ANATOLY IVANOV / PROSE / 2008-08-26

MY BROMPTON P3L SPECS AND MODS

by Anatoly IVANOV

CYCLING / TRANSPORTATION / TRAVEL / ESSAYS

BIKE PURPOSE

My daily personal transportation device. I use this bike to get anywhere on asphalt within a 30 km (20 mi) radius. Night and day. Any weather except snow.

It’s customized for speed, urban traffic and small folded size.

Depending on what’s in my backpack, I ride approx 30-35 km/h (19-22 mi/h) on flats, max 60 km/h (37 mi/h) downhill.

The bike folds into a custom backpack and travels with me on trains. Hides under restaurant tables and enjoys minimal techno in nightclubs. Disappears in taxis, flies overseas. Loves shopping and even training. Sleeps inside a wardrobe.

BIKE HISTORY

I got a new 2008 Brompton P3L in January 2008. I have then customized the bike to suit my needs and tastes.

PICTURES OF THE CURRENT BIKE CONFIGURATION

 

Photo: current Anatoly IVANOV’s unfolded Brompton P3L / See my bikes gallery

 

Photo: current Anatoly IVANOV’s folded Brompton P3L / See my bikes gallery

 

Photo: current Anatoly IVANOV’s folded Brompton P3L with removed seat post / See my bikes gallery

CURRENT SPECIFICATIONS AND MODIFICATIONS

Main frame: Brompton custom, folding, steel.
Front fork: Brompton custom, steel.
Rear triangle: Brompton custom, hinged, steel, with elastomer suspension.
Stem: Brompton P-type custom, folding, steel.
Headset: Brompton custom.
Handlebars: Brompton S-type custom, aluminum, 48 cm (19 in) wide, slightly curved flatbar with high-density foam grips. I’ve replaced the original P-type “butterfly” handlebars. As a result, I have achieved the lowest and farthest handlebar position obtainable on a Brompton without sawing and welding.
Brake levers: Brompton custom with angled cable exits. I’ve inverted the cabling so that the right hand controls the front brake and the left hand controls the rear brake.
Shift levers: One Brompton custom shift lever for the 3-speed Sturmey-Archer SRF3 internal gear hub. I’ve slightly improved the positioning.
Front brake: Brompton custom dual pivot caliper built by Alhonga. I’ve replaced the ordinary washers by double-sided star washers, as well as the Alhonga HJ 454-11 brake pads by Fibrax pads.
Rear brake: Brompton custom dual pivot caliper built by Alhonga. I’ve replaced the ordinary washers by double-sided star washers, as well as the Alhonga HJ 454-11 brake pads by Fibrax pads.
Cables: Low-friction, unknown brand (PTFE coated inner cable, lined outer cable). Cut to fit the P-type stem and S-type handlebars combination.
Bottom bracket: ISO 6695 sealed cartridge, FAG 119 mm.
Front sprockets
(chainset):
One Stronglight 50 teeth with plastic chain stain protector.
Cranks: Stronglight aluminum 170 mm. I’ve added a rare-earth neodymium circular 12 x 6 mm magnet inside the pedal hole to use with the Sigma pedaling cadence sensor.
Pedals: Quick-release (similar to a high-pressure compressed-air coupler) MKS AR-2 Ezy with Soma double-prong toe clips (size Large) and Ale leather straps.
Chain: SRAM PC1 (1/8 in), 98 links.
Front derailleur: None.
Rear derailleur: None. A Brompton plastic chain tensioner keeps the chain taut despite the changes in the distance from the bottom bracket to the rear hub when folding.
Rear sprockets
(cassette):
One 13 teeth sprocket (ISO 10230) non-derailleur, ½" x 3 mm thick
Front wheel: 16 inch Alex Rim, Chosen hub, 28 spokes with side reflector, additional plastic locknut protector to improve comfort when carrying the folded bike in the backpack.
Rear wheel: 16 inch Alex Rim, 3-speed Sturmey-Archer SRF3 internal gear hub, 28 spokes with side reflector.
Tires: Schwalbe Stelvio HS350 16" x 1 1/8" ETRTO 28-349 slicks and Schwalbe inner tubes with Schrader valves.
Gear ratios
(inches):
47 - 61 - 83.
Gear ratios
(meters):
3,70 - 4,93 - 6,59.
Gear range: 178%
Seatpost: Brompton custom, steel, “extended seat pillar” (I’m 1 m 80 cm), cut to exact length for easy removal (undo the quick release clamp, pull out).
Saddle: Fi’zi:k Vitesse with Brompton Pentaclip.
Front fender
(mudguard):
Brompton custom, plastic, with modified rudder flap (I’ve reduced its size).
Rear fender
(mudguard):
Brompton custom, plastic, with rudder flap.
Folding-specific features: Narrow-profile Brompron roller wheels (I wear size 45,5 EUR shoes, so I used to hit my heels against the original Brompton roller wheels).
Bottle cage: None.
Rack: None.
Front light: S-Sun 3-LED (3 AAA batteries).
Rear light: Integrated, Brompton-specific, Spanninga Eclipse (2 AAA batteries) with reflectors.
Computer: Sigma BC 1606L DTS Cadence wireless (display and sensors mounted with rubber rings).

PICTURES OF THE PREVIOUS BIKE CONFIGURATIONS

 

Photo: Anatoly IVANOV’s unfolded Brompton P3L as bought with options / See my bikes gallery

 

Photo: Anatoly IVANOV’s folded Brompton P3L as bought with options / See my bikes gallery

CHANGE LOG

2008-08-26 Corrected details and added missing brand information based on input from Greg SMITH, Brompton.
2008-07-08 Updated specs and photos to current bike configuration.
2008-02-20 First publication.

12 COMMENTS

Jonathan G / 2008-11-26 01:10

Nice bike, and thanks for the info! Would be interested to hear how you get on with the cycle computer. I can’t find much online about the success of using a cordless computer, apart from the fact that the distance from the fork to the bars of the Brompton is often too much for them to work reliably. Have you had any problems? How easy was fitting?

R Verdoold / 2009-06-21 16:07

Nice bike and very good review of the oregon and colorado GPS. I have brompton regis 6 as well as my girlfriend and we both love them. 6 gears is a real use and not only in holland. Have now one here in Latvia and everybody is looking. It is really the best folding bike i have seen. As for the other replier we both have a simple 6 euro (aldi) wireless computer working perfectly. No problems only at some traffic lights interfering with the signal.

Gavin Sladen / 2009-07-02 05:04

Nice work! I opted for M-type bars on my Brompton, because, although the more aggressive riding position offered by S-type bars was attractive, I was worried about the balance of height and reach (I’m 187 cm tall). Using the P-type stem gets around that problem very neatly. Have you considered using stubby bar ends to provide variation in hand position? The Kalloy Uno is an example of a bar end that can be fitted without interfering with the folding procedure, and I think there are others that people have used successfully.

ANATOLY IVANOV / 2009-08-25 13:13

Jonathan,

Would be interested to hear how you get on with the cycle computer.

I’ve actually written a detailed post with pictures about how to put a Sigma wireless computer on the Brompton, including cadence output, but as it was during the beta phase of my web site, it has gone haywire. I need to tinker with the code and get it back online, sorry for the wait.

ANATOLY IVANOV / 2009-08-25 13:15

Thanks R VERDOOLD!

ANATOLY IVANOV / 2009-08-25 13:22

Gavin, thank you.

Have you considered using stubby bar ends to provide variation in hand position?

Yes, I have considered the bar-ends, but as I use the Brompton mainly in urban context (95% of the time), I need to keep 2 fingers on both brake levers, all the time. I ride pretty aggressively in traffic. Instantaneous control is key for my survival.

So a far-from-the-brake-levers hand position would be used only during the 5% of my total riding time. Confirmed while I had the P-type handlebars: I used the top position almost exclusively.

Alex Aranda / 2010-07-26 05:54

Really nice review, I have a Brompton also and I’m eager to change the pedals to exactly the AR-2′s, but I’ve read some fitting problems on the right one. Do you have any of this problems? If so, how you solve it?

ANATOLY IVANOV / 2010-07-26 14:30

Thanks Alex!

No, absolutely no problems fitting MKS AR-2 Ezy pedals to the Brompton.

If you wish, you can give me a quick Skype call and I can show you my setup live on video.

Mike Lowndes / 2010-08-21 14:52

Great description. I have an old C Type and was considering getting some flat bars for it and a 50 T sprocket, so you’ve been there before me with great success. I’ll be doing these mods soon so will post a piccy when done.

Paul Mann / 2012-06-08 05:06

Hello Anatoly.

This is a superb piece on Brompton variation. Thank and Thanks very much. Much appreciated your personal advice to other readers question and comments.

Thank you again.

Kristian / 2017-11-20 17:57

Hey how are you finding the s bars on p stem? I’m thinking about doing this too. Is it too low for general riding? I have a very low bar on my road bikes, but they reach is also greater. Does the Brompton become twitchy to ride at speed this low?

Anatoly IVANOV / 2017-11-20 18:14

Kristian,

For me, the height is near-perfect. I’m 1 m 80 cm, normally proportioned legs to torso. When riding, my back is close-to-flat, at about 10 degrees relative to the ground, which is great for going as fast as possible in-between cars with as little sweat as possible.

No effect on handling.

Handling is much more influenced by wheel fork rake and absence / presence of horizontal ahead stem (one of the reasons Bike Fridays are much, much better to ride than Bromptons).

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