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  1. #1
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    V-brakes OK for steep descent with weight?

    Hi, I am a tandem newbie and this is my first post here. My question is around the wisdom of riding a weighted tandem with v-brakes down a steep and long descent.

    I have a Santana Visa tandem with a Burley Piccolo tag-along bike which connects to the rear rack. I ride with my two sons - 7 year old & 65 pounds as a stoker (with a kidback raised BB) and 4 year old & 40 pounds on the Piccolo. We have been out a few times and we all seem to be learning and are definitely having fun.

    We are planning to do an overnight trip on Orcas Island in the San Juans later this month. I am thinking of climbing Mt constitution, which is a 1500 foot climb over 5 miles. I do question my legs, but am more concerned with the descent. Our bike has v-brakes. Although they function well, I am wondering if I should be concerned about all the weight (280 pounds of riders, the 30 pound Piccolo, and 25 pounds or so of panniers). I have never climbed mt Constitution, but it has 15% grade in places. We will have only bare necessities in only front panniers - we are hotelling it.

    Although we have not taken our "mysteryship" on anything this steep yet, we have done well on shorter steep climbs, and the bike tracks very well and feels safe at 35 mph, which is the fastest we have been able to go. (I have ridden extensively as a solo cyclist, and also with my oldest son on the Piccolo with a solo bike).

    I'd like your expert opinions and advice on safety. Thanks.

  2. #2
    pel
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    Suggest you go up and down the same way, namely on the up in short not exhausting sections so you can enjoy it and too in sections but a bit longer. The point being for the down hill run to avoid your rims becoming over heated and placing the tubes at risk of a blow out. This has not happened to me but friends have had this nasty experience.

    We have mechanical disc brakes (Avid bb7) which worked well on a 30 km descent in the Alps with a fully laden tandem pulling (or in this case being pushed by) a 40kg trailer load. 200kg all up.

    Take it easy. You should be fine.

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    You can do it, but I would not want to. 15% is just too steep if it goes for any distance, and completely scary if turns, sand, cars or other things are involved. Generally speaking, if it is scary on a single, it is a nightmare on a tandem.

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    The brakes are plenty strong enough but remember they work by converting kinetic energy into heat. Your rims can only absorb so much heat before your tires explode, either due to the high pressure of the hot air in the tubes or because the sidewalls melt. If the conditions are such that you are going to be continually trying to slow down then you are going to be in trouble. If the descents are fairly straight and you can run down them wide open, then no problem. Otherwise, alternate your front and back brakes, and don't be afraid to stop frequently to check rim temperature.

    Years ago a group of us descended Smokey on the Cabot trail in the rain on fully loaded touring tandems. This is about a 300m descent over 2 km with lots of switchbacks. We (incorrectly as it turned out) assumed that the heavy rain would provide lots of extra cooling. No-one actually blew a tire, but we had more than one badly melted sidewall that had to be replaced.

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    Thanks bikeinxs, jgg3, pel. I hear various degrees of caution. We can always turn back and choose another ride if after starting the ascent, the reverse seems like it would be too scary. What I'm hearing is that as long as we take the descent in chunks, the heated brake factor should be mitigated (although the overall wisdom of such a descent may be questionable, depending on the terrain, about which I will try and learn more.) I appreciate all your advice.




    Quote Originally Posted by bikeinxs View Post
    The brakes are plenty strong enough but remember they work by converting kinetic energy into heat. Your rims can only absorb so much heat before your tires explode, either due to the high pressure of the hot air in the tubes or because the sidewalls melt. If the conditions are such that you are going to be continually trying to slow down then you are going to be in trouble. If the descents are fairly straight and you can run down them wide open, then no problem. Otherwise, alternate your front and back brakes, and don't be afraid to stop frequently to check rim temperature.

    Years ago a group of us descended Smokey on the Cabot trail in the rain on fully loaded touring tandems. This is about a 300m descent over 2 km with lots of switchbacks. We (incorrectly as it turned out) assumed that the heavy rain would provide lots of extra cooling. No-one actually blew a tire, but we had more than one badly melted sidewall that had to be replaced.

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    This sounds like a pretty steep descent. Rim heating depends on 2 factors: How comfortable you are with speed and how necessary it is to keep the speed in check. If there are a lot of switchbacks, stop signs or intersections that require you to dump a bunch of speed frequently, the rims can get hot. If it is a relatively straight shot and you're comfortable going 30+ mph, the wind drag on your bodies will absorb energy and keep your speed within reason.

    Another alternative is to get an Arai drum brake that can absorb this energy without heating the rims. Many tandems are made to accept a drum brake as an add-on.

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    Here's a link to http://www.bikely.com/maps/bike-path...t-Constitution which is someone's tracing of the route. Up in the Bikely toolbar, you can pick "show" to see an elevation profile.

    Looks like the 15% sections are a small proportion of the total. Since you'll be coming back down the way you went up, you may recognize the "steep descent ahead" clues, and be able to stop ahead of the descent to let the rims cool.

  8. #8
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    We did Everest Challenge Road race on my Cannondale Tandem. Thats 29,000 feet of climbing over 200 miles in two days. I use Avid shorty brakes with Shimano XTR brake pads. Overheating was a huge concern. I would pump the brakes on the long decents, alternating between the front and back. On the long straight decents, I would let the bike go, sometimes reaching speeds in excess of 40 mph. We had no problems...John

  9. #9
    Senior Member zonatandem's Avatar
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    Alternating (fast) between front/rear V-brakes would be our suggestion/experience.
    Scrub speed before the curves/steep sections; sit upright to help slow down a bit.
    Have done long/curvy descents (11 miles @ 6 %) down Kitt Peak in AZ (just under 8,000 ft elevation) with just cantilever brakes front/rear. No issues except that fingers started to cramp up from the braking. Stopped to give fingers a break and felt the rims; they were warm but not hot. Continued descent.
    Had been told by 'tandem experts' . . . "you can't do that without a drum brake."
    A small section of 15% descent should be do-able.
    Be careful and enjoy the trip!
    Pedal on TWOgether!
    Rudy and Kay/zonatandem

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    How can I say this delicately.....we are talking two small children here !!!! Mysteryship you are smart to question the risk and there IS risk. Even if you were not a new captain on newer equiptment, any combination of steep hills, a trailer, children, new pieces of highway and the like do deserve the respect you are giving them.

    While the brakes... "may or should or probably or can or whatever..... why take the risk for the sake of a few dollors for readily available saftey equiptment. I respectfully suggest you at least put an Arai drum brake on your rig and give you and the kids the extra margin of safety. It may save more than we could imagine.
    Welcome to the group, be safe and have fun.

    Bill J.

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    I've never ridden with a tag-along or trailer. How stable are they decending on a steep grade with hard braking.

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    rmac - the tag along that we have is surprisingly stable. The Burley Piccolo (http://www.burley.com/products/child/piccolo.cfm) does not attach to the (stoker) seatpost, as most tag-a-long bikes do. It attaches to a robust steel rear rack, in such a way that the "headset" attachment of the Piccolo is positioned - and rotates - directly above the rear hub. Much like those huge RV trailers you see mounted into the bed of a pickup. That said, I have never had to slam on the brakes going down hill (but in all my years of solo riding I have never had to do that either...). In all experience so far (I have been using the Piccolo attached to a solo bike for the past 4 years) it tracks, brakes, and handles surprisingly well. And my kids love it.

  13. #13
    Senior Member zonatandem's Avatar
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    Piccolo is the most stable/predictable tag-a-long bike. It follows the lead bike 100% and will not clip curb or road edge as is possible with other systems.
    Burley has a special rack (called Mooserack) for attaching the tag-a-long to the bike, as mysteryship described.
    Might be advisable to do a couple hefty climbs/desents before tackling Mt. Constitution on Orcas to see how the whole choo-choo-train behaves under heavy braking/climbing.
    Pedal on!
    Rudy and Kay/zonatandem

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    Quote Originally Posted by rmac View Post
    I've never ridden with a tag-along or trailer. How stable are they decending on a steep grade with hard braking.
    I have ridden a limited amount with a Adam's TAB - few 100 km- if you get into really steep stuff, >30%, on your single, under HEAVY braking (chopping 60 km/h for the hairpin at the bottom) they get a little exciting - largely as a result of the rear wheel on the half bike getting light while the TAB is pushing. On the tandem, I never know the TAB is back there - the tandem allows for so much more rear wheel braking that I never have an issue with it getting light (ok, my son has 3 years and 30 lbs on mysteryship's but my daughter on the TAB matches) and the longer wheelbase makes the push much less when turning and forces aren't lined up straight.

    If you keep the speed down, just about any descent is possible. My kids, mountain bike with me on the tandem, and yes, there are sections that will be a blast in a couple years but today, we dismount and WALK. Remember, they recommend big trucks come down at the same speed they went up.

    Prairie*boy (who now lives in foothills of Cdn. Rockies)

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    15 % grade for anything more than a few hundred feet is extremelly hard with a loaded tandem. I don't know waht kind of gears you do have. Can you test your team/equipment in some similar hills near by? I would defenitely get a drum brake or come down very slowly.

  16. #16
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    I have never done that one (I'm in Eastern Canada), but I have ridden a few 4-5 km long hills with a 12-18% grade. How safe depends on your stability (yours and your kids), how good the road is, how wet it is, etc. At the time, I had a tandem + Piccolo; our total weight was 265 lb (175 + 50 + 40), plus roughly 200 lb for the fully loaded contraption (camping trip).

    Basically, I tried to minimize overheating risks by alternating between both brakes, using the front brake 1/5 of the time, the rear brake 2/5 of the time (not too hard, for fear of skids)... and letting my speed increase the rest of the time. My reasoning behind that pattern is that if I ever had any overheating problem, it would be with the rear wheel, and that a rear-tire explosion isn't as much a problem as a front-tire explosion.

    Regarding safety, the worst speed seems to be around 25-30 km/h. At high speed, it's the wind that brakes you, while at a crawl speed, you simply spend so much time going downhill that brakes can't overheat. So if asphalt is good, let it build some speed between curves (make sure everyone hangs tightly), and otherwise, ride fairly slowly.

    Since you are on a tour with kids, take your time. Nothing prevents you from stopping 2-3 times for 10-15 minutes to watch the scenery.


    One last word regarding packing: unless you haven't done so, I suggest you experiment with weigh distribution. With the kind of weight distribution I have on my tandem + piccolo, it handles much better if I keep the front end very light and put as much weight as possible on the rear wheel. The first stoker is just too light otherwise.
    Michel Gagnon
    Montréal (Québec, Canada)

  17. #17
    pel
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    Quote Originally Posted by specbill View Post
    How can I say this delicately.....we are talking two small children here !!!! Mysteryship you are smart to question the risk and there IS risk. Even if you were not a new captain on newer equiptment, any combination of steep hills, a trailer, children, new pieces of highway and the like do deserve the respect you are giving them.

    While the brakes... "may or should or probably or can or whatever..... why take the risk for the sake of a few dollors for readily available saftey equiptment. I respectfully suggest you at least put an Arai drum brake on your rig and give you and the kids the extra margin of safety. It may save more than we could imagine.
    Welcome to the group, be safe and have fun.

    Bill J.
    Well said specbill.

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    Be very careful. Speaking from experience, 35 mph on a steep twisty grade (17% in our case) is no place to be having a blowout due to heat/pressure/meltdown. I bought a new tandem with disc brakes for this very reason.

    -Couch

  19. #19
    hors category TandemGeek's Avatar
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    Quote Originally Posted by mysteryship View Post
    I hear various degrees of caution. We can always turn back and choose another ride if after starting the ascent, the reverse seems like it would be too scary. What I'm hearing is that as long as we take the descent in chunks, the heated brake factor should be mitigated (although the overall wisdom of such a descent may be questionable, depending on the terrain, about which I will try and learn more.)
    By George, I think he's got it.

    Common sense, an appreciation for the risks, and a realistic appreciation of one's own skills and experience will get most cyclists who are new to tandems through even the most demanding situations.

    You might try contacting the Evergreen Tandem Club based in the Puget Sound area to see what the folks who've ridden this loop on their tandems might have to offer.

  20. #20
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    I've seen a lot of questions about disc brakes vs drum brakes, but until today I hadn't seen any actual data about the heat capacity of any of them. Velonews has an article about the new Magura hydraulic disc brakes, and they are tested to a fairly rigorous standard. Two cycles of absorbing 800 watts for 15 minutes, with a two minute cool off in between each cycle. That's claimed to be the equivelant of a single bike descending a 15% grade (for 15 minutes!! twice!!).

    Does anyone have hard numbers for drum brakes or any mechanical discs?

  21. #21
    hors category TandemGeek's Avatar
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    Until such time as an independent testing lab does any testing subject to peer review I doubt there will ever been any meaningful "hard numbers". The reason I say this is years ago there was also a bunch of data published in a German cycling magazine that compared all of the current disc brake offerings, much of which has since failed to translate to practical application or experiences. Similarly, independent empirical disc brake testing by at least one major tandem builder has also failed to generate meaninful data that can be directly correlated to real-world performance with any consistency.

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    Thanks all for the advice. Update: after talking with folks who know Orcas Island roads and Mt. Constitution, and taking in all your advice, I decided to change our plans and take the mystership and my two sons to Lopez Island and San Juan island instead - terrain which is relatively flat, and known to me, as I did the trip with my oldest on the trail-a-bike + solo bike last year. Browning, who said "man's reach should exceed his grasp" was not likely a tandem rider...

  23. #23
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    Sounds like that will be a great adventure. Best of all, it leaves you with something to shoot for in future years.

  24. #24
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    Lopez is great, and quite bike-friendly. Practice waving -- the islanders all wave when they pass you on the road.

    Try to get all of the way to the south end of the island; take the walk out to Watmaugh Bay, etc. Be aware that there aren't many stores/snack stop places south of the Village. And, take a trip over to Spencer Spit park, and the kids will like the walk out to the cabin at the end.

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