Originally Posted by DannoXYZ
I make that assessment based upon stopping distances; there are zero cars on the market that can stop as fast as a bike, period.
Demonstrate please. I think that you're assuming that bikes can decellerate over 1G and/or that Cars 'on the market' cannot.
I look at the RotorDiameter-to-mass ratio. Bikes with their big rims require minimal amounts of clamping force to generate resistive torque on the wheels while the car's smaller discs require much more torque.
Sure, but the car can clamp harder on its disks than the bike can, _because_ of the greater mass (greater inertia, better traction mean that the wheel will continue to turn with higher clamping forces. Also, the car most likely has much better friction compounds in its brake pads.
I also look at the mass-to-BrakeSwept area. This determines how much heat a braking system can shed for its total braking-force requirements. The total surface-area of the braking surface on a bike is much larger relative to the mass when compared to a car, thus a bike's brakes will not heat up as much for a similar deceleration rate as a car; it can shed more heat/second/lb than a car.
Isn't that "... a similar deceleration energy..."? The bike starts with much lower inertial energy in the first place.
<snipped the discussion of traction of a rubber tire fs. friction - I was going to point that out, but you beat me to it!>
Back to bike tyres, yes, due to the lower mass of the bike+rider combination, along with the high-pressure tyres that really bite into the road, a bike can ALWAYS stop much, much faster than a car.
Lower pressure tires grip better by heating up better and by deforming to fit the surface of the road better. They also have much more surface area, which as you point out in the bit I snipped above is an advantage.
Going from 40mph on a bike down to zero requires only about 40-50ft. Calculate deceleration-G from that. Try that in a car... heh, heh... Well, a $450K Porsche CarreraGT with 60-0mph braking distance of 101ft actually comes close, but not any off-the-showroom floor you're likely to see out there...
I want to see you accelerate at over 1 G for any appreciable length of time. I need evidence, here.
Due to the change in weight-shift to the front-tyre, optimum F/R brake-balance MUST always change with deceleration rate. There's no way anyone can claim that a 60/40 split will work all the time, or a 70/30 split. It HAS to be customized to the particular deceleration rate.. And there's such a thing known as training. We spend years and years training firefighters, doctors, underwater welders, F1-drivers, fighter-pilots for a reason. There IS a way to get maximum braking-force out of a bike-tyre so that you're sliding the front-tyre with the rear-tyre off the ground without going over the bars... Until you've slid the front-tyre under maximum-braking, you really have no idea how powerful the brakes are on a bike (refer to disc-brake thread somewhere).
Absolutely, my dispute is that the limiting factor (on a good, dry surface) is going to be the simple of the leverage of the mass and the force the caliper applies to the fork. I may be mis-generalizing from my experience on motorcycles, which tells me that this is absolutely true. My back wheel comes off the ground before I get to 1G of decelleration. I may be wrong, prove it with data or a vector diagram! I know you're up to it