Thread: Road Discs
View Single Post
  #12  
Old September 10th 17, 09:54 PM posted to rec.bicycles.tech
Andre Jute[_2_]
external usenet poster
 
Posts: 10,422
Default Road Discs

On Saturday, September 9, 2017 at 11:28:59 PM UTC+1, jbeattie wrote:
My concern with getting rim brakes is not really even a performance issue because in dry weather, I've never had a problem with rim brakes -- but to listen to the guys at the local shop, rim brakes are going the way of the dodo. I'm worried about buying an antique!


I agree with Lou, you can wait until December if you really want discs. But I don't think obsolescence is all that likely; for the next several decades there will thousands of heritage bikes requiring parts for rim brakes.

I have bikes with roller brakes (good, bad and ugly, the ugly the strong and sudden latest model from Shimano which require constant attention if you want to avoid a face plant), discs (constant maintenance because they chew pads, a pain in the ass), standard rim brakes, and hydraulic rim brakes.

I really love the hydraulic rim brakes for their progressive nature, though I understood from the snide remarks from the usual one-size-fits-all idiots on RBT when I specified the hydraulic rim brakes without the booster on my Utopia that you can set them up to be quite as nastily sudden and unpleasant as Shimano's latest roller brakes. You might consider the Magura hydraulic rim brakes a 622 (rim size) disc brake: all the components are there, hydraulic calipers, but with pads (which last an immensely long time, my set now having lasted 10K though admittedly I don't commute and hardly ever use the brakes on downhills) and very fine control being possible if it matters to you (it might in traffic).

On the subject of pads, you can buy pads of many different specifications for hydraulic rim brakes: they look just like standard pads. I don't ride often in the wet but I live on and among steep hills and generally ride as fast as I can, so sometimes I need good brakes in the wet, and for this I have no complaint about the standard Magura pads for the hydraulic rim brakes, and bought spares of the same for when the current set wears out, possibly after another 10K; I haven't been tempted by the pads advertised as especially for wet weather, and well thought of by all-season commuters and major tourers other groups.

Something to ponder: under any and all circumstances, retardation (i.e. braking performance) is limited by the frictional interface between tyre and road; rainwater acts as a sort of lubricant and thereby in most cases reduces retardation. Skids are often the result of brake-clamping exceeding road-tyre friction. There are no modern bicycle brakes known to me that cannot be arranged to exceed road-tyre friction; you'll probably have to go back to spoon brakes to find a brake that incompetent. This train of thought is an argument for smoothly progressive brake take-up, long-movement handlebar controls, and minimal force multiplication in the connection between handlebar control and pad (on discs this means choosing -- if there is a choice -- the larger rather than the smaller expansion chamber in the caliper; unfortunately, there is no longer a choice of caliper chamber size on the Magura Rim Hydraulics). The larger the disc between the pads, the easier a progressive skid-avoiding response is to arrange. And there is no larger revolving disc on a bike than the rim. Rim hydraulics add virtually no weight over other rim brakes and save a lot on hub-mounted discs.

Before I go, one more data point: Shimano disc brakes on my mountain bike required new pads every thousand miles, max, in the winter sooner, and on my Gazelle the front disc was no better behaved nor more economical of my time or pocket. On my Utopia with rim hydraulics, albeit a different class of bike used in a different manner, 20,000K seems reachable on a single set of pads, and replacement takes seconds rather than hours.

Andre Jute
All things in moderation, even moderation itself
Ads
 

Home - Home - Home - Home - Home