V-brakes and STI
OK, so I bought a used 'Dale MB tandem (a '96) with cantilever brakes and flat bars. Wanted to put drops and something with more stopping power on it (riding it on the road - I know, could have just bought a road tandem, but this was a deal I couldn't pass up).
Put 105 STI on it (off another bike), and then, per many forums, added V-brakes with a 'cable doubler'. They worked very well. However, then decided to do some other jiggling around, which required removing cable inner. Also removed cable doubler, just for giggles, and it works fine still!
So my conclusion is that one can use V-brakes with Road levers, and that which I have read about road levers not having enough travel is not correct.
1. we live in a hilly area and yes, we use our brakes copiously
2. front rim is very straight, about 3mm tolerance between rim and pads. Might explain need for small amount of travel
3. left the doubler on the back one. Don't know why. Feels like the longer cable might need it?
4. V-brakes are the $14.95 ones from Performance (sorry Nashbar! I bought all my other stuff off you). Man, they are bomb proof, light, and cost less than dinner at Carls Jr.
Hmm. 3mm is 1/8 inch, which is actually pretty far for rim to pad spacing. I have a CoMotion with V-brakes (Avid SD5) and 105 STI, using travel agents. I was considering going to cantilevers! Why did you think V-brakes would be better?
No, technically it is correct: STI/Ergo type-road brake levers and linear-pull brakes are not directly compatible. The grey / subjective area becomes "having enough travel" and, as you note, it's the rear brake that most exhibits the incompatibility. The 'travel agents' correct for cable travel and also reduce the amount of cable tension to provide a rider with a net increase in braking power with less brake lever travel and hand effort.
Originally Posted by TriGit
So, yes, while it is true that you can adjust a linear pull brake to work without a travel agent, there are other trade-offs that need to be considered. Therefore, at least for the major tandem producers who live under the threat of product liability lawsuits, idiot-proof brake installations with lots of safety margin become the default. This sets the benchmark for the industry and your average shop mechanics to follow because, again, it's a prudent practice.
The prudent good samaritan who offers advice on public forums will also usually default to the 'safe' recommendation, perhaps knowing full well that there are alternatives.
My experience with trying this just to see how they would work was that not only did the pads have to be adjusted really close, but it made the brakes "grabby" or too easy to lock up. The added weight on the tandem might take care of this, but you'll probably find that you need to use the full travel of the brake lever to get them to work and if you have a steep descent you just might wear off enough pad that you can't get the lever to work at all. One of those liabilities that TandemGeek pointed out shops need to be concerned about.
The statements I bolded are not correct. Cable tension is doubled and travel halved (compared to V brake designed lever) between the TA and the brake lever. This DOES halve lever travel, but at the expense of requiring twice the force. QBP does make an in-line version of the Travel Agent. If such is installed near the lever end of the cable run, then cable stretch related problems common on tandem rear brakes can be minimized vs. the normal "noodle replacer" TA installation.
Originally Posted by TandemGeek
The bolded statements would be correct if the TA were used "backward" to control road calipers or straddle-cable type cantis with V-brake ratioed levers, which is doable with the in-line version.
Cantilever brakes versus V-brakes or disc brakes
This is from R&E Cycles in Seattle Washington http://www.rodcycle.com/ They have been building custom tandems since 1973.
"Why do you use cantilever brakes when everyone else is using V-brakes or disc brakes?"
As your mom used to say "if everyone else was riding over cliff would you?"
The short answer:
Cantilevers work better because they were designed for use on road and tandem bikes. V-brakes and disc brakes were designed for mountain bikes, and then adapted for use on road and tandem bikes.
The long answer:
(The long answer is based on years of working in busy bike repair shops and designing bikes. It's the same answer, but if you're like me, you'll want more info to convince you that what you read in the catalogs and magazines isn't true.)
Since the (short lived) days of the U-brake I have always said "the problem with cantilevers is that they are lighter, easier to adjust, less expensive, and work better than the other types of brakes."
Most tandem manufacturers use V-brakes or disc brakes , and will tell you that they are better. What they don't know (because they don't have a service shop that deals directly with the public) is that every year, we change out several 'other' brand tandems to cantilevers.
The truth is, it would sure be a lot easier (and less expensive for us) in the retail department to use V-brakes or disc brakes and just avoid this question all together....just pretend that V-brakes or disc brakes are the best. But, because we are a full service shop, our customers will be relying on us to make them work well. We know from experience, that educating you is much less expensive then replacing, at no charge, 48 pairs of brakes for unhappy customers (1997 V-brake fiasco). So, here it goes, the method to our madness:
Cantilever brakes were used on touring bikes and tandems for decades before mountain bikes were even invented. The cantilever evolved into an extremely powerful and reliable braking system. Loaded touring bikes and tandems put more severe weight loads on the brakes than did bikes with just one person on them. Cantilever brakes provided the power and durability that it took to stop a 400 pound tandem team on a 45 pound tandem, barreling down a 7 mile descent at an 8% grade at over 60mph.
There was another advantage to them though. They would accommodate wide tires. When the mountain bike was invented, cantilever brakes were used in order to accommodate the balloon width tires. For years, all went well (except for a short love affair with something called the U-brake in the late 1980's). But then, in the mid-1990's, bike manufactures developed a new brake system for the mountain bike. What they came up with was the V-brake.
V-brakes were specifically designed for off-road use on a mountain bike. The needs of loaded touring bikes or tandems were not taken into account by mountain bike designers. Thus, the resulting design wasn't even compatible with a standard road bike brake lever. Adapters, or special levers had to be used by manufacturers who put them onto road bikes or tandems. None the less, the road bike and tandem industries embraced the new standard, using the following logic: 'if the V-brake is powerful enough to stop a mountain bike, of course it will be great on a tandem or a touring bike'.
One question they forgot to ask themselves was "what does a 400 pound tandem team, or 250 pound loaded touring bike, barreling down a pavement highway at speeds of over 60mph have in common with a 179 pound guy going 20mph down a dirt road?" The answer is "very little, if anything." Well, after we had a summer full of really bad experiences with the new V-brakes (including on my own tandem), we went back to the old fashioned cantilever. This wasn't easy, and we ended up having to import them ourselves. This is the reason that most manufacturers don't offer them, it's hard to bring them into the country yourself, but we think it's worth it to have our bikes perform better than other touring bikes and tandems. Now, don't get me wrong, if you want V-brakes, they use the same braze-on as cantilevers and we'll put them on at no extra charge. We've had a few customers choose V-brakes over cantilevers (they loved the brakes on their mountain bike), but they both had us change their bike to cantilevers before a year was up.
The disadvantages when using V-brakes on touring bikes and tandems are many, the first of which is probably the most important.
On a mountain bike, you don't put on lots of miles. I mean, you don't ride 50 miles + in a day very often. On a touring bike or a tandem, these distances are common. In an off-road situation the weight of the rider and his bike might be 175 pounds or so, whereas a loaded touring bike and its rider will be more like 250 pounds (and well over 400 pounds on a loaded tandem). In an off-road situation a high speed might be 25 miles per hour, and the terrain is loose dirt or mud. If you pull the brakes, the tire skids, and your brake pad isn't getting worn much, versus 40 to 60mph on a pavement surface...no skidding and much faster pad wear.
A V-brake pad is very thin. As a matter of fact, they only have 2mm or so of brake pad to wear off before the pad is worn out. Then you're running metal on metal. In contrast, even the thinnest of cantilever brake pads have 5mm of wear (some almost twice that much). I was only getting 250 to 300 miles on my V-brake pads when I had them on my tandem, but I can get thousands of miles on a set of cantilever pads.
The mountain bike V-brake requires an adapter to make it compatible with a road bike brake lever. In our service shop we see hundreds of bikes per year with centering problems when people have to use these adapters. On my own tandem, I had to center the brakes a couple times a day when I was using them a lot.
The V-brake has long arms that extend higher than the rack bosses on most bikes. This makes it very difficult to install a rear rack (something that every touring bike should have).
The Road V-brake:
Some manufacturers have come up with what they call the 'road' V-brake. This is a V-brake with shorter arms, and addresses the 'adapter' and the 'rack mounting' problem. Unfortunately, it creates another problem. The arms are so short, that you can't put fenders on most of the bikes that use them. The pads still wear out just as fast, and the other problems of V-brakes still exist (read on).
Nothing is more annoying than brakes that squeal louder than a jet engine. Since V-brakes weren't designed to be used at the speeds and weight loads of tandems and loaded touring bikes, they tend to squeal (really loud) when being used in this fashion. They don't always have this problem, but more so than cantilevers. When a bike has this problem, it is very hard to correct.
Most road and tandem bikes with V-brakes can be easily fitted with cantilevers. As a matter of fact, we do several a year right here in the repair shop for customers who have reached the end of the rope with their state-of-the-art V-brakes.
Disc brakes have come a long way in the last 10 years. They have really evolved into a brake that will stop a tandem almost as well as a cantilever. The cost of them has dropped substantially as well, and I far prefer them to a V-brake now. A few years ago, I would've rather had a V-brake, but now I think the disc is less troublesome.
Most tandem companies now use disc as they are superior to the V-brake, and because the conventional wisdom says "why fight what everyone is asking for?"
If we simply manufactured our bikes and sent them to dealers, then the dealer would have to deal with any problems. In our company though, we are the only dealer, so we are the ones who will be taking care of your new bike.
I want to make it clear that if you want disc brakes on your tandem, we're happy to build for them. But I want to make sure you know that just because you like them on your mountain bike, that doesn't necessarily mean that you'll like them on your tandem.
You've all heard the ravings of how great they are, but I wanted to let you know that there are a few disadvantages that you should consider. These are the things that most companies won't be bragging about.
A disc brake stops the wheel at the hub. This causes a lot more stress on the spokes, rim and frame at the points where the wheel attaches. When we build a bike for disc brakes, we build with heavier chain stays and seat stays, and often install a brace between them. We've found that if we don't, the frame has a tendency to break at the dropout. The bike winds up heavier, but only slightly.
For a bike using disc brakes, we build the wheel with a little heavier rim and more spokes. At Rodriguez, we offer a 3 year warranty against broken spokes and rims, so we build wheels to hold up. We've found that if we build the wheel at the same weight as we build for cantilever bikes, the spokes break at a much faster rate, or the rim sill start to crack around the nipple area.
The disc and the caliper together weigh more than a set of cantilevers. Increased weight is not usually something that we look for, unless there is a dramatic performance improvement.
Most of our disc brake customers find that the discs warp a little bit, and them make noise as the wheels roll. Most people don't mind noise, but again, unless there are dramatic performance enhancements, I see no reason to put up with noise.
Difficulty of portability:
Most tandems and touring bikes that we sell now are designed for easy packing for travel. Disc brakes hinder easy packing as the rotors get in the way, and often have be removed so as not to get bent. This adds time and frustration that's not necessary.
Difficulty of mounting racks:
The calipers are constantly in the way for mounting a rear rack. This is more of a nuisance than a problem I guess, but it still is trouble that's completely avoidable.
None of these disadvantages effect the mountain biker, and I highly recommend disc brakes on mountain bikes.
Cantilevers work better tandems and touring bikes because they were designed for use on road and tandem bikes.
V-brakes and disc brakes were designed for mountain bikes, and then adapted for use on road and tandem bikes.
Not convinced? Don't worry about it, we'll put on anything you want, as long as you understand 'there is a method to our madness.'
Have you tried removing a wheel from your bike yet?
Originally Posted by TriGit
Are you sure about that?
Originally Posted by kevbo
While you are correct in what a TA does, it does not represent what the user experiences when you move to linear pull brakes with a TA. Remembering that context matters, my comments pertained to the OP's proposed configuration of using a 5.6:1 ratio road brake lever to control a linear-pull / V-brake designed to work with a brake lever using a 2:1 ratio compared to how that same configuration works when you replace the V-brake noodle with a travel agent (TA) .
Perhaps I'm missing something, but the way I've come to understand it, a TA significantly increases the amount of brake arm travel (which you correctly note) for the same amount of brake lever pull, and also increases the braking force once the brake shoes contact the rim when compared to the amount of hand force it would take without the TA.
This increase in power for the same given braking force is what gives tandems equipped with TA's what is often characterized as a 'mushy' feel compared to how road brake levers matched to a proper caliper feel. This same initial mushy feeling vs. the higher resistance experienced on a road brake lever /road brake set-up with lower mechanical advantage is why road/road devotees knock the road/v-brake + TA set-up for having poor modulation / tactile feel. As you'd expect, while this is initially true, most folks who have v-brake equipped tandems quickly adapt to the 'feel' and enjoy all the modulation they'd like. However, in either case, it takes less hand effort to achieve the same net braking force (at a somewhat lower amount cable tension) that it would using either the road/v-brake without the TA or even the road/road caliper brakes.
Again, you are also correct in that placing a TA at the lever-end of the tandem would halve the amount of cable tension over nearly the entire length of the cable run, which is why Ibis (with their LOVE unit) and even KHS mounted their cable pull adapters at the handlebar end of their road tandems... and what a gawd awful looking mess that is. TAs have also found a place with some of the tandem teams using a rear disc to mitigate the need to maintain tight tolerances between the rotor and pads give the way TAs modify road brake lever pull.
Frankly, you won't get a compelling argument out of me in favor of V-brakes with TAs for road tandems. I'm not a fan and my first hand experiences are limited to test rides and trying to get v-brake tandems from squealing like Banshees. Instead, and because we're a lightweight team, normal road brake calipers operated by road brake levers is all that we've ever needed, augmented with a rear disc in lieu of the rear caliper when we head to mountains where we expect to encounter technical descents. If we were a heavier team or did loaded touring we'd likely use cantilevers coupled with a supplemental disc or drum brake operated by the stoker for truly demanding terrain.
I would note it's refreshing to see that Dan T's article on brakes hosted on his shop's (R&E) website has apparently been recently updated relative to disc brakes whereby it is far more objective than previous words that have appeared in this same article. I tend to agree with most of what he's saying about discs at this point... assuming we're talking about a rear disc. I'm still not sold on dual discs, but that's a personal bias that has more to do with how a road bike 'should look', added complexity, weight, cost and serviceability when touring, etc...
As Retro Grouch has alluded to, the very tight tolerances the OP will need to get a V-brake to 'have sufficient travel' for acceptable use takes a lot of attention to achieve and maintain. Moreover, once so-adjusted, these tight tolerances makes wheel removal nearly impossible UNLESS you are using them with Campy Ergo levers where the brake quick release is integrated into the lever instead of the brake caliper... or use some other type of in-line cable tension adjuster.
Bottom Line: V-brakes and 5.6:1 road brake levers don't play nice together and really do require the use of TA.
Last edited by TandemGeek; 04-27-08 at 11:21 AM.
OK, there is something I am confused about here. The big article (Rodriguez?) says that road cantilevers were the first on the block. That would imply they are designed for road lever travel (whatever that is, does anyone have numbers for this?). But since cantilevers are used on mountain bikes, that implies they are designed for flat-bar brake levers.
And the article says they have to "import" (really, almost everything is imported) special cantilevers. Well, you can't say they are normal road issue and then claim they are some kind of rarity. So which is it?
Count me as a Shimano 105 STI (9sp) lever user with V-brakes using TravelAgents and not being entirely satisfied. And yes, I am a former racer and love "real" brakes, but I don't think I can mount them on the CoMotion, which has mounts for cantis/V. And the pad wear seems really high (Avid 20R pads). I would like to change to cantis and try them out. It doesn't sound like an expensive test. What do I need?
1. Canti's, obv. But which ones?
2. Some kind of cable center hanger?
3. What else?
When V-brakes came out Shimano redesigned the brake lever to go with them. A few flat bar brake levers have two alternate cable anchor positions so they cen be used with either brakeing system.
Originally Posted by jgg3
That would imply they are designed for road lever travel (whatever that is, does anyone have numbers for this?). Back before the DiaComp Aero levers came about road brakes used a 4:1 ratio, which was a better match for cantilevers. The current 5.6.:1 road brake levers when used without a TA only provide about 40% of the travel needed for a linear-pull/V-brake, but about 70% of what a conventional cantilever needs.
But since cantilevers are used on mountain bikes, that implies they are designed for flat-bar brake levers. Were, not necessarily so today, per Retro Grouch's comments. However, unlike linear-pull / V-brakes, conventional cantilever brakes have variable mechanical leverage based on how you set up the yoke / straddle cable which permits some adaptability inherent to the brake itself in addition to any alternate brake anchor positions used on current MTB levers. Frankly, most folks today simply run either V-brakes or discs on mountain bikes. Of course, the problem with the yoke / straddle cable and mountain bikes was tire clearance which, when coupled with heel clearance with the arms, is what precipitated the linear-pull / mountain bike specific designs. However, back to road bike use, you'll find a wealth of information on how to properly adjust cantilevers at Sheldon Brown's Website.
And the article says they have to "import" (really, almost everything is imported) special cantilevers. This is interesting because last time I checked they were fabricating their own tandem cantilever brakes in-house. Their in-house canti purportedly fairly cost-effective and simple to produce.
1. Canti's, obv. But which ones? Most of the newer canti's have been modified to work well with STI/Ergo brake levers. I'll defer to the folks who are using what's out there.
Last edited by TandemGeek; 04-27-08 at 10:47 AM.
Nope. The TA changes the "gearing" of the brake cable. Just like when you change gearing in the driveline, if you want to move twice as far per crank revolution, you are going to have to mash twice as hard on the pedals.
Originally Posted by TandemGeek
Noise: V-brakes have a fair bit of mass a long way from the mounting studs. (large moment of inertia) TAs add quite a bit more. This makes the resonant frequency quite low and easy to excite.
One advantage that has not been mentioned is that the spherical washers used with V-brakes make it a lot easier to align the pads than with the plain studs found on cantis. I can do V-brakes with only two hands, where cantis require that I deploy my prehensile tail as well.
Also not mentioned is the main reason that V-brakes are more popular than cantis on MTBs: Suspension. Cantis require a cable stop that moves with the wheel axle and is quite a ways from the tire.
Hmmmm. I guess that would be correct.
Originally Posted by kevbo
Perhaps the missing element here is how the longer arms of the linear pull brakes factor into the equation since the normal comparison isn't between V-brakes coupled with road brake levers with and without Travel Agents (TA), but between v-brakes w/TA adapters and either cantilever or caliper brakes and STI / Ergo road levers.
Again, I'll be the first to admit that I really don't like to mess around with linear pull brakes on road tandems but, that said, using them without the TA is problematic.
I take it from your commentary you're using linear pull brakes and a TA mounted up front instead of on brake arm?
Last edited by TandemGeek; 04-27-08 at 12:12 PM.
For the rear, cable stretch isn't an issue for the front.
Originally Posted by TandemGeek
Nice summary of the History Of The World As It Applies To Stopping Your Tandem! Thanks.
Good to get the bike shop perspective, that often helps in the decision-making process for an individual rider.
A few points:
1. I'm not so sure how convincing the "because they were designed for road" argument is for cantilevers. I find cantis harder to adjust than V-brakes - I can never get the pads in the right place in the former (individual user, not bike shop, but then I do most of my own maintenance, so that's what's relevant). I'm pretty sure suspension seat posts weren't designed for use on the road but my wife thinks it's the best tandem add-on ever....
2. haven't found in the past that pad wear is a problem on any given ride, but over time I do note that even my MB V-brakes wear out quicker than the cantis they replaced. (that is, I don't think it's a 'danger' - not like they're suddenly going to go through 2mm on a descent - just require more frequent replacement)
3. I get all the technical descriptions of the incompatibility between road levers and v-brakes, I'm just pointing out that I have not experienced any of the hypothetical problems - I find them easy to use with a very small amount of travel, they are neither mushy nor grabby. As far as I can tell they work just like the set up I have on my road bike (with standard road brakes)
4. someone asked if I've tried to remove my wheel - yes, I undid the QR and popped it out, after undoing the 'noodle'. I'm guessing that the TravelAgent might make that a bit harder, but I can pop the TA out fairly easily too, so I doubt it.
1. I'm not so sure how convincing the "because they were designed for road" argument is for cantilevers.
I seem to remember Shimano cantilevers being easier to adjust up until the V-Brakes came out. It's like Shimano made them worse to make the V-Brakes more appealing. They added an unnecessary spring that made it difficult to get a pad to sit in one spot once they had been tightened down really good in another. You really wanted to get them right the first time. They also started making the spring retainer out of plastic on some models. The retainer breaks and then it is impossible to center the brakes. However, I know Avid currently makes a cantilever brake now that is a bit like the V-Brake design. It uses the V-Brake style pad, however has the cantilever style cable pull. This would still have the issue of thinner pads, however I have not had any problems with the thinner pads other than having to replace more often. I however have also not done loaded touring on a tandem yet.
2. haven't found in the past that pad wear is a problem on any given ride
Even the road calipers have thinner pads now. I think it's just a way to sell more brake pads.
4. someone asked if I've tried to remove my wheel
The reason he asked that is that the pads can end up so close that the noodle is impossible to remove without disconnecting the brake cable. Because you say that you can do this, I begin to wonder if you don't have the version of V-Brakes that has a shorter arm. Avid makes one that eliminates the need to run the Travel Agents. When you disconnected your TAs was the cable just on the larger wheel or was it threaded through the small hole onto the smaller wheel?
The posts from those who have studied this issue in detail is very educational.
It reinforces the addage that engineering is the art of compromise. We have had V Brakes with Dia-Compe 287V levers on from the beginning. It has worked well for us but many would consider the compromise of not being able to use STI brifters unacceptable. I didn't realize that cantilevers might be better suited to a road tandem than V-brakes. Also, I always assumed that caliper brakes wouldn't be "powerful" enough for a tandem but now see that they can be and may be the best compromise for certain teams & conditions. With a bit of adjustment and clean rims, squealing hasn't been an issue.
I ride my bikes like I drive my car - I try to avoid using the brakes by anticipating conditions ahead. On a bike I do this mostly because of laziness - I don't want to throw away that hard-earned kinetic energy.
When we do descents of steep roads with tight turns, I do use the brakes quite a bit. If rim heating is the limiting factor (don't know this for sure) then it wouldn't matter if the brakes were V, canti or caliper.
As far as pad wear goes, it's not much of an issue for us because as I said above, I try to avoid using the brakes and we very rarely ride in wet conditions (which really accelerates pad & rim wear).
Riding Heaven's Highwayson the grand tour
Thanks everyone ! Great thread on a popular subject..great info in a condensed version....this is one reason I love this forum. FWIW I went through the same decision making process this past winter on our upgrade project. After much research, alot of it here but sourced through many different archived threads I ended up converting from barcoms to STI and went with: TA's in place of the noodles front and rear, Avid SD 7 V's with CW2 pads. A 1000 miles later and riding in a quite hilly area, I could not be happier...great stoping power, outstanding feel and resonable wear to date. I set up the TA's exactly as directed and they have been flawless.
While this route worked great for me that is not to say that a canti solution would have been any less satisfactory...like many other things on our bikes, there our often multiple ways to accomplish our goals....chasing the options and executing the choosen one properly is a lot of the fun. Thanks again