Bromptons are great – and from the factory they’re perfect for what they’re designed for, short journeys around the city.
But the Brompton design is capable of a lot more, with some modifications it can become the ultimate folding bike! Think of it like what Cooper did for the Mini – taking a very good bike, and improving it a bit…
I make a bunch of kits that can be bolted on to your existing Brompton to improve the gearing and brakes, or I can custom-build you a Brompton from scratch.
If you want a complete custom Brompton, I can build everything for you – have a look at the Custom Brompton Order Form to add all the options you want.
For lots of ideas and examples of different builds, have a look at the Custom Builds section of the website.
I also make the MTBrompton, a Brompton with big knobbly 20″ tyres for off-road use.
Or it can have 20″ touring tyres and an integrated rack for panniers, the Expedition version.
The new Brompton G Line can also be upgraded with better gearing and other improvements – see the G Line upgrades page.
To see what upgrades will work with which version of Brompton, check this page.
I make five different wheel sizes for the Brompton, for a comparison of them see the wheel sizes page.
If you want to send me your bike for conversion, or a bike you’ve bought elsewhere, then also go straight to the Custom Brompton Order Form to add all the options.
If you want to convert your own bike yourself, or have a local shop do it for you, you can buy the individual kits.
Rohloff rear hub gearing kit
Alfine rear hub gearing kit
Enviolo rear hub gearing kit
Disc brake kits
Belt drive kits
If you want to do almost everything yourself, you can buy just the custom forks and rear triangles you need.
If you’ve already got a kit – or just want to see what’s involved with fitting – have a look at the Technical Info.
Hi. Will your 8 speed conversion fit a 1995 vintage Brompton?
It’ll be a bit of a squeeze because bikes of that age are 112mm not 115mm – but it will go, or you can bend your frame slightly to suit.
Hey Ben. Brompton has introduced a new colour in 2018 – Raw Black Lacquer. Have you tried matching it yet for a rear rack / front fork?
According to my powdercoater, it might be possible – but the raw lacquer finish looks a bit different on stainless steel anyway, it’s pretty hard to get an exact match.
Hi Ben,
I bought the rear rack with Rohloff speedhub. I did all the stuff by myself – not too difficult but twice a time the Allen key broke.
Now I like to ride my Rohloff Brompton every day. Worth every Euro I paid
Regards Karl
Great, thanks! I break a few Allen keys on those bolts too…
hello Ben,
I am riding your alfine 11 conversion now for a year and your Rohloff kit for almost half a year.
I am still thrilled about the improvement of your conversions.
Both hubs are fantastic and your stainless steel triangle with it´s fine brass seams
is a kind of an art, an eye catcher indeed.
I am riding my bromptons daily to work, no matter what season or weather, 26 Km one way,
hills included on my way.
I can only confirm that these conversions turn the bike into a grown-up touring bike.
I do not need no other bikes.
Thanks a lot, for these fantastic conversions.
All the best, Jörn
Hi there,
A few dumb questions:
1) I have a 10/12 year old Brompton that I am thinking of upgrading (gearing, brakes etc.) would this be something that (if shipped to you) you could upgrade? (Or is it better to sell that one and start again?)
2) Cosmetically the bike would also benefit with a fresh paint job (frame and accessories – wheels, handle bars). Is this something that could also be done?
3) Do you upgrade some of the bolts, clamps, easy-wheels etc. to titanium versions?
Sure, I can upgrade an older bike, including repainting it. Repainting starts from £200, depending on the colour. I can upgrade other parts at the same time if you wish.
Hello,
May I know whether you have Brompton (6 speed) in your store please?
Thank you.
Rgds,
Anna
I am not a Brompton dealer, I don’t stock normal Brompton bikes.
Hello,
Is there an agency in Japan?
No, I ship direct to Japan.
Just received my Brompton Rohloff bike from Ben yesterday in Singapore. Super efficient shipment by UPS from Scotland to Singapore. Arrived within 3 days after being shipped. The ride of the bike is superb and the selected colour finishing (in Nine Streets Edition) is amazing.
As we all aware and understand that Kinetics is all about only one person, Ben Cooper, however, he will deliver a high quality product and lots of patience is required.
Thank you
Just had the opportunity to ride the Brompton Rohloff. The ride is amazing and very very smooth indeed. Slopes which I would have difficulty riding my other Brompton M6L was a breeze and quite effortless. Once you have ridden the Brompton Rohloff you would not want to go back to the other standard Brompton. I am writing again to thank Ben Cooper for a fine job and have ordered and awaiting delivery of another Brompton Rohloff in Nickel Plated finish but with 18″ wheels with Big Apple tyres.
Hi,
Which conversion kit will greatly improve the bromptons efficiency?
I plan to do long distance touring on my brompton, currently on the stock 6 speed I seem to only be able to maintain a 14mph average over a 10hr day.
Will the kinderlay, alfine or rholff greatly improve the efficiency?
Yes I know I should really be considering a full size bike but storage is an issue for me and I do not want more than one bike.
Comments and ideas would be greatly appreciated
Drivetrain efficiency is pretty good with the 3/6spd anyway, the Rohloff and Kindernay are similar – for lower rolling resistance, it might be worth looking at the 20″ when conversions I do.
Hi
I have an A type Brompton which uses an older frame. Will your conversion kits, rear and front, work with this bike?
Thanks
Yes, my kits work on any Brompton from the past 20+ years.
Hi, I wish to purchase the MTB fork and rear triangle for the Brompton.
Can I use mtb cogs instead of internal gear drive?
Yes, it can use a derailleur hanger for normal derailleur gears. You need to be a bit more careful when folding, as the chain goes slack.
Can I just bye the rear triangle for Rolhoff please – how much and what sort of delivery times
Thanks Mike
Yes, rear triangles are available here: https://www.kinetics-online.co.uk/folding-bikes/brompton/brompton-rear-triangle/
Love your front and rear fork / triangles. Exactly the tire clearance I need for Edinburghs lousy roads.
Since your rear triangle + wheels with internal hubs replaces the Brompton rear end anyway… Is the cheapest way to buy a used A-line or Brompton frame-only and then get your kits? Any constraints in the A-line or older frames when modifying w your fork and triangle?
My kits will fit to any Brompton – I’d generally recommend staying away from very old short-wheelbase bikes, just because they are more prone to breaking. Another thing to consider with second-hand bikes is that the frame should be fine, but the other parts (catches, seat post shim etc) might have to be replaced, so factor that into the cost.
Hello! May I ask if you have the Brompton P line design available for the rear triangle? (The P line redesigns the stop block area, featuring a screw hole with a limit plastic component included, while the installation for the easy wheel has a direct metal tube instead of an additional forked structure, providing higher strength.) Thank you!
No – Brompton redesigned their rear triangle to make it stronger, but my rear triangle is stronger than theirs already, so any change would only be cosmetic. I don’t think I’ve ever had someone bend a roller tube.
Hello !
What is the largest cog I can use with a nexus/alfine hub ?
Thanks,
Guy
18t is the biggest that’ll work with the tensioner. To get lower gears, a smaller front cog is the way to do it.
Why the Jtek shifter rather than the Rapid Fire for Alfine 11?
The JTek works better on the M and H bars because it can fit part-way around the curve, the Rapidfire is better on the S bars.
If sending in own bike for conversion (11 speed Alfine) what would be the cost of having the complete frame resprayed, contrasting main frame and forks/rear triangle with a combination of the £0 finishes from the custom list.
Regards
I own a Brompton C line Electric 6 speed bike, is there any way you would be able to increase the wheel to 18”or 20” in any way?
I look forward to hearing from you.
Martin
Yes, I can do that – I just finished off converting a Brompton Electric to 18”. There’s some pictures on my social media – to do it, you need one of my rear gearing kits (the one I just finished was Alfine 11), a rear disc brake, and a front rim brake. This one used a V-brake at the front, but Magura hydraulic rim brakes would also work.
As a guide to price, this conversion was £1480 to do everything.
Thanks so much for your quick response, would it be possible for you to do the conversion , if so could you give me a ball park figure for the work.
I look forward to hearing from you.
Martin
Hello, I’ve emailed you directly.