Brakes caliper selection

[Archit]

I am having trouble in selection of brake calipers.
How much of a difference does it make if we mount calipers on opposite sides of axle line, ie the right one on the front and the left hand caliper on the rear of the axle line.
We are facing this problem as we are contemplating putting calipers of an Indian motorbike and they are only one-sided. The wilwood/brembo calipers are not available on short notices

[Archit]

I am having trouble in selection of brake calipers.
How much of a difference does it make if we mount calipers on opposite sides of axle line, ie the right one on the front and the left hand caliper on the rear of the axle line.
We are facing this problem as we are contemplating putting calipers of an Indian motorbike and they are only one-sided. The wilwood/brembo calipers are not available on short notices

[Wesley]

Why exactly must you mount them this way? Can you not flip them around? The bleed screws will be upside down perhaps, but if you can remove them to bleed, it may not kill you. How do these calipers mount? On a pivot pin or are they simply bolted?

[The_Man]

Replied on the Teams for India thread.

Do not double post. We are listening http://fsae.com/groupee_common/emoticons/icon_smile.gif

Cheers,

[Wesley]

Ok. It's been too long away from real engineering. After serious some serious FBD action, I have deduced that there is no effect on suspension loading.

What IS impacted is the overall loading on the hub bearings. By placing the caliper so the force reacted by the rotor occurs straight up, the top of the bearing will bear the increased stress. If it is placed so the force reacted by the rotor occurs down, you will add braking loads to the bottom of the bearing, subtracting overall bearing load from the load induced by vehicle mass.

Here's my chicken scratch.

http://i53.tinypic.com/nozk8m.jpg

In other words, the hub force is reacting the braking loads, and the force is transmitted to the caliper via the upright - net equations are zero, no reactionary forces go to the suspension from the actual braking torque. The only unbalanced force in the equation is the braking force at the tire, which is what slows you down http://fsae.com/groupee_common/emoticons/icon_biggrin.gif It has no effect on weight transfer or ride height due to anti-dive or anti-squat.

[flavorPacket]

This is 99% correct, Wesley. But the effective bearing reaction will change. On one side, the braking torque reaction adds to the bearing load, on the other it reduces it.

[Archit]

@flavorpacket-
Can you further explain it please.

[Thrainer]

We have used calipers that don't come in "right" and "left" in the past and have mounted them on the same side of the axle.

[Bobby Doyle]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Archit:
@flavorpacket-
Can you further explain it please. </div></BLOCKQUOTE>

FBD, spreadsheet, and ten minutes.

Eventually you'll find that the ideal angular position of your caliper (as far as superimposing reaction forces goes) is a function of whatever COF you are using to generate your loadcase.

[Wesley]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by flavorPacket:
This is 99% correct, Wesley. But the effective bearing reaction will change. On one side, the braking torque reaction adds to the bearing load, on the other it reduces it. </div></BLOCKQUOTE>

Right, that's what I was trying to imply by indicating the direction of the force (resulting from which side you put your caliper on) instead of explaining it case-by-case for either side.

Glad to know I still at least have some of a brain left.