Equinox

We have experience on a Tandem, but we have a new C0-Motion Supremo. We have less than 400mi on it and we are still getting used to it's handling characteristics. We came to a steep downhill yesterday. I'm guessing 16%-18% for about 3/4mi. with some gentle turns. We got off and walked down because I was afraid. We have Dura Ace caliper brakes. We are 275lb team weight. I'm afraid of popping a tube due to excessive heat build up. I just don't know where that point is. I'm good with the brakes. I know how to feather them and alternate them. I like my technique. I just don't know at what point i will exceed the capabilities of the brakes themselves. I'm not going to get a drum brake because I would rarely use it. Can I ask you to share your experiences and offer suggestions?

Ritterview

17% grade for 3/4 mile would be one of the steepest stretches of that length in the nation (this according to the Complete Guide to Climbing (by Bike). I seek out such on my half-bike in Northern California, which is the region most richly endowed with super steep climbs.

An example of 1/2 mile of 17% is Blackberry Hill in Los Gatos.



Or Summit Ranch in Clovis.



On Blackberry Hill at some point the grade exceeds 20%, and I get off an walk my half-bike. I'd not descend these on my disc-brake equipped tandem. Ever.

The grade you were descending was not likely 16-18% for 3/4 mile. It would be helpful and easy, however, to figure out the actual grade, if you have the name of the road and its location, such as a cross street.

dstrong 

Is "half-bike" another name for a unicycle?

TandemGeek

Brake fade begins as the brake blocks heat up to a point where they start to outgas.. that is, where materials in the brake pads begin to vaporize. You can typically feel this layer of vapor (or air) developing between the brake block and the rim's brake track through your brake levers: it comes on gradually as a distinct increase in vibration that almost has a 'gritty' feel accompanied by a similar, gritty sound. At the same time, you'll find yourself trying to apply more brake pressure but to no real effect since the layer of vapor disrupts your braking power.

If you get to this point, and you've been careful to use only one brake at a time on the descent, this is when you'll need to stop using the brake that has faded (aka, glazed-over) and start using the other one so that the faded brake can be cooled by air flow and recover its stopping ability. Of course, if you're on a really steep, unfamiliar grade where you're not sure what lies ahead, you may want to simply use that "healthy" brake to bring your tandem to a safe stop so that you can let both brakes and the rims cool down before continuing your descent.

Where folks get in real trouble is when they "ride" both front & rear brakes and bring them both to the point where they begin to fade, hence the recommendation to always alternate the use of front & rear brakes to allow for cooling. With practice, and on moderate to steep grades, you can usually keep your brakes and rims well away from the point of fading with that diligent attention to alternating brake use. A rear disc simply lets you abuse the rear brake a little bit longer than you could with a rim brake and without fear of blowing the tire off, hence the reason that they are somewhat popular, i.e., you can go easy on your front brake while you cook the rear to the point of near fade, then use the front for just a short while as the rear quickly cools off...

As for if and when a tire might let go, that's too hard to know as different tires seem to "blow-off" for different reasons. There was a tandem at the Santana Rally in Chattanooga that had a tire blow-off three times, never under really demanding conditons.. in fact, the last time it was simply parked. That scenario was indicative of a bad tire / rim combination and, or simply a tire with a bad bead as this particular tire seemed to have, i.e., it was purportedly a loose fit on the rim to begin with.

So, if you have a good tire that has a nice tight fit to the rim (i.e., it was hard to put on in the first place), is relatively "fresh" such that the bead tape is in good shape and the tire is still supple, you might never blow that tire off your rim even under severe rim heating.

Ritterview

Everywhere else in the world. Here on the BF Tandem Cycling Sub-Forum, however, that two-wheeled, one-seated conveyance you call a "single bike", we call a half-bike, as its rider capacity is but half that of cycling's ne plus ultra, the tandem.

And half is being generous. When I am on my half-bike I cycle alone, whereas on my tandem my lovely and favorable watt/kg stoker is at my side (figuratively; at my rear literally). My stoker increases the enjoyment of cycling far more than half. The increase in cycling joy is non-linear, logarithmic, exponential.

If you were to go on a date, and instead of being accompanied by your charming and lovely gf/wife, you dined and danced alone, would you rate your experience as a half-date? I think not. So too it is with cycling.

So, yes dstrong, a single bike here among those who have experienced the joy of tandem cycling is charitably referred to as a half-bike.

Equinox

It was on Blanchard Rd. between Lewis Rd. and Olean Rd.(Route 16) near Holland (14080) or South Wales (14139), New York.

Homeyba

For that short of a steep descent I'd just ride it and my tandem team has 100lbs on you. TG's advice is pretty good but it takes developing a "feel" for what your bike is doing. I don't know if everyone has those skills or the inclination to learn them? Another alternative is to just ride down very slowly so that the brakes don’t have the opportunity to get really hot. Ultimately you have to go by how you feel. If you are concerned about it then you did the right thing by getting off and walking.

Equinox

It is a skill I have not yet mastered, but i admire those that possess this courage and ability. Out of curiosity, do you guys's have a drum brake?

Ritterview

Well, you weren't that far off. It is certainly steep and relatively long. For 3/4 mile it is 10%, but the steepest 0.4 mile is 15.7%. It looks like some parts are at least 17%.

Equinox

That's cool! you know, when I looked at that picture of Blackberry Hill, I thought it was close to the grade we were on last night.

Homeyba

Ritterview, can you do that for Santa Rosa Creek Road 10miles+/- from Cambria??

Bug Shield

A strategy that works for us on grades up to 8% is to let the bike run on the straights and sweepers. By sitting tall in the saddle and hanging a knee out in the breeze, the bike tops out under 50mph, then I just have to dump speed for the switchbacks and let her run again to cool off. So far so good.

If your hill was anything less than wide open that may not have worked given the grade, but I thought I'd share anyway. One more tool for the toolkit.

Ritterview

I had to plot my own for Blanchard Road, but there is no need with the popular Santa Rosa Creek Road. By doing a climb search at Strava, it is easy to find the climb already mapped, quantified, and placed with a leaderboard. There is the entire 2.6 mile 8.5% Santa Rosa Creek Road climb and the 1.7 mile, 9.4% Santa Rosa Creek --The Steep Part.

So, if you register and upload your Garmin into Strava, you can see how you place on the Santa Rosa Creek leaderboard.

For those without a Garmin, there is the Strava smartphone app, which can do the same thing.

I have brought up with Strava need to have a tandem designation, and they say it is on their 'to do' list. So did another tandem rider named 'Marco'. It would be super if Strava had a tandem designation, as we could have competitions on popular hill climbs, and other routes, amongst ourselves.

oldacura

If your major concern is rim heating leading to tire blow off, I'd recommend using your brakes in a normal fashion in the steep section. When you think the rims are getting too hot, stop the bike and (carefully) feel the rims. That way, you can calibrate yourself. Then, later when you encounter a similar steep descent, you can know if you need to be concerned or just ride as normal. It is my contention that those who get into trouble are those who are ignorant of this potential problem. If you are aware, you are probably safe.

Equinox

Thank you.

waynesulak

Very well said!

conspiratemus1

^ Agreed. Beautiful. Definitely one to stick on the fridge, or even to inscribe inside an anniversary card.
Love long and prosper.

joe@vwvortex

Steep isn't usually the issue - steep and twisting curvy roads are the issue. I've got dual discs on the tandem now and i'll never go back to rim brakes. We've done several roads with sections near 20% on the tandem and don't even worry about it.

geranimo57

Poetic nice analogy Sir Ritterview !

Dean V

To take this idea one step further you could also check the tire pressure.
You could even go down a steep hill and deliberately give the rear brake a hammering. See if you can get fade or blow the tire off.
You should be able to control a rear tyre blow out easily if the speed isn't too crazy and the road is straight. Then you will really get a feel for what the limits are.

uspspro

Yeah, for now I just made a separate account with "tandem" at the end of the last name.

TandemGeek

Found on Hobbes last night... Tandem Unicycle

tredlodz

Why risk it? It wasn't fun the 2 times it happened to me on a bike Friday tandem.

conspiratemus1

And it even has a chromed fork!

professorbob

We're nearly a 400lb team and had a dicey time on an organized ride last year. There was one section on the ride that had several hills of about 10-12% for about 1/2 mile. Climbing was hard, but we made it up every one without having to stop and rest. However, on the downhill side, there were times when I did feel my brakes starting to fade, despite pumping them alternately between front and back. The problem was that there were stop signs at the bottom of most of the hills. Granted, my pads were 9-10 years old, and I was almost metal on metal. You can bet that I changed them out the next day. If it weren't for the stop signs, I would have just let the bike run until my wife pinched me in the bum and told me to slow down. However, it was a bit of a wakeup call and I will endeavor to pay closer attention to my pads in the future.