The difference between rear and front brakes of a bicycle

In summary, the conversation discusses the effectiveness of front and rear brakes on a bicycle and how it relates to weight transfer and Newton's laws of motion. The person is seeking a scientific explanation for this phenomenon and is open to detailed explanations, but asks for them to be broken down due to being new to physics.
  • #1
Kimusubi
14
0
Hi,

I'm a sophomore student at Arizona State University studying Aerospace. I'm currently taking my first physics class ever and I'm loving it. Although there isn't enough calculus, it's mostly formula based, so it's a bit disappointing on that end. Anyways, ever since I started taking the physics class, I've become curious on how certain things in the world work. I mountain bike a lot, so recently I started thinking of how the front and rear brakes differ from one another. By that I mean, why does it take longer for the bike to stop when using the rear brakes versus using the front brakes when you are moving forward, and vise-versa when you are moving backwards. And also why is there a tendency to fly forward when using the front brakes. I asked this of my professor, and he wasn't able to give me an explanation on it, and told me that he would get back to me. I mean, I understand why it happens (in the most common-sense non-physical way), but I was wondering if anyone could explain this to me in more of a scientific way. Does it have anything to do with Newton's laws, or is it because of center of mass, or some other reason? If anyone can give me a detailed explanation of this, I would really appreciate it. But just keep in mind that this is my first physics class ever, so if you're trying to explain something a bit more advanced, please break it down for me. Thank you all in advance for your contribution.

- Ali
 
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  • #2
Welcome to PF, Ali.
The effectiveness differs because of weight transfer. Whichever way you're going, the leading wheel will be pressed into the ground harder, while the trailing one loses traction.
 
  • #3
Oh ok, that seemed simple enough. Now, when a person is going at a fairly high speed, uses the front brakes to come to a sudden stop, and ends up flying forward, is that because the translational acceleration is changed to angular acceleration or is it because of torque?
 
  • #4
That's simply Newtonian physics rearing its ugly head. Your body doesn't want to stop when the bike does, because its momentum tries to carry it forward. The same basic thing happens when both brakes are used, but when you use only the front one, the rear of the bike also wants to continue forward and will pivot over the front.
 
Last edited:
  • #5
Awesome, thank you so much for your help!
 
  • #6
You're more than welcome. Others here can give you more detailed answers, with formulae if you wish, but that's a bit beyond me.
 

1. What is the main difference between the rear and front brakes of a bicycle?

The main difference between the rear and front brakes of a bicycle is their location on the bike. The front brake is located on the handlebars and is typically operated by the right hand, while the rear brake is located near the back wheel and is operated by the left hand.

2. Which brake should I use to stop my bike?

Both the front and rear brakes are important for stopping a bicycle. However, the front brake provides more stopping power and should be used as the primary brake. The rear brake can be used to help slow down and maintain control of the bike.

3. Why is the front brake more powerful than the rear brake?

The front brake is more powerful because when you apply it, the weight of your body and the bike shifts forward onto the front wheel, increasing the friction between the tire and the ground. This results in more stopping power compared to the rear brake which has less weight on the wheel.

4. Are there any situations where I should only use the rear brake?

The rear brake should be used sparingly and typically only in emergency situations. If you only use the rear brake to stop, it can cause the wheels to lock up and result in skidding and loss of control. However, in situations where the front wheel cannot make contact with the ground, such as going over a curb or uneven terrain, the rear brake can be used as the primary brake.

5. Do I need to maintain my front and rear brakes differently?

Yes, the front and rear brakes should be maintained differently. The front brake is typically used more often and therefore may require more frequent adjustments or replacements of brake pads. The rear brake may also need to be adjusted more often to compensate for the wear on the front brake. It is important to regularly inspect and maintain both brakes to ensure they are functioning properly for safe riding.

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