Folding Bikes - Brompton Mods - for a newbie

Hi All,
So I bought my Arctic Blue M3L Brompton about three months ago and commute on it daily. Within two days of owning it I had modified some skate wheels to replace the factory fitted castors and that is as far as I have got, until now...

I want to change the M handlebar I have for a lower riser bar. I also think the stick gear shifter for my standard 3 gear sturmey archer is ugly and want to replace it. If I am doing that... then let's also look at the brake levers, grips and bar ends.

My question to you bike gurus out there is, what components would you recommed and will go together? They should not interfere with the fold (hence a riser bar should be perfect) and the total weight should be comparable if not lower than what is there already.

Brompton bars are 25.4mm at the clamp. What about gear shifters, do they have specific mounting diameters? Same question for brake levers?

Also, what complications do I need to look out for? Do I need to replace my factory fitted cables or will they slot straight into the new 3 speed gear shifter and brake levers?

Lots to get wrong here, and as a bike lover but a newbie bike tech, I need your help.

I'll be reading this with interest. I'm very curious to know the weight of stock Brompton components, particularly the stem and handlebars for all 3 types. I'm guessing the M bar is heavy. Perhaps Dahon's Andros stem plus a flat bar could offer a highly adjustable solution with more space for brakes/shifter/lights etc..

If you check Bromptons web site "bike explorer" you can see all the different weights for the various components and options.

http://www.brompton.co.uk/explorer/bikes/index.asp?s=1

This link will give you the weights for each model both standard and TI

http://www.brompton.co.uk/page.asp?p=3060

Move your mouse over the model to see price and weight.

You will see for example that a M3L TI will cost you £450 more than the M3L standard. At 1kg difference that's £450/kg :eek:

If I had the money, I would buy a M3L-X remove back brake, 3 speed hub, brake lever, gear changer & cables and replace them with a S/A Duomatic 2 speed kickback hub with coaster brake. I would then fit Kojaks which would probably bring it down to between 9.5-10kgs :D

Regards

Jerry

Will the coaster brake work with the chain tensioner?

I replaced my stock Brompton bars with a cheap aluminum MTB straight bar from a closeout sale. I got a SRAM GripShift 3-speed shifter (intended for the front derailleur of an MTB) to replace the SA trigger shifter. The shifter came with its own cable. The only oddities are (a) it's "backwards" if you mount it on the right side of the handlebar, (b) it moves the brake lever quite far inboard if you use standard MTB grips w/o cutting them short. Neither mod interferes with the fold.

Will the coaster brake work with the chain tensioner?

Yes it does because I have tried it. Its not perfect but works ok. The fold is not compromised and the coaster brake works fine.

I am told it is better to use the tensioner on the two speed changer whereas I used the one from my three speed.

Regards

Jerry

All the mods must be based on what you want to achieve. Is it speed, comfort, style or any combination of these topics? I have about 5 years of experience "mod'ing" Bromptons, I can point you in the right direction.

Before we start, please let me know your hight and your overall budget available for these improvements.

Let the fun begin!

Jerrysimon, I'd like to know the specific weights of the individual components that differentiate the models. I would have weighed the M bars and stem already if they were easier to get off the bike.

Is it speed, comfort, style or any combination of these topics? I have about 5 years of experience "mod'ing" Bromptons, I can point you in the right direction.


Do you think speed and comfort are mutually exclusive ?

Regards

Jerry

Do you think speed and comfort are mutually exclusive ?

Regards

Jerry

Yes. For speed, you need a rigid bike where all forces generated from you are transferred, through the bike, to the pavement.

For comfort, you need all forces generated from irregular pavement NOT transferred through the bike, to you.

Besides, comfy stuff are typically heavier than racing stuff.

Does it make sense?

Here is my experience with what i have changed (will change) on my 2009 M3L. I did learn that using stuff that is not stock/designed for Brompton rarely fits. You can still mod the bike but try to stick to stock-ish components.

Bottom Bracket: Phil Wood 120 mm Campagnolo taper (The stock one developed some grind in about ~4000km and quite some play after ~5000; it lasted me through 2 winters and LOTS of rain). Overall this seems to be a weak spot for the Brompton.

Crankset: You can change it but remember 170mm crank length MAX, 119mm spindle; square taper JIS or ISO (Campagnolo) on BOTH the crank and the BB.

P-type stem+handlebars: I am pretty tall so although the M-types are OK, I want something a little higher and more forward. It would also give me a lower position as well. I have the stem on order from SJS Cycles, so when it arrives I will change it (and will have an M-type stem+handlebars+brake levers spare if anyone is interested). In your case you can put a S-type straight bars on the P-type stem to get an even lower sporty position and that would leave you plenty of space for risers without compromising the fold. If you decide you can go back and put P-type bars for a multi-position at the cost of some weight. In addition I am not sure but you can probably substitute the M type handlebars for S-type as well.

Sturmey-Archer AM Medium ratio three speed hub: Look up "Some hub gear tinkering in Google" done by rogerzilla, it is a very simple conversion and would give you nice gears for some fast cycling.

2 speed derailleur: I did consider the hub gear/derailleur hybrid gearing a monstrosity, however, getting to think about it it is a way to add some gear range. When using the 13-15 cog combination and the AM hub you have overlapping ranges but it would give me the same low end as the AW hub and another top gear if needed (I currently run 54/14). I see it as Low Range and High Range 3-speed rather than a 6 speed. Newer SA hubs have a narrower driver so you might have trouble fitting 2 cogs, you can swap the hub internals for an older model ones with no trouble.

You can upgrade the headset to a Chris King 1-1/8 inch (Gripnut or 2Nut) if you are so inclined/have the money, however, the Brompton headset seems to do its job just fine.

As I mentioned earlier the Brompton in it's current state is what has crystallized over the years, so there is pretty much stock parts to suit every rider's need. Anything else looks like a Frankenbike, I particulalry I am not a fan of that look (nice looking rides go fast, eh?=))

Without actually trying, it is tough to say what will work or not for you, however, if you ride a lot you learn through trial and error what needs to be changed. Also always remember, if it ain't broken, don't fix it. Trust me on that last one. =)

If you want to save weight, you can buy the titanium frame parts but they do cost quite a chunk of change. You can get an the alloy seatpost for some weight savings and at a reasonable price

-Carcinogent

Hi All, thanks for the keen responses.
To summarise where my head is at so far.... I am cycling through London daily and hence my standard 3 gear SA drive train is perfectly acceptable so thanks for the recommendations but right now I want to focus on the cockpit - I want to lose the granny bars (too upright for me) and improve the brompton gear shifter. If I can make the cockpit look more streamlined and less happy-shopper that would be good.

I am 64kg and 5'7" - yep I'm small and light so no broken spokes for me, it means I am able to accelerate from those flaming London traffic lights considerably quicker that most other riders. I am looking for a ride that is more quick than comfortable otherwise I would stick with the M bars... however, this bike is my commuter not my racer so flat bars are out and a small riser bar would seem to suit. Plus, (no offence meant) I don't like the look of the S-Type Brompton. I also use the C-Bag daily so for functionality and cost I am not intending to change the steering post.

Cost wise I am flexible... but I'm not rich so need to be realistic, maybe aim for under £150 all in? (that seems a lot to me but do not want to restrict the component solutions). That should cover: Riser Bar / Gear Shifter / Brake Levers / Grips / Bar Caps / Bolts and Cables-if needed.

Oh and Chagzuki, I found on SJSCycles web site that they reckon the P-Type bar is 465g.... however, I don't think you can then use Bromptons quoted weight difference on their Bike Explorer page because it would make the M-bar something like 197g.... which would rival carbon fibre! So closer to an answer but not there yet.

J.

Does it make sense?

Yep:p

I just popped into town on my M3L and tried a S2L-X. It was actually quite nippy though I just can't ride that stooped over for any length of time. I found I had to sit up and put my fingers tips on the bars after a short power ride to get my breath back. I guess being older my back just can't take that riding position for long.

I guess that is where the P bars come in.

I am still not sure the TI (X) premium is worth it, though I must admit the ride feels a little different so I guess its not just a weight thing ?

Regards

Jerry

I am still not sure the TI (X) premium is worth it, though I must admit the ride feels a little different so I guess its not just a weight thing ?

Regards

Jerry

The way i see it Ti is just less carrying weight/minimalistic without that much effect on ride quality. Steel and Ti are in the same boat when it comes to comfort, etc. And of course Ti doesn't rust, a desirable quality in an all weather commuter.

-Cacinogent

Oh and Chagzuki, I found on SJSCycles web site that they reckon the P-Type bar is 465g.... however, I don't think you can then use Bromptons quoted weight difference on their Bike Explorer page because it would make the M-bar something like 197g.... which would rival carbon fibre! So closer to an answer but not there yet.

Does seem a bit odd. Dunno, downhill bars are overbuilt and tend to be around 300g. They're probably about the same length overall. . . actually the M bars would be about 80cm if straightened. I'm wondering how much of the flex in the front is down the bars rather than stem. I was surprised when first riding the brompton that the ride wasn't as harsh as I expected, which I initially put down to the steel frame. But perhaps the suspension effect of the M bars has a lot to do with it. . . unfortunately the degree of flex is annoying when hill climbing.

I am 64kg and 5'7" - yep I'm small and light so no broken spokes for me, it means I am able to accelerate from those flaming London traffic lights considerably quicker that most other riders. I am looking for a ride that is more quick than comfortable otherwise I would stick with the M bars... however, this bike is my commuter not my racer so flat bars are out and a small riser bar would seem to suit. Plus, (no offence meant) I don't like the look of the S-Type Brompton. I also use the C-Bag daily so for functionality and cost I am not intending to change the steering post.

Cost wise I am flexible... but I'm not rich so need to be realistic, maybe aim for under £150 all in? (that seems a lot to me but do not want to restrict the component solutions). That should cover: Riser Bar / Gear Shifter / Brake Levers / Grips / Bar Caps / Bolts and Cables-if needed.


Well P-type might be the bike for you after all. It meets all of the above-mentioned requirements including price. =P

-Carcinogent

Having just inspected my bike I can see that the M bars don't flex much front-to-back but they do vertically. Actually seems like quite an effective design. Unfortunately most of the front-to-back flex does appear to come from the stem. I'm guessing from the quill section. Dahon's A-head design strikes me as superior, though there's still plenty of flex in that too.

Well P-type might be the bike for you after all. It meets all of the above-mentioned requirements including price. =P

-Carcinogent

Hi Carcinogent, I see where you are coming from, combining my wish for speed and commuting! :-)
Althought you present an interesting option, I am still keen on a low riser bar, somewhere between the flat bar of the S and the high rise of the M (and in between the two of a P).

The S-type bars are apparently around 8 cm lower than the m-type and the M bar has around 16cm of rise. So the S stem must be 8 cm higher than the M stem. Add a riser bar and you'd have a little control over reach too.

The only way I could see a solution with the M or P stem would be in conjunction with something akin to Dahon's Andros stem, unless a different handlebar with around 12 cm rise is available.

I would go with used mountain bike raised bar like seen here:

http://www.btwincycle.com/products-pictures/asset_7488807.jpg

Ergon grips with or without bar extension. Most ergons don't require bar caps.

Google flat bar road bike brake lever. Make sure you get ROAD BIKE compatible, otherwise they will not have the long reach you need. Believe me on this one.

Good luck on your final mods.

Bottom Bracket: Phil Wood 120 mm Campagnolo taper

-Carcinogent

Is there any Chris King BB that is compatible with the Brompton? I am quite ignorant about BBs...

S Bar has a taller front steer stem.. such as :
http://www.sjscycles.co.uk/brompton-handlebar-stem-assembly-s-type-black-qhbsa-s-bk-matt-prod20013/

the trad klick lever is what i use, but now there is a thumb-shifter for the 3 speed..

Chris K and Phil W are both in the external bearing BB game,
but CK does not do square taper (Phil has, since founding of company)

http://chrisking.com/bottombracket so you need an the new type crankset too..

No personal experience... on bromptons,
[ have Phil for BB on trad road bike].


For my Brompton, I adopted Schlumpf Mountain drive 2 speed crankset.
a 54t..Use with AW3/BSR hub, 15t, low range in crank is
at between a 21,22t equivalent, so the 3 speed is used twice..

Ergon GR3, folds, [GR5 sticks out so fold down of stem
won't reach the catch..]
Mountain Drive is offered in a Brompton version, it's a quick install..

.. but inappropriate, I expect, for Flatlands like Florida .

Speed Drive crank, perhaps if you can turn monster gears ,
as the overdrive is 165% then a small chainring acts much larger
in high range

but the gear system is not weightless. and some frame install mods.

Looks like they fit one on this bike: http://www.flickr.com/photos/35131329@N03/5539678826/in/pool-bromptonfolders/#/photos/35131329@N03/5539678826/in/pool-68401638@N00/

Hi All,
So I bought my Arctic Blue M3L Brompton about three months ago and commute on it daily. Within two days of owning it I had modified some skate wheels to replace the factory fitted castors and that is as far as I have got, until now...

I want to change the M handlebar I have for a lower riser bar. I also think the stick gear shifter for my standard 3 gear sturmey archer is ugly and want to replace it. If I am doing that... then let's also look at the brake levers, grips and bar ends.

My question to you bike gurus out there is, what components would you recommed and will go together? They should not interfere with the fold (hence a riser bar should be perfect) and the total weight should be comparable if not lower than what is there already.

Brompton bars are 25.4mm at the clamp. What about gear shifters, do they have specific mounting diameters? Same question for brake levers?

Also, what complications do I need to look out for? Do I need to replace my factory fitted cables or will they slot straight into the new 3 speed gear shifter and brake levers?

Lots to get wrong here, and as a bike lover but a newbie bike tech, I need your help.

It depends on what you wish to accomplish on your modifications. I tend to go for the simple and true approach to modifications to both my Brompton & Raleigh Twenty. If you visit my Google Website (for the recent Raleigh Twenty's restoration), and my Flickr sites for the Brompton over the 5 years I had it, you will see the changes for yourself.

Interesting discussion...

I'll just list some of my changes and see if it applies to you. I started with an M6L in Seattle to cover some big hills. I found the shifting routine cumbersome and the 2 speed derailleur would jam too easily because of all the road grime sticking to it. To combat the shifting situation, I switched to a 5 speed S-RF5 rear hub. I love it...covers enough range without being much heavier than the 3 speed. Singlespeed-style drivetrain is much better...not a problem for you if you have a 3 speed.

For the cockpit, I also started out with the M-bars because I like the looks better. I thought I might be able to get a high rise MTB bar, but nothing was high enough (other than some steel ones). So, I purchased an S-stem and put on a 2" (50cm) riser and it's spot on (I'm 5'9" and about 80kg). For shifting, I went with the SA thumbie-style shifter after unsuccessfully modifying a gripshifter. For the other cockpit mods, I went with Paul Component Cantilevers (any road-compatible flat bar brake will work fine, but I have wanted a reason to buy these) and Ergon Biokorks.

I absolutely love my Brompton. I had a Bike Friday Tikit for about 4 months, but the fold just didn't cut it. The Brompton is as close to a perfect multimodal commuter as I could imagine :D

The reason I ask about Chris King stuff is because there is a history of BB and headset failure around 5-6K on Bromptons. This video shows how dry it comes from the manufacturer:


http://www.youtube.com/watch?v=gMgxx1JrTys

My next bike will feature a CK headset that is just left over from other projects. Might be a good idea to have matching bb's, just for the Q effect.

Chris K and Phil W are both in the external bearing BB game,
but CK does not do square taper
http://chrisking.com/bottombracket so you need an the new type crankset too..

No personal experience... Schlumpf Mountain drive
is offered in a Brompton version, it's a quick install..

.. but inappropriate, I expect, for Flatlands like Florida .

Speed Drive crank, perhaps if you can turn monster gears ,
as the overdrive is 165%

but the gear system is not weightless.

The bottom bracket i mention is NOT external bearing, just a good old ISO square taper. (I should get myself to put pictures online of things I mod for others to use as a reference...)

When you ask for a PW bottom bracket that is what is usually implied. Phil Wood does make external ones as does Chris King. I am not sure what cranks are compatible with PW though...(I assume Shimano due to popularity). Chris King has 2 models Road and MTB. Road and MTB each come in two varieties Shimano (Hollowtech, think Ultegra, Dura Ace) and SRAM (GXP, Gossamer etc). As with all Chris King stuff you can convert a Shimano one to SRAM and vice versa. It holds true for all BB crank combos that the chainrings must clear your chainstays and give you the desirable chainline. On the Brompton the chainrings should not interfere with the rear triangle when parked. Using an external BB on a Brompton might work, however, I personally will not go down that route. Get a Phil Wood one in square taper and you are set for many, many miles and customer service seems to be top notch if you ever have problems. You are in the US so sending it back is even easier. That way you can keep your current cranks as well.

When it comes to the headset, if you have a CK spare I would say go for it=)

-Carcinogent

If I could also ask about Mods as I'm about to order a S6L...

What I'd like to do:


Fit black or carbon bars
Fit a black seatpost
Fit black mudguards
Change the gear shifters to something mainstream, and more logical!


Thanks

Interesting discussion...

I'll just list some of my changes and see if it applies to you. I started with an M6L in Seattle to cover some big hills. I found the shifting routine cumbersome and the 2 speed derailleur would jam too easily because of all the road grime sticking to it. To combat the shifting situation, I switched to a 5 speed S-RF5 rear hub. I love it...covers enough range without being much heavier than the 3 speed. Singlespeed-style drivetrain is much better...not a problem for you if you have a 3 speed.

I'm used to the old non-wide ratio X-RF5 on my Dahon. I've come to view it as ideal for my needs and if I stick with my Brompton (not convinced yet) I want this hub installed. Thing is it's no longer available and apparently even the shifters are different since the move to the 'W' range (the 5 speed version of which looks like nonsense to me, the gear jumps are too large). So it's going to get harder to come by spares. . . it's already very difficult to find shifters.

Incidently, are there issues with installing the S-RF5 on a Brompton? Do you have to remove spacers? I have a spare X-RF5. . . not sure what the axle length is and the required axle length.

wandt, do you have any pics of your bike online?

Hi All,
Thanks, some great suggestions here and componentry advice. Just what I needed. I am still a little unsure of the way to go on a 3 speed shifter. I have seen the 3speed SA thumb shifters and SA grip shifters - anyone got any advice/experience in addition to wandt? I am looking to go with the smallest, cleanest solution and am happy with either action having owned bikes with both mechanisms.

I will go away, do some homework and come back with what I find before putting my hand in my pocket. Thanks, J.

SA has a bar end shifter for the new three speed fixed gear,I dont know if they work with the regular three speeds. http://www.sheldonbrown.com/harris/sturmey-archer-hubs.html

SA has a bar end shifter for the new three speed fixed gear,I dont know if they work with the regular three speeds. http://www.sheldonbrown.com/harris/sturmey-archer-hubs.html

Sturmey Archer has the same shifter for classic 3 speeds as both handlebar and bar-end mount. Although quite stylish it compromises the fold... The standard 3 speed shifter on the Brompton is quite functional though and it fits with the rest of the bike. A bar end on a p-type handlebar was something i have been pondering but until the parts arrive i won't be able to test it. Good luck with the mods and keep us posted!

-Carcinogent

hi,everyone

Really good to see Brompton moding disscussion.

I have just bought a P6R, and to tell the truth, I bought a lot of brompton stock spare, which costs me almost half the price of Brompton, that is because it's quite difficult to source brompton compatible spares since no Brompton dealer here.

Like cityjim, I found the derailleur and brake really both old fashioned and inefficient, and want them replaced. But after google, I have found little information. Could experienced Brompton 'mod'er elaborate on the gear shifting and brake system?

Cheers!

YuY

hi,everyone

Really good to see Brompton moding disscussion.

I have just bought a P6R, and to tell the truth, I bought a lot of brompton stock spare, which costs me almost half the price of Brompton, that is because it's quite difficult to source brompton compatible spares since no Brompton dealer here.

Like cityjim, I found the derailleur and brake really both old fashioned and inefficient, and want them replaced. But after google, I have found little information. Could experienced Brompton 'mod'er elaborate on the gear shifting and brake system?

Cheers!

YuY

Hey realyuy - check out Sturmey Archers own website.
I have not made my mind up but they have thumb and grip shifters. With the two shifters you have it will be a bit more complex but they do have three gear thumb and grip shifters. Was hoping someone on here could review them... ?

Anyone? New Sturmey Archer three speed shifters? Any thoughts? Have you got one?

I would go with used mountain bike raised bar like seen here:

http://www.btwincycle.com/products-pictures/asset_7488807.jpg

.

Hey R14
Question - I have been looking at lots of bars and have fancied getting a carbon bar if there is one in a sale but they are all 650 or even 700mm wide. With the M Bar being 530mm am being an idiot? I don't think I want to try cutting a carbon bar down, so should I focus on a good aluminium bar that I can reduce?

I am quite satisfied with the standard AW3 trigger shifter,It sits on top of the bar , so fold is unimpeded.
newer one looks rust free, double lever is a convenience.
M bar works for me .. new ones better. Mk2 was bigger than 22.2..

Cityjim can hacksaw down the high priced CF bar if they wish,
[careful of those fibers, your lungs receive them like asbestos ]
a thick wall aluminum one would be a lot more durable.

wandt, do you have any pics of your bike online?

I'll post some current pics tonight.

Hey R14
Question - I have been looking at lots of bars and have fancied getting a carbon bar if there is one in a sale but they are all 650 or even 700mm wide. With the M Bar being 530mm am being an idiot? I don't think I want to try cutting a carbon bar down, so should I focus on a good aluminium bar that I can reduce?

I personally believe it will be difficult to find what you are looking for on carbon. I strongly suggest a different material, Titanium, Aluminium, CroMoly, stainless steel or even Scandium.

Carbon bars were developed for mountain bike racing bikes, with lots of traveling room on suspensions. On small wheels without suspension, the "karate chop" effect could take place, your carbon bar could shatter, and the next thing to go is your mandible/anterior teeth against the stem.

I'll post some current pics tonight.

Here is one pic

195071

Sorry about the quality. I can try to get some during the day tomorrow with more light

What type of shifter did you opt for for the S-RF5? Any 3/4 pics where you can see how the handlebar looks on the bike?

What type of shifter did you opt for for the S-RF5? Any 3/4 pics where you can see how the handlebar looks on the bike?

I went with an SA thumbie. It works WAY better than the gripshifter. No mushiness at all.

Here are some other pics.

195113195114195115

Nice. That's basically the setup I want, I think. Except I want 305 wheels with Big Apples (!). . . which actually isn't entirely impossible. I might be foolish enough to try to fit one on the front, which would involve using a longer drop caliper brake. It might just fit the fork, it'd be tight.

Nice. That's basically the setup I want, I think. Except I want 305 wheels with Big Apples (!). . . which actually isn't entirely impossible. I might be foolish enough to try to fit one on the front, which would involve using a longer drop caliper brake. It might just fit the fork, it'd be tight.

Sweet! FrankenBrompton

Won't fit a wider tire in the chainstays , standard tire barely does.

Look forard to seeing your custom made frame and fork to accomplish this

need a wider fork crown too. so other than heavily modifying both ends
with some brazing and cutting,to make tire clearance.. then putting on V brake bosses is easy.

Or you could just buy a daHon that is already built around wider 305 tires.

It looked to me that fork clearance was just about doable, keeping in mind that the widest part of the tyre is further from crown with 305 rims. I tried shoving in the front wheel from my Curve SL to see how it'd look. . . reminded me of a tractor, had a definite farming aesthetic. But of course I discovered Dahons have a different axle diameter so I couldn't really get the wheel in.

Brompton's rear extremity has chain stays that stay parallel for quite a ways ,
before they flare outward for the hub width.

After several hours of more studying, budgeting, analysis of my riding style, traveling pattern and deep meditation, I ended up ordering my brand spanking new bike 45 seconds ago. Brompton S6-E, BWR, 16-12 in the back, 53 front with upgraded "this and that".

My sincere recommendation to all of you: For those in the market for a Brompton, www.bfold.com. David and Peter consistently exceed my expectation on genuine care, service, integrity and above all, respect.

as to your #26 above

I Expect: probably able to retrofit a Chris king Gripnut 1.125" headset onto that,
when It comes in.

After several hours of more studying, budgeting, analysis of my riding style, traveling pattern and deep meditation, I ended up ordering my brand spanking new bike 45 seconds ago. Brompton S6-E, BWR, 16-12 in the back, 53 front with upgraded "this and that".

My sincere recommendation to all of you: For those in the market for a Brompton, www.bfold.com. David and Peter consistently exceed my expectation on genuine care, service, integrity and above all, respect.

Congratulations on reaching the final decision. You certainly have given it great thought.