Tandem Cycling - Another drivetrain upgrade post . . .

We have a CoMo Speedster, purchased used, about a 2004 model - we're not sure. In any case it has the 28.5" BB spacing. It came with Race Face cranksets, 34-44-54 rings, and 175/170 crankarms. The chainrings are too big for us and so are the crankarms. We're both fairly short. I'd like to use the same crankarms as our singles: 170 for captain and 165 for stoker. So my plan is to replace both cranksets. The only thing I can find that's close is FSA Gossamer with 172.5/165 cranks and 30-39-52 rings. We'd like to replace the 30 ring with a 26. That gives us two 13T shifts. The bike came with an Ultegra 9-speed FD with a clamp mount. The bike shifts perfectly now. I'd like to retain that FD, though I've heard that the new 10-speed Ultegras may work better in this application. If we went to a 10-speed FD, do we replace the brifter also?

As long as we're doing this major upgrade, I thought it might be nice to go carbon belt drive, too.

What we're trying to accomplish is to have more comfort and endurance on long rides. I think we'd do better to spin faster in lower gears. Hence the shorter arms and smaller rings.

Thoughts? And thanks!

We have FSA Gossemer cranks with a 53/39/26 setup. It shifts well. Took some work to get it to consistently shift down to the small ring under load, but with someadjusting it now hits well.

Personally, I might wait on the carbon fiber belt. We're still having trouble with ours (I'll elaborate on that in the CF drivebelt thread.)

I don't know if you have been reading this thread (http://www.bikeforums.net/showthread.php?t=555505).

It sounds like a great idea. I just don't know get the benefit for the cost. Maybe it will be a motorcycle chain vs shaft debate after it matures.

We have a CoMo Speedster, purchased used, about a 2004 model - we're not sure. In any case it has the 28.5" BB spacing. It came with Race Face cranksets, 34-44-54 rings, and 175/170 crankarms. The chainrings are too big for us and so are the crankarms. We're both fairly short. I'd like to use the same crankarms as our singles: 170 for captain and 165 for stoker. So my plan is to replace both cranksets. The only thing I can find that's close is FSA Gossamer with 172.5/165 cranks and 30-39-52 rings. We'd like to replace the 30 ring with a 26.
Thoughts? And thanks!

We're running DaVinci arms - also considered Sugino XD600s - with Race Face rings; 48-36-24. I don't know whether these particular rings are still available or whether they stopped making them last year. Both the DaVinci's and the Suginos come in 165 (and 170). These are square taper cranks. Don't know about the Race Face cranks.

If you really want 170 on the front, FSA shows it is available on their web site for the Gossamer.
It might be hard to come by though.

DaVinci cranks will provide the combination you need; we have 170 front and 165 rear.

I am on the "Snap" thread. And I will also look into the DaVinci, thanks. And I'll prompt the dealer to check into those 170 captain's cranks. They are definitely shown on the website. I don't need them for another 6 months, but a tandemer buddy advised to get cracking on this early, as it may not be that simple.

If you go 10 speed the largest Ultegra cog set that you can get is 27 teeth or 28 in Scram. The Shimano mountain bike cogs sets are 9 speed. The IRD 10 speed is problematic but the Santana 10 speed cog set works well for us. The Santana cog set is expensive at $170.

I am on the "Snap" thread. And I will also look into the DaVinci, thanks. And I'll prompt the dealer to check into those 170 captain's cranks. They are definitely shown on the website. I don't need them for another 6 months, but a tandemer buddy advised to get cracking on this early, as it may not be that simple.

Sometimes you have to wait for the DaVinci's to be machined and if you want them annodized you might have to wait for that also so it's a good idea to check early.

Our 12-30 10sp IRD cassette works as well as a 12-27 Ultegra. I think DuraAce now comes in an 11-28.

Thanks, folks. We'll stay with the 9 speed mountain cogset. It's just the FD that I'm concerned about.

I have a 2008 Co-motion speedster

I am running a 53/39/22 and an IRD 11-34 with no problems. I know the IRD 11x34 topic has been beat to death but mine works well.

I use this set up for loaded touring ....just yesterday finished a 300+ mile journey in the Adirondacks mountains with sustained climbs of 12% + at times.

I did put an N-gear chain stop which works flawlessly because of the drop from the 39 to the 22. We did many shifts to the 22 all flawless.

you can read about the tour here if you are interested----

http://www.crazyguyonabike.com/doc/Tourdemiller2

The Jump Stop works very well for us also. Well worth the money (inexpensive)

PK

bikeguy - what BCDs does your crankset have? Normal road triples have an inner BCD of 74mm, which will only take down to a 24 tooth inner ring, so I'm wondering how you got a 22 tooth on there. For anything with a smaller inner BCD, I would think it would be hard to get 39/53 tooth rings that go in the outside positions. So I'm very intrigued.

As for the OP, I can sympathize with the crank arm length options. Our Speedster came with the 172.5 / 170 cranks. My wife and I use 170mm cranks on both of our bikes, so the rear is fine, but I can feel the difference in the length of the front cranks - may leg has to compress an extra 5mm at the top of the stroke to keep the knee extension the same at the bottom of the stroke. This extra compression seems to make my pedal stroke a tiny bit less efficient.

I'm not sure why the 10-speed Ultegra FD (i.e., 6600 or 6700 series) would be better than the 9-speed Ultegra (6500 or before). I would go with what you have to start with. The 10-speed FD likely has a slightly narrower cage and so would cause more chain rub with a 9-speed chain when in certain gear combinations than the 10-speed version would. You could avoid this by using a 10 speed chain (without needing to change anything else), but the better solution would be to stick with the 9-speed FD.

We ran a 26-39-53 setup for a while. But, the 26-39 was too big of a cadence shift for a tandem, and the 39-tooth ring didn't give us a good range of gears for cruising in. I've therefore now gone with a 24-32-42-53 quad setup. We can stay in the 42 tooth ring 80% of the time, and only use the 24 tooth granny gear for the steepest climbs. You can't do this with an integrated brake/shifter unit for the front derailleur, but I was already using a bar-end shifter to control the FD, which gives you the necessary range. Getting the FD in the right place laterally is pretty tricky, though, and I had to try a few methods, but eventually I got a clamp-on 105 triple FD to just work.

[quote=Chris_W;9356072
We ran a 26-39-53 setup for a while. But, the 26-39 was too big of a cadence shift for a tandem, and the 39-tooth ring didn't give us a good range of gears for cruising in. I've therefore now gone with a 24-32-42-53 quad setup. We can stay in the 42 tooth ring 80% of the time, and only use the 24 tooth granny gear for the steepest climbs. You can't do this with an integrated brake/shifter unit for the front derailleur, but I was already using a bar-end shifter to control the FD, which gives you the necessary range. Getting the FD in the right place laterally is pretty tricky, though, and I had to try a few methods, but eventually I got a clamp-on 105 triple FD to just work.[/quote]


Long live great granny!!!

For a team that does minimal climbing, great granny is a welcome friend on a road trip.

PK

We ran a 26-39-53 setup for a while. But, the 26-39 was too big of a cadence shift for a tandem

That's why I love Campy levers, I can dump 3 gears higher (or however many I need) in the rear while I shift to the granny in front. Thus way we can keep the cadence steady.



...and the 39-tooth ring didn't give us a good range of gears for cruising in. I've therefore now gone with a 24-32-42-53 quad setup. We can stay in the 42 tooth ring 80% of the time...

I also prefer the 42t to the 39t

The 42x28 and 42x32 can get you up plenty of hills, while the upper range of the cassette still get plenty of speed.

The 42t is great for rolling terrain.

I currently have 30x42x52 and also find the 42 useful, but wonder why a 39 would be a problem single most singles use it. I would think it is roughly equal to using one cog smaller on the back. On my next build I am considering 28x39x53 since FSAs come with a 39 and the SRAM 11-28 cassette. I was concerned about shifts between the 28 and 39 but from what I am hearing its not a problem.

I currently have 30x42x52 and also find the 42 useful, but wonder why a 39 would be a problem single most singles use it. I would think it is roughly equal to using one cog smaller on the back. On my next build I am considering 28x39x53 since FSAs come with a 39 and the SRAM 11-28 cassette. I was concerned about shifts between the 28 and 39 but from what I am hearing its not a problem.

I agree, the 28-39 shift should be ptrety straightforward. The thing that we found with the 39 tooth chainring is that we ran out of gears on the high end way too quickly in rolling terrain, necessitating too many double-shifts for my liking. The 39-tooth ring is not such a problem on single bikes because they don't pick up speed so quickly on the slight downhills.

As for the 11-28 cassette, I've tried it on a tandem and a single, and didn't like the 19-22 jump in the middle of the cassette in either situation. My favorite cassettes are the SRAM models with a 26-tooth biggest cog, so that the upper gears are 19-21-23-26, which is ideal spacing. I've also put together a custom cassette with largest cogs of 19-21-23-25-28, the spacing and range was great, but it didn't shift ideally because I had to take the 16 tooth cog out of the middle of a 12-25 cassette to add the 28, and this caused bad shifting from the 15 to 17, a shift that we make frequently. Going with the quad setup removed the need for the 28 tooth rear cog, and I'm now very happy with our 40 gear combinations.

170 for captain and 165 for stoker. So my plan is to replace both cranksets. The only thing I can find that's close is FSA Gossamer with 172.5/165 cranks and 30-39-52 rings. We'd like to replace the 30 ring with a 26. That gives us two 13T shifts. The bike came with an Ultegra 9-speed FD with a clamp mount. The bike shifts perfectly now. I'd like to retain that FD, though I've heard that the new 10-speed Ultegras may work better in this application. If we went to a 10-speed FD, do we replace the brifter also?

As long as we're doing this major upgrade, I thought it might be nice to go carbon belt drive, too.

What we're trying to accomplish is to have more comfort and endurance on long rides. I think we'd do better to spin faster in lower gears. Hence the shorter arms and smaller rings.

Thoughts? And thanks!

Did this all about 6 months ago.

First, you should be able to order the Gossamer combo in whatever front/rear arm length you desire. I was looking over my LBS owners shoulder while he was looking this up and the front and rear are boxed separately and there are distinct part numbers for the front and rear. In fact, they don't even have to be ordered as a pair.

Second, I was questioning the 30/39/52 but in fact, it's not the number of teeth that matter, but the fact that you get two 30% shift changes. FSA doesn't sell the exact same rings as replacements as they do as new stock on cranksets (Yes, WTF is up with this??) so you won't be able to find a 28 in the exact same ring and you probably don't need it anyway.

Third, Shimano has redesigned their triple front derailleurs. You need to read the spec carefully to find the middle/big rig minimum difference. You need an FD where this number is 13t NOT 11t. I used and Ultegra 6603 FD and it shifts like a charm.