Short and concise article,

http://www.racingjunk.com/news/2016/08/17/do-i-want-radial-or-axial-brake-calipers/?utm_source=Newsletter&utm_medium=email&utm_campaign=Burnoutnewsletter

Please forgive me if I'm lost, but...  they talk about NO shearing forces on radial bolts ... if the bolts were in the same position, equally spaced and far from the axle... wouldn't the shearing forces be the same? If so, the benefits of radially mounted calipers are just about the bolt position and not about their direction.

He got the description of the terms 'radial' and 'axial' correct, but the rest of the technical analysis was largely wrong.

Shear loading vs tension loading

BIG difference

Largely is the key word.  A good monoblock caliper is better than a mediocre cast radial.  Anyway, IMO, the biggest advantage is race teams can easily adjust for different size rotors by adding and removing spacers.  I do wonder when I see a bike with radial calipers and rubber hoses.

Quote from: S21FOLGORE on August 21, 2016, 12:36:03 PM
Shear loading vs tension loading

BIG difference

I see. My uneducated impression was that there'd be shearing forces by the red arrows, but maybe it's more around the purple arrows....  I'm still wondering how that makes them tougher and/or more rigid for better feel...  Is shearing a caliper bolt even a possibility?

QuoteI do wonder when I see a bike with radial calipers and rubber hoses.

I wonder when I see these ...

Radial mount caliper adaptor

QuoteI'm still wondering how that makes them tougher and/or more rigid for better feel...

In theory, yes.
In the real world, at the street riding level, no. You won't notice the difference. At the track, unless you’re racing at national level and always finish in top 5 kind of rider, no. There are other parts that would play bigger roll. (such as radial “master cylinder”, pads and rotor, etc.)

Place the pencil on top of the kitchen table or the work bench, and place it so that the half of it is supported with the table top, and the rest is unsupported.
While keeping the pencil on the table with one hand, press down the unsupported side with the other hand.
Try not to “bend”, keep the force 90 degree to the pencil.
It doesn’t take that much force to break the pencil, right?
(Incidentally, this is called single share load.)

Now, using two pairs of the pliers, grab each end of the pencil.
Try to break the pencil, by pulling it at each end.
How much more force do you have to apply now?

QuoteIs shearing a caliper bolt even a possibility?

Under normal circumstances, no.
If, someone replaced the caliper mounting bolt with anodized aluminum ones, and repeatedly try full braking from 160MPH, then, maybe.

I'm just trying to understand.... the load is still 90 degrees on the radially mounted bolts or are you saying it's tension load?

Interesting

Imagine the bike is not running. You apply the brake as hard as possible, so that the bike won’t move forward.
Now, start the engine, put the bike in the gear, and try to launch the bike, but keep the brake on.

The caliper and the caliper mount bolt(s) are getting some force, but which direction?


You think, the caliper that is trying move along with the rotor is creating the force in the green arrow’s direction, but the caliper (that is trying to rotate around on the same axis as rotor / wheel, NOT trying to move on the straight line) is actually creating the force in the purple arrow’s direction. The caliper mount is, therefore, pushing back the caliper with exactly the same amount of force in the exactly the opposite direction. (Isaac Newton’s third law (action reaction law.)
Thus, caliper mount bolt(s) are getting tension load, not shearing load.