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Old 11-01-2019, 09:41 AM   #11
Dick Steinkamp
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Join Date: Apr 2016
Location: Bellingham, WA
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Default Re: What revs at 60MPH

Originally Posted by aermotor View Post
It is my opinion (for what ever it's worth) that a model A with brakes in proper working condition is limited in stopping power by the small tire foot print rather than the brakes at any speed, assuming the tires have good tread.

I would agree with John. However, "proper working condition" would have to be defined as being able to slide all 4 tires evenly. To do that, you would have to adjust the brakes differently than Ford instructed.

Stock adjustment instructions have the rear brakes coming on first and the rear wheels sliding first. In fact, the front wheels are not supposed to slide if the brakes are adjusted to the instructions.

Since the weight shifts to the front of the car upon braking, the fronts need to come on first in order to have all 4 wheels fully involved in the braking process right up to 4 wheel lock up. All automakers changed to this process soon after the Model A era. On newer cars, the front brakes are always bigger than the rear brakes and braking force is hydraulically proportioned more to the front to accomplish this.

With the Model A brakes adjusted so that all 4 wheels will slide at the same time during brake pedal travel, then the tire footprint will be the limiting factor in stopping distance. The shortest stopping distance will be with pedal force just prior to lock up.
All steel from pedal to wheel
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