V-brake on road bike question
 

I'm sure wishing I could add a little more stopping power to our tandem but, dont want to go with disc's. We're using the stock set of Avid lucky sevens V's with the power boosting roller,the lever is an Ultegra STI.

Here's my question: If I was to go with an LX set (which is a true linear pull) and use the rollers. Would this work a bit better than the Avids V's (which are not a true linear pull)?

also

I've been told by someone that tried it with XTR, they said the squeal was maddning. They said the squeal was due to the light weight construction of the XTR calapers (394 grams). I wonder if LX would do the same (542 grams)?

You could add a drag brake to the rear hub. Lots of tandems have those.

Brad: Brakes don't squeal because they're light weight. Any brake can make a racket. To prevent brake squeal, just toe in the leading edge of the pads.

If you have a threaded rear hub, the suggestion that you install a drag brake is a very good one. The Arai drag brake asssembly is about $100~$125.00, easy to install, and works very well at modulating your downhill speed and saving your rims.

See Sheldon Brown's article on tandem brakes here:
http://www.sheldonbrown.com/tandem-brakes.html

Harris Cyclery sell the Arai drum brake kit here:
http://www.sheldonbrown.com/harris/ha-hubs.html

Have you sent off a note to/called Dwan or Dan at Co-Motion to get their recommendations?

There are a lot of ways to fine tune the performance of your brakes and several alternative brake designs that might work. Dwan & Dan will most likely have encountered your very same question in the past and have an answer ready for you. Moreover, if you do get into parts swapping perhaps they can give you 'Bro' pricing or do an exchange.

As for switching to Shimano's V-brakes, Avid's Single Digit series of brakes are -- for all intents and purposes -- the same "type" of brake and will give you similar performance. Therefore, before heading down that road I'd explore some other options:

1. Make sure your cable routing and the Travel Agent (what I think you're referring to as a roller booster) linerar pull adapter are working smoothly and that there's not any excess friction or kinks in your cable runs.

2. Make sure you've got enough brake lever travel to give you good modulation and maximum purchase as you use the brakes. I like to have my levers set up to move a cm or so before the pads begin to hook up, but not so much that the brake lever contacts the bar before they are locked up.

3. Different brake pads (although, Avid's Rim Wranglers are pretty good); again, get Dwan or Dan's recommendations on which compound they've found works best with your Velocity Dyad rims.

4. Keep in mind, any type of linear pull brakes and forks / rear stays will struggle push against each other when you apply max braking and the forks and stays will actually begin to be pushed outward at a certain point. If fact, this is why many folks have problems with brake squeal & linear pull brakes. So, you may want to consider trying one of daVinci's "Little Stiffy's" to "boost" your brakes performance before investing in new arms. IMHO, daVinci's boosters are the most aesthetically pleasing of the bunch and there's no question that they are stiff: http://www.davincitandems.com/index.html

5. Before spending money on the same type of brake consider putting a dual pivot brake caliper (road bike brake arch) on the front wheel and -- if the rear brake bridge on your Speedster has a hole for a pivot brake -- on the rear wheel too. The current crop of Shimano dual pivot brake arches (touring model, 105, Ultegra & DuraAce) will all perform as well or better than any linear pull brake. Linear pull brakes came into vogue because they allow tourists to easily mount fenders (mud guards for the folks across the pond) and LARGE DIAMETER tires, whereas calipers are a bit more restrictive. From what I've read in your previous postings on tires, having room for 32mm tires doesn't seem to be a priority. However, if you wanted to have future adaptability for fenders, the touring model of Shimano's brake arches easily accommodates fenders & up to a 28mm tire.

6. A rear drum brake is a good idea if you expect to find yourselves touring in the Rockies, Alps, or some other mountainous terrain where you need a drag brake to scrub off speed on long and/or very steep descents where over use of rim brakes would surely superheat your rims and cause a tire to blow out. However, in most parts of Texas that I've seen it merely be a parking brake on your bike, impractical to use as a "performance brake".

7. Avid mechanical brakes as a rear primary brake are becoming a popular option on Co-Motions. Not sure if your Speedster even came with the International Standard (I.S. or I.S.O.) disc brake mount but if it did that's another slick option when combined with the aforementioned front dual pivot rim caliper.

As you can see, lots of options. But, I think you'd be well served to speak with the folks who made your tandem and spec'd the brakes that are on it first before experimenting.

Thanks for the ideas folks. Dont think a Aria is what I'm looking for as I'm in Texas and wont be screaming down the Rockies anytime soon:) I'm just looking to squeez the most stopping power I can out of the bike without going disc. I've read a few posts like one of the ones above that mention "locking up the brakes". My brakes were set up by a very qualified mech. and re-adjusted, played with and tinkered by others and are set up as good as they can get. As they are now I cant lock up the brakes. I dont know why, cable stretch, frame/fork flex, dont know. I know it's not because the brakes are not set up correctly.


thanks for the ideas/help,
Brad

Oh, and yes, the light weight linkage bars on XTR will squeal when they vibrate. Like when they are trying to stop a tandem, they vibrate, no matter how they're toe'd.

Clarification: My use of "locking up" relative to your lever touching the handlebar implies "maximum braking force" which is not necessarily meant to imply skidding a front wheel. In fact, I've never ridden a tandem with a stoker on board at speed where any type of rim brake (brake arch, cantilever or linear pull) would "lock-up" and cause a front wheel skid on dry pavement. Riding solo is a different story -- "stoppies" are easy to do alone but not recommended since the rear end of the tandem usually comes around when the rear wheel looses contact with the road, aka. Jacknifing. The rear wheel is another story as they can be locked up at will under most normal conditions with an average size stoker on board.

The only brakes that could accidently "lock-up" the front wheel of a tandem in a panic stop on a hard, grippy surface with two people on board are large hydraulic disc brakes with large diameter rotors, e.g., 185 - 205mm, i.e., the ones that you would see on an off-road tandem with a beefy front suspension fork.
http://home.att.net/~mark.livingood/...2/ecdm221a.JPG

Ok, Mark. Again thanks. I guess the brakes work as well as they are going to.

Here is the deal:

When we are doing a rally we usually have a ton of people drafting off us (welcome to tandeming). Usually for the first hour or so we are with the main pack of racers up front (we usually get dropped as soon as we hit some hills).

A lot of times we'll be in the middle of a pace line as they are taking turns pulling then ducking behind us to draft for a while. As tight as the paceline is, if someone for what ever reason hit their brakes hard, I'd have a hard time slowing as fast as them and not knocking them. With the length of the bike and the weight I'd have a hard negotiating around them too.

Is that just a fact of life on a tandem? I was in hopes I could beef up the brakes so our bike would behave more like our singles.
I guess if I'd have asked that question first it'd saved a lot of time, huh.

Two quickies then onto the Paceline:

1. Back the previous lock-up postings. A cautionary note. If you should happen to death grip the front front brake on a tandem in a turn the front wheel WILL lock-up and the tire will skid out from under the bike. It's something I think most folks would expect, but after re-reading my previous two postings I wanted to be sure I was clear.

2. Your assessment of your brakes is probably about right. However, if you had the time and inclination to mount a DuraAce or Ultegra dual pivot to your front wheel I do believe that with the elimination of the travel agent and the clamping force of the caliper brakes you might find they feel more like the brakes do on your single bikes. A lot of this feel isn't so much from the braking action at the wheel as it is the feel of the braking action at your hand. Travel agents really do much up the "feel" of your brakes and that can play games with your head. Again, just something to think about.

Now, the paceline post....

Wow, there are so many thoughts running through my mind given your scenario -- many of them cautionary. Such as, if you're riding in tight pacelines where single bikes are using their brakes find another paceline. This is an accident waiting to happen.

Anyway, in answer to your question, YES. Physics dictate that -- all other things being equal -- a tandem with 275lbs of team weight and a wheelbase of 5.5 - 6' will not stop nor change direction as fast as single bike with a 170lbs rider and a 3' wheelbase. Over time, if you ride with several good single bike riders on a regular basis you can learn to ride well with each other. However, there is a lot of give and take -- but the rewards are usually worth the individual sacrifices. Sometimes you gotta push hard, sometimes you gotta hold back, and sometimes they get a free ride or have to wait at the top of a steep hill. All and all, it's not a bad way to share road time.

Back to pacelines, let me emphasize a few points on riding tandems in pacelines.

1. DON'T ride a tandem in tight pacelines with riders of questionable or unknown abilities (actually, that's a universal rule regardless of what you're riding).
2. If there are tandems and singles lining up for a pace line keep the tandems nose to tail as much as possible to reduce the potential for accidents and slinky effects of gapping and recovery that go on with mixed fleets. NOTE: sometimes it's just better to suck it up and let the tandems rotate in their own paceline in front of the single bikes -- they usually don't complain.
2. Leave a few more inches of gap between your front wheel and the rear wheel of the bike in front of you than you would if you were riding on a single bike -- it may be the difference between a wheel touch and a FDGB (Fall Down Go Boom).
3. NEVER let your front wheel overlap the rear wheel of a single bike in a pace line.
4. Raise your chest into the wind and soft pedal to scrub speed and try not to use your brakes in a mixed company paceline.
5. If you absolutely have to use your brakes in a pace line to keep from over running the rear wheel of the bike in front of you do it ever so gently earlier rather than abruptly at the last minute. The latter is the worst thing anyone can do in a paceline. If a paceline falls apart on itself I'd rather run off the road into the unknown than auger into the bikes in front of me and then have the pleasure of being crashed into by the bikes behind. Been there done that on a single and it ain't pretty.
6. Apply these same guidelines when you ride in tandem-only pacelines. It is an exhilarating experience when you can find 10 - 20 other tandem teams of matched abilities who can share an invigorating tandem paceline at a rally. However, at the same time it can be a nightmare if a squirrel gets loose in the pack.

hi there
have you considered magura hydraulics ????

i think they are less expensive than discs

i had probs with the brake cable stretching

on my lx brakes

never had a prob with maguras

:D

Ah, Margura HS66 hydraulic drop bar brake levers and rim brakes -- the mother of all rim brakes when it comes to clamping force.

The HS66's are indeed excellent binders; however, they are not compatible with integrated shifting systems such as the Ultegra levers on our friends Co-Motion. Therefore, to use them you'd need to do one of two things:

1. Give up your integrated STI brifters and use bar-end shifters with the HS66 brake-only levers.

2. Go with an 8 speed rear cluster and use a pair of the rare Edco IGP levers to preserve you integrated shifting/braking. Edco developed the IGP levers several years ago that made an attempt at providing Magura users with integrated shifting on their 8 speed bikes but they were not all that successful. You can still find a few sets sitting on the shelf but they're not usually cheap -- $475 comes to mind and, as I said, they were only made for 8 speed (Shimano?) systems.