×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# help needed with brake calculation

## help needed with brake calculation

(OP)
what is the force required to completely lock an 130mm drum brake(purely mechanical) assuming the vehicle is stationary and weighs about 160kg (not including rider).

### RE: help needed with brake calculation

I'm wondering what the "locking" will need to resist.
Prevent rolling downhill on a slight grade? Being nudged when a vehicle parks behind? Prevent being dragged off by a roving punk?

### RE: help needed with brake calculation

I think it is safe to say it needs to resist rotation with the tyre dragging on the road. So now we have 3 pieces of information - only need another 5 or so and we can have a shot at answering the OP's question.

je suis charlie

### RE: help needed with brake calculation

By definition, if the vehicle is stationary, the force required to "completely lock" the drum brake should be zero, right?

One nice characteristic of drum brakes is that they are self-energizing if the force is applied to the leading edge of the brake shoes. But this only helps if the drum brake is applied in one direction of rotation.

You can roughly calculate the braking torque needed from this 130mm drum brake simply from the static coefficient of friction at the contact interface, the normal force applied to the brake shoe, and the torque produced about the axle of the wheel being braked.

### RE: help needed with brake calculation

I think karmesh has left the building.

"After joining Eng-Tips Forums on February 14, 2015, I've logged in 5 times. My last login was on Wednesday, February 18, 2015."

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!