Lowest Gear needed?
We're thinking of getting a good road tandem (about 37 pounds), and wondering about gear selection. With a triple in front (smallest chainring 30 iirc, specs not in front of me), the stock cassette of 11-34 (10 speed) seems like overkill. It's pretty much the same gearing I have on my mountain bike. Both my wife and I are strong riders, and I wonder why we'd need such a low gear (we've only ridden a tandem once, and I confess I don't remember it's gearing or our gear selection that day). I know that tandems do tend to give up a little on the climbs, but is it that big a difference that we'd need such a low gear? Of course, the reason I ask is to get better gear selection (as many 1 tooth jumps on the cassette as possible).
Of course, the wildcard in this question is that it's a periscoping tandem, and we'd do quite a bit of riding with our one of our kids on the back.
We live in area with lots of rolling hills. The steepest grades we'd encounter would be 10%, but those would be quite short (couple of 100 metres at most) and any longer climbs would be at a much easier grade.
We weren't able to make it up the nastiest hill we ride once a year until I replaced both cassette and inner ring. That low gearing is pretty much unused the rest of the year. It's good to know that we have what it takes (mechanically) for godawful hills.
pan y agua
It's a misnomer that Tandems climb poorly. Tandems have an aero advantage on the flats, so a team of a given average power will be faster than a single rider of same power on the flats. Thus a tandem can keep up with more pwoerful riders on the flat.
When you hit the hills, the aero advantage goes to almost nothing, and now the Tandem will only climb with single riders of equivalent power to weight ratio, and the stronger rider that the Tandem could keep up with on the flat pulls away. Thus it's not that the Tandem climbs poorly, it just doesn't have an advantage climbing like it does on the flat.
One limiter climbing is that some teams don't like to stand. So if you're not going to climb standing, you need to figure your gear choices by what cadence you'll spin sitting.
Second, you also need to consider that if one rider is weaker than the other, you need to figure how well you'll climb based on the power to weight ratio of the combined team, which will be lower than the power to weight ratio of the stronger climber.
All that said, you should be able to climb a tree with a 30/34 combination.
Last edited by merlinextraligh; 03-10-08 at 10:26 AM.
I thought 28-34 was overkill on our tandem, we are both pretty fit. But we still used it the other week. Our tandem is considerably more than the weight of our 2 solos, yours might not be. You could always have 2 cassettes, depending on what ride/stokers you are anticipating. Not too expensive and quite quick to change if you still keep the long cage rear der. You'll probably have 700c wheel on the tandem too vs 26" on you mtb, so it is a bit higher.
We seldom use our 34T cog or our inner chainring combo, however we have been glad to have 'em on rare occasions.
Fitness level and terrain/altitude are the big decider.
Our motto on gears: better to have 'em and not need 'em, than to need 'em and not have 'em.
Low gears are like Internet bandwidth, you will use what you've got at some point. We have 29x36 and have used it on ocasion. Actually I think it goes on for every ride climbing out of the garage, but that is only to impress the neighbours.
We live in Portland Oregon and ride the area including climbs in the Columbia Gorge, Larch Mtn, in town, the west hills area and do numerous organized rides including centurys each year and our low is a 30/29. That's not to say we haven't perhaps wished for another gear on occasion but our current range hasn't stopped us yet.
I [I]am[I]comtemplating going to a Shimano cassette on our new bike, probably a 32t, combined with a Jtek for use with our Campy drivetrain. The only reason I'm considering the change is our plans may include more miles in Southern Oregon/Northern Cal this summer. My wife is not a rider at all other than the tandem however she's been a runner for 30yrs, is 5'2.5" and only weighs 110lbs and her power/strength to weight ratio is huge, thank goodness.
We live in Eastern MA, and there is no real hills to speak of. That, and the stoker wishes not to descend any hill of note (she doesn't care about the up), have led me toward putting a 12x23 on the back for an experiment (from an 11x32 that came with it). We never hit the granny (30t) except as an experiment in riding over 2000 miles, and I wanted to dump the double (I hate the lack of trim on the triple), but using the triple and getting the same low (a 30x23 is roughly equivalent to a 42x32) is the cheaper option. I tested on some of the steeper sections we do, and we never went below 42x28.
We are not touring at all, obviously. Just fast group rides. I have yet to take this out with the new gears, but it definitely makes gearing sense. We will see how much common sense it makes. And I am really looking forward to not having those humongous thumps when shifting one position and feeling like I just changed 4 cogs on the single.
Production tandems and component specs are established with the lowest common denominator in mind and the average tandem buyer will likely use every gear that a tandem has available unless they live and ride in a place that is devoid of any real elevation changes.
Originally Posted by hscoach2
However, if you look at Co-Motion's racing tandems you'll see how the faster / stronger than average teams address the gearing on a tandem: the spec is a 12x27t cassette.
Cassette changes are the easiest way to fine tune the gearing on a tandem as, it's where you get the most bang for the buck by converting unneeded low-end gearing for tighter spacing and faster shifts with that smaller cassette. As for how small to go, that's really something every team needs to figure out for itself. As zonatandem notes, while that small chainring and large rear cog is a combination that's not often needed, it sure is appreciated when you venture out to new places and find yourself facing something greater than 10% and that's just too long to attack in a single all-out effort. However, if most of your riding is done on familiar local routes and you can get away with a 12x25t, then knock yourself out: just remember to remove a few links from your chain as you downsize and keep a second, longer chain in your tool box with that 12x32 or 12x34 "just in case".
We usually ride here at home with a 12x27 and put a 12x32 on when we head for the mountains. Our road tandems have had 54/44/32t rings for about the past 10 years and on our most recent tandem I opted to go with 53/42/30t. We've not had to walk up any climbs, but the folks with those 34t rear sprockets don't seem to grimace as much as we do. Then again, we've also seen really strong teams who showed up with double chain rings and a 27t big cog who simply sucked it up and attacked those hills as if their survival depended on it.
Bottom Line: Everyone just needs to figure out what they need and, from the manufacturer's perspective, 9/10 buyers will probably be very happy with the stock gearing.
Riding Heaven's Highwayson the grand tour
We are a 50's -60's recreational team with average power living in a hilly area. We are glad to have the 30/34 combo when needed as they are cheap health insurance for knees and such. I would go with more gear than needed to start with and swap out cassettes later if you aren't using all of the big ones. Have fun.
Thanks for all the replies. I think we'll probably have to keep the low gearing, as one of its main uses will be riding with our kids.
It all depends on the terrain you are riding on and your fitness. We have only used 1st gear on the extended climb up Mt. Diablo in the SFO Bay Area. Climbing up over 3900 feet. We spend most of our ride on the 53 chainring even on some of the short climbs. You would not want to be in the position of wanting lower gearing and not have it. It would put a damper on an otherwise great ride! I have seen some tandems running corn cobs in the back...must have been from a very flat place.
We managed to get out today for a 35 mile ride using my new 12-23. It was a fairly flat route, so we still never went into the granny, but we did use the lowest gear of the middle ring, a 42x23. So far, I am very satisfied with the change. The shifting was much nicer (though I think the new cogs have to get to know the chain a little better). For stronger teams and no mountains, this is really a better setup, in my opinion.
Now I just need a gear indicator. I hate not knowing what cog I am on, and this change has thrown my mental calibration out of whack. The cassette is so far away on a tandem, it is like riding in the dark. I am sure with time I would re-calibrate, but changing bikes so often makes it harder.
Why do you need a gear indicator?
If legs tell you to: shift!
Originally Posted by zonatandem
I haven't seen a gear indicator that tells when to shift. My FlightDeck shows me what gear I'm in which I find very convenient. The cadence meter is what tells me when to shift. Regardless of what my legs tell me, I can keep the stoker in her cadence range.
Originally Posted by zonatandem
Main use of the flight deck gear indicator is to keep the pilot apprised of where
the chain is at the present. A few pilots can keep up with this, most don't
have the short term memory computer wired up. The in line cable indicator
works reasonably well to tell you if you have 1 or 2 more cogs going in or out
on the cassette. As to gearing, some of this will depend on how much big
changes in gearing bother you. 11-34 cassettes have some pretty big jumps,
so if you are riding with a group you may find your cadence bouncing around
more than you like, or be in a speed where the cadence is just 'not right'.
OTOH riding alone or with kids you will need that 34 from time to time if
you are in a hilly area. We have an 11-26 and have found only one hill we had
to walk, a hair pin at 20%+ grade. It is really nice having a close ratio cassette.
My pilot likes his HRM/grade Sigma computer too much too go back to flight
deck so we occasionally get shifts into the 30t CW when he doesn't remember
he is already in the 42t and not on the 54t CW.
SRAM lists an 11-28 cassette (10spd) but you might have to hunt for it.
The 11t sprocket is for moderate or steep longer downhills when you want
to let it all hang out in the 36-42mph range. Above 42 we spinout and coast.
Interesting to hear everyone's take on this. We switched from a 48 lb Motobecane with a 30x28 to a 35 lb CoMotion witha 30x34 last year. You would think that we could just throw the big sprockets away (we are also pretty light at 260lbs total), but we occasionally use the 30x34 just for the heck of it (we have a 16% grade right next to our house). I would say that we don't really need it, but it's nice to know it's there. Here in West Central Ohio we rarely even use the inner ring, but we definitely need it once in a while especially since we are pushing mid 60's. I'm a strong older rider and my wife rides a lot but is pretty slow and power is definitely not her strong suit. I've been kicking around the thought of doing the Hill Hundred in Indiana on the tandem, but I'm not sure we can get up Mt Tabor at 20% even with the 34.
Well, to answer the question to my statement about gear indicators: Oh, I know when to shift. The problem is trying to remember what chainring I am on. Today, for example, was a very fast ride. We were on the big ring most of the time, and we hit this gradual incline on the way back, and I dropped it to ... the granny! Yuck. Felt stupid. Stoker loves those missed shifts. I must have been on the middle ring, and not recalled. Or maybe I dropped right past it.
We have Shimano 105 Flight-Deck compatible shifters, but I was just going to go for one of the simple o-ring in a tube things like I have on my single -- which is lame, but it came with it and I decided I like it.
But the bottom line on the 12-23 cassette is success. Won't go back to the 11-32, I am certain.