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Post by ronniebrain on Nov 4, 2010 16:50:19 GMT
 Can anyone help me with this one?, as BB types are a blimmin minefield!...I have a mk2 Bomber which I am currently doing a mild custom on...not too far from original but different enough ,more when finished  ...anyway what I want to know is...has anyone done or know of whether you can fit a square taper bottom bracket set up?...the BB shell width is odd(78mm) and most cartridge bb shells are 68 or 73mm widths...only 4mm diff but dont want to shell out the money if its not going to work...on the bay there are a couple of so called Raleigh conversions from cotter to square but none of the dimensions tally up with what came out!...anyone shed any light?... 
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Post by mushroom on Nov 4, 2010 16:56:39 GMT
Those conversions don't work
I had one on my 5 speed bomber custom.
They are a few mm out, so I packed the difference in large washers and it ended up chewing the cups to pieces.
It used to work loose after a few mins riding.
I went back to a cottered crank from a an old ten speed racer and it's been fine ever since
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Post by mushroom on Nov 4, 2010 16:59:58 GMT
I used the conversion one to put this 3 ring chainwheel on  but ended up with this 2 ring set up   |
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Post by ronniebrain on Nov 4, 2010 18:57:55 GMT
Cheers Shroom   ...thanks for that,I wont bother with one of the conversion kits then  ...what I am going to do then to drag the Bomber kicking and screaming into modern times is...using my skills as a Toolmaker and running a machine shop then I will simply machine the frame bb shell to 73mm instead of 78mm (2.5mm per side wont make a difference to frame strength etc),this should then enable me to start using modern components but not cartridge units as the bb axle length isnt wide enough(the cranks wont clear the chainstays ) but what you can get is a sealed bearing cup kit and a wide choice of axles for 73mm shells the closest one I can get is a 134mm wide and the Bomber cotter axle is approx 140mm at present so should be close but I will let you all know how I get on  ...could all work out perfectly or see me feck up my frame all in the name of progress  ...oh if you want to see the parts im on about...here they are etc... www.sjscycles.co.uk/yst-atb-sealed-bottom-bracket-5-piece-cup-set-prod22176/www.sjscycles.co.uk/cotterless-axle-7r-134mm-prod22175/www.sjscycles.co.uk/tapered-square-cup-and-cone-dept655_pg1/ |
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Post by mushroom on Nov 4, 2010 19:28:27 GMT
Let us know how you get on
I've got a proper bomber/maverick 5 speed chainwheel for a tapered crank if you're interested.
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Post by ronniebrain on Nov 17, 2010 17:15:35 GMT
Right a little update on this...I have modded the frame now...machined to 73mm shell width ...easy...now Raleigh dont tap the original threads in the shell very deep so running out of thread for the cups so have bought a tap set to deepen it myself and all should be good ...will post a few pics when I have done it for you all to see...if it works out ok I will offer this service to others if they should want it doing Some useful info for you all too... sheldonbrown.com/raleigh26.html |
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...anyway what I want to know is...has anyone done or know of whether you can fit a square taper bottom bracket set up?...the BB shell width is odd(78mm) and most cartridge bb shells are 68 or 73mm widths...only 4mm diff but dont want to shell out the money if its not going to work...on the bay there are a couple of so called Raleigh conversions from cotter to square but none of the dimensions tally up with what came out!...anyone shed any light?... 
...thanks for that,I wont bother with one of the conversion kits then 
...what I am going to do then to drag the Bomber kicking and screaming into modern times is...using my skills as a Toolmaker and running a machine shop then I will simply machine the frame bb shell to 73mm instead of 78mm (2.5mm per side wont make a difference to frame strength etc),this should then enable me to start using modern components but not cartridge units as the bb axle length isnt wide enough(the cranks wont clear the chainstays 
...could all work out perfectly or see me feck up my frame all in the name of progress 
...oh if you want to see the parts im on about...here they are etc...