Bike Forums

Bike Forums (http://www.bikeforums.net/forum.php)
-   Tandem Cycling (http://www.bikeforums.net/tandem-cycling/)
-   -   Another drum brake thread (http://www.bikeforums.net/tandem-cycling/753409-another-drum-brake-thread.html)

Carbonfiberboy 07-20-11 05:46 PM

Another drum brake thread
 
As our 300 lb. team has gotten stronger, we've been doing ever more ambitious rides. This summer we had in mind to take the tandem up into the mountains. We have Avid 7 V-brakes, and they've always been fine, even loaded touring, in ordinary rolling terrain. But I wasn't comfortable taking precious Stoker down 4000' descents with just the rims. Plus they do wear out and that's expensive, too.

Our sport rear wheel has a Chris King hub, and they don't come threaded, so I built a second rear wheel. I bought a used Arai drum brake on ebay and married it to a White Industries 36H hub with a Deep V rim and 14-15 DT spokes. I control it with a Shimano 8-speed bar end shifter mounted to the right captain's bar, and set to friction mode.

Yes, the wheel is heavy. Our kitchen scale says just a little under 5 lbs. with cassette, tire, tube, and skewer, whereas my sport wheel weighs 3 lbs. 3 oz. on the same scale, same condition.

We've done two rides in Mt. Rainier National Park with the new wheel. The Park roads are not steep at all, only 4%-6% grades, but the descents are long. The brake worked perfectly. The best thing is that it's butter smooth. I can't tell it's on, other than the bike goes slower. That does great things for stoker confidence, because I don't have to be constantly on and off the brakes.

I set it for the highest speed I feel like attaining, in this case 35-40 mph, and then use the V-brakes normally for the corners. On the Park roads, we were fast enough that cars didn't show up behind us, and controlled enough to steer around the bad stuff. Stoker loves the brake. I think we could ride just fine with only the rim brakes in that terrain, but I prefer the drag brake and will run it in the future for those sorts of rides, and for any loaded touring.

hup 07-20-11 09:17 PM

I have the same feeling regarding the smoothness of the brake. I'm a relatively inexperienced captain, and our drum instills confidence in me as well as my stoker. On one of our earliest rides on this bike, I hesitated to apply the brake early and found out just how quickly the speed can come on at -10% :eek:

steve53mg 07-21-11 07:24 AM

It is really a shame that the Arai brake is no longer being made and becoming scarce; there is no alternative that works the same way or as well! The profusion of new bikes with disc brakes has made the Arai redundant (in some peoples' opinions), but there is no substitute for that "set and forget" mode; sort of like flaps or spoilers on an aircraft.

oldacura 07-21-11 07:39 AM

We have an Arai drum but haven't had it mounted for years. We also have Avid V brakes. On a recent ride we did a descent of Rabbit Ears Pass near Steamboat Springs, Colorado. Don't know what the average grade is but it is pretty steep, long and big sweeping curves. By sitting up on the bike (arms straight) our speed didn't get above 48 mph. I'd say the average descent speed was about 45 mph. Wind resistance does a good job of limiting speed - especially at higher speeds. I used the brakes very little.

I find the greatest need for a drum brake is for very steep descents (~10%) with frequent, tight switchbacks. In that case, you have to scrub off speed frequently and this really heats up the rims.

Carbonfiberboy 07-23-11 03:26 PM

Quote:

Originally Posted by oldacura (Post 12962254)
We have an Arai drum but haven't had it mounted for years. We also have Avid V brakes. On a recent ride we did a descent of Rabbit Ears Pass near Steamboat Springs, Colorado. Don't know what the average grade is but it is pretty steep, long and big sweeping curves. By sitting up on the bike (arms straight) our speed didn't get above 48 mph. I'd say the average descent speed was about 45 mph. Wind resistance does a good job of limiting speed - especially at higher speeds. I used the brakes very little.

I find the greatest need for a drum brake is for very steep descents (~10%) with frequent, tight switchbacks. In that case, you have to scrub off speed frequently and this really heats up the rims.

All very true. We could descend good road, like the west side of White Pass on US 12, by letting the bike run at 50 or so. I make that descent at about 42 on my single. But on the narrow park roads with bad pavement and switchbacks, the drum was real nice even on lower gradients. And a run through an online bike calculator says that a 2 lb. drum brake will add about 40 seconds to our 12 mile climb of Cayuse Pass. Not a difficult choice for me.


All times are GMT -6. The time now is 06:37 PM.