Tandem Cycling - Compression-less Brake Housing

Anyone out there using compression-less brake housings on a tandem... I am hoping to try some to remove some spongy feel from the rear brake, but a quick google search came up empty on lengths for tandems from the usual suspects... Avid Powerlines, Nokon, etc.

What do you use? Hobble together a couple Nokon kits? Just accept mediocre braking performance?:lol:

No-Nokon here. Our last three road tandems have used Campy Chorus / Record differential brakes and Campy cable kits with either tandem-length cables for derailleurs and rear brake, or two (2) each derailleur and rear brake cables with cable splitters on the travel tandems.

Does your tandem have STI or Ergo levers? What brand / model tandem do you have, what type of brake is it fitted with, do the brakes have cam-like roller devices, and are you running the stock pads?

As for finding tandem-length housing, tandems don't usually use full-length rear brake housings so standard bike housing kits are usually sufficient. You just need to substitute with tandem-length cables or two cables with a cable splitter.

Rear rim brakes on tandems are usually as marginal as they are on single bikes, just for opposite reasons. Rear discs have become popular in part because they usually provide more braking power with less effort than rim brakes.

"Rear rim brakes on tandems are usually as marginal as they are on single bikes, just for opposite reasons"

???

"Rear discs have become popular in part because they usually provide more braking power with less effort than rim brakes."

Why not more popular on the front? Because of weight distribution?

I ask because it would be a pretty straight forward conversion for an older tandem like mine (with new fork) to upgrade on the front from cantilevers and leave the rear alone.

???

More power on singles than you can effectively use, and not nearly enough to be of much use on tandems.

Why not more popular on the front?

Front rim brakes work pretty well or at least "good enough" for most teams and the limited availability of tandem-rated disc forks / cost of conversion vs. easier rear installation and dual benefits of improved brake power and higher heat capacity. Add to that, discs add weight and preclude the use of lightweight carbon forks. In a weight conscious world, it's a tough sell for the average tandem consumer.

No-Nokon here. Our last three road tandems have used Campy Chorus / Record differential brakes and Campy cable kits with either tandem-length cables for derailleurs and rear brake, or two (2) each derailleur and rear brake cables with cable splitters on the travel tandems. Can you clarify in bold... no you don't use Nokon, no you use Nokon... no you use no-Nokon...;) Are you saying you use standard housings that come with campy cable kits or Nokon housings with campy kits?


Does your tandem have STI or Ergo levers? What brand / model tandem do you have, what type of brake is it fitted with, do the brakes have cam-like roller devices, and are you running the stock pads?
I have a Campy Ergo levers with a Tektro Mini V on the front and Avid Mech disc on the rear.. standard housings... it is a Tsunami circa 2003? that I built before both my GF and I were taking turns playing expatriate work assignment games... Now she is back and I tuned it up and we went for a ride, but the rear braking seems limited by housing flex... it works, but not as great as it could be. I know the disc has stock pads, can't remember on the Tektro front (but it has plenty of bite). Part of the problem is if you get the disc pads to not rub, you have little brake power when you take into account cable limited lever movement and stretch/housing compression... no cam like roller devices... is this a cable travel enhancement aid?

FWIW the fork isn't drilled for a standard dual pull brake, but I am probably going to upgrade it to the Alpha Q and drop the Tektro (though it works very well)... the purpose of my post was to see a way to improve the rear brake feel/performance.



As for finding tandem-length housing, tandems don't usually use full-length rear brake housings so standard bike housing kits are usually sufficient. You just need to substitute with tandem-length cables or two cables with a cable splitter.
Doh, right you are! I wasn't thinking clearly as it is pretty late:o


Rear rim brakes on tandems are usually as marginal as they are on single bikes, just for opposite reasons. Rear discs have become popular in part because they usually provide more braking power with less effort than rim brakes.
I figured as much 5 years ago when I built the thing after our first beater Cannondale proved to have insufficient braking for the high speeds we achieve:innocent:... but the mechanical disc seemed to be the best option over hydraulic at the time (are there better options now to use with campy levers?). It does a great job... but I wouldn't mind being able to open the pads some more to lower drag and get less flex from the cable to maintain same brake performance.

Can you clarify in bold...

We use standard housings that come with campy cable kits

Avid Mech disc on the rear..

Assuming it's a BB7 Road model, there are at least three things you can do to improve the mechanical advantage (note the hyperlinks to addt'l info).

1. Coupled with using the least amount of brake cable / housing needed for the installation, install a compression spring (http://www.bikeforums.net/showpost.php?p=4102517&postcount=2)between the reaction arm and the integrated cable stop; this seems to help with keeping the brake cable in tension. The newest models of the BB7 seem to have a stronger spring and may not need this.

2. Make sure you've cleaned the rotor, lighty sand the brake pads, and then give them a little time to bed back in.

3. If neither of those two things yield the desired improvement, consider the installation of an in-line Travel Agent (http://www.bikeforums.net/showthread.php?t=133131) or Side-Track BPB (Brake Power Booster). As was noted in a previous thread by kevbo, the ideal place to install either of these devices to minimize cable stretch is as close to the brake lever as possible vs. near the brake caliper. The latter isn't as aesthetically pleasing, but if it improves your braking... so be it.

As for using the Nokon housing, I've seen it used on a few tandems with rear discs early on and others have even used it with rear canti-brakes. It does seem to help, but I can't recall anyone saying the improvement was 2x; however, it sure couldn't hurt... aside from the wallet.

The last thing I'll mention regarding our Avid disc installations is that they were both made on travel tandems where the brake cable run was made using two single bike brake cables joined by an in-line cable connector. While the use of the connector was to facilitate disassembly of the tandems for travel, I have always had a sneaking suspicion that the two cables (2/3 front half & 1/3 back half) might stretch less than the longer, single cable installation. I say this only because I vividly recall doing an initial installation on our '02 Erickson with just the single cable as I didn't have an extra connector and the Avid's performance was awful, not unlike what you and others describe. I addressed part of that with the compression spring, which helped quite a bit but there also seemed to be an improvement when I finally got a connector and went to the two-cables + connector installation. Just thought I'd throw that out there.

are there better options now to use with campy levers

Not really. In fact, you need to search out the older Record or Chorus rear caliper brakes to find ones that use the differential (dual-pivot) design instead of the newer models that have gone to a single pivot rear caliper, ref my earlier comment about having excess rear brake power on a single bike. Campy figured out somewhere in the late 90's that they could save weight by using a single-pivot rear brake with no real loss in useable rear brake power. I believe the Chorus brakes were the first to get the rear single pivot followed by the Record group in '01 or '02. This is all fine and well for single bikes, but on it makes a profound difference on a tandem where I can easily tell the difference between our Erickson's '01 Record rear brake with the differential mech. and the Calfee with the '08 Record Skeleton single pivot. I believe Shimano may have some brake sets that use dual-pivot front and rear-pivot rears as well, but I'm not positive about that.

FYI. Shimano DA, Ultegra (& SL) and 105 are all dual pivot designs front and rear.

Our co-Motion triple came with compressionless brake housing... I think it's Avid Flak Jacket. Seems to help keep both front and rear discs "firm." But the rear cable routing — from TT stop to caliper — also helps, because it is nearly a straight line. The rear housing acts a lot like a long guide. Standard "compressible" housing really can't compress unless it is bent into a curved configuration (think of a Slinky in its lowest energy, straight/relaxed state vs. one bent 180 degrees, poised to "walk" down stairs).

Can you clarify in bold...

We use standard housings that come with campy cable kits
Gottcha!


Avid Mech disc on the rear..

Assuming it's a BB7 Road model, there are at least three things you can do to improve the mechanical advantage (note the hyperlinks to addt'l info).

1. Coupled with using the least amount of brake cable / housing needed for the installation, install a compression spring (http://www.bikeforums.net/showpost.php?p=4102517&postcount=2)between the reaction arm and the integrated cable stop; this seems to help with keeping the brake cable in tension. The newest models of the BB7 seem to have a stronger spring and may not need this.
Ooooh nice idea, yeah the stock return spring is too weak for a long tandem cable.




3. If neither of those two things yield the desired improvement, consider the installation of an in-line Travel Agent (http://www.bikeforums.net/showthread.php?t=133131) or Side-Track BPB (Brake Power Booster). As was noted in a previous thread by kevbo, the ideal place to install either of these devices to minimize cable stretch is as close to the brake lever as possible vs. near the brake caliper. The latter isn't as aesthetically pleasing, but if it improves your braking... so be it.
Quick question what requires the use of the inline travel agent vs the plain travel agent?


As for using the Nokon housing, I've seen it used on a few tandems with rear discs early on and others have even used it with rear canti-brakes. It does seem to help, but I can't recall anyone saying the improvement was 2x; however, it sure couldn't hurt... aside from the wallet.
Wallet lightening is all a part of the game when you are leaving no stone unturned in the quest for optimum performance...LOL

Quick question what requires the use of the inline travel agent vs the plain travel agent?

Location, location, location....

The original Travel Agent was a knock-off of the World-Class V-adapter... a right-angle configuration designed to replace the noodle on V-brakes that were being used with Shimano (and Campy) drop-bar road brakes that had a mechanical pull mis-match with the V-brakes, or when installed with the cable in the opposite setting to allow folks to use the newer V-brake compatible brake levers with older Canti-lever brakes.

The Side-Track BPB was an in-line cable pull modification device from the git-go and could be placed anywhere along the rear brake cable run. There was also something called the Love Unit from Ibis that had two cams like those on the Travel Agent in an enclosure that sat between the brake levers... noting that the folks at Ibis looked to take advantage of both the cable pull modification and lower cable tension over the longest part of the brake cable. KHS did basically the same thing but using a pair of the right-angle Travel Agents between the brake levers and downtube cable stops. Like the Love Unit, it cluttered up the "dash" and looked a bit out of place: function over form.

Somewhere along the line someone apparently realized an In-Line version of the Travel Agent would be nice to offer up for installations where the right-angle wasn't desireable and there you have it.

Why not more popular on the front?

Front rim brakes work pretty well or at least "good enough" for most teams and the limited availability of tandem-rated disc forks / cost of conversion vs. easier rear installation and dual benefits of improved brake power and higher heat capacity. Add to that, discs add weight and preclude the use of lightweight carbon forks. In a weight conscious world, it's a tough sell for the average tandem consumer.

I think the Wound Up Duo full carbon fork adds about 200g over the Alpha Q fork. The wheels and the discs probably add most to the approximately 3 lbs difference between full discs and calipers.

I use Nokon's, IO Dupont cables, and both came in tandem lengths. I got them from Steve May [717-679-1151 Cell]. The are operated by Campy Record levers [brake only, shifters on downtube] and older dual pivot front and rears. They operate with great modulation and firm braking. I had to get liners so the cables would fit into the Nokon's.

My experience with a rear disc on tandem is that it really doesn't have much more power than a caliper or V-brake. I didn't expect it to have more braking power either. The advantage to having a disc is that when it overheats, it merely fades instead of blowing your tire out due to excessive heat.

If the disc were to overheat and begin to fade, you could use the front brake to slow the tandem to a full stop, assuming you have been favoring the rear brake.

I think the Wound Up Duo full carbon fork adds about 200g over the Alpha Q fork. The wheels and the discs probably add most to the approximately 3 lbs difference between full discs and calipers.

Yeah, I seem to recall it's something like 660 grams for the disc-compatible Duo vs. 445 for the caliper-only Alpha Q. Of course, you pay for that super-low weight on the Alpha Q vis-a-via a lot more deflection under load and in hard cornering. It doesn't bother us -- we've had three tandems with the Alpha Q forks -- but you can see and feel the difference if you switch back and forth between the Alpha Q and a Wound-Up or steel fork. The Reynolds Ouzo Pro Tandem (non-disc) is also a very stiff fork @ 650 grams or there abouts.

The Wound-Up forks lost a lot of weight when they changed out the aluminum crown for the all-carbon design as the non-disc earlier versions were something like 800 - 900 grams.

Anyway, at least for the racing crowd and others who are looking for lightweight tandems, the front discs just never gained traction. Other than the Cannondale tandems that come standard with dual discs, I just haven't seen that many other dual disc road tandems. We have friends here in Atlanta with one of Erickson's earlier dual disc customs that uses a steel fork made by Steve Rex and there's a hefty weight penalty for the entire set-up.

Even with the Wound-Up fork you're still looking at about a 1 lb weight penalty on the front wheel once you factor in the added weight of the caliper & rotor (~350 grams net, less the front caliper) and a disc hub (+100 grams over non-disc). In the grand scheme of things, 1 lbs isn't a lot; however, it's just not the nature of non-tourists to add weight when they can avoid it, notwithstanding the rear disc installations which have been readily accepted for the previously noted reasons.

My experience with a rear disc on tandem is that it really doesn't have much more power than a caliper or V-brake.

I suspect the V-brake set-ups with travel agents are a lot more powerful than a rear caliper... particularly something like the newer Campy rear calipers with their wimpy-for-tandems single pivots. I say that as someone who has a collection of Campy Record and Chorus brakes, the older ones with the rear differential (dual pivot) mech. and the newer ones with single pivot. The dual pivots seem to have at least twice as much braking power as the single pivots which, when you consider that at higher speeds the single pivots have almost no stopping power on a tandem, isn't all that much to brag about. I can't speak to the stopping power of a rear V-brake equipped tandem on a fast descent since I've never been-there or done-that with one. We've used calipers exclusively since '98.

Therefore, speaking from my own experience, I believe the folks who have switched over from a rear caliper to rear disc are the ones who experience the big 'wow' with the braking power of a rear disc and that's probably why they have been so warmly embraced by folks who configure their tandems with a lightweight carbon fork & caliper up front but who want a rear brake that actually works.

Just an observation which may or may not be universally accepted, but an observation none-the-less.

Therefore, speaking from my own experience, I believe the folks who have switched over from a rear caliper to rear disc are the ones who experience the big 'wow' with the braking power of a rear disc and that's probably why they have been so warmly embraced by folks who configure their tandems with a lightweight carbon fork & caliper up front but who want a rear brake that actually works.

I had a v-brake up front and have a dura-ace dual pivot caliper now. If I just was concerned with braking power I would have a dura ace caliper on the rear too. I have the disc because I don't want to heat a tire up so bad it blows off the rim. The conditions we ride in range up to insanely hilly, with descents so bad I need to flex my fingers periodically in between activating the brakes so they don't cramp up.

It's not about how much braking power, it's about the safety of not having a critical failure upon overheating the brake, which is what a blowout while descending could quickly become. If you haven't had to face a steep and curvy enough road to really push this issue yet then it's difficult to comprehend just how quickly you can overheat a brake on a tandem. If I was not regularly riding hills like this I might consider setting up the tandem for a caliper on the rear as well, possibly with the option to switching to the disc for the few times that warranted a disc brake. We however have been riding in the hills enough that it just makes sense to keep the disc on.

When I saw the topic, I cringed thinking that the compression-less housing being discussed was similar to what is used for deraileurs. A few manufacturers released a reinforced version of this housing however it was recalled.

The Nokon and Powerlines looks safe to me though. I don't think I' would ever run the Nokon cables though. I don't like the exposed alloy beads on these cables. They can cause rattling noises depending on where the cable guides are on the frame and it seems they might be more likely to scratch a frame. The Powerlines seem to address this better.

It's not about how much braking power, it's about the safety of not having a critical failure upon overheating the brake, which is what a blowout while descending could quickly become.

I don't disagree that what you state IS the reason that most folks -- ourselves included -- fitted rear discs to our tandems in the first place. In fact, we and other Erickson owners were using rear discs as light-duty drag brakes back in the latter part of the 90's. They were a far cry from the performance of the current Avid discs, but they worked just fine as light-duty drag brakes.

However, myself and others whom we ride with who replaced rear calipers -- Shimano or Campy -- with rear discs all seemed to enjoy having a rear brake that had more stopping power, as well as higher heat capacity, than the caliper they replaced. We made the switch over back in '03 and put about 12,000 miles on our Erickson travel tandem using an Avid BB7 with a 203mm rotor and it was awesome. Our first real test of the brake was riding up and back down from the Blue Ridge Parkway around the Pisgah National Forest near Brevard, NC, in the rain.

If our Topolino wheels were disc compatible we'd likely have our disc on all the time as well. However, until such time as Topolino releases a different axle assembly that will accommodate a disc rotor the rear rim brake will have to suffice... or we'll do a temporary change over to the disc and one of the other two wheelsets that are disc rotor compatible for any severly challenging terrain. It's a minor weight penalty that buys you a ton of control and brake heat capacity.