Compact/Standard gearing experiment
 

One of our tandems has a 53/39 double on the front and I normally use a 12-27 on the back. This works well but low gear is still a bit high for extended 10% grades and a higher top gear would be useful for the fast bits.
I would of liked to try a 50/34 and 11-28 but couldn't due to having a 130pcd crankset.
So I thought I would try a 56/39 and a 11-34 and am very pleased with how it is working out.
Low gear is low enough and top gear is great too. The larger jumps in the cassette are not a problem and we can do most of our riding on the big chainring as you tend to do with normal compact gearing.

What derailleurs are you using? Who makes the big ring?

Shimano 105 triple front derailleur and Deore rear. Chainring is made by Qbp. Front shifting is ok but I think it would improve with a Dura Ace 7800 chainring.

Have switched from decades of riding with triple cranksets on tandems.
Currently doing test riding with Di-2 on our tandem and using an in-the-seatpost NMH battery. Going to Di-2 necessitated switching to double chainring . Utilizing 48/32 chainrings and 10 speed 11/34 cassetteand 10-speed cassette/chain.
Has the gear range we need/prefer.
Pedal on TWOgether!
Rudy and Kay/zonatandem

We use XTR front and rear with an Ultegra triple, so can't really compare. But I'm interested in the big ring. We currently run a 53, but in the past had 54 and liked it. We find the bigger big ring useful when we are on the more moderate descent (2-4%?) where we can spin it up and hear the singles gasping behind. Would love to try a 56 like you have some time. Punish the singles, I'm thinking...

Just be aware that to use a 56 you need a wide range cassette. When we had an 11-25 on the back with a 56 it was virtually useless except for when going quite fast.
The rest of the time you would be cross chaining a lot. You could of coarse get away with it if you are a strong team that regularly cruises along at 25+mph.

So, you are suggesting something like an 11-34 cluster? We use that for mountains, but take it off for our regular riding.

It is just that at say 20mph you would be in something like a 56/19 or so. This is already getting near the low range of an 11-25 cassette. You don't need to slow down much more before you will have to drop it into the small chainring which is a nuisance if you have to do it all the time. Like I said before if you are strong enough that your cruising speed is more like 25mph then you will be working more in the middle of the cassette which is better. You could swap the middle chainring for a 44 and use that most of the time and just use the 56 for when things get fast.

You're in New Zealand, right? I had not thought that New Zealand abounded in extended 10% grades, but I was wrong. For example, there is Dyers Pass Rd Climb, 1.8 mile, 10.2%. And Purau Port Levy Rd Climb, 2.6 miles, 10.1%.

So, on extended 10% climbs like these, you've found the 39t inner ring and 27t cog (a ratio of 1.44) a bit high? Not gearing too high... just a bit high?

By figuring that a mashing cadence of 60 is a bit high, the speed with 39/27 is 6.9 mph. According to Kreuzotter, at a grade of 10.2% (e.g. Dyers Pass Rd), with a mean team weight of 140 lbs (e.g 120 lbs and 160 lbs) on a 30 lb tandem, 6.9 mph would require a mean team wattage of 238 watts, e.g. 200 watts for stoker and 275 watts for the captain.

That is most impressive!

Pretty much how we run, except we have a big ring of 54. Middle to 4, 5, or 6 in the back.

PK

Agreed.

One of my current training loops for my single, which also has a low gear of 39/27, contains a 1.5 mile 10% climb.

My 39/27 is just low enough, but I suspect I'd be a faster with a slightly lower gear.

I can't imagine schlepping the tandem up this grade in so tall a gear.

I just don't understand tandem teams seeing how much gearing they can get away with not having. If living in Florida or or the Great Plains, or some other tabletop flat location, fine. But if the team might encounter hills, too much gearing is just right.

It is a different thing for a half-bike. On my BMC I have a 50-34 compact crank, and 12-29 cassette, and with it I can do okay. For example, on Montebello, a grade of 7.1%, I've averaged 8.7 mph, which is the speed of a cadence of 80 on a 25t cog, so the 29t gives some reserve.

On our tandem on the same climb, we've averaged 7.2 mph. That is the slowest speed allowed at a cadence of 80 with the with a 50-34 and 12-29 arrangement. But a compact arrangement would have us spinning out (26.1 mph in 50t chainring, 12t cog) in our attempts at a KOM on this segment where we average 27.7 mph, and are still pedaling at 33 mph.

The solution for us then is a triple, which at 53-42-30 and 12-29, allows with a cadence of 80 speeds as slow as 6.5 mph and as fast as 27.7 mph with cassette jumps of 1-2 mph.

Maybe we need a triple only because we are too heavy and wattage impaired. A mixed team would have to be pretty good to not need one that climbs a 7% grade. With cadence of 80, 53-39 and 11-28, the slowest speed is 8.7 mph. Kreuzotter has it that for a 30 lb tandem, a 150 & 125 lb team, it would take a team average of 210 watts to climb at 8.7 mph. Figure 245 watts for the captain and 175 watts for the stoker. A compact crank wouldn't work for a team with that much wattage, as they will fly at 24.6 mph at a 0% grade (according to Kreuzotter), on the verge of a compact crank spinning out.

I've found that 8% grade is the tipping point for us. We can do sustained 8% in the middle ring reasonably comfortably.

Even then, if it's going to be a really hard, long ride, with worse than 8% to come, we'll use the small ring so we don't have to work as hard turning over a bigger gear.

I agree with Ritterview, what is the issue with running a triple? We rarely use ours here in the flat Midwest but we are inclined to put the tandem in the back of the Ody and travel. Hence the triple will stay.

How much weight is saved by removing the triple and going to a wide ratio cassette?

Pretty much on the same page as everyone else here.

We run a 52/42/28 chainring set paired with an 11-32 cassette.

We don't have many extended climbs around here, but we have a lot of long rollers that take a couple of minutes to climb. Many of these are 10%, some are more.

The middle ring is enough gear for us under ordinary circumstances, we probably use the little ring for less than 0.1% of our mileage. Nice to know it is there though.

There a 300 yard, 10% hill (Strava verified, I no longer trust my exercise-impaired memory) we encounter on one of our routes only a couple of miles inbound to home. Under most circumstances we'll just muscle over it, but Saturday with 50 HOT miles having cooked the crew it was nice to shift down to that little ring.

I don't have any issue running a triple and still do on 2 of our tandems.
It isn't about the weight either. But if you can use a double and get the gearing you want, why not?
- A number of people on here have said they like a narrow Q factor. Our 2 tandems with doubles are 145mm and 140mm. Try and get that with a triple.
- Simplicity.
- Better chain lines.
- Able to run any road cranks if you go to a set up like the Paketa V2R
- Able to run Shimano 7900 (electronic or mechanical).

• Which double crankset that you use on your tandem has a 140 mm Q-factor? There aren't anything but spindly exotic cranks on the Fairwheel [double] crank review that have a Q-factor less than 145 mm. The need for a sync chain on either the right or left would presumably increase your Q-factor above the half-bike road doubles listed by Fairwheel.

• The Lightning triple tandem crank has a Q-factor of 155 mm. Just outside of the range of the highest Q-factor doubles.

• The Athena triple about to be introduced will have a relatively narrow Q-factor and close-in chainline, as the Campy cranks have a favorable Q-factor to start, and the 11-speed has closer chainring spacing. But, alas, there is no tandem version.

• Neither V2R and/or Di2 do anything about gearing. It seems that those with V2R or Di2 would have gotten triple versions, had these been available.
  

• Simplicity is a reason to stick with a double, though in going to a tandem everything else is more complex, so why not the crank too?

The Q=140mm cranks are a TA tandem crankset on our Bob Jackson. I guess you would call them spindly and old rather than spindly and exotic.

This seems to be a 'Whatever" kind of topic. DeanV the OP says he found joy with his 56 /39 > 11/34 setup and doesn't mind the big jumps. Others find it not quite for them, and I doubt we would follow his path, but it works for him.

Ritterview is correct, here in Florida, where we ride with no appreciable elevation, our preference is tight gear spacing. When we do head north, the narrow spaced rear has remained, and we use the wider range of the front rings when needed.

I doubt there is any correct solution for this topic.

Everything is a compromise.

PK

Living in Ohio with mostly just rollers, we can ride 53/39/28 with a 12/25, but going out of area with more significant hills requires a change to 11/34. I got tired of changing all of the time so we just run the 11/34 mostly now. Tuned correctly, this setup works well anywhere. Also at 140 total years, we don't have the power that we had 20 years ago, so having the lower gear options is nice, even when we don't really need them. I do ride a compact on my single and like it a lot.

Living in the SW, we can do rides that are literally flat for miles in the Rio Grand Valley, ride in the mountains, or anything in between. We decided we did not like big jumps in gearing between the cogs so we have opted to run a granny up front with the 53/39/26 combined with an 11/28 cassette on the rear. This gives us the tight gear spacing we like with the option to drop into the granny when we hit the big climbs.

The one caveat with this setup is that we can experience chain rub on the RD if we drop to the 3 or 4 smallest cogs on the back while in the granny. That is not a big deal for us however because we only resort to the granny when we are on serious climbs and don't need the small cogs.

I agree with the others that this is a personal decision for each team and involves some compromise whichever way you decide to go.