What's a good way to get a 50-34 double crank, if we want 130 BCD on the timing side in order to run a belt drive? I'm asking in the context of getting a new bike, so all parts are open at this point.

- Gates Carbon Drive Belt System

the 50-34 is just the chain driven crank on the right side of the Rear BB. a square Taper BB really is Neutral

as to what crank is installed on the ends.. work with your tandem bike builder to get the parts that all work together.

the 2 toothed belt cogwheels and the Typical front Eccentric BB will tension crossover belt and chain alike.


- Gates Carbon Drive Belt System

Another option. I have not used it but know one guy is happy with his. Basically shimano compatible double or triple bar end shifters grafted to brake levers to make a combination unit. Available as 9, 10 or 11 speed.


http://bikeforums.net/attachment.php...hmentid=461426


CX Shifters for Road Derailleurs & Short Pull Brakes - Gevenalle

I have thought about this some more but still have not yet come to a decision. I've been riding my single road bike (ultegra derailers, brakes & brifters) as well as our tandem (ultegra derailers, V-brakes, 287V brake pulls and bar-end shifters). I never paid much attention to this but I think our tandem shifts better than my single. Maybe the reason that people are so taken with Di2 is that they work so much better than brifters. When brifters first came out, I thought it was a bit of a solution looking for a problem. They really don't shift as well as dedicated shifters. I think the best shifting bike I ever had was with downtube shifters. This provided a very direct mechanical connection with the derailers. The bar-end shifters on our tandem are not as quick as downtube shifters on a single but they are pretty close. The right/rear shifter is click-bang click-bang. The left/front is less direct but it is infinitely trimable and we rarely have noise issues. I've never tried brifters on a tandem. Maybe this is what people are trying to fix with Di2. I don't think that I would want to ride a tandem with downtube shifters but the bar-end shifters may be the most direct mechanical link with the derailers and still be able to keep both hands on the handlebars.

Maybe the best compromise if one wants a wide range and rapid shifting is to go with bar-end shifters.

Has anyone ridden a bike with V-brakes with dedicated brake pulls and compared this to caliper brakes with brifters? Is the latter setup as good (or better) than the former? I may be with Zonatandem on this one.

I installed Microshift 9 speed brake/shifters on our 2002 Santana Sovereign about 400 miles ago. I've used their bar ends on other bikes and was impressed with the shifting and these shift well, also. However, it's another shifting combo to get used to despite being Shimano compatible because they use a different combination of levers and buttons to shift.

I have to admit, though, that I like bar ends the best on tandems.

I have re-read earlier posts in this thread and I think I may have come full-circle on my understanding and possible choices. I assumed that if we went with Di2, we would sacrifice range. Now that I realize that we rarely use our small chainring (it is a bail-out gear), with correct cog selection, we may only give up a bit of top-end.

For those that have Di2 & hydraulic brakes, are you using the integrated Shimano Ultegra Di2 with hydraulic levers? I think I read that you are using 180mm rotors right? Is Calfee willing to use these on their tandems even if Shimano hasn't blessed it? Has anyone with Shimano hydraulic brakes overheated them on a big descent?

Thanks again for your help & experience.

if you do not require low climbing gears then why would you consider disc brakes? Can you live with a wide ratio cassette? KISS!

i tried bar ends on an earlier tandem and did not feel comfortable with them. I ride most of the time on the hoods and did not like moving my hand to shift. It felt a little unsafe for me.

On a road tandem with drop bars to use hydraulic brakes and DI2 the only choice is the integrated levers. Calfee is building many tandems with hydraulic brakes and until just recently used 203mm rotors on the rear. They are now recommending 180mm rotors. We are still using 203 XTR rotors without issues. Calfee recently (last fall) changed their frames and added an additional strut between the seat stay and chain stay to better distribute the loads these brakes can generate. When we built our new frame i chose to use a thru axle fork and thru axle rear dropouts to further distribute the load across the frame. Last year in Europe we did some rather large descents with only the rear Shimano hydraulic brakes and had no issues with overheating it. It should be even less of an issue with both front and rear. FWI I don't think there are any true tandem rated brakes out there and if so what is the rating based on? As far as range if you pick the right crankset you can have whatever range you want. Pick a crankset with interchangeable spiders and make it whatever you want within the parameters of a double. 40/34 is proven to work for a low end using the XTR 11-40 cassette and a K edge rear deraiileur mod and a 11-52 or greater on high end is possible, although not at the same time However a 40/34 and 11/50 can be achieved with the same setup. With just an extra chain and a different cassette one can quickly go from a flat land setup to mountainous setup in a matter of minutes. Does one need either DI2 or hydraulic brakes obviously not, but do they work, absolutely . I/we will never go back to mechanical shifting or rim brakes.

I don't think you really have to sacrifice range (maybe if you really like that big 54t chainring). When we spec'd out our most recent tandem, I had a similar thought process that you are going through. We were coming from a 52-39-30 cranks with 11-28 cassette. I wanted to go with Di2, but was unsure if I'd like the range and a wider range cassette. So rather than invest in the $$ electronic shifting, I had the frame spec'd to accommodate the wiring but used 2x10 mechanical shifting with the thought that I would convert later as the price of electronic shifting came down.

A couple year later, I'm still using the mechanical shifting (Sram 2x10 52-34 with 11-36 cassette). No issues with this set up the low end gearing is actually lower. We live in Colorado too and do our fair share of climbing, so it is a fair representation for you. I currently have the bike set up with caliper brakes but have also run rear disc.

I still may go electronic at some point. Most that have ridden with electronic shifting swear by it and don't want to go back (I think Rudy may be the exception). If I were to go electronic, I'd probably change the chainrings to 52-36 and MAYBE go to 11-40 cassette, but could likely still get away with 11-36 cassette. It is nice to have less than 1:1 ratio as a bail out.

Thanks colotandem.

I'm a late adopter. I really appreciate early adopters. Without them, technology wouldn't move forward.

If we do go for a Calfee, this would be a huge leap for us: To go from a 17 year old steel Co-Motion to a brand new carbon fiber Calfee is a big jump. I want to embrace the latest proven technology. This will be a very expensive bike for us but I don't want to cheap out and settle for less than optimal choices. I know that there is no best - just what compromises are best for the chooser.

Mel at Tandems East is suggesting 3x11 mechanical derailers and cable operated discs. Many here are pretty adamant about going all the way to Di2 & hydraulic brakes. Mike at Calfee is pushing toward Di2 and rim brakes. There are many strongly held opinions. I'm just trying to decide what might be best for us.

By the way - in your avatar - it looks like there is a sign above you heads. I can't read it but I assume it marks some pass or high point. Where is this?

That photo is from Mt. Ventoux.

Is this going to be a travel bike with couplers or standard frame? I think for coupled bikes that are frequently taken apart the Di2 has even more advantage as you just connect a wire and no adjustments are necessary. When we traveled with our Calfee prior to DI2 it always seemed to take a bit to dial it in every time.

No couplers. Our current bike has couplers so I think that we will forgo them on this one.

Any idea why Mel (Tandems East) is such an advocate of discs but Mike at Calfee thinks they are unnecessary? Based on what I have read from many here, the downsides to hydraulic discs are cost, weight and possibly boiling the hydraulic fluid on big descents. The upside is that they work much better in most conditions.

One more upside to hydraulic disc brakes is that they are much easier on your hands as they take much less effort to pull. We were on a Cycle Oregon ride a few years ago and there was a very steep descent on a back mountain road. Steep enough that they stopped everyone at the top to check brakes. Even with decent brakes one lady's hands cramped so bad she could not stop and had a horrible crash and broke her pelvis. The Shimano brakes take only two fingers to pull with much less effort then the calipers.

Based on all that I have read on this forum and all of the reasoned replies to my questions, I now think that I will spec Di2 and caliper/rim brakes. Those are my current thoughts but they have evolved and may change again.

Mel at Tandems East suggests adding a disc (rear) that is operated by the stoker if we elect to go with rim brakes. I assume this is to assist the rim brakes for big descents. If we do add a disc, I assume this would be a cable-operated disc (correct?). Likely an Avid BB7? If I do go this way I could either have the bike built with the disc and remove it if we decide it is unnecessary or alternatively have the frame & rear wheel built to take a disc and add it later if I decide that we need it. How will the rear wheel be built differently if we allow for the addition of a disc?

The only difference will be a disc acceptable hub.

That's eesentially what we did. Caliper brakes with the ability to add a disc brake. The frame modifications are just having the mount for the Caliper added to the dropout, and a cable stop (Calfee adds an additional strut to strengthen the rear traingle.)

It can affect your choice of droput spacing. 145mm is kinda standard for tandems these days, but a number of high end tandems are being built with 130mm or 135mm spacing. If you're going to run a rear disc it pretty much rules out 130mm spacing, so you need 135mm or 145mm.

Then you just need a disc compatible hub. And install the rotor when you need it. A disc wheel needs to be more robust, but most wheels that you'd want to use on a tandem will be strong enough to put a disc on.

Just remember that the third brake being a disc is not a drag brake as they are not designed to dissipate that much heat if drug. It is better to do the frame for both options then to add the capability in the future. Avoid disc brake calipers with plastic parts (i.e. BB7) You might look at the new Paul"s components Klamper looks pretty nice Klamper Disc Caliper
Good luck on your new frame and build.

Oldacura, we do indeed have a similar setup, but our bike may be heavier because we have an Arai drum brake. (We ride a lot of hills in California, and often tour in other hilly locations) As we consider a new bike now, we're simply looking for something lighter and more dynamic. I think we're down to the choice of a newer Comotion or a Calfee. We've test-ridden the Comotion Carrera, and it feels like quite an upgrade over our current bike. Using the shop scale, a coupled Carerra, with pedals and water bottle cages, would come in around 37 lbs. A Calfee would be significantly lighter.

One observation that complicates our thoughts is what to do about gearing. From group rides, it seems that our current 3 x 9 ultegra shifting may be more reliable than the currently available 3 x 10 mechanical choices -- we never drop a chain or otherwise have balky shifting. We also have the convenience of knowing what gear we're in via the flight deck, something no longer available. So whichever bike we go for, I'm now leaning toward specing an Ultegra Di2 with K-edge extension, with 50-34 chainrings and an 11-36 cassette, or perhaps even a 11-40 cassette. From advice on these forums, it seems like the best way to do that is to get the lightning crankset, as that way you can get the 110 bcd on the drive side for the compact front, and the 130 bcd for the Gates timing belt.

Because we tour a lot, we very much value reliability. Every time we unpack the bike in some remote location, we simply need it to work without undue fuss. I have high confidence in a new Comotion to do that, but I am also attracted to the lower weight of a coupled Calfee, and I hope that a Calfee would be equally reliable for travel. Our packed Comotion is inspected every time by TSA, and we've had damage caused by them twice -- once a bent rim and another time a bent rear derailleur. I wonder if carbon bikes get inspected as frequently as steel bikes by TSA. If so, could they cause worse damage to carbon fiber?

We're close enough to Calfee that I'm arranging a test ride in a couple of weeks.

What choices are you leaning toward?

Fyi ... we're a 300 lb team with average strength.

Right now I'm thinking Di2 50-34 & 11-36. Ultegra rim brakes and maybe provisions for a rear disc.

Have you picked out a frame yet? We're trying to make the choice now -- it's hard to find appropriate bikes to try, so I thought it would be worth comparing notes.

We did test ride a Comotion Carrera a few months ago. It was a stock configuration, not coupled. We only rode it 10 miles or so, but it seemed to be much more fun and responsive than our current Copilot (with original 48 spoke wheels, Arai drum brake, etc).


We're hoping to arrange a test ride on a Calfee shortly.

We're probably going to order a Calfee carbon sight-unseen (unridden). We can't easily find one to try but everyone who has one raves about it.

That was my situation before we bought ours. It was a leap of faith and talking to other people.
It easily exceeded my expectations and is one the best investments I have made despite the large amount of $$$.
It is our third and likely last tandem, I don't see how it can be improved upon.

Despite the preponderance of love toward Calfee on this board, we opted for Paketa. Loving it. Climbing powerhouse. Do your homework...