 50T, you just use a cassette that starts one cog smaller. That's why I use an 11-25 with my 50/34 compact instead of a 12-25. This setup gives me a little more top gear than a 53/12, but the low gear of 34/25 is virtually identical to a 39/29. I tried using my old 12-25 one day, but the 50/12 top gear is just not enough when you ride mountain descents and want to maintain a decent speed. I was spun out a lot.

I've had absolutely no problem switching from a 53/39 to a 50/34 other than the occasional wish for a 16T cog, in the big ring. The ratio created by a 53/17 simply does not exist without the 16T cog, using a 50/34. When 11 speed comes out, that will change! Currently, the only other option is an 11-23. Then you get the missing 16T cog, but the gearing range increase with the compact is reduced to only one closely spaced shift. A 34/23 is not as low as a 39/27.

[RPS]

If you're only using the big ring 2% of the time, you need a smaller big ring. Change it to a 50t or 49t or 48t.+1

Mud, as Tobias and benb also stated before, using the large ring makes most sense. And if it requires slightly too much effort, I'd first downsize it to a 50T so that the crossover gear keeps it in the straight block part of the cassette. However, even that shouldn't be necessary. I'd just ride what you have which sounds about right.

IMO if a rider has a bike with two chainrings and hardly ever uses one of them, then his/her gearing is not right for him/her. The average gear should be very close to the average riding condition so that most gears get used on a regular basis.

[Mud]

but I will change the cassette at some point so that 13 is the second smallest ring. You may disagree but I know where my comfort index is. Moving along at 17mph in the 39 is just fine with me.

[fiamme red]

but I will change the cassette at some point so that 13 is the second smallest ring. You may disagree but I know where my comfort index is. Moving along at 17mph in the 39 is just fine with me.If you spin at 90 rpm, you can use a 39x16 at 17 mph.

[benb]

Get a 12-25 or 12-26, you'll have the ability to use the 13.

Work on your spin... 39x13 should be good for 22-23mph quite comfortably.

But there will be no extra effort in the big ring.. it's the same gears after all...

[Ahneida Ride]

I run a 13-29 (Campy) TA Zephyr 22-36-48

the 36 keeps me outa the 22 granny ... ( not on 15% Grades)

the 36 also gets me up into the 48 ring asap.
48/16 is a sweet gear.


There are times when I really could use a 48-12 ...
Perhaps I should install a 50 ring ?

But the 48 offers so many opportunities to spin.
I'll keep the 48/13 for now.

Let's hope for Campy 12 speed (12-32) :D

[my2cents]

I don't think so. like the OP, i find that gear inches that are nearly identical feel very different. using the small chain ring you create in essence a longer lever (the distance from the center of pedal spindle to the small chain ring) than yhou do using the big chain ring, and the longer lever requires less force, no?

[Birddog]

The 15-17 shift hesitates and jumps, if the cogs are not properly timed relative to one another. When you mix cassettes, the 15 and 17 do not have the same timing that the 15-17 has in my 11-25 cassette.

I'm not following this. That would imply that the design is slightly different on the 15/17 loose cogs as opposed to the ones on your 12/25 cassette. What am I missing? The cogs have to go on the splines, the splines are the same. How can the timing be different? I'd like some more edumacation on this.

Birddog

[Dave]

I'm not following this. That would imply that the design is slightly different on the 15/17 loose cogs as opposed to the ones on your 12/25 cassette. What am I missing? The cogs have to go on the splines, the splines are the same. How can the timing be different? I'd like some more edumacation on this.

Birddog

Yes, the cogs all go on the splines the same, but the teeth do not all have the same position relative to those splines.

Go the the linked PDF, page 25. An 11-25 cassette with a 15-17 shift pairs a 15A cog with a 17G for proper shifting. The 17 tooth from a 13-29 is a differently timed 17A cog, not a 17G, so it's not timed to shift with a 15A. It's timed to shift well with a 16A.

http://www.campagnolo.com/repository/documenti/en/Spares08_B_1007.pdf

There's also a small dot stamped on one tooth of each cog. When they are in a properly mated sequence, those dots create a uniform spiral. If you put a cog in the sequence with the wrong timing, those dots will indicate a timing problem.

[Dave]

I don't think so. like the OP, i find that gear inches that are nearly identical feel very different. using the small chain ring you create in essence a longer lever (the distance from the center of pedal spindle to the small chain ring) than yhou do using the big chain ring, and the longer lever requires less force, no?

Definitely NO. A gear ratio or gear-inch value that calculates to be the same is the same. For example, a 52/13, 48/12 and 44/11 will all drive a bike to the same speed with the same cadence and torque from the rider, since each one is a 4/1 ratio. There may be an extremely small difference due to the inefficiency of the smaller chainring, but it's so small, you'd never be able to measure it.

[fiamme red]

Definitely NO. A gear ratio or gear-inch value that calculates to be the same is the same. For example, a 52/13, 48/12 and 44/11 will all drive a bike to the same speed with the same cadence and torque from the rider, since each one is a 4/1 ratio. There may be an extremely small difference due to the inefficiency of the smaller chainring, but it's so small, you'd never be able to measure it.Even more due to the inefficiency of the smaller cog, because of the greater chordal effect.

http://groups.google.com/group/rec.bicycles.tech/msg/f2cb455b0b1a7a7e

[Birddog]

The 17 tooth from a 13-29 is a differently timed 17A cog, not a 17G, so it's not timed to shift with a 15A. It's timed to shift well with a 16A.

Got it.
Thanks,
Birddog

[Mud]

and it is nice to see a technical discussion again. I believe that I am wrong about things:torque, gear inches, etc. My first goal is to get my cadence up to where I feel comfortible with what I am doing. The Topofusion program I use enables me to break things down by mile so I can see high and average for each mile. It also gives me the terrain in elevation gain and loss for that mile. I don't want to appear too techie but the last mile to my house certainly slows the spin and the MPH. It also tells me where I am working well, can do better and JRA having a Bud.

Each year I have set a goal. This discussion is pushing me to rethink and set the bar higher. Having the best of "toys" and not trying to see how fast it goes or how high it flies is not the answer. I know I will never win a race or ride with the "A" ride but there is definitely more I can do. I will let you know.Thanx.