Results 1 to 16 of 16

Thread: Lug/BB Reshaping (changing angles)

  1. #1
    mxboy349's Avatar
    mxboy349 is offline VSalonistas
    Join Date
    Sep 2011
    Location
    STL
    Posts
    56

    Default Lug/BB Reshaping (changing angles)

    Question on lug/bb reshaping. BB shell I purchased is a 60° x 62° x 7.5° (“Richie-issimo Series”). My design with the fork I am using will require the 62° to be more like 66°. Can the CS sockets be “reshaped” for this much of a difference? Bend the CS slightly to make up the difference? Am I crazy and I shouldn’t even be close to 66° for an angle of the CS? Am I way off base on anything? For my design I am just copying and existing frame that I ride with a slightly less “standover”. Attached is a pick of my design.

    8263789839_a0fd91e510_z.jpg
    Eric Brandt

    Hobby builder that just likes to make stuff.

    MJB Frameworks
    My Flickr

  2. #2
    Pi Guy is offline VSalonistas
    Join Date
    Jul 2008
    Location
    Orygun
    Posts
    216

    Default Re: Lug/BB Reshaping (changing angles)

    Assuming this is a standardish road bike your BB drop seems a bit small to me. Please keep in mind that I am only speaking from my limited experience (10 frames).
    Jason Henkle
    flickr

  3. #3
    Eric Estlund's Avatar
    Eric Estlund is offline VSalonistas

    Join Date
    Feb 2009
    Location
    Springfield, Oregon
    Posts
    2,622

    Default Re: Lug/BB Reshaping (changing angles)

    No comment on the design (I haven't clicked on it yet), but changing angles in lugs and shells is par for the course. Stick a piece of bar in there, grind away, hammer, etc. Make the parts work for you. Of course, some parts might need less "encouragement"- that's why there are so many great BB shells on the market. But don't be afraid to lean into it a bit.

  4. #4
    Andrew R Stewart's Avatar
    Andrew R Stewart is offline VSalonistas

    Join Date
    Jul 2008
    Location
    Rochester, NY
    Posts
    545

    Default Re: Lug/BB Reshaping (changing angles)

    The chain stay sockets can be bent a bunch. Do as much as you can prior to attaching any tube, if you screw up it's easier to start over with only the shell the loss.

    I will comment on the design. Why so tall a BB height? Are you running 185mm arms? Pedals from a exercycle (which have a lot below the axle)? Will this be a fixed gear bike?
    Andy Stewart
    10%

  5. #5
    Andrew R Stewart's Avatar
    Andrew R Stewart is offline VSalonistas

    Join Date
    Jul 2008
    Location
    Rochester, NY
    Posts
    545

    Default Re: Lug/BB Reshaping (changing angles)

    As I look more at the design i have more questions. Axle to race is 365mm- Is this correct? Is the tire diameter 688? If so then the fork height is really tight. If you are running long arms or have big feet or run fenders the front center is a bit tight (espically with the 33mm tires).

    One of the reasons to build your own frame is to try out stuff no one else is building. But there's a reason that the manufactured bikes fall into such a narrow range of geometries... Andy.
    Andy Stewart
    10%

  6. #6
    mxboy349's Avatar
    mxboy349 is offline VSalonistas
    Join Date
    Sep 2011
    Location
    STL
    Posts
    56

    Default Re: Lug/BB Reshaping (changing angles)

    Andy-Fork is off the shelf and it is 365mm Axle to race, I have measured it twice.. Don't have the skills to build a fork yet. I have the tire diameter drawn at 668 (700x23 tires). BB height is a "result" of the fork. From what I can tell the "off the shelf" fork is painting me in a corner with the rest of the frame geometry. Seems like I may have to play with the DT socket on the BB and the DT/HT socket to get the geometry in the norm.
    Eric Brandt

    Hobby builder that just likes to make stuff.

    MJB Frameworks
    My Flickr

  7. #7
    Eric Estlund's Avatar
    Eric Estlund is offline VSalonistas

    Join Date
    Feb 2009
    Location
    Springfield, Oregon
    Posts
    2,622

    Default Re: Lug/BB Reshaping (changing angles)

    Not sure why the fork is painting you in to a certain BB drop. Get the bike where you want/ need it, and make the parts work (or get parts that will).

    (Edit- that read harsh to me; it isn't meant to be. Draw it out as you want it, and then assess the best plan of action.)

  8. #8
    mxboy349's Avatar
    mxboy349 is offline VSalonistas
    Join Date
    Sep 2011
    Location
    STL
    Posts
    56

    Default Re: Lug/BB Reshaping (changing angles)

    Not harsh at all Mr. Estlund. I think I understand now. Lugs and BB shell will need to be "massaged" to my needs. Thanks.
    Eric Brandt

    Hobby builder that just likes to make stuff.

    MJB Frameworks
    My Flickr

  9. #9
    suhacycles is offline VSalonistas
    Join Date
    Nov 2009
    Location
    North Carolina
    Posts
    1,170

    Default Re: Lug/BB Reshaping (changing angles)

    Yup, might work (and ride) better overall if you dropped the BB a little, make the ST-DT angle more like 59 and the CS-ST angle ends up closer to 65. HT-DT angle might end up being around 58-59 too but that's no biggie or live with a head angle around 72. Have fun... =)

  10. #10
    Andrew R Stewart's Avatar
    Andrew R Stewart is offline VSalonistas

    Join Date
    Jul 2008
    Location
    Rochester, NY
    Posts
    545

    Default Re: Lug/BB Reshaping (changing angles)

    Eric- Sorry but with my poor eyes and monitor it looked like 33mm tires were in the plans. hence my wondering about the fork height, and the vanishing clearance... I do agree with others. Make the frame parts fit your design and the design fit your needs.

    BTW this is very close to the frame I'm building right now for myself. I'm making the fork to free myself of the industry narrow mindedness that manufactures seem to have about tire sizes and braze on options. Frame #830 is the thread link. Andy.
    Andy Stewart
    10%

  11. #11
    Dave Anderson's Avatar
    Dave Anderson is offline VSalonistas
    Join Date
    Aug 2008
    Location
    Minnesota
    Posts
    426

    Default Re: Lug/BB Reshaping (changing angles)

    I agree with whats been said here, but thought I would throw in a couple of photos of how I adjust angles & such. See below (they also sometimes need some heat and a little "blacksmithing"). It's very common to have to tweak lug and bb shell angles. In fact it rare that I don't have to tweak several things when building a lugged bike. I also agree with whats been said about your BB height. It's pretty high...unless your maybe building a track bike that will actually be ridden on the track....and you shouldn't have any trouble using an RS BB shell with a more typical road bike BB height.

    Dave

    PS: When adjusting angles, go easy and check them as you go. Watch for and correct any ovalization or etc.


    Dave Anderson
    Anderson Custom Bicycles
    www.andersoncustombicycles.com
    ACB on Facebook
    ACB on flickr

  12. #12
    mxboy349's Avatar
    mxboy349 is offline VSalonistas
    Join Date
    Sep 2011
    Location
    STL
    Posts
    56

    Default Re: Lug/BB Reshaping (changing angles)

    I completely understand now. I was under the assumption that the lugs would be “fixed”. Here is an updated design with the DT adjusted to 58°. Still playing with some of the measurements, but I now see how you have to “manipulate” lugs and BB shell to get the final geometry. I can also see why some people Fillet Braze/TIG weld.

    8267927354_bc6d41d40a_z.jpg

    Larger res pic here.

    Mr. Anderson- thanks for the pics, worth a 1000 words. Is that solid stock for “cheaters” or tubing? Are they mitered so that it fits close?
    Eric Brandt

    Hobby builder that just likes to make stuff.

    MJB Frameworks
    My Flickr

  13. #13
    Dave Anderson's Avatar
    Dave Anderson is offline VSalonistas
    Join Date
    Aug 2008
    Location
    Minnesota
    Posts
    426

    Default Re: Lug/BB Reshaping (changing angles)

    Quote Originally Posted by mxboy349 View Post
    Mr. Anderson- thanks for the pics, worth a 1000 words. Is that solid stock for “cheaters” or tubing? Are they mitered so that it fits close?
    Yes...see below. I got these from Omar Khiel: Oasis Custom Cycles | Handmade Bicycles and Custom Wheels


    DSCN4161.jpg
    Dave Anderson
    Anderson Custom Bicycles
    www.andersoncustombicycles.com
    ACB on Facebook
    ACB on flickr

  14. #14
    ToddFarr is offline VSalonistas
    Join Date
    Aug 2012
    Location
    Taichung City, Taiwan
    Posts
    327

    Default Re: Lug/BB Reshaping (changing angles)

    ^ Those are awesome! I def need to make me a set! Thanks for sharing. I may just use a heavy gauge tube though. Seems like a lot more material than I want to remove :)

  15. #15
    Cooper Cycles is offline VSalonistas
    Join Date
    Nov 2010
    Location
    Portland, OR
    Posts
    31

    Default Re: Lug/BB Reshaping (changing angles)

    I like having BB cups threaded in when using brute force to manipulate the BB to prevent ovalizing...

    Have Fun!
    Travis

  16. #16
    mxboy349's Avatar
    mxboy349 is offline VSalonistas
    Join Date
    Sep 2011
    Location
    STL
    Posts
    56

    Default Re: Lug/BB Reshaping (changing angles)

    Made a "persuader" and it worked like a champ. All I had was a short piece of stock, but it was long enough to put a "cheater" bar on and get the job done. Thanks to all for the tips.

    8288107566_041db32fe8_z.jpg
    Eric Brandt

    Hobby builder that just likes to make stuff.

    MJB Frameworks
    My Flickr

Similar Threads

  1. The right bike for you and changing your mind
    By AntLockyer in forum General Discussion
    Replies: 10
    Last Post: 06-25-2012, 04:50 PM
  2. Check out this 36'er: steep angles, short chainstays
    By acotts in forum General Discussion
    Replies: 39
    Last Post: 05-04-2011, 11:14 AM
  3. Angles... for an 82 Colnago Super
    By xjoex in forum General Discussion
    Replies: 2
    Last Post: 02-22-2011, 10:35 PM
  4. Can I show off my jig for changing cleats?
    By Tristan in forum General Discussion
    Replies: 10
    Last Post: 08-14-2010, 11:14 PM
  5. Changing sprinting style over the years?
    By bdaghisallo in forum General Discussion
    Replies: 43
    Last Post: 07-24-2010, 01:37 AM

Bookmarks

Bookmarks

Posting Permissions

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