Builder says the tabs for the Vs in the rear would interfere with placement of calipers, so the frame can be built to accommodate only one or the other. Not an issue up front, with different fork options.
Anecdotal Brake Observation:
After putting 200 miles on my disc-equipped road bike I'll change the front brake on our daVinci to a disc if I ever have to replace the fork. I can stop the road bike on a steep descent with two fingers on each lever, feathering the rear of course, but there is no fade whatsoever. While the front V-brake on the DV is effective, we do get fade in steep descents and the front disc would be especially effective with the short cable run.
I can see where hydraulic would be especially effective for the rear tandem brake application, but would be interesting in the case of a coupler-equipped bike.
Volagi - Triple"ized" and Tubeless
daVinci Joint Venture
OP here. Fork and frame are being built to accomodate both Vs and discs. Just haven't decided which to start with yet. Current bike uses Vs, which (so far) have successfully stopped us on some very steep terrain. Experience counts for a lot. But discs, which I've not used before, have some attractive traits (and some not so attractive ones, as noted in other posts on this thread). The new frame should be delivered in late February, so there's time still to make a final decision, AND second-guess it.
Options are good.
I have cable disk brakes on my tandem--Avid BB7's to be exact. I am very please with how they operate. I am curious about the several statements that hydraulic brakes are better. Can somone fill me in on the advantages over the cable operated ones?
i'm not sure hydraulic disc brakes are ideal – unless the entire system was specifically built to handle the additional mass and greater speeds that come with road tandems. Even so, Santana offered disc brakes with a cable-hydraulic interface several years ago, but many found they would bind up due to the fluid expansion in the brake lines under extreme braking conditions. Their current disc brake offerings no longer include hydraulic disc brakes.
Last edited by coloroadie; 01-15-12 at 06:37 PM.
To the OP: How did this turn out?
We're in the early stages of a hunt for our next tandem. Like you, I was 99% sure we were going to go carbon. But recently, after test riding both a Seven and a Calfee, I was amazed with the Seven's ride and responsiveness -- made no difference to stoker.
So I'm deeply curious if your delivered Seven has lived up to your expectations. Please let us know!
I would love to hear how this has worked out for the OP. We are currently working through design parameters for a Seven Ti.
Most economic fallacies derive from the tendency to assume that there is a fixed pie, that one party can gain only at the expense of another.....Milton Friedman
OP here. The bottom line reaction to our new Seven is ... love it love it love it. With about 1,500 miles in the saddles now, the bike is proving to be exactly what we hoped to get. The ride quality is simply outstanding. The bike is incredibly smooth and compliant, soaks up road noise, and does a masterful job of taking the edge off the road's bumps and jolts, all of which make century distances so much more comfortable. Handling is predictable and sharp. Laterally, the bike is plenty stiff for us, and comparable in feel to the Seven we test drove, even though our baby is nearly 3 inches longer than the tester (tall stoker).
Very happy we sprung for the S&S couplers. The break-down/build-up process is pretty darned easy, and the ability to pack such a big-@ss bike into two regulation-sized suitcases is a marvel of engineering. Neither the S&S ti couplers nor the travel cases are cheap, but the ease with which we can take the bike anywhere makes it very worthwhile. We had one minor issue with the coupling system that had an easy two dollar fix. The cable splitters banged and rattled against the frame tubes, which was highly annoying. We simply replaced the thin rubber O-rings that came on original splitters with thicker ones. Problem solved.
As noted my prior posts, our main objectives with the build were flexibility and reliability, rather than weight weenie-ism. For components, we opted for:
Fork -- Wound Up Tandem Duo (uber-sturdy; disc-ready)
Cranks -- FSA SL-K (more options than the new Ultegras for crank arm lengths and chainring sizes)
Derailleurs -- Ultegra (front and rear)
Brakes -- Avid Single Digit Ultimate linear pull (front) and Avid BB7 disc (rear)
Wheels -- White Industries disc hubs with Deep-V rims (front and rear)
I chose different brake types just to see which I liked best, but may end up sticking with the current configuration. The Ultimate linear-pull up front has much better braking power than I expected. The grip of the rear disc is enormous. We also added V-tabs in the rear for a future 3d brake, and designed the cable bosses so that either captain or stoker can operate either rear brake. Options are good. At least as of now, I'm not second-guessing any decisions on the components. If we stick with the Ultimate linear-pull brake up front, we may swap out the disc-ready hub for a non-disc, but that's about the only change I can anticipate at the moment.
Finally, the bike Seven built for us is a work of art. Over the past weekend, we heard "awesome bike!" multiple times. We certainly think it is.
Sounds like a great setup up with reliable components. Have any pictures to share?
It sounds wonderful, please do post pics.
Do you mind sharing where you sourced the frame? You mentioned in your first post something about the Blue Ridge. I'm in NoVa and am amazed that the closest Seven tandem dealer to me is TandemsEast outside Philly. In fact, we went up there for the Tandem Expo and and test rode a Seven tandem and I am wondering if that's also where you did your testing.
I'll try to take/post some pics over the weekend. We're also in NoVa (Falls Church), and used Mel at Tandems East. It's a bit of a schlep from the DC Metro, but for us it was well worth the effort. Sounds like we test drove the same two bikes. See you the road!
We'll look for you on the W&OD!
At long last, here are few pics of our new(-ish) Seven, now with about 2k miles ...
Packed, the bike fits in two airline-regulation cases. Actually, one case hold everything except the rear rear wheel, rear triangle, and stoker bars. Break-down and build-up take us a bit under two hours...
Here are the twins as originally configured. We're going to replace the stoker cowhorn bars with standard drops ...
Like the bike as a whole, the welds are beautifully done...
And finally, this past hot-n-hazy weekend, the bike faithfully carted us up Skyline Drive in Shenandoah Nat'l Park ...