Tandem Cycling - Replacement rim brake options
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The brakes on my Trek T2000 are over 5 years old now and done around 30,000 miles. Most of our rides involve a lot of climbing and long slow technical descents so it is vital that we have effective brakes,. This obviously increases the wear and so are continuously having to adjust them now which is taking up far to much time.
I believe the brakes are Avid shorty but with the reduce distance the brake arms on the STI shifters have to travel, combined with possibly a kink in the cable which seems to cause some of the slack in the system, we just can't seem to find a setup which gives good braking without rubbing. I'm sure replacing the cables would help but my pilot would still like a braking system which has some sort of adjustment built in to make it easier to adjust them as the pads wear.
Any suggestions would be welcome.
06-28-11, 07:13 AM
I guess that Trek used the shortys with their shorter cable pull so they could work with the STI levers. If you went to conventional v-brakes with a travel agent amplifier that includes adjusting barrel, you might accomplish what you are looking for. There are also teflon coated cables availabe or you could go with the more expensive Gore Ride-On cable system, which virtually eliminates friction.
Is there an off-the-shelf product that comes with everything in one? Or do we need to buy the brakes and travel agent/adjuster separately?
06-28-11, 09:02 AM
As far as I know, there are no conventional v-brakes that are compatible with road levers, without the use of seperate travel agents. There was an oddball brake that was made some time ago, that had a built in cam...my buddy has it on his Co Motion. My XTRs with travel agents, however, work better, are more reliable, and are easier to adjust. If I had it to do again, I would not use the XTRs because the parallelagram mechanism (exclusive to XTR) is made for wide mountain bike seatstay spacing and does not allow enough adjustment. In order to work on my tandem, it needed to have its springs rebent. I'm not sure how this will hold up, with the passage of time. For this reason, I would use any other v-brake.
Apologies if this is an obvious question but why isn't this a problem for solo bikes with STI levers? Or bikes set up for TTs with integrated brakes that have limited travel? Is it because they don't need to apply as much force to the rim to stop?
06-28-11, 10:11 AM
Before you give up on the Avid Shorty's, you might try a shorter straddle cable. Doing so will give you greater mechanical advantage and might make a difference for you. The downside of doing that will feel like you've lost your ability to "feather" the rear brake. It will either be none or all, but on a tandem the "all" shouldn't result in locking up the rear wheel.
I'm presuming you're saying your cantilever cable hanger doesn't have an adjusting barrel. I just converted our rear brakes from V to Canti's, and had a tough time finding a hanger that would work (actually, any hanger), but it does have an adjustment mechanism. They're out there if you can find them.
06-28-11, 10:46 AM
We have a stock '07 Trek T2000 with Ultegra STI shifters and the original R600 caliper brakes. While these brakes are fine for normal riding we won't use this Tandem for long, steep, tight technical downhills where a lot of heavy breaking is required because I have to be way too careful to not over-heat them which is easy to do.
We have other tandems with much better stopping power for those conditions. Our old reliable C'dale has STI Shifters and Avid Single Didgit 7, V Brakes, with travel agents both front and rear. This set up works far better as far as managing the excessive heat for those difficult downhills, They require very little maintenance, are fairly inexpensive and are easy to set up. They will still overheat and still require some disciplined technique but are far more durable than the caliper R600's. Prior to the V's we did run some old school Shimano SLX canti's on this tandem with non STI levers and they were nearly as good as the V's and way better than the caliper R600's
Lastly we also have a current generation tandem with Avid BB7 disc brakes front and rear. While we are not riding this one very much, we have had it in moderate steeps a few times and the brakes are incredible...I just abused them with no regard for heat build up and they have outperformed even the V barkes by a large margin.....however, these brakes have proven to be more difficult for me to set up drag and squeak free....they dive me nuts at times but they can flat stop a tandem. They also give me a sense of making the tandem slow to get up to speed....no hard facts just a sense of heaviness to that tandem that weights the same as the T2000 and old C'dale. Additionally, I have read here on BF that some folks have had over heating issues with some of the earlier versions of the BB7's....we did not, but again we have not put big mileage on them.
Bottom line: If I were to look for a way to improve our T2000's brakes I would find a way to put a BB7 disc set-up on the rear of it. With the existing Bontrager Carbon fork up front, I see no way to put a disc brake there cost effectively. I would even be willing to give up the Bontrager Race Lite Tandem wheels on the Trek if I had to, to get a rear BB7 disc.
Without seeing your current set-up I don't know how much better just going to a good V brakes will be for you. A good set of Canti's can be made to work really well. I can say that my experience with Avid Shorty's, particularly the 4's, was quite un-impressive even on a cross bike...I sure wouldn't want them on a Tandem in the steeps. Suggest you have a bike shop that knows Tandems take a good look at your current set-up...you may just need some better canti's. Good luck.
06-28-11, 11:56 AM
It sounds like the reason you're having to adjust them all the time is to compensate for brake pad wear. I can't see how changing to any other type of rim brake is going to help this. Regardless of what type of rim brake you choose, the brake pad wear will be in direct proportion to how much you brake. The only difference might be how easy it is to adjust for the wear.
We have a 1998 Co-Motion with V-brakes, bar-end shifters and Dia-Compe 287V brake levers. These were specifically designed to pull enough cable to work with V-brakes without a Travel Agent or similar. I don't know if the 287Vs are still available or if this would work for your situation.
06-28-11, 01:56 PM
Ian, Caliper brakes found on road bikes require approx half of the cable travel as v (or linear) brakes. This is why they are fine with STI or most other road brake levers; in other words, their geometry matches. The mismatch happens when you try to set up v-brakes with road levers. The geometry of the sti levers won't generate enough movement in the v's to allow any rim clearance when not applied. If you've never seen the travel agent, they consist of, essentially, 2 concentric pulleys. The inner pulley is acted on by the cable coming from the brake lever. The cable then snakes through to the outer pulley, which is approx twice the diameter of the inner. This is the part that activates the brake. Being that the outer pulley's circumferance is greater than the inner, it moves twice as much cable. It is a very simple and elegant solution. This setup works very well on my Santana Visa. A great improvement in stopping over the origional low-end cantis.
06-28-11, 04:50 PM
I have a 2004 Trek T-2000 with Avid shorty6 brakes. I just switched to Kool Stop salmon pads and like them. They work well enough for us, so am content.
In response to the OPs questions:
I do wish there was a barrel adjuster, and have been meaning to try an inline barrel adjuster or whatever else is out there. I assumed one of these would let me easily adjust for brake pad wear and also to loosen the brakes to get the front wheel off easier when the tire is full of pressure. Some items here: http://www.universalcycles.com/shopping/index.php?category=1613
Also, I was thinking that, since the Bontrager rims have a threaded hub for a drag brake, that there were disc rotors available for you. So, a BB7 could be installed on the rear, which is where your's could probably use the most help.
06-28-11, 05:30 PM
Linear pull brakes with Travel Agents were a very popular tandem spec for roughly 10 years. For any component to hang around for that long it must work adequately. If it was my bike I'd buy Avid SD-7 calipers.
07-01-11, 07:43 PM
I have seen a racing tandem with linear pull brakes and road levers, sans travel agents. The rider was an experienced tandem racer, and claimed to have no problem with the set up, as long as everything was kept near-perfect: cable adjustment; brake balance; wheel trueness, etc.
A travel agent on linear pull brakes will work fine with road brake levers. I recently converted an old Marinoni racing tandem from center-pulls to linear pulls on the rear, using a problem solvers cable stop (since the original brake cable stops were brazed on "noodles" which would not work with the linear-pull cable routing).
07-01-11, 09:40 PM
On our T2000 the hanger needed some fine tuning. To get a straight cable run into the brake I 1)loosened the hangers adjuster screw all the way and 2)fine tuned the length of the rear cable housing.
When applying the brake the hanger would pivot on its mounting screw so I zip-tied the bottom of the hanger to the seat tube, going between the seatstays. Now it's solid.
You NEED to install an in-line cable adjuster.
FWIW newer STI shifters and calipers use a cable pull that is compatible with V-brakes. I don't know what year/model Shimano changed.
07-02-11, 11:44 AM
Another Avid-7/Travel Agent user here. We run the Kool Stop dual compound pads. Shimano STI shifters. Brakes work great, very seldom need adjustment, stop the bike, plenty of cable travel to allow for brake pad wear. We can't lock the rear wheel, but that's fine, wouldn't want to anyway. We've noticed that some bikes have problems with V-brakes squealing. We don't have that problem, we don't know why, whether from adjustment or sturdiness of the mounts. We mostly ride in hilly terrain. We do have to be careful not to overheat the rims, but so far haven't ever done that, even touring loaded. We use wind resistance when descending, alternate brakes, etc.
We are building another rear wheel with a drum brake to give us more confidence when doing pass rides in the mountains. Pity that we'll add 2 lbs. to the bike to ride in the mountains. We'll see how much we use the drum. Maybe we'll find we only need it for certain descents. Each disc adds about pound too, so . . .
I have not been impressed with the V brakes + travel agents that I have used. I prefer either cantilevers or a good caliper brake, eg Dura Ace 7800.
Wow. Thanks for all the feedback. Sounds like this is not an uncommon problem.
Just to clarify though, the braking itself is fine. It's just the continual adjustment and associated faff that is the issue.
I also have a 2007 C'dale which I picked up recently that had hardly ever been ridden. This has the BB& discs which do work well, although are also difficult to set up well as another member also noted. We've also already broke a spoke on this bike after only a few hundred miles which I'm guessing is as a result of the heavy braking and load on the spokes. A couple of friends with this setup on a C'dale tandem also mentioned that these brakes had failed, possibly as the pads wore in, but not quite sure which is a little concerning. So I'm leaning towards moving to rims brakes on this bike as well.
Sounds as though an inline adjuster would be worth trying on my current set up before trying anything else. Pity there's not a all-in-one option though.
07-04-11, 01:33 AM
Some of the new top-end cantilever brakes now have intergrated barrel adjusters. However, they are made with cyclocross racers in mind, and so are expensive, and are optimized more for mud clearance than they are for power, and so are not a good option IMO. Adding a simple barrel adjuster to your current setup seems like the best option for you. That will also be a good opportunity to change the cables and housing at the same time.
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