Originally Posted by
Camilo
I think you're over-stating this. What you've probably read and heard is that the rear brake doesn't give nearly a much stopping power as the front. But to say it doesn't add to it is just wrong.
At the risk of committing heresy, let me quote from the
Holy Scriptures:
Originally Posted by Sheldon Brown
Maximum braking occurs when the front brake is applied so hard that the rear wheel is just about to lift off. At that point, the slightest amount of rear brake will cause the rear wheel to skid.
and again
Originally Posted by Sheldon Brown
Skilled cyclists use the front brake alone probably 95% of the time
and finally,
Originally Posted by Sheldon Brown
Generally I advise against using both brakes at the same time. There are exceptions, however:
-If the front brake is not sufficiently powerful to lift the rear wheel, the rear brake can help, but the best thing to do is to repair the front brake.
...
I had also drawn the same conclusion from reading
Bicycling Science, and looking it up I find something suspiciously close to the first verse I quoted above,
Originally Posted by Bicycling Science, 3rd Edition, page 245
...(calculations)...
Thus, the rear wheel is in only light contact with the ground. Only a slight pressure from the rear brake will cause the rear wheel to lock and skid. The front brake therefore has to provide over 90% of the ******ing force at a deceleration of 0.5g, even if the tire-to-road coefficient of friction is at the high end of the typical range (0.8).
However, on re-reading I find that the author here is only arguing against the sufficiency of the rear brake alone and goes on to talk about weight distribution in a manner similar to what cyccommute said and mentions that tandems and recumbents don't have the same limitations related to rear wheel lift as other bikes.
Originally Posted by
Camilo
I guess I'm just wondering if you have a brake adjustment issue. My wife is 5-1, late 50s very small weak hands and uses Tiagra STI's with rim brakes no problem.
Yes, everyone seems to be wondering that. I think it's funny, but I guess I brought it on myself.
My "problem" is/was largely a theoretical one. Since I never get to the point where my rear wheel is lifting off the ground, I reasoned that I must not be achieving maximum possible stopping power. I actually have pretty good stopping power, but it seemed like it should be theoretically possible to increase it.
FWIW, I'm guessing that I have significantly more weight planted over my rear wheel than your wife does, and at any given speed I probably have close to twice as much momentum. Maybe it's not even my weak hands that are at fault. It might be the size of my gut.
