Changing to 44T was the best mod I’ve ever done. Didn’t realise a 40 and 39 were available too. Many thanks for this informative video. 👍👍

My wife bought a 44 for me years ago. I just put it on last night. It’s a wonderful change. I live in a hilly area. 6 speed 2013 brommie with same touring bars you have. I found those to be the most comfortable for me although the ugliest

I changed mine to a 39t and it transformed the bike. Brompton should offer this as an option 😊

Hi paul the 44 chain ring is probably the best like me clipping in with spds gives the best pedalling effort personally the A line probably the best out of the box 4 this as a set up .😊

What a wonderful workshop so organised brilliant

It really should come with the 44t as standard. I changed mine to 44t and I could actually use all the gears!

I did exactly the same thing a couple of weeks ago, and couldn't be happier with that setup. I'm really enjoying your videos, and look forward to viewing many more. Thank you!

I recently switched to an H&H 40T (and made a video about it too!). Like you I started with the standard 50T on my M6R, found that a bit too long and swapped it out for a 44T which worked fine for most things but left me struggling on the occasional steeper inclines. The 40T is definitely better and still gives me a long enough top gear for my leisurely riding style.

Fascinating! I'm about to take the plunge on a Brompton C-Line Explore, that will become an "adventure bike" to take on trips and holidays. It's just too much faff to take either of my full-size bikes on trains, and impossible on buses, and inconvenient in the car. My adventures always involve lots of climbing, often on long, steep ascents, so low gears are critical (and having several gears is important - hence the choice of the 6-speed C-Line). I've asked the bike shop to replace the stock 50T chainring with a 44T, which along with the 3-Spd Sturmey-Archer/BWR IGH and the 13/16 sprockets, will give me a 315% gear ratio, from 29 gear inches to 88 gear inches (and 5.2 mph to 26.2 mph at 60 rpm/100 RPM, respectively). I think the low gear may still not be low enough, but I plan to stick with it and if it's too much of a struggle, either reduce the chainring size or increase the two sprocket sizes. Although I am fit enough to cycle along at 25 mph, I don't choose to, and am happy to coast down hills, so the upper gears and speed (26 mph at 100 RPM on the planned purchase with 44T chainring) are less important. Your chat perfectly resonated with all the calculations and rationale I have been going through over the past few days, thank you!

Awesome effort, Paul. And your English weather just puts me in mind of what a hardy bunch of cyclists you have to be, while here in Calif. I wouldn't think of riding in the wet! . Great video. Love the content!

I fitted a 39T Shimano Ultegra chain ring to my Brompton that I had lying around unused but not before, I had gone through the hassle of buying two TA ones, but wasn’t impressed with the poor quality, lots of rough edges on the casting of the teeth so sent them back, twice. I didn’t bother shortening the chain. Hasn’t had any negative affect and the gear change still works fine. Means if I want to revert to the 44T chain ring I can pretty easily do so. With the 39T chain ring I spin out at about 24-25mph in top. Std spec 6spd Bromptons are massively over geared with whoppingly large 50T front chain rings. Ridiculous unless you have the leg power of a Pro sprinter. I have toured all over Gran Canaria on my L6 which has very steep hills and I can ride up all but the steepest where I had to get off and push. Fitting a 39T chain ring is the easiest and most cost effective mod you can make on a Brompton to lower the gearing. You could go for a 15-17 rear sprocket combo if you felt the need I suppose but I haven’t. Fitting a 39T front chain ring is a great and easy mod to make.

Spa Cycles of Harrogate sell Stronglight T55 chainsets for £30 in all sizes from 38T to 50T. I fit whatever I need for the area 38T in hometown Bradford! All you need is a cheap puller.

Another beautifully produced and very interesting video (yes...Brompton owner!) - M A N Y Thanks for taking the time to share... I definitely have P handlebar envy too!

My brother has just given me his Brompton. I'm going to pick it up from London next week. I live in Edinburgh and all my routes are much hillier so I reckon i will be doing this to it. How do people who put two chain rings on handle chain length? Is it that critical? Would it be better to favour tighter or looser if you had to? (BTW I grew up in Bristol so it is fun to see you on hills i used to try and cycle up over 40 years ago! Constitution Hill, St Michael's Hill, Stoke Hill were dreaded. Even Park Street.)

I did the same work on my M6R... now it's perfect for touring... 👍🏼

Thanks so much, I just got a Brompton 6 speed here in the US. I THINK I'd rather get the H&H with the chain guard - but I really don't know the pros and cons of a chain guard. Wramest regards Jennie

Hi there, thanks for the video! Does the lack of chainguard affect the fold at all? In particular, can you still rotate the cranks while the bike is folded or does the chainring without a guard interfere with the cables?

Good work. I live in a hilly area and use a 44 tooth chain ring and would like to try a 39 or 40. Question: is there a chain guard that fits your setup?

Nice video....I'd like to know if it's possible to replace only the sprockets with 17 and 14 and keeping the 44t chainring. Regards from Turin (Italy).

Using the Sheldon Brown gear calculator, it seemed the best chainring size would be a 36T. This would drop the 6th gear from 85.3” to 69.8”, effectively moving each gear back one gear, if that makes sense (eg: 6th becomes 5th, 5th becomes 4th etc) and making 1st gear 23.1” (as opposed to 28.2” as it is with my 44T). I seem to spend a lot of time riding in 3rd & 5th, which with a 36T would become 4th & 6th. I had contemplated running a 44/28 double chainset, but that would only give 2 gears lower than the 44T 1st (17.9” & 22.1”), then the 28T starts overlapping 3rd to 6th by 0.1” per gear, so no point and a waste of money. For the record I’m still on my original 44T swaged chainset, not bad for a 2012 bike.

My 2019 "SuperlightM6LXBrompton" has 6 gears and when I had bought it (During High Covid19, for the vacation money saved), I at first I wondered for which use I had the low gears, till I met a very steep Danish Serpentine Road (On the Danish Island of Bornholm), and had to walk on top, to go up! I have seen double chainwheels for the front, but I can't - imagine for which conditions I would ever need a gear which was further down than mine (I'm able to walk faster than that). My bike has been much modified down to now 8,75 kilo, and still with its mudguards (I think about the same as a T-line with 4 gears, and mudguards?) As a Rainy Dane I never leave Home without them! I expect to reach 8,5 kilo with a little further changes and work! Finn. Denmark

I love your videos! And looking to do this myself. If you were going from a 54T to 39T - Do you got an idea how many chainlinks would this be? Thank you! Also - do you know of any third party guard for a 39T?

Hello Paul, Interesting video... I plan to swap my chainset for shorter cranks 1(60mm) to help with my replacement hip and have a 144 bcd so I can experiment with my old Campagnolo chainrings to find a suitable setup for me... Thanks for sharing. Take care. Paul,,

Both my wife and I changed to the smallest front chainring available from Brompton. I think the default gearing is just too high for the majority of users.

would any chainring work as long as its 130 bcd and 5 holes? I see options of 39T from inner chainrings for 2by cranksets. Do those work aswell? I still have the 50t installed but want to try 44 or even 39 since I almost never use the hardest gear event on flats in my commute but I have hills on my daily commute/rides. The 44t brompton chainring is quite expensive here in my area so I wanted to try a 44T or 39T first (from cheaper brands) before I commit.

Hi ai own Brompton and is due for new tyre soon, at the moment it got it standard Marathon racer so which tyres would you recommend for commuting? Thank you

Hi, How many links do I have to remove in order to convert from 50 teeth (6 speed C line explore) to a 39 teeth chainring? thanks

I've been riding this bike for about a month kzfaq.infoUgkxwC0IIeIomGQVeBWg-kKJaToZkLEFIA2W and a half now and I think it's fantastic. It helps me get to work on time every day since I'm able to fit it inside of public transportation rush hour. The price is great too, people are always shocked when they ask me how much I paid for the fold up and I tell them "200". It's easy to fold and installation when it ships is insanely easy. All you have to install when the bike arrives is one foot pedal, everything else is done for you. I do recommend you carry some sort of wrench to tighten any loose screws on the handle bar and seat whenever they get a little bit loose. Other than that I think it's a fantastic bike. Easily fits in the home, can fit inside a car trunk and can even fit in subway rush hour.

Hi, thanks for the video. We changed our brompton to the 44t but after watching your video i think the 39t would be better as we live in a very hilly part of the sw. Could you please pass on a link or let me know where i can order one? Many thanks for your helpful videos😊

I went from 52 or 54 (whatever the stock was when I bought my 3 speed) to a 44. Haven’t taken the plunge yet on a 39 as I’m a bit worried about not having the guard. Expect its not a problem in reality?

Hi, I have cassette sprockets 11-13-15-18(P Line ) , I want to purchase a 44T and don't want to change the sprocket size, How many link chain i will use? Thank you

Had a mad moment about buying an electric Brompton. We get a big cash back from our local government here in Montpellier for the purchase of an e-bike. Just seems like the Brompton hasn’t got much range ? And even plenty of issues on reliability ?

Has anyone said you look like Rene Redzepi? 😜