Brompton CHAINRING SWAP! Change/Replace 50t to 39t with a Dura Ace Tutorial How to do it at Home

This video will show you how to swap the chainring on a Brompton with a 50 tooth chainring to a 39 tooth chainring. This will also work if you have a 44 tooth chainring
You will need:
-new chainring (used the dura ace: FC-7900 DURA-ACE 39T)
-chain removal tool (please review how to use this if you are not sure)
-set of hex keys (5mm for the chainring screws)
If you're going from a 50t to a 39t = remove 4 links
If you're going from a 44t to a 39t = remove 2 links
If you have any questions = post them below :)
1.)put the bike in the track stand as shown in the video
2.)break the chain
3.)remove and replace the chainring
4.)remove the proper amount of links from the chain (see above)
5.)reattach the chain
6.)ENJOY :)

[@xiaoyunguo8356]

Thank you for the detailed part list. Exactly what I am looking for

[@nateums]

Glad it was helpful!

[@Tony211289]

How are you finding the hills? Can you get up the steep ones with relative ease?

[@nateums]

the 39t makes climbing moderate hills (~7-10%) doable while still giving you great speed on flats as long as you ride around 10-15 mph, but if you really want easy/ touring kind of set up I recommend getting the 33t, but that installation is much harder bc you'll need to take out the bottom bracket to place a spacer

[@tonsterdang]

thanks for the video, looking at your Dura Ace specs would Shimano Ultegra FC-6700 130mm BCD 5 Arm Inner Chainring 39T be ok too

[@DesChew]

How about the 34T or 36T chainring, would it work?

[@nateums]

39t is the smallest you can go without additional modifications..

[@livejew]

How the ride with 39T feels on flats, not too slow?

[@nateums]

not at all... there is plenty of speed on flats... with downhill you just have to kind of roll though.. but its great if you stay at around 10-12 mph on flats

[@원자방-z7v]

이너쪽 체인링인데 호환 잘 되겠죠?

[@fadzblumer]

Do we need to tune gear hub after changing the chainring?

[@nateums]

you do not need to tune the gear hub after shortening the chain