Tandem Cycling - Switching back to 11-32 from 12-27

Not too long after we bought our DaVinci tandem I switch the SRAM 11-32 Cassette out for a 12-27 Ultegra, my reasoning being that the closer spacing would better accommodate the small overlap in cadence between myself and stoker (DW). My decision had a relatively sound basis, but was made with very few tandem miles under our belt(s).

So I switched out the cassette last night a took a relatively easy 32 mile ride today. I'm convinced I've made the right decision in returning to the 11-32. Here's my reasoning:

On the Flats: You give up a little by not being able to pick exactly the right gear, but unless you're racing what's a few tenths of a mph?

Descending: Probably would accelerate ever so slightly faster by being in the "right gear" with the 12-27, but you're terminal velocity, fear limited anyway. Do I need the 11t cog? No, but it came with the bike and if you're not spinners you can actually use a 60-11 combo at something less than an insane velocity.

Rollers: With the greater spacing of the 11-32 I just don't have to shift quite so rapidly. With the 12-27 I was shifting very quickly to keep the speed up, "powering" (we're 60+ remember) up the hill as it were.

Ascending: Here's where the 11-32 will pay off. Even though our small chainring is effectively a 24t and the common wisdom is that climbing speed will be the average of captain's and stoker's, I believe this is under ideal conditions. The available 24-32 combination will give us a gear that will enable my stoker to carry herself and 1/2 of the tandem up the steeper climbs (>8%) without unnecessary fatigue. On the longer rides (100K, 100mi) any time we would gain by grunting up something steep at 5-6 mph versus 4 mph pales in comparison to what we loose for all the remaining miles.

Incidently, the SRAM cassette seems to be quieter ( with an SRAM chain) than the Ultegra. Go figure.

I view the 12-27 experiment as an excursion to the roadie dark side. I have seen the light. Consider this tandem newbie wisdom.

Go with what you are comfortable with and what works for you! There isn't anything wrong with that. I prefer a tight cluster and really hate being between gears so I usually run a 11-28 on my tandem. Gearing is very personal and should reflect the strengths and weaknesses of the riders in conjunction with the terrain you will be riding on.

btw a 60-11(which I have on my tandem) is good for right around 50mph which isn't anywhere near my terminal velocity. ;)

We were pedalling a 53-12 gear at over 45 mph / 75 kph a couple of weeks ago, but that was a bit nuts. I agree that we need to get an 11 tooth cog on there, but I certainly don't think that you need it with your 60 tooth chainring. If I was you, I would build a custom 13-30 cassette, but that takes a lot of fiddling around. If you like the 11-32, then go with it, but I could never handle those big spacings (I can't even put up with the 19-22 jump in the middle of the 11-28 cassette).

I had my new Calfee built up with a FSA Triple 53/39/30 and DA 12/27 cassette. I have to say I was really worried about climbing. Turns out I was worried about the wrong end of the gear range. My stoker and I managed 700 metres of >20%, during one 60 mile hilly ride. It was the downhill that caused us more problems; ended up tucked and coasting on anything steeper than 5% as we spun out our 53/12 quite frequently.
Now that our Calfee is packed away until next summer vacation, I’m thinking about gearing changes before next July’s cycling vacation. One definite change will be the big ring is going up to something like a 56. I plan to do more climbing next summer, so I’m thinking a 28 underdrive to keep the cadence high during the climbs. The big question is will my DuraAce FD & RD handle this large a gear range?

I guess I should mention that my team will still be riding our Santana in Sicily until next July. Next summer the Calfee is coming back to Sicily with us!!!

Realistically there's not a huge need for an 11. 53x12 is 42.5mph at 120 rpm, and right at 50 mph at 140rpm.

Once you're above 40 mph, the return on effort from pedalling, as opposed to coasting in a good tuck is very marginal.

And the speed in descending typically comes from accelerating at the top of the hill, which doesn't require a huge gear.

Last year doing Everest Challenge, we had no trouble getting over 60 mph descending with a 53-12.

Appreciate all the responses. I can find reason to agree with most everything said: 60 is too high, 11 is to low, 11-32 spacing is too wide. I'm going to keep the 11-32 on until I find that we're not using the larger cogs in our 24t chainring. We've got a relatively bad climb (2900 ft in 11 miles) 2 miles from our house that we'll work on 1 day a week over the next 3-4 months. I don't know that we'll ever get to the top on the tandem, but if we can wean ourselves from the larger cogs we'll be ready to go back to the 12-27.

I had my new Calfee built up with a FSA Triple 53/39/30 and DA 12/27 cassette. I have to say I was really worried about climbing. Turns out I was worried about the wrong end of the gear range. My stoker and I managed 700 metres of >20%, during one 60 mile hilly ride. It was the downhill that caused us more problems; ended up tucked and coasting on anything steeper than 5% as we spun out our 53/12 quite frequently.
Now that our Calfee is packed away until next summer vacation, I’m thinking about gearing changes before next July’s cycling vacation. One definite change will be the big ring is going up to something like a 56. I plan to do more climbing next summer, so I’m thinking a 28 underdrive to keep the cadence high during the climbs. The big question is will my DuraAce FD & RD handle this large a gear range?

I guess I should mention that my team will still be riding our Santana in Sicily until next July. Next summer the Calfee is coming back to Sicily with us!!!

There is really no need for a 56. 54 with an 11 in the rear would do just fine if you want more gear. With a 56 - you'll be riding in the higher gears of the cluster with more chain overlap on the flats. You also won't find any front derailleur that will handle the 28 to 56 range - at least not well.

As mentioned above at a certain point - you'll go faster coasting. We've hit 69.5 mph downhill and the 54-11 was worthless.

I think you have to take into account how fast you spin as well as the terrain and your condition. You can't just say this gear works and that one doesn't. That may be for you where you ride but it might not be for me. 140rpm for me is spinning like a blender! I do a lot of ultra distance races with long extended (15-20+ miles) 2-3% descents, I live in my 60/11 gear. Sure you can coast down those hills at 30mph or you can pedal at close to 50mph. I've passed up more people coasting along than I can remember. Since I don't climb real fast I have to make up some time somewhere and the flats and descents are where i do it!

I think you have to take into account how fast you spin as well as the terrain and your condition. You can't just say this gear works and that one doesn't. That may be for you where you ride but it might not be for me. 140rpm for me is spinning like a blender! I do a lot of ultra distance races with long extended (15-20+ miles) 2-3% descents, I live in my 60/11 gear. Sure you can coast down those hills at 30mph or you can pedal at close to 50mph. I've passed up more people coasting along than I can remember. Since I don't climb real fast I have to make up some time somewhere and the flats and descents are where i do it!

You have to consider the relative efficiency of this. Given that wind resistence is a squared function of speed the energy necessary to raise speed even a small fraction becomes huge as your speed gets higher and higher. A hill that you would coast down at 30mph would be about a 4% grade. To get to 50mph on that same 4% descent you have to put out over 1500 watts.

The payback for pedaling at a point above where you spin out a 53x12 just isn't very big and the energy cost is huge.

Or take a closer example. Descending an 8% grade coasting gets 43+ mph. Raising that speed to even 47 mph takes over 300 watts.

Thus when we're talking grades sufficiently steep to spin out a 53x12, the fastest,most energy efficient approach to descending them is going to be to hammer the top part of the descent, accelerate qucikly, then tuck, letting gravity and momentum take over.

Particularly in an ultra event, you'd be better off using the descent to recover, once you've got the speed in the high 40's.

I am fully aware of that theory. :) I've seen the wattage numbers and I also know exactly what kind of effort I have to put out on those descents . I've tried resting onthe descents and if/when I do that in an ultra I'm SOL. It's as simple as that, I can't make up that time on the climbs. Over the years I've learned that I have to go fast where I can go fast. I go fast on the flats and I go fast on the descents. You have to go with your strengths. I don't climb fast enough to stay with the leaders so. I rest on the climbs. :) I don't go slow (well relatively) on the climbs, I go fast enough to sustain a decent pace and recover. I've been racing ultra's for a very long time and I know what works for me and have a few course records to go along with that. I'm not the only one who does it that way, Sheana Hogan comes to mind, she rides in a similar style and is very fast. She's the only lady I know who runs a 60T front sprocket. I think it goes along with the fact that many Ultra racers are mashers, not spinners. I've actually tried to reform into a spiner but it never fails that 300-400 miles into an event I revert to mashing.

When I do a 1200k or event like that I am more likely to coast earlier on descent. It just depends on my mood. If I want to go fast though I have to use those gears!

Personally, I think both Merlin and Homeyba are correct. I just think it depends on which ride you are on.

Say you are running RAAM on a team. Yeah you have been out there for five days, but for your pull you have to maximize your speed. If that happens to be a 20 mile descent that is straight as an arrow, you had better have the big gears (brake shoes might be helpful too :roflmao2:).

On the other hand, if you are running a 1200k spinning out at the top of the hill and getting into a good tuck is not bad. (As long as I am drafting Homeyba going downhill, I am good - he can pedal all he wants.)

I would love to have some really big gears, but there is no way I am giving up my granny (No death panels for worn out low gears! :lol:). Since the derailleur can accommodate only so much of a range I am forced to choose between a low, low gear or a really high, high gear. My wife and I have agreed to disagree on this issue. She wants a bigger high gear, but we have a low, low gear - and spin out at the top of hills and tuck. (I am the one who works on the bike, I get to choose... some of the time... she reminds me that I am wrong about this just about every time we spin out.)

Your results may vary.

Now if you want to argue about something, let's talk about those stupid looking skinny tires. :lol:

Personally, I think both Merlin and Homeyba are correct. I just think it depends on which ride you are on.

Absolutely!!! The logic that Merlin has makes sense for a lot of people but not everyone! ie me and anumber of other long distance riders. :) There are a lot of other variables to take into consideration. I'm a big guy. I'm not a spinner but I can put major power to the peddles. The key for me is to not ride into the "red zone." If I get into the red zone I'm toast because it takes a long time to recover. Therefore I have to ration my output on the climbs and try to make it up elsewhere. I use my weight and power to maximize my advantage. If I weighed 150lbs, could spin like a blender and climb like a billygoat I would probably do exactly what Merlin (and others) have said.


On the other hand, if you are running a 1200k spinning out at the top of the hill and getting into a good tuck is not bad. (As long as I am drafting Homeyba going downhill, I am good - he can pedal all he wants.)

Not that that has ever happened! :p


I would love to have some really big gears, but there is no way I am giving up my granny (No death panels for worn out low gears! :lol:). Since the derailleur can accommodate only so much of a range I am forced to choose between a low, low gear or a really high, high gear. My wife and I have agreed to disagree on this issue. She wants a bigger high gear, but we have a low, low gear - and spin out at the top of hills and tuck. (I am the one who works on the bike, I get to choose... some of the time... she reminds me that I am wrong about this just about every time we spin out.)

The world is full of amazing things, that there is one of them! :roflmao2:


Now if you want to argue about something, let's talk about those stupid looking skinny tires. :lol:

Hey! I resemble that remark! Don't hate me just because my tandem won't accept a tire bigger than a 25...:p:p

Maybe to put a finish on this thread I posted a question in the Bicycle Mechanics forum about building a custom cassette. One of the responses pointed me to a 13-30 9 speed that is available from Harris Cyclery. While this is pricey at over $100 any experimentation I would undertake would cost even more. I'll get a 10% lower gear than the 12-27 and still pretty reasonable spacing. (They also have a 12-30).