Biggest cog on Brompton? (chain push type tensioner)
 

These are 22T applications (some have pushed to 23T), yes major operations required :lol:.

So, what mods more than a new chain tensioner, rear hub and sprockets? What is the cost and what are the sprockets? Will an 11 tooth go on there and are they standard shimano or sram? Thanks, Ron

When did they, Brompton, start using chainstay tubes that are not open on both ends?

Never. What makes you think they did?

that picture, they make a rose metallic now?

The hub is not Brompton's but custom 21 spoke, made in Asia*, It has a lockring , Brompton's 2/6 speed uses a snap ring.
3 speed cogs also secured with a snap-ring.

* a hotbed for aftermarket bling parts for folding bikes.






...

I would think it is the standard 2 speed hub. Peopel have started using three slim cogs instead of the stock two. You get them from butchering a 11 speed rear casette or you can buy them in titanium. Same can be done for 3 and 5 speed SA hubs with the nine spline driveside. I am using a 16t cog from a Shimano casette on my 5 speed hub.

I guess you can make a superlight three speed like this, especially if you use the titanium cogs.

11 tooth is possible (12-16-22 here), and hub that is compatible with external 3 speed or 4 speed cog (standard two speed hub will only takes cog up to 17t if you are lucky, 19T with some frame filing), X-tensioner with longer arm. Shimano cogs.

Jockey wheels and chain pusher can remain stock. Thumb Shifter can be stock two speed with modification (or 3 speed version?).

Other than that this bike does not look rose metallic at all to me: They probably started this at the same time when they invented violet rear carriers and rear wheels with less spokes and a three spoke pattern... :p

Rainbow brompton, custom painted or body parts swapping , factory demo bike . :)

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