Does anyone have suggestions on putting together components for a new Co-motion? We're going to order a Co-motion Speedster Copilot. We don't compete, we just want it for long (50 mile plus) rides, and we both like to climb. Does anyone have suggestions regarding:

1) Drum vs. disc brakes? Someone told us to get a shaved drum from Tandems East. We love to climb, and have a lot of hills here in Sonoma County. We see a lot of tandems with drums; the shaved drum sounds like a good option, to save a little weight. But how would disc brakes compare to using a drum?

2) RE climbing: Gear ratios? The Speedster comes with a 54-42-30 chainring. Someone told us to get a 53-39-28, to manage the hills around here (Sonoma County), which is similar to what I have on my Calfee single (53-39-30).

We're getting the wound up carbon fork, the Chris King headset, the suspension seatpost, and the carbon cranks. Anything else we should be thinking about?

Thanks for any suggestions.

I haven't done temperature tests on drums, but I don,t like the idea of a shaved drum on the West Coast. Hills in the Appalachians are often steeper than on the West Coast, but they are shorter (say 5-10 km max.), so the drum won't become too hot and will have time to cool down before the next hill. But when you face 15-25 km long downhills, you'd better have a brake that will cool down easily.

Drum vs disc ? The drum adds about 1.5 lb over the disc, and it's rotating weight. You will notice the difference if you lift it on your car and migt see it if you compete, but otherwise, I'm not sure. As to which one you need, it depends on your riding style, the roads you actually use and your desired margin of safety.

Some will say that unless you are heavyweights and/or pack lots of cargo, you could be OK with just the rim brakes if you enjoy high speed descents. If you prefer to ride at high speed and slow down drastically for each turn (or when it's too fast), then a rear disc is probably a better choice : you would "let go", then slow down with the rear disc before a curve, cattle guard, etc., and use also the front brake when additional braking is required.
On the other hand, if you prefer to slow down the bike all the time during a descent so it doesn't accellerate too quickly, than a drum brake is preferable. With the drum brake, you apply it moderately for a good portion of the downgrade (either with a brake lever as I do or with a shifter lever) to keep your speed at a steady 30-40 km/h, and you do additional braking before curves with the two rim brakes. If you have really bumpy roads or a nervous stoker – or if both of you weight 250-300 lb –, then the drum brake is the way to go.

Climbing gears ?
What gears does your wife has on her single? What are your climbing styles?
Assuming they are similar to yours and assuming you both have a similar climbing style, your suggeted 53-39-28 would work. Otherwise, you might try 53-39-26 or even 24, especially at the beginning.
If you are used to climb while standing on pedals, forget that for a while. You'll need to master your tandem skills and especially synchronise your climbing techniques before you stand.

On the brakes, what's your total team weight and how much braking do you use on the descents, e.g., do you let it fly and brake hard before turns or do you tend to use moderate braking throughout the descent to keep your speed in check?

In general, the only thing I would suggest is keeping your options for future changes wide open by making sure the frame has both the pac-man for the Arai drum and the I.S. mounts for the disc which will give you lots of flexibility down the road, even if it requires a second rear wheel/hub.

For climbing, either of the combinations will work fine. It's all about preferences for cadence and top-end speeds. If you don't try to spin-out on descents to attain max speeds before tucking or mix it up in fast pacelines, then the smaller chain rings will work just fine.

On our Co-Mo Speedster, we use our 54-11 gear quite a bit, a lot more than I use the 53-12 on my single.

Any thoughts on a 54-39-26? Personally, I'd like to try this setup since we could go with an 11-28 on the back and have tighter spacing than my 11-32. I seem to be hunting for gears quite a bit.

-murray

I am interested in hearing from any teams who are running wide-range chainrings too. 54-39 is a big jump. 54/53-42/39-28/26/24: anybody running these combinations? How does it shift?

i have a suggestion the Rohloff' Speedhub 500/14 is a Incredible alternative to a convensional drive train sistems, yes on a full suspension MTB the mass centralization of the hub is noticiable specially do to the sprung weight that slow down the suspension reaction but on a road tandem were you are not jumping or doing extreme manuvers is not really a concern, yes it will bring a little more gyro forces to the rear wheel do to the extra mass but is not that critical



in the braking deparment they offer a disc brake compatible interface (and I think a drum set up but don't quote me on this one) on the shifting department is no comparation to anything in the market (I pretty much try it all) the 14 gears spread out at even spaces,,i think 7.3% in between each gear, you can also chose to do a little cheating and run two chainrings (i set up a few bikes this way) to multiply your options (oviuslly some overlap will become present) the smallest ring they recomend is 38T (do to the extreme torque produce by smaller gear rathios) but that is sufficient to compare with a 20T front 32T in the back, and then for the high speed stuff you can install a 44T or something and you will a have a gear exivalent to a 68T /12T(just gestimating)



another beautyful side effect of running a single rear chainring (you can NOT (in safety) run two driven and one timing ring) is that you don't need the timing chain to be on the left leaving the market wide open to any crank set in the market and not just the specific cranks made for tandems since you can run the two chains on the right side ussing the inner and outher chainring mounts of a convensional crank

personally I'm saving the money at this very moment to get one for my mountain tandem (much better ground clearance since i can run a much smaller drive chain ring plus a lot less prone the derreileur damage in the dirt)

Oh another great feature is that the speed hub is that the "Index" sistem is perform at the hub (not at the shifter) making it ideal for long and maybe complicated cable routings like on the tandem were the rate on compression and expansion on the wire can affect shifting even more

I hope this is not to complicated, my Ingles do suck plus this is a multifaceted topic, anyway hopefully it opens the door for a few more options

ricardo

We don't but I'll offer some observations anyway...

What we've used:

54/44/28 was our 'OEM' set-up. The 28 was a bail-out gear that didn't see much use because it could only be used in combination with the three largest sprockets on the rear cassette and the jump in gear inches when you dropped down into was pretty dramatic, even though our largest sprocket has never exceeded 32t (Campy RD). The limitation on the sprockets was chain drag on the back end of the front derailleur that had to be set high enough for the 54t sprocket. From a practical standpoint, we only used it when we surrendered to a hill as it killed our momentum. We have good friends who ended up with a 54/42/26 and they almost never use the 26 for the same reason... well, that and they're a ton stronger than us and rarely need anything lower than a 42t x 32t on anything less than 12% grades. However, that said, they have used it to take on some serious climbs and were glad they had it.

54/42/30 was an intermediate set-up. The 30t apline gear was a bit more useable in that two more rear sprockets were useable. However, what I found was that I would usually remain in 54t ring all the way through the cassette vs. using the 42t as it seemed to be a little too small. Probably just me, but it was bothersome enough to cause one additional change.

54/44/32 is now our preferred set up. We normally run a 12x27t cassette and pop-on a 12x32t for the mountains. The 44t gets a lot of use on just about anything that's not flat or rolling and the 32t also sees a lot of use on steeper climbs in that it is tall enough to give me access to 6 of the 9 rear sprockets without crossing up with the 44t ring or dragging on the back of the FD cage. The 1:1 ration of the 32t x 32t "granny gear" has proven to be OK thus far but there have been a few times on very steep grades where I've gone looking for another sprocket and lower gear only to realize we were as low as it goes. Of the three combinations, this one shifts the best between all three; however, the others weren't troublesome so long as you soft pedalled the front shifts... a good thing to do regardless of what your gearing.

We're running 24/40/54 on the front and 12-34 9 speed on the rear of our Trek. The only front shifting problem we have is the chain occasionally is reluctant to drop off the 40 onto the 24. Otherwise front shifting is great. We do have bar-end shifters. Have only been in the 54-12 combo once or twice-if we are going that fast down a hill we are usually coasting!

We took our tandem on a nice tour of Sonoma County a couple of weeks ago that included the second half of the Terrible Two course. If those are the kind of Sonoma roads you plan to regularly ride (i.e. steep, prolonged descents with bad pavement and multiple off-camber hairpin turns), you will probably want a full on drum brake unless you are a very light team or very confident descenders (or both). I am not known for being particularly timid on descents, but I have to admit that in some places (like the descent from the summit of Ft. Ross to Cazadero) I was on our rear disc brake so much and so hard that I was worrying about melting the knobs off --- something which other posters to this forum have apparently accomplished. To our delight, we found that our disc brake passed this harsh test very well --- but we were definitely riding the brakes in places and a drum would have been more appropriate.

It's nice to know our current brakes will get us down that kind of hill when necessary, but if we were doing that on a regular basis I think we'd definitely be considering a drum.

Disc brakes work and work effectively. Never had a problem on downhills as we use the accepted method with disc brakes of letting speed build up- then braking hard to bring speed down- when speed builds up again, we brake hard again. Then again we have never taken in the mountainous drops that some people have to. If a constant brake to keep speed down is required, then Disc brakes are not the ideal.

We have used the Tandems East shaved drum with great success. It is mounted on our Co-motion Co-Pilot and our team weight is around 325lbs. I would guess that we are about an average descender. We're not the slowest down hill but not about to take any unnecessary chances. Most of our riding is east coast with short steep hills. We did a two week trip in France a couple of years ago with no problems. This trip included several long descents to include Mt. Ventoux. On the longer descents we would stop occasionally to check the brakes, let them cool, and enjoy the scenery.

Those Sonoma County hills are pretty special. At the Terrible Two double century yesterday, two guys on a beautiful Ibis tandem (equipped with rim brakes only) crashed on the Geysers descent. The explanation I heard was that they cooked their rims and blew a tire off. Three other tandems completed the ride no problem, but it does underscore the fact that if you're going to be riding in that kind of terrain you should pick (and use) your brakes very carefully.

We sure appreciate all the input from everyone, which has been super valuable. We ordered our Co-motion today; went with the full drum brake, figuring the added weight would be offset by the feeling of security that it will give us. I know Richard will be dragging me up the Geysers eventually, so I don't think we'll regret having the drum!

After pondering all the gear ratios, the mechanics at Norcal in Santa Rosa talked us into keeping the ratio that Co-motion offers, at least for the time being: 54/42/30 in front, 11/34 in back. Richard is a strong climber, so we'll see how that goes.

Our only final issue is: Co-motion offers carbon cranks as an upgrade. The difference in weight between carbon and the standard FSA Gossamer Mega Exo is only around 1/2 lb. Can anybody think of a compelling reason to get carbon cranks on their tandem, other than the fact that they look cool? It's around a $350 upgrade.

Thanks again to everyone for weighing in.

You'd be paying an extra $350 to save the weight of what, one water bottle? You live in Sonoma, for gosh sakes! If you have the extra coin, do a weekend of wine tasting instead.