Oh dear. I spent so much time reading the manual and watching videos, twiddling various knobs, took the entire thing apart and put it back together... And it was just the little plastic part that got unhooked. I hooked it back up and all I have to do now is readjust the grub screws back to normal, which I wouldn't have touched in the first place if I'd found your video first. Thank you so much!

Very helpful. Who’d a thunk all those cable could get so twisted. Thank you.

Thank you. I’m 2/5 of the way through a 100km ride in France today and I got stuck on 3. Your video rescued me just now ❤️

May God bless you! Your advice helped me avoid a $180 repair shop bill. I simply cleaned the 2 speed shifting gears, and the Brompton shifted fine again.

So glad I watched this. Cables were twisted. That was it! Thank you!

Thank you. Saved me a lot of time -- it was the twist on the cable. Straightened it out and it works again.

Thanks a million mate. Was looking for two hours what was wrong and then finding that the little plastic rod wasn’t in place. All works well now.

Wow!! I have only rode my NEW Brompton 6SP, a few times and it would not shift. I was angry and was ready to call up Brompton. After looking at this video, the cables and the little plastic holder before the spring was out of whack. I adjusted, and violia, it shifts now. Love my bike. This video really helped and is Brilliant.

Thankyou thankyou thankyou!!!! Had my Brompton (also British Racing Green) flipped upside down in (and basically filling) a hotel room in Frankfurt, as the derailleur (or whatever it is) wouldn't go into the higher / smaller gear. First things you said about the cable routing and checking the plastic thingy was hooked in properly fixed it. Brompton's own video was naff all use.

Thank you! I struggled for about an hour trying to fix it. Turns out the plastic piece was just loose. Really glad I found your video

Just so you know, I watched your video under an overpass in Tokyo Japan, riding on the Arakawa River Bike path. I was wondering why I felt like I only had three of six gears. Watched a more in-depth one first, and breaking the shifters down sounded like a right nightmare. Watched yours next . . . turns out while the cables weren't twisted, the buggers had managed to stack on top of each other in the little 'cage/guide' and brace tight. How, I'll never know. So thanks for saving me untold anguish and 30 more miles with only the lower gear. As a Brompton newbie, I hadn't the foggiest on the derailleur system.

Great little vid and might I say better than Brilliant Bikes one about derailleur adjustment which misses out a load of steps and makes no reference to that horrible bit of plastic which was the culprit in my case, many thanks !

Felix top man. My issue was the plastic clip at the back. fixed and saved going to the shop. Many thanks

03:18 I have the same issue on the losse rubber hook in my Brompton. Really save me thousand times on fixing it.THANKS. Love your channel. CLS.👍

Thank you! Loosening my tightened wires worked!!! SO Easy to shift now

Thanks for the video, I didn't realise there was a cable tension adjuster. Although it is the most likely thing to go wrong it has been functioning for quite a few years with little attention from me. Thanks for sharing.

Perfect swift solution - that pesky bit of plastic had detached itself.

Thanks! Both my gears were getting hung up because the cables were twisted through the cage near the rear wheel and that plastic derailleur cable guide was hung up on the other cables. Quick fix thx to you.

Thanks so much for this video! The 2nd tip saved us on the road as our little clip holder thingy had come loose!

Useful video, and that plastic bit is well worth checking but having riden my Brompton over several years commuting in all weathers down muddy lanes etc. my 1st thought is always the chain tensioner when the 2 spd shifter misbehaves. Its simple to remove, a big nut, and if you have a 6spd like me there's the Sturmer Archer chain to disconnect too. Takes about 2 minutes to remove, then it's much easier to clean, do that and rei-nstall. That in my experience fixes it almost every time. I cleaned mine, when commuting in bad weather, every two weeks. I only once had to adjust for a stretched cable in 5 years, and maybe twice a year I dismantled the 2 spd shifter for a clean and a small drop of light oil. Its really useful to have a spare chain tensioner, a simple swap out and then clean the dirty one over the next few days. If you have an ultrasonic cleaning tank they make cleaning it a breeze too 😁

Thanks Felix this really helpful video got my 2 speeds back 👍😁

wow the shifter rotating barrel thing should be discussed more! its the easiest solution!

Thanks so much for posting this video. 02:30 fixed my problem in seconds. It’s disappointing to have such a cheapo bit of plastic on a bike that retails for £1k+. I’d expected better from Brompton.

Holy shit I just wasted an hour meddling with the tensioner and all the rest when the solution was to look first at the cables. Your vid wins

Great tips, thank you!

The twisted cable tip worked fit me

Excellent! Most helpful!

Thank you for these informations.

Great vid!

Great video

Unfortunately most of the rear derailleur issues arise from the shifter which gets stuck due to some kind of swelling of the plastic parts. There is a video how to fix this. CLeaning the bottom end also helps, but is comparably easy. I would not apply much grease down there as it will just attract dust and dirt which will stick to it. I keep this area dry and clean. Not the best engineered part of Bromptons.

Thank you! What kinds of lube would you recommend for those plastic tubes that slide together? Silicone spray that dries after application? Graphite powder?

Thanks 👌

I just ordered this same bike in Los Angeles. Green. 2 speed. Fenders no rack.

Also check the Chain tensioner to see if bent. Couldn’t work out what was wrong then noticed it. £25 part replaced works like new. Must have taken a whack !

Good video interesting and posh workshop

Just thinking out loud here…what about using a hot glue gun and gluing that plastic tube that has the hook-end to the frame? Hot glue is easy enough to scrape off later if you have to take things apart for some reason

I wish they'd just give the 6 speed with a full 6 speed internal hub instead of these fiddly derailleur bits. Close to zero maintenance, that'd be.

One thing I would like to point out is do not increase tension on cable too much. If your Derailleur is not functioning properly after tightening the cable then you need following adjustment. Tightening cable too much can break your cable and reduce its lifespan. There are screws in Derailleur as shown in this video that are used to move your Derailleur up and down to match small gears on the head of the Derailleur to the one at the wheels. Please refer this video. kzfaq.info/get/bejne/sNuefMurv8zRpH0.html

Brand new out of the box and 3rd und 4th gears slipping! They should fix it since it's bloody brand new! Help!

making me dizzy. but thank you .

great vid. no fun working on it though.

Manual states adjusting the barrel adjuster is rarely if ever needed but the limiting screws are to be adjusted - just need to get used to it.

Hi Felix, I've come to realize that I never use the derailleur shifter on my 6 speed M6R. So can I remove the shifter, chain pusher assembly, cable anchorage spring and the whole cable but leave the original chain tensioner and both sprockets? Will the chain just continue to run on whatever sprocket it's on? I would like to leave it on the 16T sprocket to be able to climb hills. Speed is not a major desire. I should lose some unwanted weight too I presume.

Super useful! The Brompton cable pusher is a real tureen of turds.

WD40 is not a lubricant. It's a water displacement (WD) fluid.

Thank you! Though it was the adjustment issue for me - for those who these solutions still doesn’t fix it for you, have a look at this Brompton video kzfaq.info/get/bejne/sNuefMurv8zRpH0.html

WD-40 is NOT a lubricant - do NOT use it to lubricate your chain. Only use a dedicated chain lubricant.

You say turn the adjuster clockwise to increase tension at 5:30. Are you sure? because that will move the threaded adjuster further into the lever and so shorten the effective length of the outer which will decrease tension.