• dick breaks

    And thus they shall ever more be referred to as.

    They must get a harder time in a dick breaked wheel than a rim braked one no? Not saying too hard a time, well within what they can cope with, but you are braking the hub and the forward momentum of bike and rider and the friction between the tyre and the ground are trying to make the rim rotate (or rather, continue rotating) and you are relying on the spokes to stop that. Seems like that is asking more of spokes than on a rim braked wheel where the brake acts upon the rotation (rotating mass?) directly.

    If the spokes on a dick breaked wheel deal with no more forces than a rim braked wheel, why aren't radially spoked dick break front wheels a thing?

  • If the spokes on a dick breaked wheel deal with no more forces than a rim braked wheel, why aren't radially spoked dick break front wheels a thing?

    For the same reason that radial on the drive side rear should not be a thing. The load path is slightly different between disc brakes and rim brakes, but the actual external loads are the same and they get from the tyre contact patch to rider via the spokes either way.

    Think about a rim brake for a while; the ground pushes the bottom of the rim upwards and backwards, the caliper pushes the top of the rim backwards (and downwards a bit, as it isn't usually right at the top), and the fork ends push the hub forwards and downwards. All the vectors have to sum to zero at equilibrium. To a first order approximation, the hub is pushed forward by twice the horizontal force at the tyre contact patch and downward by the vertical reaction force at the tyre contact patch. Somehow, all these forces get from the rim to the hub. That somehow is called spokes.

  • Just can’t get my head round it, not doubting you, just it’s something I struggle to comprehend.

    Anyway, got s bit of a ride in en route to work today and didn’t hear a peep out of the wheel. Put a half a turn on each nipple at work (Id usually go round a wheel after it’s first ride and tweak it up a bit) but no truing needed.

  • Disc brakes do place more braking loads on spokes than rim brakes can. You can work out what the difference is by taking the ratio of the rim diameter to the rotor diameter.

    Force(rim) x d(rim) =force(rotor) *d(rotor)

    So for a 160mm rotor a disc brake thd braking torque goes through the hub fglsnge. Braking forces on spokes are therefore 10 times as much load on the spokes as a rim brake can at the limit of tyre adhesion.

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