Prototype 20" Brompton

Fastpedaller

Well-Known Member
The difference in bb height as measure is indeed as expected very close to 2 inches, being the difference in rolling radius of the 2 tyre sizes. maybe Brompton will look at a slightly lower BB? One advantage of the larger tyre is the extra ground clearance where more gear/range dictates a longer derailleur/tensioner. With a higher bb, a really large chainring won't drag on the ground either :laugh:
 

berlinonaut

Über Member
Location
Berlin Germany
With a higher bb, a really large chainring won't drag on the ground either :laugh:
Seems not to be a huge problem currently:

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(photo by @chriscross1966 from the Gallery: https://www.cyclechat.net/media/persephone.9817/)
 

tinywheels

Senior Member
Location
South of hades
any idea what's going on with the rear hub?
is it electric?
This is an interesting bike.
Judging by the accoutrements on the handlebars he's either got a long commute or possibly just likes the world traveller look.
 

berlinonaut

Über Member
Location
Berlin Germany
It‘s a Rohloff hub at the rear - not a motor

No. It's a motor. You can see the cables go there (coming down the seat stays) while on the other hand there are no shifting cables (which are on the left side of the hub with a Rohloff) and on the bars there is a derailleur shifter on the left but no Rohloff shifter. Also, a Rohloff with disc brakes always has the external shifting box which is lacking here as well.
 
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