Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Folding Bikes (https://www.bikeforums.net/folding-bikes/)
-   -   Brompton Mods - for a newbie (https://www.bikeforums.net/folding-bikes/721778-brompton-mods-newbie.html)

14R 03-23-11 11:51 PM

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:


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.

Carcinogent 03-24-11 02:20 AM


Originally Posted by fietsbob (Post 12402162)
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

ningnangnong 03-24-11 06:38 AM

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

chagzuki 03-24-11 07:07 AM


Originally Posted by wandt (Post 12402850)
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.

chagzuki 03-24-11 07:17 AM

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

cityjim 03-24-11 09:19 AM

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.

Dynocoaster 03-24-11 09:35 AM

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/s...cher-hubs.html

Carcinogent 03-24-11 02:03 PM


Originally Posted by Dynocoaster (Post 12404428)
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/s...cher-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

realyuy 03-25-11 06:32 AM

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

cityjim 03-25-11 08:27 AM


Originally Posted by realyuy (Post 12408759)
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?

cityjim 03-25-11 11:30 AM


Originally Posted by 14R (Post 12400652)
I would go with used mountain bike raised bar like seen here:

http://www.btwincycle.com/products-p...et_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?

fietsbob 03-25-11 12:30 PM

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 03-25-11 04:32 PM


Originally Posted by chagzuki (Post 12403765)
wandt, do you have any pics of your bike online?

I'll post some current pics tonight.

14R 03-25-11 06:38 PM


Originally Posted by cityjim (Post 12410092)
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.

wandt 03-25-11 08:58 PM

1 Attachment(s)

Originally Posted by wandt (Post 12411597)
I'll post some current pics tonight.

Here is one pic

Attachment 195071

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

chagzuki 03-26-11 08:35 AM

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?

wandt 03-26-11 11:27 AM

3 Attachment(s)

Originally Posted by chagzuki (Post 12413890)
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.

http://bikeforums.net/attachment.php...hmentid=195113http://bikeforums.net/attachment.php...hmentid=195114http://bikeforums.net/attachment.php...hmentid=195115

chagzuki 03-26-11 11:58 AM

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.

wandt 03-26-11 05:56 PM


Originally Posted by chagzuki (Post 12414523)
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

fietsbob 03-26-11 07:46 PM

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.

chagzuki 03-27-11 05:14 AM

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.

fietsbob 03-27-11 11:05 AM

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

14R 03-29-11 02:52 PM

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.

fietsbob 03-29-11 03:43 PM

as to your #26 above

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

SesameCrunch 03-29-11 04:12 PM


Originally Posted by 14R (Post 12429727)
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.


All times are GMT -6. The time now is 06:33 AM.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.