Announcement

Collapse
No announcement yet.

D-brake reinforcement support

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • D-brake reinforcement support

    Made this using aluminum flat bar 1/8 inch thick 1/2 in wide. Twisted the upper end so it could be attached to lower brake boss. Lower end attached to the outside D-brake bracket.

    Click image for larger version

Name:	IMG_20191108_105845-600x800.jpg
Views:	1
Size:	127.1 KB
ID:	2480892

    Click image for larger version

Name:	IMG_20191108_105754-600x800.jpg
Views:	1
Size:	133.2 KB
ID:	2480893

    Click image for larger version

Name:	IMG_20191108_105736-600x800.jpg
Views:	1
Size:	100.6 KB
ID:	2480894
    Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
    Be our muniprohpet for many years more.
    -Dani Buron


    Website
    Videos
    Facebook

  • #2
    I would have thought it would bend under load over such a great length.
    Triton 36" + 29" | KH 29" | KH 26" | KH 27.5" Muni | Nimbus eSport Race 24" | Torker LX 24" | Qu-Ax Luxus 20" | Qu-Ax Profi 20" | KH / Impact 19" hybrid

    Comment


    • #3
      Originally posted by OneTrackMind View Post
      I would have thought it would bend under load over such a great length.
      It's simply an auxiliary support to help buttress the D-brake. It would not bend since there is no evident movement of the D-brake during braking. The braking forces originally stressing the bottom arm are now partly shared by the added strut. The added reinforcement makes it less likely that the D-brake arm will fail. If this were to happen, then and only then, would the strut be likely to bend under the stress of the breakage.
      Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
      Be our muniprohpet for many years more.
      -Dani Buron


      Website
      Videos
      Facebook

      Comment


      • #4
        Originally posted by MuniAddict View Post
        It's simply an auxiliary support to help buttress the D-brake. It would not bend since there is no evident movement of the D-brake during braking. The braking forces originally stressing the bottom arm are now partly shared by the added strut. The added reinforcement makes it less likely that the D-brake arm will fail. If this were to happen, then and only then, would the strut be likely to bend under the stress of the breakage.
        Sure, but in order to perform as a strut, a member must resist bending. It will make some contribution to strength but not much.
        Triton 36" + 29" | KH 29" | KH 26" | KH 27.5" Muni | Nimbus eSport Race 24" | Torker LX 24" | Qu-Ax Luxus 20" | Qu-Ax Profi 20" | KH / Impact 19" hybrid

        Comment


        • #5
          Originally posted by OneTrackMind View Post
          Sure, but in order to perform as a strut, a member must resist bending. It will make some contribution to strength but not much.
          The main problem with dBrakes isn't so much bending (although that does happen) but chatter and vibration. The strut should help with that.
          Unicycling is the fountain of youth.

          Comment


          • #6
            By the way Terry, if you're worried about bending there is a newer version of the dBrake which is a bit more beefy than the one you have.

            Old:


            New:
            Unicycling is the fountain of youth.

            Comment


            • #7
              Originally posted by lightbulbjim View Post
              By the way Terry, if you're worried about bending there is a newer version of the dBrake which is a bit more beefy than the one you have.

              Old:


              New:
              Very cool, thanks for letting me know!
              Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
              Be our muniprohpet for many years more.
              -Dani Buron


              Website
              Videos
              Facebook

              Comment


              • #8
                Terry, do you have problems with disk brake chatter on steep downhills? I do, and had to add a bracket to support the D-brake adapter.

                I'm just curious about when other people have issues with chatter. For me, I'm riding a KH 29" with a 203-mm disk and TRP 4-piston calipers with steel pads. If I'm on a hill that is >22 degree grade, this setup chatters really bad. So far, my little bracket has fixed the problem. But, what a hassle.

                It makes me think that there is room for KH or UDC to develop a better out-of-the-box production solution.

                Comment


                • #9
                  By the way, I have the newer D-brake bracket. I think it looks even beefier than the "new D-brake" in the picture above. Plus, my D-brake bracket is 7075 aluminum which has a slightly higher Young's Modulus than 6061AL.

                  Actually, the higher modulus makes the 7075 bracket stiffer. There is a chance that this may make the chattering worse (don't remember my vibrations class that well). Are there any mechanical engineers out there that would know if chatter would be worse with a D-brake made from 7075 AL vs 6061 AL?

                  Comment


                  • #10
                    I don't use a d-brake bracket but I wonder if this would help. On my bearing caps I add carefully selected washers/shims so that the bolts can be tightened without deforming the bearings. Maybe using shims on both bolts that hold the d-brake and bearing cap on would help. With the correct shims the bolts can be fully tightened and maybe would help reduce any vibrations or looseness in the d-brake.

                    Comment


                    • #11
                      I was just about to order a new 7075 version D brake when I discovered that I already had one! It was buried in a drawer and covered with swirl dip from an old paint job. So I cleaned it up. Here it is next to the original 6061 version.

                      Click image for larger version

Name:	IMG_20191109_121939.jpg
Views:	1
Size:	184.4 KB
ID:	2461867

                      And here is a more direct method for reinforcing the D brake, with no attachment to the frame required.


                      Click image for larger version

Name:	IMG_20191109_123552.jpg
Views:	1
Size:	308.5 KB
ID:	2461868

                      Click image for larger version

Name:	IMG_20191109_123600.jpg
Views:	1
Size:	211.3 KB
ID:	2461869
                      Last edited by MuniAddict; 2019-11-09, 08:41 PM.
                      Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
                      Be our muniprohpet for many years more.
                      -Dani Buron


                      Website
                      Videos
                      Facebook

                      Comment


                      • #12
                        Originally posted by SanJoseUnicyclist View Post
                        I'm just curious about when other people have issues with chatter. For me, I'm riding a KH 29" with a 203-mm disk and TRP 4-piston calipers with steel pads. If I'm on a hill that is >22 degree grade, this setup chatters really bad. So far, my little bracket has fixed the problem. But, what a hassle.
                        There are lots of reports of chatter (and pictures of braces) in this thread.

                        Originally posted by SanJoseUnicyclist View Post
                        It makes me think that there is room for KH or UDC to develop a better out-of-the-box production solution.
                        Nimbus has switched to welded mounts in their current gen.
                        Unicycling is the fountain of youth.

                        Comment


                        • #13
                          Originally posted by lightbulbjim View Post
                          There are lots of reports of chatter (and pictures of braces) in this thread.



                          Nimbus has switched to welded mounts in their current gen.
                          I wish KH frames came with disc tabs on the left side as well for those who want to run an external system.
                          Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
                          Be our muniprohpet for many years more.
                          -Dani Buron


                          Website
                          Videos
                          Facebook

                          Comment


                          • #14
                            Originally posted by MuniAddict View Post
                            I wish KH frames came with disc tabs on the left side as well for those who want to run an external system.
                            The Mad4One frames have double disc mounts. Not sure that they do a 36" though .
                            Unicycling is the fountain of youth.

                            Comment


                            • #15
                              Originally posted by lightbulbjim View Post
                              The Mad4One frames have double disc mounts. Not sure that they do a 36" though .
                              yeah, unfortunately they don't make any frame larger then 29er.
                              Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
                              Be our muniprohpet for many years more.
                              -Dani Buron


                              Website
                              Videos
                              Facebook

                              Comment

                              Working...
                              X