We've run the same pair of Ti6's since about '04, originally on the Cannondale and now on the Ventana, and they're still going strong.
Obviously, our experience may be different, but I've found them to be excellent, and have utter trust in them, which on a tandem coming down the red run at Glencoe is worth more than anything.
To pick up on the previous comments-
They would look cool on a tandem though, wouldn't they.
Yep they sure do!
It's not just about power when you're talking about tandems
Agreed, you tend to use the back brake more, and it can do a hell of a lot more stopping than on a solo because there's more weight on the back wheel. The Cannondale could only fit a 185mm rear disc, but the Ventana is running 203mm.
on a tandem I'd imagine any 'give' in the hose becomes significant for the rear brake given the length of the run. you wouldn't need to have much hose expansion under pressure to lose a lot of braking force.
Yep, braided hoses help, as does careful bleeding as there's a lot of hose to hide air bubbles. Another benefit of Hope's - the bleeding is very easy.
We've had no problems with fade so far with Mini Mono brakes on Clee Hill or the Black Mountains, so this may all be overkill anyway
The words 'brake' and 'overkill' cannot be used in the same sentence when discussing MTB tandems!
You'll save an arse load of weight over the M6's - mostly in the ridiculous almost motorbike heavy lever the M6 came with.
On something that weights around 50lbs + 2 people and cannot hop, wheelie, or unweight a wheel, and therefore survives by being the slightly more irresistible force than the immovable object, saving weight is well down the priority list. Durability, function, 'please don't break and kill me and my wife' and more durability are top of my list. Also that big lever is handy, as you can get a second or even third finger on there if need be! On a big descent (as per the pic above) you'll pick up speed so fast that you'll be braking almost all the time, so one-finger braking soon gets tiring.
After that descent at Glencoe, which we did a number of times, the discs were blue with heat at the bottom. No boiling fluid but just a hint of them starting to loose bite.
I recall JD Cycles in Ilkley, purveyors of all things tandem, tested loads of tandem disc brakes by steaming down the big hill into Ilkley and seeing what stopped quickest, and what didn't fade. I think Magura Gustavs came out top, followed by Hope.
On all the high end MTB tandems I've seen, I don't recall Shimano being the brake of choice on any.
As I said, just our experience, others may disagree, but I'd put a pair of Ti6's on a tandem any day.
Rob & Sandy