Advertise on Bikeforums.net



User Tag List

Results 1 to 12 of 12
  1. #1
    Senior Member RJMurphy's Avatar
    Join Date
    Sep 2011
    Location
    Denver, Co.
    My Bikes
    2012 GT Sensor 4.0, Aventon Mataro (Custom).
    Posts
    99
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    '70s Bridgstone Crankset Removal: Can't!

    So, I understand modern crankset removal. Awesome. Trying to update my super old Bridgestone crankset due to it being bent and causing huge problems in a crunch. The biggest problem is I can't figure the thing out. it's nothing like modern cranksets. There's one screw. "Start with undoing that." Nothing. The scre itself seems to be welded ot part of an interior piece that doesn't move. Poke, prod, pull. Nothing. There's no endcap covering anything (where it would be normally is solid metal). I searched the forums and found one post with my same bike, but the OP never responded. You tube is a no go as well. Ideas folks??

    My bike is a 1971 Bridgestone. There is no name as far as I know. But I guess that was the C. Itho & Kabuki era. Pictures for bike & crankset below.
    Attached Images Attached Images

  2. #2
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    22,556
    Mentioned
    69 Post(s)
    Tagged
    1 Thread(s)
    OK you have cottered steel cranks. The pin is a tapered wedge that engages a flat area milled into the spindle. Removing cotters is sort of a lost art but there are a few tutorials available here on removing them.

    The key is you have to remove or back off the nut, then drive the pin out either with a press or a hammer. If you go the hammer route it's important that you support the crank arm both to protect the bearings, and to concentrate the hammer's energy. Then use enough force to drive the pin out in one shot. Otherwise you'll be mushrooming the bolt rather than driving the pin.

    If you've already mushroomed the nut, saw it off flush then use a punch to drive it out (after properly supporting the crank arm).
    Last edited by FBinNY; 11-17-11 at 11:42 PM.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  3. #3
    Bicycle Repair Man !!! Sixty Fiver's Avatar
    Join Date
    Sep 2007
    Location
    YEG
    My Bikes
    See my sig...
    Posts
    26,418
    Mentioned
    21 Post(s)
    Tagged
    2 Thread(s)
    Your bike has a cottered crank and the best way to disassemble it is to remove the nut and use a cotter press to push the cotter pin out... it only feels like it is welded in place and they can be very resistant to removal.

    Alternatively, you can use a hammer and a punch... the crank arm needs to be braced from below or most of the force from the hammer will be wasted and in cases where you want to re-use the parts, prevents one from bending the spindle.

    If you use a hammer you want to be firm and take out the pin in a single shot as tapping away will only mess up the pin.

    Your Bridgestone also appears to use Aluminium lugs which is a feature that is rather unique to Bridgestones of this era.

  4. #4
    Senior Member RJMurphy's Avatar
    Join Date
    Sep 2011
    Location
    Denver, Co.
    My Bikes
    2012 GT Sensor 4.0, Aventon Mataro (Custom).
    Posts
    99
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I LOVE THIS FORUM. You two are amazing. Thank you. It will be a bit more work than I thought then. No big, at least I know it. I guess this means I have to change all of the innards of the BB if I want to use a modern crankset. Is this a terrible idea?? Not that I'm sure this bike is worth much, but would that hurt it's value? I mean I adore the thing and wouldn't sell it anyways. Just kind of peace of mind thing.

    Sixty Fiver: Is that bad or good?? And I knew it was lugged, but how did you know it was alum?

  5. #5
    Bicycle Repair Man !!! Sixty Fiver's Avatar
    Join Date
    Sep 2007
    Location
    YEG
    My Bikes
    See my sig...
    Posts
    26,418
    Mentioned
    21 Post(s)
    Tagged
    2 Thread(s)
    Quote Originally Posted by RJMurphy View Post
    I LOVE THIS FORUM. You two are amazing. Thank you. It will be a bit more work than I thought then. No big, at least I know it. I guess this means I have to change all of the innards of the BB if I want to use a modern crankset. Is this a terrible idea?? Not that I'm sure this bike is worth much, but would that hurt it's value? I mean I adore the thing and wouldn't sell it anyways. Just kind of peace of mind thing.

    Sixty Fiver: Is that bad or good?? And I knew it was lugged, but how did you know it was alum?
    I have come across a good number of Bridgestone bicycles with these aluminium lugs and you can check this with a simple magnet... because the steel frame tubes run into the lug there will be a slight pull but will be a major difference between that and the main tubes.

    Can't quite see the seat post well enough in the picture and if there is no real clamp you will find that the seat post is a quill type with the nut located at the top of the seat post beneath the saddle... because the aluminium castings do not flex like steel this quill post design is a requirement.

    Upgrading the crank to a modern one is a good idea... esiest method would be to install a cartridge bottom bracket and square taper crank set and am sure that if you keep your eyes posted in the sales forum something suitable will present itself and people always seem to have spares stashed away.

  6. #6
    Senior Member RJMurphy's Avatar
    Join Date
    Sep 2011
    Location
    Denver, Co.
    My Bikes
    2012 GT Sensor 4.0, Aventon Mataro (Custom).
    Posts
    99
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Just checked, and yes you're right. Nice trick with the magnet. And yes, the seat post is most definitely a quill one. That's one of the first things I found out. Pretty neat I must say. Thanks for the advice about the BB. I was trying to figure out what to look into next, I guess that is applicable and suitable to me needs. Hell of a learning curve bikes are. Thanks again.

    Quote Originally Posted by Sixty Fiver View Post
    I have come across a good number of Bridgestone bicycles with these aluminium lugs and you can check this with a simple magnet... because the steel frame tubes run into the lug there will be a slight pull but will be a major difference between that and the main tubes.

    Can't quite see the seat post well enough in the picture and if there is no real clamp you will find that the seat post is a quill type with the nut located at the top of the seat post beneath the saddle... because the aluminium castings do not flex like steel this quill post design is a requirement.

    Upgrading the crank to a modern one is a good idea... esiest method would be to install a cartridge bottom bracket and square taper crank set and am sure that if you keep your eyes posted in the sales forum something suitable will present itself and people always seem to have spares stashed away.

  7. #7
    Insane Bicycle Mechanic Jeff Wills's Avatar
    Join Date
    Mar 2008
    Location
    other Vancouver
    Posts
    6,961
    Mentioned
    22 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    OK you have cottered steel cranks. The pin is a tapered wedge that engages a flat area milled into the spindle.
    Yep. Here's a couple more tips from the late guru of all things bicycle: http://sheldonbrown.com/cotters.html
    Jeff Wills

    All my bikes.

  8. #8
    Senior Member Homebrew01's Avatar
    Join Date
    Jul 2004
    Location
    Ffld Cnty Connecticut
    My Bikes
    Old Steelies I made, Old Cannondales
    Posts
    16,030
    Mentioned
    7 Post(s)
    Tagged
    1 Thread(s)
    I've removed cotter pins with a hammer by loosening the nut until the end of the pin and nut are flush. Then tap with the hammer, so that it's hitting the nut and pin at the same time, spreading the load to the end of the pin & the threads at the same time. If the BB is getting tossed out, you won't care about what happens to the bearings. The shock might even help loosen the cups a bit if you're lucky.
    This isn't the perfect method, but it usually works.
    Last edited by Homebrew01; 11-19-11 at 11:17 AM.
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  9. #9
    gbg
    gbg is offline
    Senior Member
    Join Date
    Jan 2009
    Posts
    628
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thank goodness cottered cranks are a thing of the past.
    I remember when my brother and I tried to remove one when we were about
    10 years old. We tried and tried and tried but couldn't do it, so we took it to a LBS
    to do it for us. The "mechanic" took it to the back, put it in stand and started
    wailing on it with a hammer. You could hear pieces of metal hitting the floor of what
    I assume were parts of the pin. I love hollowtech

  10. #10
    Newbie
    Join Date
    Nov 2011
    Location
    Vancouver, WA
    My Bikes
    Mongoose 24" dirt jump bike
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I had a bike like that once, all you have to do is remove the nut, spray some WD-40 or some other lube in the pin, and hammer the wedge out.

  11. #11
    Bicycle Repair Man !!! Sixty Fiver's Avatar
    Join Date
    Sep 2007
    Location
    YEG
    My Bikes
    See my sig...
    Posts
    26,418
    Mentioned
    21 Post(s)
    Tagged
    2 Thread(s)
    Quote Originally Posted by bmxstyle98 View Post
    I had a bike like that once, all you have to do is remove the nut, spray some WD-40 or some other lube in the pin, and hammer the wedge out.
    Once...

    If you are lucky all you need to do it hit it once and the pin will come out but this is not always the case... pins can corrode / shift and get jammed so badly you might think they were part of the spindle.

    In some cases where I was not going to be re-using the cottered crank I have removed them with a cut off wheel.

  12. #12
    Can'tre Member 3alarmer's Avatar
    Join Date
    Nov 2010
    Location
    ,location, location...
    My Bikes
    old ones
    Posts
    9,910
    Mentioned
    189 Post(s)
    Tagged
    4 Thread(s)
    Quote Originally Posted by CbadRider View Post
    Your friends on FB are very different than mine.

Posting Permissions

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