Disc brake vs. Caliper
Hi, I am new to this site. My wife and i have a Co-Motion Supremo. We live in Colorado and had a Avid Mechanical disc installed on the rear when we bought the bike. I am now thinking of switching over to a Dura-Ace rear caliper for the following reasons. When I take the rear wheel off to switch cassettes I have to spend about 10 minutes re-adjusting the disc brake. There also seems to be a little bit of drag associated with the disc brake.
Do I really need a disc brake? We don't tour but rather go out for 40-60 miles at a good pace. I am thinking that a standard caliper will provide ample braking and heat rim build up won't be an issue.
I would appreciate any feed back.
I drink your MILKSHAKE
If your brake was set up properly you could remove the rear wheel at will. Something else to try: Once the brake is properly adjusted (preferably by a bike shop) remove the wheel wave it in the air once or twice (just to get it OFF the bike) then set the wheel back in the drops withouth closing the QR. Now use a rubber band to pull and hold the brake lever what this will do is position the wheel in the caliper while you close the QR. Release the band and spin the wheel. Vi O la
Originally Posted by tjwaugh
The need for a disc brake is a personal decision that only you can make for your team depending on your team weight, desire or adversion for fast descents, and riding terrain.
As far as your rear disc installation goes, a fellow Colorado cyclist named Bryan Boldt has done a lot of work to improve the performance of the Avid brakes. You can read about them at the following web link:
I am hesitant to claim to be qualified to answer the question under any circumstances, but for the benefit of others who may be, I want to qualify a few issues:
1. Where do you ride in Colorado?
2. What is the total weight of bike and team together?
Without this information it is probably impossible to assess the degree to which a hub brake would be preferable to, or a good adjunct to, a rim brake. We want to know if you do steep descents with switchbacks.
There is a separate debate with regard to whether or not the Avid can qualify as a functional drag brake, owing to pad size and disk size. I'm not going to touch that one either.....
The double-pivot caliper brakes do not necessarily accept all tire sizes that are likely to be used on tandems. Hammering a (nominal) 32mm tire through the pads on Ultegra sidepulls is just about the upper limit.
The function of a "drag" hub brake is to convert the potential energy of height into heat without running it through the rim, where it might cause various types of tube and tire failures. One might suppose that if your rims are not getting noticeably hot (and of course you do check?), you don't need a hub brake. Until tomorrow, when you try a new route.
My notion of responsible captaining verges on paranoia. My stokers like things that work ALL the time. Tires that never go flat (so I use kevlar-belted tires), chains that never drop when going for the triple (have N'Gear Jumpstop, or whatever you call that thingie that Peter White sells....), spokes that never break (use Aerospokes, so no wire spokes), wheels that never go out of true, captains that never screw up, etc., etc. I do my best to make decisions about componentry as though I were them with my body of knowledge. In country where I needed a drag brake, I know my choice would be equipment thought to be reliable with a long history behind it. Certainly a modern large disk is tempting in comparison with the Arai drum brake.
Just Say No to 26" Wheels
If you decide you don't want the rear Avid disc and it happens to be a 203mm - I would be interested in a possible purchase of it from you.
Originally Posted by tjwaugh
To answer your ?'s. We live in Grand Junction. Our team weight is approx 300-310. We currently run a 700x25 tire and have no problem making it through the Dura-Ace on the front. We do have some big passes here, such as the Colorado National Monument or off the top of the Mesa. We hit 54 mph the other day. I just don't think that we need the disc. We have some riding buddies that have the set up that I am looking for and they son't have a problem. I might try their rig next time we go out.
Originally Posted by SDS
Thanks for the reply.
Originally Posted by livngood
Try these links instead:
Bryan is quite familiar with Colorado's various descents and is very active in the Colorado Tandem Club. I'm sure he would welcome your questions and provide you with excellent counsel on how to proceed. You can reach via an Email link through the CTC Website:
FWIW: We have been riding for about 8 years now, approach some 30k miles together on the tandem, and have not found our dual pivot rim brakes lacking, with few exceptions. However, I do have deep section rims on our road tandems in part because of their outstanding "heat sink" characteristics. Those exceptions mentioned above include coming down climbs like Brasstown Bald here in Georgia, Mount Mitchell (so I'm told, haven't tried that yet), and for upcoming trips to Europe. It is only for those special ride events that I even bother intalling the disc brake. We have a team weight of 280lbs (325 w/tandem & "stuff"), we don't do loaded touring and seldom ever carry a trunk bag, and love blistering flat descents, particularly ones with lots of of twisties. There have been perhaps 4 or 5 times when we were riding somewhere and wished we had a disc or drum drag brake (going down the South side of Tepusquet Road after it was damaged by severe weather and before it was repaved on a day when the temperature was 110 -- hottest day of '02 in Solvang, CA -- comes to mind: http://www.sbc-rides.com/StreetRides...tepesquet.html), as well as a few descents in the mountains above Asheville, NC).
If I was spec'ing a new tandem today I would probably have it set up to work in 3 configurations:
1. Front & Rear Dual Pivots (Primary)
2. Front Dual Pivot & Rear Disc (Domestic Mountain Rides/Events)
3. Front & Rear Dual Pivots + Disc Brake (European Tours / Loaded Touring)
But that's just me.
Last edited by livngood; 06-06-04 at 08:27 PM.