Hard to Find Oversized Vintage Bottom Bracket Options?

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IanHurrell
Posts: 14
Joined: 19 Mar 2020, 9:55pm

Hard to Find Oversized Vintage Bottom Bracket Options?

Post by IanHurrell »

Hi All,
I have a 1950s Elwick Hooper model W trade bike. It has an oversized (150 mm) bottom bracket spindle which snapped.

It has T.D.C. No. 14 stamped on it
BSA thread
Shell sixe 76mm
Symetrical and if i'm measuring correctly 43 - 64 - 43 mm proportions

It's the width that's the issue, I have just 5mm gaps between the pedal arms and frame

I've worn Google out looking for a replacement and am now thinking of other options.

I'm happy to go for spacers, adapters, change whole chracnkset/BB combination.

Any pointers/suggestions greatfully recieved so that i can kepp the old boy rolling

Thanks....Ian
slowster
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Joined: 7 Jul 2017, 10:37am

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by slowster »

IanHurrell wrote: 29 Sep 2021, 1:26pm It's the width that's the issue, I have just 5mm gaps between the pedal arms and frame
What is the Q factor of the current cranks, and what is their length?

Assuming they are traditional straight cranks at 90 degrees to the spindle, it might be that a relatively more modern MTB chainset, the crank arms of which splay outwards, would have a sufficiently large enough Q factor not to foul the chainstays, despite having a shorter axle (which would be a good thing, since it is probably much less likely to snap than a 150mm axle). Some Shimano square taper and Octalink triple MTB chainsets have ~185mm Q factors.
IanHurrell
Posts: 14
Joined: 19 Mar 2020, 9:55pm

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by IanHurrell »

Thank you Slowster, very interesting about the splay

Very standard traditional pedal arms: 8 inches (or 7 inbetween centres)
90 degreees to the spindle
Crank Q factor is zero or the width of the arms
Q factor is 140mm ish
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slowster
Moderator
Posts: 4631
Joined: 7 Jul 2017, 10:37am

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by slowster »

Hopefully some more knowledgeable members will be able to offer better suggestions.

Mercian have a 150mm cottered axle.

https://www.merciancycles.co.uk/online- ... cket-axle/

They only specify the length, but you may be able to determine the other dimensions from the photograph:

Image
rjb
Posts: 7200
Joined: 11 Jan 2007, 10:25am
Location: Somerset (originally 60/70's Plymouth)

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by rjb »

Mick F had this problem on his chopper if I recall. I believe he cut a standard length axle and had a tubular sleeve welded or brazed over it to elongate it. :wink:
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
slowster
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Posts: 4631
Joined: 7 Jul 2017, 10:37am

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by slowster »

Another 150mm cottered axle, but the other dimensions differ somewhat:

https://www.bankruptbikeparts.co.uk/bot ... bbp2213068
IanHurrell
Posts: 14
Joined: 19 Mar 2020, 9:55pm

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by IanHurrell »

Slowster!
The Mercian one looked to be spot on and i just ordered it.
I can't tell you how long i've spent searching. I've even been to the Mercian website before.

Fingers crossed that it works out. I'll update the post.

Of ther three times i've used this group I've alway's got such great help.

Thanks once again Slowster
IanHurrell
Posts: 14
Joined: 19 Mar 2020, 9:55pm

Re: Hard to Find Oversized Vintage Bottom Bracket Options?

Post by IanHurrell »

Slowster, I got the bottom braket as sugested from Mercian and managed to fit it last weekend.
A perfect fit.
I am so greatful for your help in keeping my old butchers biike on the road. I've been using it every day for 20 years and will do for another 20 now.

Thank you
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