Question for the techy people out there

michaelo said:

Not 29er topic.

Why are disk brakes mounted where they are? Is it cosmetic, reduced crud into them, reduce dive or for best braking performance?

Was just wondering if there was a logic to it

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What do you mean by "where they are?"

michaelo said:

Not 29er topic.

Why are disk brakes mounted where they are? Is it cosmetic, reduced crud into them, reduce dive or for best braking performance?

Was just wondering if there was a logic to it

Click to expand...

What do you mean by "where they are?"

I'll venture to guess that it is the location where the forces are best absorbed (the strongest) on the bike relative to the wheel location of the disc, and the least like to be damaged (i.e. the back rather than front of the fork).

where else would they be ?

they could be..

on the front of the fork vs the back, under the rear chainstay vs on the seat stay, or some other bracket arrangement.

Most cars have the the front brakes in front of the axle. (don't know why)

back seem to be varied, but on the whole vertical or just off it seems.

Is this for a reason or just happened that way. I was curious about bikes to see if it was for a reason or just happened.

michaelo said:

on the front of the fork vs the back, under the rear chainstay vs on the seat stay, or some other bracket arrangement.

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More likely to get hit by rocks in wayward maneuvers using your locations.

Forces push calipers into fork/frame as designed, v.s. pulling away from fork/frame in your choice. I'm not an engineer, but am willing to bet that metal and welds are significantly stronger in compression than tension, plus less likely to get hit while riding. :thumbsup:

michaelo said:

Most cars have the the front brakes in front of the axle. (don't know why?)
Is this for a reason or just happened that way.

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On cars it is for better cooling
Always for a reason, engineering, frame design and component packaging

1) Caliper needs to be in a position that allows wheel removal relative to the dropouts. In the front this usually equates to behind the axle/fork, and in the rear, in front of the axle.

2) Tucking the caliper behind the fork and/or into the frame protects it from abuse.

3) Already been stated, but the mechanical advantage gained by having the caliper "push" into a tube vs pulling at a couple of mounting bolts.

Some older frames used a 22mm (?) Hayes rear brake that mounted on the top of the chainstay.

How about dual front brakes run off the same master cylinder at the lever?

Maximizes heat dump and shorter radii mean less contact with icky rocks?

I forgot about the old Chameleons...that was not a good idea, put the caliper down where it could get ripped off like a rear mech.

I like the Retrotec idea. The only issue I see is there is no way to brace that lil' chainstay. Seems to me you might want to add some material there. Simple clean looks though and added room for rack braze ons. I wonder if there is a limitation on rotor size in that position (probably not, but I haven't had enough java this AM). Great idea for a custom frame...thinks to self.

meat tooth paste said:

Retrotec mounts the rear disc caliper on the chainstay. The first generation Santa Cruz Chameleon had the disc brake mount on the underside of the chainstay:

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michaelo said:

...Most cars have the the front brakes in front of the axle...

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No, "most" cars have the disc caliper mounted behind the axle, at least on the front wheels.

Soupboy said:

Some older frames used a 22mm (?) Hayes rear brake that mounted on the top of the chainstay.

How about dual front brakes run off the same master cylinder at the lever?

Maximizes heat dump and shorter radii mean less contact with icky rocks?

Click to expand...

great notion once we have more room between dropouts:thumbsup: