colotandem

Can anyone provide some advice on disk brake set up for a full suspension mountain tandem. I know that Avids are cheaper and likely easier to set up/maintain. I don't know that much about Hydraulic brakes other than the fact that they seem to cost A LOT more.

Pros? Cons?

Specific recommendations?

Thanks,
Dan

MB1

I hated the Formula hydraulic disc. Way too much maintenance.

We are running the WinZip now which is cable actuated, much better.

justcrankn

I have ridden different road bikes with the Avid BB7 (road with 203mm rotor) and was unimpressed with their braking power and the attention required to make them work right. Our hydraulic Hope Mono6ti brakes work great and I have yet to make any adjustments to them.

sch

Anecdotal stories about tandems with hydraulics, loooong California downhills
hot fluid expanding and locking up the brake. Haven't seen any lately but
this was from a few years ago. Our rear BB7 has excellent braking but
occasionally seems to drag, perhaps once out of every 6-8 rides. We have
gradually gotten used to adjusting it correctly then not fiddling, the fiddling
generally makes it worse-something to do with bifocals (or lack of on the ride
and sunglasses).

TandemGeek

It all depends on how you plan to use the tandem, e.g., total weight, terrain, and just how aggressive you plan to ride and how willing you are to learn hydraulic brake maintenance.

The Avid BB7 w/203mm rotors are more than adequate for average size teams doing mostly XC-type riding and are a no-brainer to set-up, adjust, and maintain. They are also very durable and reliable and VERY affordable.

For average size teams who want more clamping force the Magura Louise Tandem hydraulic two-piston brake is the default and probably the best all-around disc brake for off-road tandems. The mineral oil system is somewhat easier to live with than the DOT systems if only because mineral oil is pretty easy to maintain and work with. While mineral oil has a lower boiling point, it doesn't breakdown over time the way DOT will... which is why DOT systems need to have their fluid changed out ever year or so. Cost wise, almost twice the cost of the Avid.

For larger teams or teams who will be doing any significant downhill riding you'll want to look at a four-piston brake like the Magura Gustav M. The larger caliper and four pistons provide more mass and have more heat capacity than any of the two-piston, which make them ideal for high-heat applications. Again, Magura uses mineral oil. Cost is about 2.5x more than the Avid.

As for DOT-based systems, we have used Hope's 04DH ('00) and Enduro ('02) four-piston models running Motul 600 brake fluid. They, like all hydraulic disc brakes, provide exceptional modulation and massive brake power... which only hydraulic brakes can do. However, for what ever reason, our Hope disc brakes have always squealed like banshees which is annoying as all get-out. Hope also makes a six-piston caliper (Mono6) which is the mother of all off-road tandem brake systems and I've not heard any compliants about brake squeal. The Enduro is about 2.3x more expensive than the Avid and the Mono6 is closer to 2.6x the cost of the Avid.

As for overheating hydraulic disc brakes, the tandem-rated discs brake systems are all open-systems that use a master cyliinder to deal with heat expansion. While open systems don't eliminate the possibility of overheating disc brakes, it takes either a poorly set-up system (e.g., air bubbles left in the lines, etc.) or some really extreme riding to cause a system to lock-up.

Santana's hybrid Formula road disc was prone to overheating because it was a cable-actuated closed system and, well, just a poor design for the masses because it took more than knowledge to properly set-up and maintain that even your average bike shop wrench might have. In general, all of the single or dual piston closed hydraulic systems designed for single mountain bikes are a Bozo-no-no for tandems. Anyway, less I digress....

Here's another big caution for hydraulic discs: If anyone must remove and reinstall the brake lines on a hydraulic disc brake for any reason they darned-well better know how to work with hydralic lines and fittings as the only catastropic failure condition I can think of for a disc brake is one in which a brake line develops a leak or pops off a fitting under pressure.

Lastly, after any crashes (remember folks, we're talking off-road tandems here) special attention needs to be given to the brake fittings at the caliper and levers. These fittings are usually positioned so that they're semi-protected; however, it they do take a hit they are very succeptible to damage.

As you can see, the mechanical Avid BB7 is the no-brainer unless you really need or want the added stopping power and superior modulation of a hydraulic brake system. Hydraulics can also be very reliable and easy to live with if they are set-up correctly. Magura's are even easier to live with given their use of mineral oil. For the true brake-geek, there are systems like those offered by Hope that allow you to use high-temp brake fluilds like Motul 600 and that offer truly exotic calipers like the Mono6 with its six titanium nitrade-coasted titanium pistons, but at a price.

Finally, and as mentioned in the past, I strongly recommend speaking with Alex at MTBTandems.com. He probably sells more off-road tandems than anyone else, he offers all of these brakes, and will no doubt have the benefit of feedback from his clients. Yes, there are probably a few Etailers out there who will low-ball prices to sell folks off-road tandems, but few of them have the product experience and knowledge that Alex has. The latter means, you're more likely to get good advise and the right off-road tandem & set-up from Alex right out of the box vs. going through the anguish and sometimes a long walk in the woods that can come from having the wrong set-up or at least being forewarned as to what you could expect.... noting that off-road tandems and their components do have a tendency to break.

colotandem

Thanks TandemGeek. I am already working with Alex @ MTBTandems.com and am just trying to get some additional opinions from other users in the field. We are a light (er) weight team 270-275? And we do plan to ride long mountain rides (I don't think we're talking full body armour DH style riding). I'm not as concerned about the cost as the performance of the brakes on long descents.

For what its worth, Alex is very positive on the Avid BB7s.

As always, thanks everyone for your feedback!

TandemGeek

Aside from the squealing, the Hope brakes have been outstanding with one user-induced rear brake lock-up back in '01. Just before heading off to a weekend at the Bent Creek Lodge in Asheville, NC, I decided to change the brake fluid in our first set of Hope's on our '00 Ventana ECdM. Somewhere in the process I neglected to draw-off a few ml's of brake fluid needed for brake fluid heat expansion and left the master cylinder's reservoir filled to the top. That effectively turned the open system into a closed system and on the very first descent out of the Bent Creek Lodges' access road the rear brake locked up as the brake fluid heated up and dragged the tandem to an uncommanded full stop by the rear wheel. I immediately realized what I'd done, unscrewed the master cylinder cap, removed some of the brake fluid, and put everthing back together and away we went.

Early on, the Hope and Magura Gustav M with 185/160mm rotors were pretty much what most of us were using, as they were the only no-kidding, manufacturer approved for tandem disc brakes out there. There are, of course, folks who were using smallish rotor Hayes mechanicals as well as the Avids and for the most part they seemed to work well for the more experienced teams, whereas some of the more cautious teams were cooking and warping the rotors. Once the larger rotors came on the scene all of the disc brakes gained a lot more heat capacity and then I believe Magura came out with a tandem-rated version of their Julie or perhaps it was simply the Louise dual piston disc brake. This was a nice alternative to the very expensive and somewhat massive four-piston and six-piston downhill disc brakes. However, in the background the Avid BB7 with the larger 203mm rotors was proving its mettle on factory race tandems like daVinci's wrecking crew and I believe Sherwood Gilbson may have been using them as well.

I waivered on the Avid's back in '02 when we spec'd our current tandem and, at the last moment, opted to err on the side of the more robust Hope Enduro four pot hydraulics. As noted, we have been very happing with the Enduro's aside from brake noise. They have never flinched under some of the most demanding technical descents... descents that left the rotors smokin' hot.

If I was spec'ing a new ECdM tandem today I'd like to say I'd go with the Avid, but being a geek I'd probably go with DH discs again: they just seem more proportional to the size and weight of a full-suspension tandem with a 7 lb fork.

stapfam

After doing a lot of Offroad on a Dale MT with V.Brakes- I went With Hope Mono M4's with 200 mm discs front and rear. The V's were OK but after 60 odd miles- Hand pressure required to keep them working efficiently was hurting. New Wheels and for the type of offroad we do- I went for full Downhill spec rims on Hope Bigun hubs. On the brakes- They fitted straight out of the box- except for the extra long hose required for the rear caliper. On the effectiveness of the brakes- Awesome. Only thing is that I should probably opted for a 180mm disc on the rear as it easy to lock the rear wheel on severe braking.

Only thing I would remind you about- If using Disc brakes- Get a bolt through axle on the front. QR's can cause a problem with the wheel falling out under breaking strain.

And 4 years on- Those brakes still work superbly.

bbudell

We are also running Hope Mono6Ti brakes with 203mm floating rotors. After the initial setup I haven't needed to do anything to them and they have worked WONDERFULLY!! We have never had issues with squealing. Even when descending for miles out west in the mountains we haven't had any issues with heat buildup and have never had to use more than one finger for braking. Modulation is great. I have used several different stokers so our team weight has varied from 300 lbs to 400 lbs and there has always been more than enough power. I got the extra long hose for the rear straight from Hope's US distributor and they were wonderful and prompt to deal with.