In January, in anticipation of the long steep downhills of the 3 State 3 Mountain ride in Chattanooga, TN we installed a rear disk brake; the Santana Winzip in particular. My wife and I had done this ride on singles the previous two years and found that with the sharp turns and bicycle traffic, the braking demands were much higher than we see on our regular riding. Coming down the third one, Lookout Mtn, is the most demanding for us. If it were not for the concern of overheating and blowing up a tire I would have stayed with the V Brakes - they have been great on our tandem. So...we put about 600 miles on the disk brake since the end of January and it had performed well enough. I found that setting up the alignment of the Winzip caliper was more difficult than I anticipated and I found over those miles that the pads were not wearing evenly telling me that I did not have the calipers as close to parallel to the rotor as I would have liked.
I probably braked more on each downhill than I would in hundreds of miles at home. I'd let the bike go as much as I could and then do some serious braking with the front V Brake too. I did some alternating but was trying to do more of the braking with the disk. After the first downhill, my lever was bottoming out and I adjusted the pads in close. I was doing just that when TandemGeek walked up to me at the first rest stop - pleasant surprise when he said, "Hello Bloomington!"
On the 3 St 3 Mtn ride, we were having a reunion with a friend who rode with us across America in 2005, and he rode behind us down the second moutain, Sand Mtn. I've never ridden down anything long (2 miles plus) and steep behind a disk brake and neither had he but he got an eyeful on this ride. He was amazed at the behavior of the rotor as we did some hard braking with some regularity. He said that after some hard braking and the rotor was heated up it just looked wavy as it went around. He would estimate that it was wobbling about one and a half to two inches back and forth. I didn't feel any wobble at the lever and had no idea but when I would let go of the brakes, I could hear the rotor rubbing a lot. When we got the bottom and stopped braking altogether the rotor would quickly quit wobbling and it would be silent again. (I had never experienced this in our riding in our smaller southern Indiana hills)
So...my question...Have any of you been behind a disk brake on some really long steep downhills to know do rotors do this in general when doing this kind of hard extended braking with the corresponding heat. Is this 10 inch rotor more susceptible to this than an 8 inch rotor? (I suspect it might be). At home we regularly go down a half-mile long hill that lets us reach 55 mph. It's a clear view so we never brake but for testing purposes I may actually try to fasten our little digital camera to the bike and take a little movie and put on the brakes so I can see it. Perhaps somebody reading has a helmet cam and can follow a friendly tandem down a big descent and tell us about it.
It actually scared my friend who was watching but he didn't tell us that until after the fact. I won't be insulted if any of you tell me I don't know anything about disk brakes - I'll say I'm guilty already. It's the one component of my bike that I have limited experience with.
Bloomington, IN
sch
05-10-07, 07:21 PM
It seems quite reasonable that the disk would warp, most
likely the larger the disc the greater the warp. All that
heat has to result in metal expansion and some warpage
is to be expected and evidently well designed for if it
shrinks back flat when it cools. We have noted the front
rim warms up to the point of discomfort when touching
with the fingers when slowing down from 30 or so down
to a stop on the hills around my house with rim brakes.
The much less mass in the disc rotor will heat correspondingly
more, proabably to the point of burning skin if you touched it
right after braking. OTOH, its low mass allows it to shed
heat rapidly to the air. Makes one believe the stories
out of California where tandems with hydraulic disks
locked up due to heat induced expansion of the fluid
on multi mile downhills with 4000-7000' drops. Would
be nice to see a video of the effect if you can rig it up.
On another note, congrats on doing 3 states on the tandem.
I did 3 states on my bent two yrs ago and chickened out
on the 3d hill climb, turning L on US 11, instead of R to
climb Lookout. I remembered the final hill from several
3 States in the '98-'99 when it only had 3-500 riders and
didn't want to tackle it on the bent. Have you considered
doing Cherohala on the tandem. Last time I did that, (on
the DF), there were at least 2 tandem teams. Looks
like they have introduced some alternatives.
http://www.smwbike.org/cherohala/ccMain.htm
http://www.smwbike.org/cherohala/images/Smallerized/IMG_9555a.jpg
TeamTi700
05-10-07, 07:39 PM
I'd like to hear some details on your instalation process. I had to replace my Formula disc brake this week and opted to go with another Formula. I had no interest in drilling a new hole in my frame to go with the WinZip.
For the record, my original Formula lasted for 6 years and 26,000 miles with no problems.
TandemGeek
05-10-07, 07:59 PM
Although I can't be certain, I have reason to believe that the 255mm rotors are far more prone to warping than the 203mm and 185mm rotors. The basis for my arm chair assessment is feedback I received from a certain disc brake rotor manufacturer who was engaged to develop a 255mm rotor for use on tandems. We -- that would be my builder and I -- had included the 255mm rotor design in our decision tree when we were retrofitting our travel tandem with a full-time disc to replace the rear caliper and Hope disc drag brake. In discussions with the 255mm rotor manufacturer they indicated they were unable to successfully pass their own test standards without experiencing disc warping and suggested that we stick with the 203mm rotors. Mind you, this was back a few years so things may have changed and another manufacturer may have solved part or all of the problem (i.e., it still warps but returns to true after cooling?).
As for any personal observations of rotor behavior on severe descents, while we've ridden with other teams who have rear discs I can't ever recall being in a situation where we had the opportunity to either observe or have my eye's attention drawn to a disc rotor's movement. Then again, we've only seen about 4 of the 10" discs on Santana tandems and none of them -- aside from BC's -- were at events with challenging descents.
Our personal experience with discs on tandems goes back to '98: we've had various different systems and different size rotors. The oldest design was the Hope mechanical, circa early '90's and the 185mm / 6" & 203mm / 8" rotors were noticably more robust than current designs.
From the photo below you can see how additional cooling / weight reduction holes were added to newer 185mm / 6" rotor and also take note of how much material has been removed from the earlier 203mm / 8" rotors compared to a contemporary model. All are about the same .075" thickness. Sorry that I don't have a 255mm / 10" model here at the house to stick next to the other rotors for comparison purposes.
y2kdad99
05-10-07, 09:23 PM
Hi guys,
I'm just a tandem wannabe lurking on this forum. I, too, rode the 3S3M for the first time last wknd, and I was wondering how you tandemmers handled those downhills. I'm from west (flat) Tennessee and this was my first mountain downhill, and I was riding my brake all the way down. I was impressed by the tandemmers on this ride, and can't imagine flying down those hills! Hats off to you and all the tandems that completed the 3S3M!
zonatandem
05-10-07, 09:25 PM
26,000 miles on a Formula disc is impressive!
Had Mafac cantilevers with Scott/Matthauser pads that went for 50,000 miles on the rear of our old Assenmacher tandem.
Pad/disc material/size would have an influence.
Maybe you'll need to rig a water-cooling set-up on that big Winzip?
TandemGeek
05-11-07, 05:11 AM
...I was wondering how you tandemmers handled those downhills.
...with extreme patience as you pick your way past all the very slow solo riders who love to ride 2 and 3 abreast who think they're going fast and who won't yield the left side of the lane when faster riders call "on your left", and even more patience for the solo riders in their team racing kits who are positive they're the fastest, most skilled descenders who also won't yield to faster riders approaching from behind and calling for room to pass "on your left".
Were it not for the other bikes, on descents like the 3 State I tend to let the bike run and use aggressive braking before the corners. Where more speed control is necessary, sit with hands on hoods and chest open to take advantage of wind braking and judiciosly modulate front & rear brake use so that neither brake remains "on" all the time and has a chance to cool. The rear discs do tend to fade pretty fast once they overheat and then they're worthless, so the front rim brake still sees a lot of use. Oh yeah, never and I mean never touch painted road markings while cornering or braking... that's just asking for trouble in the form of a wheel slip or skid, even with the tandem's long wheelbase and weight. I was dumbfounded by all the solo bikes that were dancing around the damp centerlines and watched a rider almost loose it about 3 bike lengths in front of us.
In general, and IMHO, the vast majority of recreational and club cyclists who under-estimate the speed and performance differences that exist between elite-level riders -- the professional, semi-pro, and amateur elite-level riders -- and mortals like themselves also don't appreciate just how much faster tandems can be on descents, how much further momentum will carry a tandem coming off of a downhill section of a series of rollers, or how much faster a tandem will slow as it comes off the flats and hits the base of a climb. Therefore, much of the potential speed advantage that tandems "could" enjoy and leverage on hilly terrain used for big events is converted into a high demand on brake performance, bike handling skills, and patience since the "passing lane" just inside the center divider strip will always be occupied by the same type of chuckle-head who drives their car at or just above the speed limit in the passing lane of major transportation arteries. To quote George Carlin, these are the folks who believe that anyone going slower than they are is an idiot, and anyone going faster is a maniac.
y2kdad99
05-11-07, 06:56 AM
...
I was dumbfounded by all the solo bikes that were dancing around the damp centerlines and watched a rider almost loose it about 3 bike lengths in front of us.
I agree. I saw a number of riders crossing the double yellow lines at 25+ mph around blind turns with oncoming traffic! Natural selection at work?
I did try to keep to the right to let faster riders (including several tandems) pass on the descents.
Thanks for the info. I'm trying to convince my wife to try a tandem -- hopefully this summer we'll join your ranks.
sch
05-11-07, 08:00 AM
If you haven't ridden with tandems, (or bents for that
matter) it is not intuitive that they are real motors
on downhills. I ride with the Goertz' on their sunday
soirees and they made this abundantly clear very early.
My experience with my bent is that once I hit 25,
DF solos float off the back even if they are pedaling on
downhills, and the roll out is terrific as well because of
the low air resistance (about the same as a tightly
tucked, nose to the bar tri rider). The Goertz's routinely
roll away from me, however and occasionally even with
my pedaling they coast away. Around here the majority
of tandoneers are sociable types who sink to the rear of
the group and don't ride with the faster riders. Riding
with the DF groups, you would never know there are at
least 8-10 tandom couples in the county. So it is not
surprising that the vast majority of DF have no idea
they need to clear a ROW for the really fast tandom
coming through.
cgallagh
05-11-07, 09:17 AM
with extreme patience as you pick your way past all the very slow solo riders who love to ride 2 and 3 abreast who think they're going fast and who won't yield the left side of the lane when faster riders call "on your left", and even more patience for the solo riders in their team racing kits who are positive they're the fastest, most skilled descenders who also won't yield to faster riders approaching from behind and calling for room to pass "on your left".
We were running downhill at the Palm Springs Century and encountered just such a situation. There was a tandem just in front of us as we were approaching a large pack of half bikes. As we called out in a very loud a clear voice "on your left" I saw several of them turn, look at us, and intentionally pull in front of us. The two tandem teams quickly became trapped in the middle of a bunch of peepee measuring idiots, with nowhere to go but to ride it out and look for an opening. I was riding my brakes the whole way down, praying no one would make a mistake and take down the crowd. My immediate conclusion was that the decision to intentionally impede our progress meant the lack of cognitive reasoning and common curtesy indicated a lack of skill as well. To intentionally put yourself and others at risk like that does not say much for your skill level or intelligence. I now approach these types of situations assuming the pack is full of fools and set up passing accordingly. If all goes well I am pleasantly surprised. If the pack acts like fools, I am not and I'm prepared.
merlinextraligh
05-11-07, 10:11 AM
We were running downhill at the Palm Springs Century and encountered just such a situation. There was a tandem just in front of us as we were approaching a large pack of half bikes. As we called out in a very loud a clear voice "on your left" I saw several of them turn, look at us, and intentionally pull in front of us. To intentionally put yourself and others at risk like that does not say much for your skill level or intelligence.
[/I]
Or it says something about the effectiveness of yelling on your left. I've always found this often confuses people, and sometimes makes them move left because they are confused about your intention.
I've always found its best to pass people in a manner that you're not relying on any particular behavior from them.
If I need someone on an organized ride that I don't know from Adam to hold a precise line in order for me to pass, I'm passing too close to them.
TandemGeek
05-11-07, 10:46 AM
I've always found this often confuses people, and sometimes makes them move left because they are confused about your intention.
If you encounter or you're riding with "civilian cyclists" at MS150 events and the like or on -- God forbid -- Multi-Use Paths I would tend to agree with you....
However, don't confuse civilians on bikes with the seasoned cyclists who KNOW what "on your left" implies and who simply refuse to yield a portion of the lane. I could run down my laundry list of poor cycling skills and social defects observed over many years of cycling but it's pointless: the only cyclists who don't know what they are are usually the ones who oblivious to their less than admirable on-the-bike behaviors.
carpediemracing
05-11-07, 02:53 PM
Or it says something about the effectiveness of yelling on your left. I've always found this often confuses people, and sometimes makes them move left because they are confused about your intention.
I've always found its best to pass people in a manner that you're not relying on any particular behavior from them.
If I need someone on an organized ride that I don't know from Adam to hold a precise line in order for me to pass, I'm passing too close to them.
+1
A long, long time ago I was told that when racing, not to yell "left" or "right" - it only gave a direction for the others to shut down. Instead, yell "Up" or "Watch it". The uncertainty of where to go usually gets (racers, in this case) to hold their line and look up and around for whatever the "threat" is.
I rarely do mass rides but the future missus and I are doing an abbreviated metric century in two weekends. I'll have to remember some of the tandem tips and experiences I've read in this thread.
As someone who loves descending fast on my solo bike, I'll have to remember the tandem speed/mass descending advantage when I hear one or know of one behind me.
thx
cdr
TandemGeek
05-11-07, 03:14 PM
I was told that when racing, not to yell "left" or "right" - it only gave a direction for the others to shut down. Instead, yell "Up" or "Watch it".
We aren't talking about races, racing, or racers.... where sharp elbows come into play in what is often times a contact sport. In a race, you expect bikes to pass on the right, on the left, and in just about any gap that may or may not necessarily exist.
cgallagh
05-11-07, 03:42 PM
Not wanting to resurrect an old topic I must say this. In my admitted limited experience (7.5 months and about over 1900 miles on a tandem and over 300 on a single bike-with three organized century rides and many club rides) I have found many, many, many people understand me when I say "on your left". This is accompanied by the stoker bell ringing. Many people acknowledge this and also say thanks as we go by. On a ride with many hundreds of riders, approaching a group of riders from the rear should include some kind of warning you are approaching along with giving as much room as possible to safely pass without intruding on the passee or impedeing motor vehicle traffic. I have never had someone move out to the left when I say on your left because they thought I was telling them to move to the left. The situation I described was not someone mistaking my intentions or the intentions of the other tandem. The pack spread out and we were pushed to the yellow stripe then cut off in front by people who knew what they were doing. When the oncoming cars finally cleared we attempted to pass and the crowd continued to impede us. Eventually we made it around them. I like it when someone lets me know they are passing. What if you were passing someone and they made a small correction to avoid some just seen road hazard because they were not aware you were there?
Anyway, I will drop this for now as I said before it is an old topic and not about disc brakes. Sorry to go off on this tangent.
zonatandem
05-11-07, 07:45 PM
A 'bent, with fairing, can go faster than a tandem team in full tuck position on long/steep descents. Happend to very experienced tandem friends on the Sierra-to-the-Sea Century.
Yes, wet/damp road lines are as treacherous as wet RR tracks.
Desending with a large group on steep/winding hills can be problematic. While 'on your left' is our usual warning, on this type of descents we holler 'coming through!' Seems other riders will stay put/keep their line, without having that 'deer in the headlights' look.
Just our observation . . .
Pedal on TWOgether!
Rudy and Kay/zonatandem
thalver
05-11-07, 08:16 PM
Regarding disc rotor size, obviously there are inherent cooling advantages to a larger rotor. That said, have people here had much experience with 185mm rotors running too hot?
We are a fairly large team,(375 on a good day) but the bike we are looking at upgrading to has some limitations on rotor size. FWIW, we should be able to install a rear V brake as an adjunct. Opinions anyone?
zonatandem
05-11-07, 09:58 PM
In case of rotor overheating, an extra V-brake could be a cheap insurance policy.
stapfam
05-12-07, 03:01 AM
Regarding disc rotor size, obviously there are inherent cooling advantages to a larger rotor. That said, have people here had much experience with 185mm rotors running too hot?
We are a fairly large team,(375 on a good day) but the bike we are looking at upgrading to has some limitations on rotor size. FWIW, we should be able to install a rear V brake as an adjunct. Opinions anyone?
I have an offroad tandem with Hope Mono M4's and 200 mm discs front and rear. I have actually had the discs glowing a dull orange on a night ride with no effect on braking or any sign of Warping. I have to admit that the 200 mm on the rear is a bit over the top and we should really have gone to a 180 to balance the brakes a bit better. Incidentally we are 400 lbs in ride trim so about your weight. One thing I should mention though is that if you are fitting a BIG front disc (Or just any disc really) then think about that quick release on the front wheel. This is some concern over wheels pulling out of the fork with just a QR and big disc. I would recommend a bolt through axle if you are that aggressive on downhills but there are still many riders using QR without any problems.
cornucopia72
05-12-07, 08:43 AM
I have never had someone move out to the left when I say on your left because they thought I was telling them to move to the left. The situation I described was not someone mistaking my intentions or the intentions of the other tandem. The pack spread out and we were pushed to the yellow stripe then cut off in front by people who knew what they were doing. When the oncoming cars finally cleared we attempted to pass and the crowd continued to impede us. Eventually we made it around them.
My sugestion: Do not take it personal.
The people that act like that are usually wanabe racers that can not diffrentiate between a race and a fun ride... just take the high ground.
For us either "on your left" or "keep your lane" has always worked.
Lastly, unless you can not master a loud yell, get rid of the stoker's bell.
Back to the topic... We had rim brakes front and back operated by the STI's and a disc operated by a bar-end lever. We got rid of the rim brake in the back. As soon as the snow melts we will test the system and report back
cgallagh
05-12-07, 11:26 PM
My sugestion: Do not take it personal.
The people that act like that are usually wanabe racers that can not diffrentiate between a race and a fun ride... just take the high ground.
For us either "on your left" or "keep your lane" has always worked.
I don't. Thanks. I knew what they were doing, just had to deal with the situation. Some people just are that way.:(
Lastly, unless you can not master a loud yell, get rid of the stoker's bell.
That bell belongs to RR. It has other functions for her and she has fun with it. The bell stays.:p:)
zonatandem
05-13-07, 11:21 AM
"The bell stays'. . . hey stokers get what they want!
We were questioned about Kay's round c/f handrests on her drop bars. "What are these?" which K explained are her preferred stoker handrests (rather than dummy brakelever-type set-up). Then was asked: "Why are they up that high?" . . . pilot butted in " 'cause that where she wants them".
'nuf said!
TandemGeek
05-13-07, 04:54 PM
Opinions anyone?
Yes, the 203mm rotor is the only size Avid has cited as the appropriate rotor spec when using their mechanical discs on tandems: bigger is better when discussing rotors (at least to a point, hence the original question posed by BC regarding excessive heat induced deformation of his 255mm rotor).
Relative to your cantilever as an augmentation, if you need more brake heat capacity than a rear disc provides why bother with the disc? Use cantilevers with a drum brake... full time or installed as needed when demanding conditions are expected. Yes, I'll accept the notion that any combination of rim & hub brake can be imployed with either system being the primary brake and the other being a 'supplemental' brake. However, one needs to carefully assess why they may need a supplemental brake in the first place before resorting to a supplemental rim brake and how, in fact, why and how they would use it.
robmitchell
05-15-07, 09:31 AM
Hi,
Fun thread to read, always good to stop and read all brake threads.
Any large group ride or charity event is full of people who think it is a race and they are racers that day.
I have heard people talking about their training and readiness while putting their numbers on at several charity rides, usually the century or metric century. There are also a few people who do race mixed in making it a dangerous combo.
I always hold back at the start, there is almost always a few fall over crashes, flats, and have seen people stop in the middle of the group riding to wait for a friend! Just avoid that early cluster.
Then when things move out, find the place you would like to ride. We usually ride with the fast people for a while then bail off the back. If the group is getting crazy koo-koo, abandone ship, let them go.
Sometimes I see riders and decide based on their bike handling, I don't want to ride with at high speed.
Plan on unpredictable riders not moving over, and underestimating tandem speeds going up and down rollers especially. Nothing worse than the rider that passes you prior to a descent thinking he is the dude racer not realizing you can coast faster then he can pedal.
Oh yeah, the stoker bell is a must. You just get tired of saying on your left after 20-30 times.
It is also easily heard, but don't over use it.
On our old bike, the Formula disc brake would squeal nicely with slight pressure. It was great for approaching riders from behind that were spread over the road. Just one tap and they would all pay attention thinking it was an auto coming up behind them.
Rob
K&M
05-15-07, 01:58 PM
Reminds me of an incident last month. We were just pulling over the top of a climb when a couple on single bikes went flashing by us. They were obviously very strong, they looked like serious racers, and they were probably in town for the Sea Otter road race. As we started down the descent we, naturally, began catching back up to them at a high rate of speed. The woman was out near the center line so I started yelling "on your left," but she made no move to drift back right. As there was a small space between her and the center line I figured that, as a racer, she thought she was leaving us plenty of room to pass .... and we shot right through that gap at about 55mph.
You should have heard the scream that came out of her! Next time she passes a tandem at the top of a hill, I'll bet she'll ride a little further to the right.
Michel Gagnon
05-15-07, 08:44 PM
Maybe it is a French-speaking thing, but if you tell me "On your left", I'll automatically think that I have to move left; IOW, "move to your left"...
If you want to tell me that you are passing, tell me "Watch out" or "Passing" and I know that you're passing on the left side. After all, I'm Canadian, so I ride and drive on the right-hand side of the road.
P.S. Actually, according to rules of the road, it's your responsibility to pass me safely, which means at a safe distance to the left. And it's my responsibility to look behind before moving sideways.
ricardo kuhn
08-13-07, 05:18 PM
After riding Motorcycles and downhill bicycles for years, I prefer to leave the Hard stopping to the disc brakes and the slowing down to the rim brakes.
In my experience disc brakes tend glaze over if over heat or over used, in short they don't like to be Drag around, no only the pads wear faster but the disc gets red hot to the point you can even voil the fluid and render them useless.
This set up is pretty heavy but works extremely well.
200MM rotor using a Hope x4 four piston hidrolic caliper and V-brakes mounted forwards or backwards (like in this picture) the "Street" rim is a mavic 121 mountain bike rim and I have a conventional fork on this 20m trueaxle F.U.N.N. downhill fork.
http://patineto.smugmug.com/photos/178809177-L-2.jpg
The "Mountain bike" rim is a Atomlab downhill rim, massive but a excelent heat sink so the rims never get hot, even on the steepest of hills, but even then you still have the Disc for when you really need them, Think Mammoth lakes downhills and stuff like that.
http://patineto.smugmug.com/photos/33121701-L-2.jpg
The two brakes are control by this side by side levers, so far no issues, very simple to operate, if anything the bars end up being a little to wide, but not much we can do about that.
http://patineto.smugmug.com/photos/25648033-M-2.jpg
ftsoft
08-13-07, 05:46 PM
I concur on the bent going faster downhill. I ride a solo and a tandem and am a pretty good descender ( I hit 60 mph on my single during Hellweek in Texas), but one of my regular partners on a bent just rides away from me on descents.
TheBrick
08-14-07, 06:30 AM
Reminds me of an incident last month. We were just pulling over the top of a climb when a couple on single bikes went flashing by us. They were obviously very strong, they looked like serious racers, and they were probably in town for the Sea Otter road race. As we started down the descent we, naturally, began catching back up to them at a high rate of speed. The woman was out near the center line so I started yelling "on your left," but she made no move to drift back right. As there was a small space between her and the center line I figured that, as a racer, she thought she was leaving us plenty of room to pass .... and we shot right through that gap at about 55mph.
You should have heard the scream that came out of her! Next time she passes a tandem at the top of a hill, I'll bet she'll ride a little further to the right.
Just to through something into the mix here. If you are going 50 + mph how well do you think you voice carries forward? Not very well. All they prob hear is a load of shouting (which may for all they know be between another group riding behind) and are prob not keen on looking round behind at that speed. Add to that wind noise and concentration of decending fast and is there any wonder people don't move over?
Just a thought for people.
oldacura
08-14-07, 07:56 AM
We too have run into the situation on large organized rides where we overtake a bunch of singles on a descent. I have a bell on the handlebars but when your closing speed is 15 - 20 mph, the bell doesn't carry far enough. I have wondered if one of those air-powered horns (run off of a pressurized water bottle) would work. I doubt that I would have the presence of mind to bring one along for just this situation but it might be the only way to get the attention of the slower bikes ahead.
lhbernhardt
08-15-07, 12:46 AM
At the velodrome, the convention when you are about to pass someone is to just yell "stick!" or "stay!" If you are up near the top of the track, accelerating along the balustrade in preparation for a sprint, you clear room for yourself by yelling "rail!" Slower riders are expected to either hold their position and expect someone to pass them real fast, or get a bit further away from the rail.
I don't like yelling "on your left" when I'm on the road. I usually whistle sharply thru my teeth (a technique I learned in Mexico), or have my stoker ring the bell.
I find the bell is one of the most useful accessories ever invented. Its tone is somehow completely non-threatening. It doesn't tell people to get out of the way, like a horn does. It merely announces your presence. I've actually had females (usually with dogs) on urban trails actually thank me for ringing the bell as I approached (on my single fixie, I have the bell attached to the pump, like the racers in Belgium).
As far as passing closely, if two riders collide, the passing rider (the one carrying more speed) will usually stay upright. The slower rider will usually crash. If the rider about to be passed ignores my "on your left," I will repeat it in a louder voice and more insistent tone (tone is everything - you can say whatever you want and get results as long as the tone is correct). If the rider still doesn't move over (and allowing that there is room for him to move over), then all bets are off. He's been warned, and now it's OK to brush the idiot. Give him a bump if I'm really pissed off because I've had to brush other guys further back. 35 years of close-quarters track racing does come in handy.
Oh, brakes. I'm currently running dual-pivot sidepulls on my tandem, but then I use 23mm tires. I've tried all manner of v-brakes and I can't stand them. Use them with brifters and you need to install a compensator, which removes their mechanical advantage. The pads are too thin, they're difficult to adjust properly, and in my experience, they have never stopped very well. Dual pivots are much more effective, as long as your tires are narrow enough.
Have never used disks, but am reluctant to install them on the front due to the quick release problem. I'm starting to think about them on the rear; the technology seems to be advancing to the point where they might be more effective than dual pivots.