Tandem Gearing?
 

The daVinci with four chainrings (60/48/36/24 - effective) and a 9 spd 11-32 Cassette has much lower gearing than what I would normally use on my 1/2 bike. My wife and I are very used to the 12/27 10 spd cassette on our road bikes, and I've got mixed feelings about setting up the tandem with similar spacing. Wife and I just returned to cycling in our 60's after 20 years and I'm the far stronger rider for the moment in hills, but even a 12-27 would give use 23 gear-inch or so. Normal hills are in the 4-8% range with stretches in the 12-15% range. I take it the compelling reason for sticking with the lower gearing is the inefficiency of our tandem climbing while we're learning to ride together plus a compromise to balance effort between the two riders. Any and all input would be greatly appreciated.

Nobody says you 'have to' use all 4 chainrings on the daVinci. You could swap out the cassette to an 11-25 and still have plenty low gears.

You may not need nearly as low gearing as what the DaVinci comes with as stock.

But it is a good idea to have significantly lower gears on a tandem than you might have on your single bikes. If you encounter a really steep section on a single bike that's hard to climb in your lowest gear you can still usually muscle your way up at a very low cadence. But that frequently involves standing and considerable tossing of the bike from side-to-side. On a tandem it's harder to maintain balance under those circumstances and doesn't feel as comfortable for either cyclist, but especially for the stoker who has less control of the bike's motions. So it's usually better to have a low enough gear on a tandem that you can still maintain a good cadence on even the steepest climbs

I think the other part of hill climbing has to do with unequal power. One of you is likely to need a higher cadence than the other to maintain power climbing a hill without damaging knees. The one with the lower desired cadence can either insist on the lower cadence and do ALL the work (since the other has to lay off at that point) or accept the higher cadence and push with less than full power (for that rider). Either way, it is hard to find the perfect balance when climbing. So you can get into a situation where one is close to optimum ability to provide power but not the other. The weight of both riders and the bike, but less than the power of both riders. So it can be harder to get up the hill than it would be on two singles.

Happily all of that only applies to up hill riding. Down hill and level, even up wind, the extra power tends to be more than in proportion to the extra weight, since the wind resistance doesn't go up much.

All of that said, in the original question I think you appeared to be contemplating getting closer gearing. With the available range of a DaVinci, you should be able to afford to lose some of the bottom end, and close gearing is especially nice on a tandem. For reasons I've not fully come to understand, our experience - widely corroborated - is that you shift more frequently on a tandem. We aren't as easily satisfied with the gear choice as we would be on a single. I use each and every cog on the tandem, making frequent single gear shifts. On a single, I make far fewer single gear shifts. Perhaps I'm just not paying as much attention.

I always seem to want the gear that I don't have. On the single you can spin just a little bit faster or push just a little bit harder, but on the tandem it seems like there is one and only gear that works just right at the moment. The tandem seems to be much more grade sensitive (on the single the difference between 2% and 3% is negligable), on the tandem it seems like we are going 18-22mph or 8-12. We have a c-dale with 11-32 9 speed and I really miss the 17 and the 19 that I have on my roadbike (12-23 or 12-25 9spd). There are times where I don't like the current gear, then shift and find that the new gear is worse. When I was at school at Ohio State, riding west of town in farming country where the biggest hill was a highway overpass, we used a 12-25 off my road bike and that was great. Back in Vermont we need the lower gearing.

Would suggest that you just ride the new gears 'as is' for a little while until your stoker has really settled in, and you've had the tandem up some of your tougher climbs. It is always nice to have more gear than you think you'll ever need than to come up short and cause your stroker to suffer on some big hills and end up hating the experience.
You can always make changes down stream to move some gear splits around although with all the combinations you already have to choose from, you should have some pretty sweet spreads across most speed ranges already. BTW..that is a great Tandem, have fun!

Bill J.

Great feedback from all. I do intend to stick with the stock gears. It will take 2-3 months for my wife to get completely comfortable and efficient being clipped in and pedaling at a higher cadence (80+). Until then our hill efficiency will definitely be low and the lower gearing will be most welcome. After that we'll see what happens. Not having ridden since the days of 6 speed freewheels and downtube shifters this new world of brifters and 10 spd cassettes really changes the way we ride.

We started with the same 11-32 cassette you have. I left it on there and sampled what gears we needed for some of the steepest climbs around us before reducing the range. For reference, the low gear on my single is 30/23 and my wife's is 30/27. The low gear on the tandem is 28/28 with a 26" wheel. I don't think we've ever used that gear.

Certainly leave some margin for the epic ride where you've burned out and still want finish! Also (on a single and the tandem), I find I/we need lower gears in the winter, when we're not in as good shape, wearing more clothes, and breathing cold air. Hills we tackle at 42/24 now might be 28/21 in February.

At first I wanted to take off both the 32 and 28 from the cassette, but then under closer consideration, I only removed the 32.

Starting point:
11-13-15 - 17-19-21 - 24-28-32
Remove 2:
11-12-13 - 14-15-17 - 19-21-24
Remove 1:
11-12-13 - 15-17-19 - 21-24-28

The "geometric" spacing of the last option appeals to me. Comparing the second to the third options, you gain the 14 and lose the 28. The 14->15 jump is the smallest ratiometric jump in that whole cassette, and it comes at the price of the 28 tooth bailout gear. I didn't like that tradeoff. On the other hand, adding the 12 is a win: 11->13 is the biggest jump in the original cassette, but high speeds is where you'll want tighter cog spacing. (Same increase in effort leads to a smaller increase in speed due to air resistance.)

With a quad front chainring setup and a 24T small chainring, personally I'd be tempted to go tighter than the 11-28.

Keep in mind that the "franken-cog" setup come at the price of additional wear on the freehub splines; I think TG posted some pictures of amazingly fast wear on an aluminum hub without the cogs pinned together. In order to add that 12, I had to remove the bolts that pinned the larger cogs together.

I just adapted our triple crankset to a quad with a 24-tooth smallest chainring. I put a 12-26 cassette on the back (10-speed), and on our first ride we had to drop down to the lowest gear combination (24/26, 700c wheels) a couple of times when the road went above 10% gradient. That gear worked well for us then, so we're going to stick with the 26 as the largest cog. We might add a smaller cog, an 11 in place of the 16 tooth, at a later date, though, because the biggest chainring is only 53 teeth. Alternatively, I'll buy a 56 tooth for the front.

Quite nice though, isn't it?

I understand what you mean by lower gearing, we've yet to use the 4 lowest combinations for riding (maybe we need bigger hills). When using the absolute granniest of the gears on a flat it is difficult to maintain balance with our legs flailing so fast. We've used the "top end" from time to time, but we havn't run out of gears yet, again maybe we need bigger hills.

While we rarely use our 28-32 combo - we have on some long climbs - like 4 miles at 10% average in the middle of long multi day rides and climbs around here that are above 15%. We do however - use our 42-32 quite a bit.

Well, we went on a 39 mile ride yesterday and I'm retracting my derranged thoughts about changing the gearing. Of course with less than 100 miles on the tandem and being older folk we've got a lot of improvement ahead of us, but the 24-32 came in real handy as we "handled" the attached elevation profile. We had ridden the climbing portion as part of the Tierra Bella and in defense of our attempt to do this so early in our tandem career I'm blaming the stoker.

It's very difficult to find a 30-40 mile ride in a valley that doesn't have hills and most of the organized 100K and 100 mi. rides will have at least 3000' of climbing. Yesterday's ride was only 1800' according to my GPS, but the quality of the 1800' was a killer. We have another loop that we've done with 1500' of climbing, but the grade is substantially less which makes all the difference.

hi to all maybe you can help just got a 5 peed tandem and wife says she feels like shes falling !!!

Is this while you're actually riding or just when you're standing still?

If it's while you're standing still, are you leaning the bike to one side when you're stopped on your single bike?

If you're not sure, chances are... you are.

Try to keep the bike more upright and give your stoker a little time to gain some trust and get a feel for the bike.

hi
 

hey thank you for helping but im not leaning the bike this the first tandem we owned its a old Schwinn DELUXE REALLY COOL TOO BLUE !!!

OK, then back to the first question: Is this while you're actually riding or just when you're standing still?

Vague questions and minimal details get vague answers and SWAGs. Also, you might want to start a new thread to get direct feedback instead of burying it in the gearing thread.

hi
 

thank you!!!

you're not kidding right? that's one heck of a climb.