Folding Bikes - Twenty Bottom Bracket - *** Style Conversion?
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12-30-05, 03:38 AM
I recently read v1nce's conversion of a Twenty using a *** style bottom bracket, with plastic cups.
It inspired me to find an old Brompton bottom bracket (*** style - 119mm) that I had and do some calculations.
Unfortunately, I knew the Twenty's bottom bracket shell was wider than standard, and as I pushed the adjustable cup out it fell off before it got to the 76mm width needed.
So to my question, how does it work as most bottom brackets are for 68mm width shells?
Thanks for the replies.
P.S. Here is my Twenty, in progress: Goldie! (http://www.andysutty.ndo.co.uk/mystable/27.jpg)
12-30-05, 06:52 AM
Nice One !!!!!
What kind of rear hub are you using ?
12-30-05, 08:23 AM
I used a very cheap shimano 5 speed freewheel hub (126mm OLN), with friction shifting. I used Sheldon Brown's technique to spread the rear triangle, to get it to fit, which worked well.
I bought a secondhand kids MTB from my LBS, and used the derailleur, gears, and wheels from it.
I'm hoping to upgrade to something a little better soon. :)
01-02-06, 01:19 PM
Is the bottom bracket cut down to help a normal 68mm shelled version fit?
Hey Easy Racer, my net acces was limited or i would have responded sooner, unfortunately i don't think my belated reply will be all that much help. But i can share this:
My LBS had several *** BB's on hand and tried different ones before he got the right width axle and cups for my BB. The BB cup on my frame is standard to my knowledge. If you have lots of trouble sourcing a Kinex (Like the *** but not quite as good) i could send you one, but you'd have to measure your BB en axle and cranks carefully.
01-08-06, 02:27 PM
I may not have explained it very, as usual, but I'm concerned the distance from the left BB cup to the right BB cup is too great a distance for the bottom bracket to span.
This is as normal BB cups are only 68mm wide, and the Twenty's are 76mm, which don't work with the *** style BB I've got here.
Maybe I'll have to look around for another style BB with longer threaded sections on the cups, to try and span the extra 8mm.
Nice! What kind of brakes are those?
01-09-06, 12:58 AM
My brakes are BMX specific U-brakes, with a mounting bracket, like these:
Mine however are are made by Tektro:
When I fitted them I also had to use a bridge bolt to lower them to reach the smaller 406mm wheels, as my Twenty was built for the taller 451mm size wheels.
They are very powerful, but they are also a bit on/off. There is some modulation, though not much, but I've found I'm getting more and more used to them the longer I use them.
Hey Easy Racer, very interesting those brakes, how much do those costs,.. do they brake as well/powerfull as Canti'?
For my trip i simply bunged on the cheapest BMX style brakes i could find (E 5 a piece!) so i would have a little time to hunt around for Canti Braze ons and V-Brake handles.
But the ones i have are god god awfull, despite the Koolstop pads they brake badly and are almost impossible to adjust due to one side springing back way more.
How would you rate yours? If the fender thing was a non issue would you prefer them over Canti's or even V-Brakes?
01-10-06, 03:39 PM
Unfortunately, unless you are like me and find some cheap on ebay, they would certainly not be a cheap options (I paid £20, as opposed to about £45-50).
In use, I would say my U-brakes have the same power as canti's, and luckily have similar linear springs to adjust the tension in the arms as V-brakes so are easy to set-up unlike most BMX U-brakes.
You could however if you are looking for more powerful brakes, look at these brake mounts made for BMXs:
Then you could use whatever brake you like. :)
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