2 Speed Hub Drivechain Alternatives

A page about various non stock gearing systems..

Converting a 2 speed to 3 speed - non IGH 

Stock hub - simple and easy 

Simply using a thinner snap ring will allow a third sprocket to be fitted to the stock hub! 
Stock snap ring is 2.2mm and the replacement needs to be 1.5mm. 
This allows you to then use a combination of sprockets such as 12-14-17 making a 2 speed ratio a lot more usable! 
You can simply use a friction shifter or other shifters may work depending on the set up. It is common to need to modify the cable run, with an inner cable going straight through the spring of the anchorage and fastened with a barrel nut / grub screw.

- On a Ti triangle you are limited in sprocket size to 18t without modification.

Hubsmith hub - 11t capability! 

Using a Hubsmith rear hub, you can replace the free hub body to one that accepts a locking, such as on traditional cassettes, rather than a snap ring. 
This allows you to fit an 11t Shimano style cog, meaning you can widen that gearing range! 

http://www.brommieplus.com/portal_c1_cnt_page.php?owner_num=c1_343119&button_num=c1&folder_id=44131&cnt_id=708310&search_field=&search_word=&search_field2=&search_word2=&search_field3=&search_word3=&bool1=&bool2=&search_type=1&up_page=1

Converting a 6 speed to 9 speed 

Simply convert the external cogs from 2 to 3 and change the shifter - see - "Converting a 2 speed to 3 speed - non IGH"



Suitable for BWR hubs, or BSR*/SRF3*/SRF5 hubs that have been converted to a dual sprocket driver.
* These hubs offer ratios of 0.75, 1.1 and 1.33, compared to the BWR which offers 0.638, 1.1 and 1.567.

Aftermarket Brompton Components + Weights

A list of common additions / upgrades and their weights! 

Pedals:

Chainrings:
Litepro 53t with bash - 105 grams 

Cranks:
Ti Parts Workshop - Forged, 53t, with bolts, - 477 grams 
Thorn Triple Solo Alloy - no ring/bolts - 140mm- 1673L140 - 484 grams 

Bottom Brackets: 
Shimano BB-UN55 - 309 grams

Front Hubs:
Jtek superlight - Xgrams
SP dynamo - sv-9-fb - Xgrams

Rear Hubs: 
Hubsmith R015R 28h - 227g
Rims:
Joseph Kuosac 38mm Carbon - 28h - 342 grams 

Spokes:

Front Wheels:

Rear Wheels: 
Sturmey Archer SRF3 / Jtek spokes / Sun CR18 - 1410 grams 

Wheel Fittings:
Jtek Allen key skewer - Front - 26 grams

Tyres: 
Nexo - 37mm - Solid - 420 grams 

Tubes: 

Rim Tapes:
Jtek Yellow Tape 349mm - 10 grams

Seat posts:

Seatclamp/clips;
Ti Parts Workshop - easy large handle - 53 grams 

Saddles:
Joseph Kuosac - wide - 273 grams 
Brooks Cambium S17s carved - 404 grams

Suspension Blocks: 

Easy wheels:

Racks:
RJT Alloy - 190 grams 

Handlebars: (All 25.4mm)
Joseph Kuosac - flat - 195 grams
Joseph Kuosac - full rise - 239 grams
Litepro Ghost - 580mm - 144 grams 

Grips:
Joseph Kuosac - 75 grams

Brake levers:

Shifters: 
Sturmey Archer - SL30 3 speed - 79 grams 

Brakes:

Headsets:
Joseph Kuosac - sealed bearing - 100 grams 

Derailleurs:
H&H Derailleur + fittings - 9 grams

Hinge Clamps:
Joseph Kuosac knobs - 124 grams 

Other; 
Ti Parts Workshop Ti hinge spindle/bolts - 23 grams 

Stock Bike Weights

One of the most common questions is how much does it weigh? So here we are, all of the weights are the standard bike, with Marathon Racer tyres, mudguards and a standard seat post. 


S1 - 10.7kg
S2 - 10.9kg
S3 - 11.5kg
S6 - 11.6kg

P1 - 11.3kg
P2 - 11.5kg
P3 - 12kg
P6 - 12.2kg

H1 - 11kg
H2 - 11.2kg
H3 - 11.7kg
H6 - 11.9kg

M1 - 10.8kg
M2 - 11kg
M3 - 11.5kg
M6 - 11.7kg 


Electric! 

Fitted as stock, marathon tyres, lighting, mudguards, standard seat post/saddle. 

M2 - 13.7kg (16.6kg total with battery)
M6 - 14.6kg (17.5kg total with battery)

H2 - 13.8kg (16.7kg total with battery)

H6 - 14.7kg (17.6kg total with battery)

Battery - 2.9kg 

Notes

- The Brompton two speed hub uses:

6900-2RS in the non-drive side
6901-2RS in the drive side

And in the freewheel body:

6900-2RS
6000-2RS

Brompton SL front hub bearings:

6900 / 61900 - 1 either side

- The dimensions of a Brompton when folded are 585mm high x 565mm long x 270mm wide (23" x 22.2" x 10.6").

(Measurements are based on a bike with folding pedal and a standard seat pillar and saddle; measurements will vary slightly by model - e.g. opting for a model without mudguards will reduce the height of the folded package.)

Every Brompton has a full-length wheel base of 1045mm (41.2"); pre-2003 models had a slightly shorter wheelbase of 1.02m (40.2").

Torque Settings

Let me know if there is anything missing! 


Aluminium brake lever - 3mm Bolt - 2Nm
Aluminium brake lever - 4mm Bolt - 2Nm
Grips - (foam lock on) - 1.5Nm
2017+ Shifter - brake lever bolts - 2Nm
Pre 2017 shifter band clamp - 5Nm

Stem Bolt - handlebars - 18Nm
Stem expander bolt - 15Nm for cone style / 30Nm for wedge style. 

Front wheel nuts - 15Nm
Rear wheel nuts - 18Nm
Chain tensioner Nut - 5Nm

Front brake - 10Nm
Rear brake - (stop disc) - 10Nm
Brake pads - 5Nm
Brake cable clamp - 8Nm

Seat clamp - 4-7Nm
Pentaclip - 15Nm

Left folding pedal - 30Nm
Right pedal - 30Nm
Crank bolts - 30Nm
Bottom bracket - 24/30Nm
Chainring bolts - 10Nm

Rear hinge bolts - 10Nm

Mudguard fittings - Secure these screws firmly 
Rack fittings - Secure these screws firmly 

Chain Length

The list below states the required chain length for each chain ring / sprocket choice. 


44t Chain Ring

12t - 96 link
13t - 96 link
14t - 96 link 
13/15t - 98 link 
12/16t - 98 link
13/16t - 98 link

50t Chain Ring

12t - 98 link
13t - 98 link
13/15t - 100 link 
12/16t - 100 link
13/16t - 100 link

54t Chain Ring

12t - 100 link
13t - 100 link
13/15t - 102 link
12/16t - 102 link
13/16t - 102 link

Cable Lengths

Full set lengths of cables for long wheel base bicycles.

Pre 2017 Shifters
Left 2spd DR:

S - 1145mm outer, 1269mm inner
H - 1283mm outer, 1362mm inner 
M - 1187 outer, 1309mm inner
P - 1283mm outer, 1362mm inner

Right 3spd Hub Gear:

S - 1250 outer, 1411mm inner
H - 1360mm outer, 1521mm inner
M - 1302mm outer, 1463mm inner
P - 1344mm outer, 1505mm inner 

2017+ Integrated Shifters
Left 2spd DR:

S - 1015mm outer, 1379mm inner
H - 1120mm outer, 1206mm inner 
M - 1072mm outer, 1155mm inner
P - 1110mm outer, 1196mm inner

Right 3spd Hub Gear:

S - 1220mm outer, 1379mm inner
H - 1320mm outer, 1479mm inner
M - 1265mm outer, 1424mm inner
P - 1291mm outer, 1450mm inner

Brake: - 30deg/alu levers
Front:

S - 332mm / 485mm outer, 1050mm inner
H - 440mm / 485mm outer, 1050mm inner
M - 366mm / 485mm outer, 1050mm inner
P - 389mm / 485mm outer, 1050mm inner

Rear:

S - 1230mm outer, 1493mm inner
H - 1355mm outer, 1493mm inner
M - 1290mm outer, 1493mm inner
P - 1319mm outer, 1493mm inner

Brompton Component Weights

Below I have compiled a list of the standard factory components and their weights:

- NB. please let me know if you think one needs updating or something is missing!

Main frame - 2000grams             (mainframe/headtube section,hinge bushes/spindle and seat sleeve included)

Rear Triangle - 755 grams
Rear Triangle Ti - 461 grams

Fork 2017 -
Fork 2017 Ti - 285 grams
Fork 2018 - 543 grams 
Fork 2018 Ti

Stem S - 876 grams 
Stem P - 
Stem H - 919 grams
Stem M - 844 grams 

Stem H - Lower section - 317 grams 

Stem H - Upper section - 602 grams 

Stem bolt - 7 grams
Stem internal bolt + expander cone - 43 grams

Handlebar S - 133 grams
Handlebar H - low rise - 241 grams
Handlebar P - 470 grams 
Handlebar M - low rise - 241 grams
Handlebar catch - 27 grams

Brake lever - per lever 79 grams each, 158 grams pair 
Brake lever/shifter Left - 133 grams 
Brake lever/shifter Right - 155 grams 
Shifter pre 2017 Left 2spd + bell - 60 grams
Shifter pre 2017 Right 3spd - 52 grams 
Grip - 100mm foam - 14 grams 
Grip - 130mm foam - 
Grip - P type - 137 grams 
Grip pre 2018 foam - lock on - 55 grams 
Grip 2018 rubber - lock on - 
Headset - steel - 162 grams
Single Steel headset cup - 30 grams
Crown Race - 15 grams
Headset - alloy - 120 grams 

Front wheel -std - 650 grams
Front wheel - superlight  - 535 grams
Front hub std -
Front hub superlight - 
Rear hub 2spd - 312 grams
Rear hub BSR - 929 grams
Rear hub BWR - 940 grams
Rear wheel - BWR  - 1397 grams
Rear wheel - BSR - 1386 grams
Rear wheel - 2spd - 
                                                                     - all wheel weights do NOT include fittings or rim tapes. -
Front Wheel nut (single) - 8 grams
Front Wheel axle tab washer - (single) - Right - 3 grams 

Rim double wall - 330 grams

Rim - single wall - 
BSR/BWR indicator chain -  10 grams 

2/6spd Chain Tensioner - 148 grams 
2/6spd idler wheel + fittings - 20 grams
1/3spd Chain Tensioner - 131 grams
1/2spd Tensioner Nut/washer - 11 grams 
3/6spd Tensioner Nut/washer - 20 grams
2/6spd Idler wheel + fittings - 20 grams 

Kojak folding tyre - 182/185 grams
Kojak wired tyre - 230 grams
Schwalbe One 35mm folding tyre - 
Brompton Kevlar tyre - 256 grams
Schwalbe Marathon Racer - 
Schwalbe Marathon - 420 grams
Schwalbe Marathon Plus - 480 grams 
Schwalbe Winter - 465 grams
Inner tube - 97 grams

Front mudguard blade - 44 grams
Front mudguard stay + fittings - steel - 63 grams  
Front mudguard stay - Ti - 
Front mudguard flap - 13 grams
Rear mudguard blade L - 63 grams
Rear mudguard blade R - 89 grams
Rear mudguard stays only - steel - 80 grams
Rear mudguard stay only - Ti - 
Rear mudguard roller wheel - 
Front left mudguard stay tab washer - 6 grams 

Chainset 44t - 608 grams

Chainset 50t - 641 grams

Chainset 54t - 672 grams
Chainset 50t - fixed - 543 grams

Cranks arms only - 487 grams 

Crank bolt (single) - 13 grams 

Chain ring 44t - 89 grams

Chain ring 50t - 120 grams

Chain ring 54t - 150 grams
Chain Ring Bolts - 22 grams

 - Chain ring weights include plastic bash guard 

Bashguard + screws 44t - 

Bashguard + screws 50t - 45 grams

Bashguard + screws 54t - 

Bottom bracket - 249 grams (FAG), 244 grams (Thun), 250 grams (old ISO)

Chain 96 link - 260 grams 

Chain 98 link - 266 grams 

Chain 100 link - 272 grams

Chain 102 link - 278 grams

 - Chain weights include a quick link as part of the link count

Sprocket (12 spline) 12t - 14 grams

Sprocket 13t (3spline) - 21 grams

Sprocket 14t - 
Sprocket (12 spline) 16t - 21 grams

Sprocket set 13/15t - 

Sprocket set 12/16t - 56 grams 

Sprocket set 13/16t - 57 grams 

Circlip - 4 grams 

Plastic Disc - 12 grams 

3spd sprocket spacer - 

2/6spd sprocket spacer - 4 grams

3spd BWR sprocket spacers -  

Front brake caliper - 2017 - 185 grams

Rear brake caliper - 2017 - 182 grams

Front brake caliper - 2018 - 188 grams
Rear brake caliper 2018 - 183 grams

Brake pad - pair - 2017 - 44 grams

Brake pad - pair - 2018 - 34 grams 
Stop disc - 29 grams 

Seat post - Standard - 412 grams

Seat post - Extended - 517 grams

Seat post - Telescopic - 706 grams

Telescopic lower - 440 grams 
Telescopic upper - 142 grams 
Telescopic Plastic insert - 8 grams
Telescopic quick release clamp/lever - 78 grams  
Seat post bung - 9 grams 

Pentaclip - 109 grams
Seat clamp + clip - 72 grams

Saddle - 345 grams

Saddle - wide - 

B17 - 560 grams

B17s - 

Pedal - Left folding - 286 grams 

Pedal - Right - 124 grams 

Hinge clamp screw (Inc. washer) - 32 grams

Hinge clamp plate - 20 grams

Suspension block - Soft - 24 grams
Suspension block - Firm - 33 grams
Suspension block - Firm 2018 - 30 grams
Suspension block fittings - 26 grams

Cateye front light mount - 51 grams

Front carrier block - 91 grams

Easy wheel - stock, single with fitting - 22 grams 

Toolkit - 170 grams 
Pump - 92 grams
Seatpost O ring - 2 grams 

Rear hinge spindle / bolts - 40.5 grams  
Pivot spindle 6.0 - 11 grams 
Pivot spindle 6.1 - 12 grams 

Cable Gatherer - 2 grams 
2017 DR cable spring set / anchorage - 24 grams