Will there be much difference in carbon rim design for disc brakes and rim brakes?
Results 1 to 5 of 5
  1. #1
    wyrd bi ful rd
    Reputation: c_h_i_n_a_m_a_n's Avatar
    Join Date
    Mar 2012
    Posts
    1,099

    Question Will there be much difference in carbon rim design for disc brakes and rim brakes?

    Side walls on the disc brake rim slightly thinner or not significantly different? Clincher tyre use that is.

    If tubular, then due to the 'boxed' design, does that mean thinner walls?

    Material around nipple hole needs to be further strengthen? Due to additional torque from the hubs?

  2. #2
    RoadBikeReview Member
    Reputation: bwbishop's Avatar
    Join Date
    Sep 2011
    Posts
    482
    All else being equal the torque should be the same. The rim should be much lighter because there is no need to support lateral compressive loads where the brake track use to be.

    The weight savings in the rim should offset some of the weight gain from the disk, especially since you're losing weight at such a large radius and gaining it at a small radius.

  3. #3
    RoadBikeReview Member
    Reputation: looigi's Avatar
    Join Date
    Nov 2010
    Posts
    7,162
    Not sure what the effect on design will be but the torque exerted by a disc brake and transferred through the spokes to the rim is pretty high, high enough to lock the front wheel with effectively all your weight on it. That's more than you can put out pedaling.

    No heat input to the rim from braking changes the material requirements, so perhaps heat resistance can be traded off for other beneficial material properties.
    ... 'cuz that's how I roll.

  4. #4
    RoadBikeReview Member
    Reputation: Wookiebiker's Avatar
    Join Date
    Sep 2005
    Posts
    6,581
    Initially ... no. This is because it will be easier to use existing rims than design new rims and have two lines (one rim brake, one disc brake).

    Down the line when disc brake equipped bikes become more and more available/popular ... rim designs will change. For an idea of how, look at the MTB market. Initially, rims didn't change but as they became the standard in brakes ... the rims changed and got lighter and stronger at the same time.

    I think it will happen faster in the road world because much of the rim designing has already been done in the MTB world, but they have more room to design with aerodynamics in mind.
    Snakebit: "How many times do I have to tell you that I don't have a source? I don't make a note of everything I see or hear on the internet and you don't have to take my word for it."

  5. #5
    Cranky Old Bastard
    Reputation: Randy99CL's Avatar
    Join Date
    Mar 2013
    Posts
    2,337
    Quote Originally Posted by looigi View Post
    but the torque exerted by a disc brake and transferred through the spokes to the rim is pretty high, high enough to lock the front wheel with effectively all your weight on it. That's more than you can put out pedaling.
    I've got road disc wheels now (cross bike) and am researching having a new set built.

    I really wish someone would do a scientific test of how much stress a disc brake puts on the spokes and nipples.
    It is confusing to me because DT recommends their SuperComp spokes for disc wheels and they are the lightest they make at 14-17-15. I would guess that a 15ga nipple is easier to pull out of than a 14??
    At least a half-dozen companies are selling 29er disc wheels with 24 spokes in the front, 2x or 3x. Most are double-butted. Until I saw these I would have guessed that less than 32 was a mistake.

    At this point I'm planning on 24F/28R with Sapim Lasers for a set of road wheels with 25s.

    As I've said, I wish someone would do some testing and give us some spoke stress numbers.
    "When you know absolutely nothing, anyone who knows 1% more than nothing sounds like an expert."

Similar Threads

  1. Disc Brakes
    By jays35 in forum Tandems
    Replies: 7
    Last Post: 07-05-2013, 04:10 PM
  2. Disc brakes with carbon rims, When can we expect to see them
    By freezin_is_the_reason in forum Wheels and Tires
    Replies: 13
    Last Post: 11-17-2012, 01:23 AM
  3. Disc brakes needed for carbon wheels? X-post from wheels
    By onespeedbiker in forum Components, Wrenching
    Replies: 9
    Last Post: 05-29-2012, 08:42 AM
  4. Disc brakes needed for carbon wheels?
    By onespeedbiker in forum Wheels and Tires
    Replies: 46
    Last Post: 12-16-2011, 09:11 AM
  5. Carbon fiber cyclocross with disc brakes?
    By hardwarz in forum Cyclocross
    Replies: 3
    Last Post: 06-16-2010, 07:01 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT ROADBIKEREVIEW

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.