Jipe

This Burke 20 is supposed to be available since many years.

Specs were excellent (even if some design choices like narrow 35mm tires, V-brakes are now a little obsolete), the folded bike should fit in a 62" linear suitcase, and the build quality should be excellent (frame built in the US by Lynskey and expert company in titanium bike frames).

But I never saw anybody owning one and Portapedalbike who was selling it doesn't sell it anymore (and is trying to get rid its demo Burke 20), I wonder why?

The price shouldn't be a problem for a full titanium frame folding bike really made in the US (and not just assembled in the US) since Brompton has no problem to sell its T-line at about the same price.

P.S. just saw the trick to fit into a 62" linear suitcase: the seatpost+saddle must be removed, with this trick a Brompton or Curl also fit into 62"linear!

V1LLAGE_ID10T

I'm giving it a test ride today. I'll document my experience.

Jipe

Very interesting, I never saw any feedback about this Burke 20.

I wonder how comfortable it is on bad roads, since its frame seems very stiff, without any suspension and with relatively narrow tires, I am afraid it will be quite uncomfortable on bad roads or off-road.

If I understand well, the frame has a mounting point for a Brompton front bag block?

V1LLAGE_ID10T

So I got to ride it this afternoon as well as take some pictures as well as a one minute video I'll be uploading to youtube in a bit. Since this is a new account I still don't think I can share links yet to keep the spam bots at bay. I was quite impressed but still had my nitpicks. I was hoping to talk with the creator of the bike but instead met with a student that was interning at the man's place of business. From what he told me the reason we haven't heard much in news about this bike is the creator has to still do his regular work to make ends meet while occasionally working on the bikes in his free time. Because of this I could not ask as many technical questions and get much in the thinking process behind the design.

Firstly it's light, and stiff which is what it should be first and foremost. I especially love the rear triangle design. It's trifold is damn near close to Brompton's but i found it to be loose on the front's hook to the rear triangle when fully folded. I suspect this is either because it is still being prototyped, or it's built with a lot of versatility in mind allowing for room to change up parts. I expected using cassettes to be a possible deal breaker for me as in my opinion the hub's ability to shift at a stop is a big deal for me. But not so much in this case. For transport that still has my concerns. Yes it's meant to be put in a suitcase, but for me that has me compare it alongside bike fridays instead of bromptons which can be just bagged.

As for the ride I found it to be stiff but not uncomfortable. I would suggest getting a redshift if that poses a problem but wasnt really a concern for me on the varying terrain. I went over uneven sidewalks, some gravel, a wooden bridge and some bike trails while it was raining today so while not a full gravel route put it through some of it's paces! My big nit pick was the steering felt very twitchy. Something I often hear people talk about with small wheel folding bikes a lot from the Brompton too but this threw me off at first. I've ridden a lot of different folding bikes including the Bike Friday Pocket Rocket, a few Dahons and a Tern, but this felt extra twitchy. I'm guessing the angle of stem is the reason for that. On the ride back I got adjusted to that. My favorite thing about riding the Brompton in particular is riding out of the saddle. Rocking back and forth using my arms to push the handlebars left and right to swing in contrast direction of the higher pedal forcing it down with my full body's weight. Feels like I'm somewhere between sprinting and flying. I got a little bit of that with this but not until the ride back going downhill. It's got me curious to check out the 16 inch model as well. The thing missing for me was the rear rack you mentioned. Another need for me since I prefer to roll my bike not carry it. Though this is light enough where I feel comfortable carrying. Lastly it does have a front block spot to attach to but this didn't have it on at the time.

V1LLAGE_ID10T

Youtube Burke 20 still exists. watch?v=qpZrmQgmh-k

Jipe

Thanks for the review and the youtube video.

If I understand well, you tested the most expensive, lowest weight Burke 20?

What do you mean by "to be loose on the front's hook to the rear triangle when fully folded" does it mean that it unfolds when you carry the folded bike?

About twitchyness, The Brompton is more twitchy than many other folding bikes but most people adjust to that quickly and do not feel the twitchyness anymore. Are you used to the Brompton twitchyness and nevertheless feel it again with the Burke 20? Would you say that the Burke 20 is more twitchy than the Brompton?

Looking at your video, it seems to me that the Kojak 35x406 are the widest possible tires on the Burke 20.

I am astonished with your remark saying that he Burke 20 is still being prototyped, this bike exists since so many years, I think that Portapedalbike had a demo one at least 6 years ago.

tds101 

For what it is, it's a beautiful bike. But considering it's 6+ years as a prototype I'd say it's still too iffy.

PS: here's your video...

V1LLAGE_ID10T

Thanks for embedding for me! To answer the first question when folded it stays folded. The issue is the front half has a lot of room to twist and turn the front fork while hooked to the rear triangle. I also want to make it super clear I am not saying this is a prototype as much as left with the impression it feels like a prototype in some places again from a 15 minute ride. I honestly wish MIke was there when I was getting a look at it because I feel like I could have gotten a better fair shake at the ride and it's best foot forward. There's also the 16 inch model which wasn't there and I would like to see if there was variations to the fold when using the front block.

As for the twitchiness I am comfortable enough to ride my brompton no handed for long periods of time and I'm saying this was noticeably twitchier. My guess is it's because of the way the stem bends forward at an angle instead of a bow but again that's a guess. Near the end of the ride I got much more comfortable with it. I really don't want to mislead readers of this thread into thinking this is a bad bike, more just 1) this bike still exists adn the reason is mainly due to the creator having to juggle his career and this project, and two what my first impressions are as a emerging new cycling hobbyist. I think come spring would be a great time to email again for a more public demo where he can hopefully answer questions and others can give it a greater test ride. Again I was riding in poor rain too so I don't think my thoughts on braking would be accurate for example. The gentleman in the video was simply there in his place and did not have the detailed knowledge to answer technical questions I was hoping for so for all I know I may not have had everything set up correctly and would have had a much greater riding experience. I'll definitely give it another go after building mine and seeing how that goes.

Jipe

The bike frame is really beautifully built, its gorgeous !

The stem that bends forward is not a problem, its the same on the Birdy with 21 degree sport stem and the Birdy isn't twitchy at all, i.e. not like the Brompton.

From what I read and see on online shop of Seattle Cycle, I think that he 16" and 8" aren't commercialized?

V1LLAGE_ID10T

Wanted to give a follow up while I have some downtime as I wait for certain parts to arrive.

I have been looking exclusively at Internal hubs this entire time assuming them to be the superior go to route and only now looking at derailleurs as a potential possibility But I thought I would get some public feedback as I wait for my parts to arrive. I've been meantime playing with the gear-calculator website to help with my decision making process here but I don't know if that site is up to snuff compared to real world opinions so I will share here in hopes the internet can tell me how wrong I am.

I'm kind of on the fence when it comes between rohloff and Shimano alfine. Rohloff is the objectively better hub but expensive as it gets and for a 20 Inch 406/451 wheel size realistically a lot of those gears would go to waste. The alfine on the other hand provides a faster speed and a more realistic usage of gear ranges I will probably take advantage of. But I have heard of the many horror stories of unreliability and leaking happening. I watched cyclingabout's video on comparing the two hubs and saw the video of the grease mod which looked promising, but another person I greatly respect who is a mechanical engineer had converted from alfine to rohloff calling the hub trash. Mind you the same gentleman wrote a glowing review of it after using it for several years and not only changing the oil at the times Shimano advised, but also would ride it before changing and flush it multiple times riding between to ensure ultimate maintenance well above what Shimano probably expected from their customers.

Since I have been looking at aliexperess and brompton copycats I have also wanted to investigate the use of derailleurs on many of these bikes. It stands to reason for me a lot of these manufacturers would have some performance advantages to justify this otherwise they would have simply used sturmeys as well or their own internal hubs. However it seems the go to is an ltwoo a7 10 speed system with a fold b chain tensioner which according to their specs indicated an 11-28t range of gears. A deep dive had me find a youtube video titled Unlocking the Secrets of the Best Brompton Derailleur System which shows an 11-36t 9 speed setup and it looks like the user utilized a 135mm rear triangle to handle disk brakes and an alfine previously to this. This triangle probably gives just enough room for the larger 36t. In all of these cases it looks like I would also be looking at a larger chain ring to maximize performance. This is again where I gotta dock points for the Rohloff in my particular use case. Again I am going by the gear-calculator dot com website (Still can't post links yet sorry!) but even with a 58t chainring on this The range would cover close 5-27mph at a cadence of 90. I could cover a higher speeds and still maintain a wide enough range with the alfine though admittedly in all cases including derailleurs I would still be looking at a large chain ring.

Alright internet your input is appreciated.

Kabuto

I have a Tern X11 with a SRAM 11 speed group set (very similar to the group set on the Burke 20 in the video linked above) and a Tern S8i that I've converted to an Alfine 11 speed IGH. The Alfine IGH feels like an absolute boat anchor in the back wheel compared to the SRAM group set. It's so much easier to get up to speed and maintain speed with the X11, and I much prefer riding it because of this. That said I've had no reliability issues with the Alfine 11, other than iffy shifting that I fixed by dumping the polymer coated Dura Ace shifting cable that frayed quickly and stuffed up the shifting, and replacing it with a 105 Optislick shifting cable.

V1LLAGE_ID10T

Another obstacle I'm seeing now is the chainring can be potentially damaged of I go up a size by the way the bike folds. It also behoves me to take a look at mountain bike groupsets rather than road bikes in order to cover proper range if I am to go this direction.

V1LLAGE_ID10T

Any Indonesian speakers here?

V1LLAGE_ID10T

So after a lot of fussing and back and forth I got it down to two possible options. The first is the Alfine 11 speed on a 50t 16t.




The other option is the Sturmey-Archer 3-speed w/disk brake S-RK3 with a 11-32t cassette


Like everyone else I wanna go fast, but realistically I need to handle the hills in my area. first and foremost. I could dial down the alfine to reach around 30mph, but the low range still has a considerable gap. I was looking for an SRAM dual drive to get the job done as I had one on my bike friday pocket rocket, but the disc brake compatible ones are long gone it seems. I think it is fitting to build a better Brompton with a Sturmey still in it especially when it's also going to make the rear lighter as a result. Would love to hear your thoughts forum.

Jipe

My solution for the same problem has been to mount a Rohloff 14s hub on an enlarged Brompton titanium rear triangle.

With a 13t cog and a 54t chainring it provides 14% equally spaced gears with a gear range of 19” to 102” (1.54m to 8.11m).

By using some titanium parts on the Rohloff, the weight is similar to the original 6s BWR + 2s derailleur (only about 150g more). Its less than an Alfine11 solution that has a narrower gear range.

V1LLAGE_ID10T

got pics of the bike?

Jipe

The base is a 2012 Superlight Brompton but most components have been replaced including the complete transmission. The original Brompton titanium triangle has been enlarged by Kinetics Glasgow.
These two pictures are a little bit obsolete, some components like the TPW easy wheels and Wellgo pedals have been replaced for lower weight ones. The chain tensionner is now a Brompfication single speed tensionner instead of the Brompton 3s tensionner. Tires are now Continental Contact Urban (that didn't exist at the time of the pictures).

V1LLAGE_ID10T

An absolutely beautiful ride! I didn't think kinetics worked with titanium. Honestly Rohloff was my first choice in all this, but from what I am seeing here I can get almost the same range of gearing and do it at 1lb less at the tradeoff of a slightly complicated shifter all for less than $200. Conventional wisdom tells me if something is too good to be true I must be missing something. From what I can tell If I would have the rohloff reliability that is expected from German engineering and consistent shifting. Is there something I'm missing that's less obvious?

Also completely different side note topic. My local Brompton dealers told me a couple months ago official Brompton workers stopped by not with one but two 20" Bromptons that were prototypes. One being the G line we've seen pics online of already the other he described to be more road bike oriented. Nobody was allowed to ride on them but the officials were looking at the mechanics thoughts and opinions on it. Mechanics tried to get a date out of them but nothing came of that. If ****** is to be believed one user high on the totem pole tells us to wait until February. Now personally I know the g-line has the ebike motor on it which means it's rumored twelve speed hub will probably not encourage going past UK ebike speed limits.

2_i 

With 3s in front and a Brommieplus hub on BWR, I have a 1.03 to 9.16m range. However, not everyone needs such a wide range. In my circumstances, it is the condition for continuous riding in an area with widespread steep gradients.

V1LLAGE_ID10T

I do have to deal with all sorts of steep angles. My bike shop I used to go to closed down The new one I go to has a lot of steep hills. This is also ultimately like I said supposed to be an all rounder bike. So flexibility is the goal still. From what I can tell though both of these rides would work. I guess I'm just curious why I'm not seeing more SX-RK3 builds. So it's now down to SX-RK3 or rohloff.

Jipe

How do you plan to obtain the chain tensionning needed when the bike is folded with the standard 9s derailleur?

The chain tensionning is the problem with a Brompton with a standard rear derailleur.

The derailleur cage extension solution (as on the Birdy 1 and Birdy 2) is well known to fail.

V1LLAGE_ID10T

Oh I figured that out a while ago. LTWOO has a great derailleur to solve that problem. Can handle quite a bit.

silverx

RD sora 105 with goat link and chain tensioner
cassete deore M8000 11-42t

Chainring 68t and 39t

custom Front RD so have longer arm for 68t

V1LLAGE_ID10T

Thanks for the quote! Though this a level of madness I don't think I should imitate and still leaving towards the the sturmey or rohloff.

Jipe

I have one LTwoo Fold B derailleur.

In pictures, it looks nice but when you have it in your hands, its huge with a very big diameter wheel on its arm, heavy and cheap built. I do not understand why they put such a big diameter wheel on it, the Brompton tensionner has a small one and works well?

The other advantage of using an IGH is that most of them overdrive in their higher gears (by a factor of 1.467 for the Rohloff) what allows to have high enough gear inches with the Brompton small wheels with standard chainring and cog sizes (54t x 13t for the Rohloff) and avoid to use of very big chainring (like the 68t explained above).