On 2019-03-18 14:45, James wrote:
On 19/3/19 6:32 am, Joerg wrote:
On 2019-03-14 18:36, James wrote:
Now I use a 25 mm rear tyre (that measures 27 mm), and to remove the
wheel I must release the brake lever (Campagnolo) or deflate the tyre.
With a 23 mm tyre I don't need to do that. With a disc brake I don't
need to fiddle with the brakes regardless of tyre width. That's a
benefit.
That I don't understand. Even the early 80's Shimano 600 set on my
road bike has little release handles on each caliper to get out a
25mm+ wheel with lots of room to spare.
The Campagnolo calipers on my bike don't have a quick release, but there
is a button on the lever that has the same effect.
That's ok if it isn't a cumbersome process. Having switched to thick
tubes and tire liners I never get flats anymore so the only time I take
out a wheel is when the tire is worn down or I need to install a new
cassette.
In fact sometimes when you go to shove a wheel in with rim brakes and
centre or dual pivot callipers, you can catch the calliper and move it
from centred. Then you have to fix that or have rubbing brakes. That
doesn't happen with discs.
Though a disc does get bent easily and you have to pay more attention
when re-installing a wheel. Fixing is easy as well as long as you do
not touch the disc with bare hands.
I haven't tried bending a disc, but it doesn't look easy to me. You
must be very rough.
You have to be gentle when bending one back. That can also become
necessary after crashes or if an obstacle got in the way while laying
down a bicycle in a truck bed. The LBS owner where I bought the MTB
showed me how it's done.
Hydraulic disc callipers are self adjusting like car hydraulic disc
callipers. ...
Ahm, sort of. The reservoirs are typically a bit small to accommodate
all the wear. I have to top off with DOT-4 at times which is nasty
stuff when it gets onto clothes and things.
Shimano hydraulics use mineral oil. Not nasty like some other brands.
Yep, debating whether to switch to Shimano when the Promax brakes are
worn. However, they refuse to give up, they are surprisingly tough.
Cable actuated disc callipers are not. Benefit and detriment.
Cable calipers are very easy to adjust, just turn a knurled trim knob.
A downside of many is that they only have one moving piston while the
opposite piston is fixed. The rotor flexes to the side every time you
brake. Beats me why they design them that way.
"Some mechanical disc brakes, such as the TRP Spyre, work by pushing
both brake pads simultaneously against the rotor. "
https://cyclingtips.com/2018/05/complete-faq-to-road-disc-brakes/
Yes, but the caliper alone will set you back almost $100. You can get a
good quality complete front or rear hydraulic setup for that kind of money.
https://www.amazon.com/TRP-Spyre-Mec.../dp/B00SUAANMW
Most mechnical disc brakes that I've seen only move one piston.
And for Frank, "Disc brakes have been around on bicycles for a decent
amount of time – as early as the 50s, in fact."
I haven't seen any before 2000. A technology is only really entrenched
if it made it into the mainstream at least to some extent.
--
Regards, Joerg
http://www.analogconsultants.com/