Avid Disc Brakes

[rmac]

We're thinking of getting a Winwood disc brake compatible fork. Does anyone know a source for Avid 203 disc road brakes? The price for regular Avid discs and calipers are around $56. The only sources I have found for 203 discs are $100 to $175.

Are the calipers the same for the different sizes of road brakes? Are the front calipers different from the rear?

[TandemGeek]

Send an Email to: Alex Nutt (Alex@MTBTandems.com) or to Mark Johnson (info2007@precisiontandems.com) as these guys deal with more Avids than anyone else I know: they were both sources for my tandem build and are long-time friends.

The front & rear calipers (road or mtb) are the same. The rotor compatibility is controlled by the mounting bracket/adapters. For tandems, you usually end up buying a box-stock Avid Caliper with the standard size rotor and mount that come with it, and then the appropriate adapter for a front or rear 203mm disc rotor, plus the 203mm rotor.

[dfcas]

Road calipers are different from mtb calipers

All calipers can be used with different size rotors,

The mounting bracket is different for front or back,and for each size rotor.

[TandemGeek]

Road calipers are different from mtb calipers

Yes, they are...

However, there is not a BB7 / Front and BB7 / Rear, just a BB7.

Likewise, there is not a BB7 Road/Front and BB7 Road/Rear, just a BB7 Road.

[dfcas]

TG- I know you know..

I just wanted to be sure the OP realized that.

Yes the calipers are the same,but its safer to say front or rear to be sure of getting the right bracket.

I have some serious Calfee tandem envy.

[rmac]

I think I understand. Avid only sells a road 160. In mountain they sell a 203. So, to get a road 203 set for front and back you have to get the calipers from a road set (front and/or rear since they are the same) and the brackets (both front and rear) and discs from the mountain 203 set. That's why they are expensive.

[TandemGeek]

That's how it seems to work.

The rear mounting bracket adapter is a no brainer: there's only one 203mm model. The front is also pretty straight forward; there are three: 203mm post mount, 203mm I.S. mount, and 203mm Boxxer mount. I believe most road forks use the I.S. mount. Again, someone like Mark Johnson would probably have the most experience with fitting Avids to road tandems, just because of his clientle and product offerings, and would also have most of the bits and pieces in stock.

[TandemGeek]

I have some serious Calfee tandem envy.

If you can avoid the couplers and use their stock sizing, $4,500 for a frame and fork + reasonable component choices will net you a really incredible tandem for not much more than some all-up steel and Aluminum production models. Again, as I learned in my own build, you also don't have to spend a fortune on unobtanium parts to get a lightweight build either: Gossamer cranks, Thomson posts, White Ind hubs & Velocity rims, etc... will all keep the weight down without draining your wallet.

By the way.... I've just seen the first photos of Lynskey's new tandem-sized frame table with their first Lynskey tandem design layed out on it. They will begin machining the tubes this week and are now gearing up to support is a product line item. So, there's yet another frame offering to lust after. Anyone who is interested should contact Tim at Cycology Bicycles in Marysville, TN: (865) 809-2476 or by email tim@cycologybicycles.com for more info. I may post a separate item on this under a new thread.

[Peak Team]

I think I understand. Avid only sells a road 160. In mountain they sell a 203. So, to get a road 203 set for front and back you have to get the calipers from a road set (front and/or rear since they are the same) and the brackets (both front and rear) and discs from the mountain 203 set. That's why they are expensive.

That's about it. We recently had a front 203 mm Avid BB7 Road disc added to out tandem. The 203 mm rotor and relevant bracket were extras. Our LBS kept the spare 160 mm rotor (and I assume the standard 160 mm bracket) and only charged us for the parts that we needed. Still quite an expensive job, but looks great and having been run in now stops great too !

[Richbiker]

As others have indicated, the road and mtb version of these calipers will work with any size rotor, as long as you have the appropriate mount adapters. If your calipers don't come with 203mm rotors, they can be purchased separately.

Before you pull the trigger on this operation, you should check 2 things:
1. Will the 203 mm rotor work on the Winwood fork, and does Winwood even rate their tandem capable fork for a 203 mm rotor? You don't want to discover the hard way that the fork isn't up to the tasks imposed by the braking forces. According to this page:
http://www.winwoodbike.com/muddydisc.html
The fork is only made or rated for 6" (160mm) discs, so it either won't work/fit or will pose a "catastrophic failure" issue.

2. Read my posts over on the touring forum on why I ditched the Avid disc brakes (w/203mm rotors) on my tandem in favor of V-brakes. The thread is here: http://www.bikeforums.net/showthread.php?t=384627&page=2, but to summarize the reasons:
-I saved over 3 lbs by switching to v-brakes and a carbon fork;
-The manufacturer of the steel fork on my tandem eventually got around to declaring that it should not be used for tandems, and I couldn't find another tandem-rated fork that would take the disc brake at a reasonable cost (I'm not even sure Wound Up's tandem fork is compatble with disc brakes).
-Too many annoying mechanical issues with the disc brakes, spoke breakage, rotor-rubbing, etc.
-Stopping power was fine, but not substantially better than other brakes (unless you live in a mountainous area and heat buildup on the rims is an important factor).

Rich

[TandemGeek]

Before you pull the trigger on this operation, you should check 2 things:
1. Will the 203 mm rotor work on the Winwood fork, and does Winwood even rate their tandem capable fork for a 203 mm rotor?

+1 and great catch... I'm not a fan of front discs on tandems so I don't pay a lot of attention to the fork options related thereto. I knew there were a few out there that were rated for tandems, e.g., Wound-Up, Cannondale's, and custom models made by a few builders for tandems. To the OP, as Richbiker notes, by all means give Windwood (a QPB company/brand) a call and talk to their tech reps regarding your proposed use of their product. Again, I'm not a fan of front discs on road tandems... or road bikes for that matter. Rear discs, you betcha, if and when appropriate.

-Too many annoying mechanical issues with the disc brakes, spoke breakage, rotor-rubbing, etc.

I think your hypothesis on ti frame deflection relative to the wandering caliper under rider loads is probably on the right track. As for spoke breakage, Alpine IIIs are notorious for breakage because of that extra thick butt at the bend. Only a few stock hubs have spoke holes that are big enough for the Alpine III's and when used on all the other hubs, the bends end up getting deformed during the lacing and tensioning process which weakens the spoke. A lot of us who thought the Alpine III's would be the ideal tandem spoke learned this little nuance the hard way and ended up rebuilding a few wheels with good old double-butted spokes of a more reasonable and compatible gauge.

[rmac]

Will the 203 mm rotor work on the Winwood fork, and does Winwood even rate their tandem capable fork for a 203 mm rotor?

Sorry, I meant the Wound Up Tandem Duo Disc Tab/203mm Rotor Style fork.

http://www.woundupcomposites.com/pricing.html

We have dual discs on our Cannondale and I really like them. We're a rather light team. We have two sets of wheels (a light-weight pair and the originals) and have never had spoke breakage.

[TandemGeek]

We have dual discs on our Cannondale and I really like them. We're a rather light team.

Now I'm really confused. Your C'dale should have 203mm discs... and a 203mm adapter: simple swap-out. So, are you building up a second tandem or retrofitting the C'dale? Just curious.

[rmac]

Now I'm really confused. Your C'dale should have 203mm discs... and a 203mm adapter: simple swap-out. So, are you building up a second tandem or retrofitting the C'dale? Just curious.

We're thinking of getting a second tandem and building it up.

We really like the Cannondale and would like to have something similar. However, we're thinking of a tandem with S&S couplers (probably not titainium) for traveling.

[TandemGeek]

However, we're thinking of a tandem with S&S couplers (probably not titainium) for traveling.

The only thing to keep in mind with travel and tandems is, keep it simple with regard to your wheels.

Short of a hub failure, the more likely wheel failure scenario with a tandem that can be a source of extra grief while touring is trashing a rear rim. Given that most tandems these days use 145mm or, worse yet, 160mm rear spaced wheels, a spare isn't something that your average bike shop will have in stock... anywhere in the world.

However, since you can use just about anything but the most lightweight single bike front wheel on the front of a tandem in a pinch, it's always a good idea to have a set of travel wheels where the tandem's front rim is the exact same rim used on the rear so that it can be cannibalized for a field repair.

With respect to discs, if you sacrifice your front wheel for the rear and have discs, you'll be hard pressed to find a spare front disc wheel. With rim brakes, again, any 36h front wheel off a single bike will do for all but the heaviest tandem teams. Heck, I even bring along my spare rear caliper brakes when we're travelling with our rear disc-equipped tandems 'just in case'. So long as your disc fork has a caliper eye or canti bosses, the same "just in case" approach can be taken.

Just something to think about.