CEBEP

What I meant is the lowest gear, which is still 11t on your new cassette. So your range is the same even though you have more speeds.

jackyharuhiko

yes but this makes quite a big difference. It’s much easier to find the correct gear to maintain my pedal cadence.

CEBEP

Sure, what I meant is the smallest cog is still 11t and 9t on birdies sold in asia. So I’m assuming 11t smallest cog is good enough for most riders.

Jipe

Its true for the pure cassette Birdy.

But the Pacific Cycles Touring uses a 3s Sturmey Archer hub with a cassette, this hub increase the longest gear inch.

And the Birdy Rohloff has also a longer gear inch than 52x11.

As already said, you will have a Birdy with a 9-32 cassette, the best is to use it and test yourself before changing the transmission.

jackyharuhiko

These hub transmissions seem to be quite heavy in comparison.

CEBEP

They use Sturmey Archer hub on only one model, so are other suppliers in Asia. The rest of the models are cassette starting with 11t.

jackyharuhiko

The SRAM derailleur and the pulley wheels with the largest gear on the Shimano 12 speed cassette.

Jipe

As said, I have a also Pacific Cycles Titanium Birdy that was delivered with a 11-28 11s cassette and 52-36 compact chainrings and it was too short. I modified it with a Hope RS4 XDR hub and 3T(Ethirteen made) 9-32 11s cassette.

This is the reason why I recommend you to first use your Birdy Touring as delivered with the Sunrace 9-32 cassette and then see what is good for you based on your own experience.

Roegmann

I recently posted a Craigslist link (and it is on Ebay) about a vastly modified Birdy Roholoff (Generation 3) for sale in Los Angeles for $5,000. It seems a bit rich for me, but now I'm rethinking that. I have a Brompton for multi-modal commuting, particularly when I have to use a bus on a leg (if it doesn't fit under the seat, I can't bring it on board, especially during peak hours). I have a Pacific Cycles Reach GT (that I got through Bfold) with a smallish footprint that I use for hopping on a train and then just riding around. After 4 years of this, I've decided I need a smaller fold and wider tires for the rougher roads (and a lot of hills), which has lead me to this point. I am trying to decide between the posted Birdy vs. a stock Alfine Helix or something else I have not thought of (with an IGH). The Alfine Helix is quite a bit less. Both bikes as pictured are not geared for luggage. I would have to add accessories to both, so I figure that it is a tie. It comes down to needed replacement parts from normal wear a tear. What is needed for the Birdy? The Helix is still new, so there is that unknown.

CEBEP

Even though R&M Birdy Touring comes with low-rider front rack and rear rack I’m thinking of using my existing Brompton bags instead of panniers. I’m not doing touring but still need a bag for short trips. I’ve also see one member mentioning that adaptor slides down a little and opened the front fork latch leading to the accident. I wonder of there is a risk of that.

I have comfort 10 degrees stem so I don’t really need a protruding adaptor to mount the bag. Do you think going with this adaptor instead of panniers a good idea? Any possible damage to the frame in the long run? At the end of the day this frame wasn’t designed for luggage mounted on it this way.

I found 3 options on Ali Express:

1. TiParts

2. Litepro

3. Trigo

4. TWTOPSE

I gravitate more towards Trigo as it seems to be the least protruding. Will appreciate ideas.

glye

The links are broken. These should work:

1. https://www.aliexpress.com/item/1005...martRedirect=y
2. https://www.aliexpress.com/item/1005...martRedirect=y
3. https://www.aliexpress.com/item/3304...martRedirect=y
4. https://www.aliexpress.com/item/1005...martRedirect=y

I have no experience with Brompton bags. It is nice to have front bags that don't affect the steering, like a handlebar bag or front panniers do. Though some people may find the Birdy twitchy, and may like some steering weight to stabilise it.

That front latch opening seems rather dangerous, best to be sure you're protected against that. One might also argue it could be a risk to load the Birdy frame in a way it isn't built for. The Brompton frame is built for this front load.

There are rear racktop bags that are as easy to pop on and off as a front bag. Since you have the rear rack already, and it is useful anyway for rolling the folded bike, I would go for that first and then consider front cargo later if there is a need.

CEBEP

Thanks glye
I have Vincita Nash Rack bag with quick release which I’ll try if it will fit on the rear rack.
Though I think placing weight in front will add stability

glye

Hi! After 3 years I have not needed any wear replacements apart from the usual: Brake pads, chain, and eventually tyres. As discussed a few posts back the Birdy has some replacement requirements for handlebar, stem and front swingarm, see that post. You should find out how far the previous Birdy has been ridden, and consider if you trust the number. If unsure, you may want to replace those parts, at least if you suspect it may have gone farther than 10 000 km. If there is any indication it has been involved in a hard crash, don't buy.

Some considerations:
Bigger wheels may be nice, but the Helix is unsuspended, right? The Birdy has full suspension. That's crucial for me. The Helix seems also to be made for fairly narrow tyres, with 40 mm the biggest option, unknown if that is mudguard compatible. Birdy can fit 50 mm semi-balloon tyres with mudguards for a very comfortable ride.
Bigger wheels make it easier to get fast gearing.
24" wheels means a small selection of available tyres. That's more or less the same for the Birdy at 18".
The one legged Helix fork makes it hard or impossible to find any hub dynamo solution for it. The Birdy has this convenient option (though it requires a special hub).

CEBEP

I wander if anyone heard of Schlumpf Speed Drive been used on Birdy? Not sure these are still produced though.

glye

If it doesn't fit, the Klickfix Rackpack mechanism will fit. Though you have to saw off a little bit on the sides of the mechanism as the Birdy rack is very narrow. I have done this and used it for 3 years, and it has held up fine.
https://klickfix.com/en/systems/rackpack

CEBEP

It has different Klickfix mechanism, no strap. The new version.

glye

I don't know. Another option is the Efneo GTRO 3-speed crank drive (130 BCD compatible). With the 38t chainwheel option this equals a triple with 38/54/68t, then you can go rather fast with an 11t smallest rear cog.
There is also the Patterson Metropolis 2-speed (130 BCD compatible), and the Truvativ Hammerschmidt 2-speed (built for small chainrings, seems no good for Birdy). All interesting options for their uses.

Schwinnsta

Trigo does look good, but the angle may not suit the Birdy stem for larger bags. With Litepro and others flipping their connecting piece changes the angle.

Jipe

I have the H&H Brompton front block adapter it works fine, there is no problem of unlatching (the video showing unlatching at a steering angle that never happen while riding was with another one, the Litepro I think).

I use it since about one year without problems. The H&H was the first release front block adapter and its specially made for the Birdy.

I have also a Brompton block on my Titanium Birdy. This bike was originally equipped with the soft 10.5 turn front suspension spring (probably because its aimed at the Asian market where riders weight is typically lower that in Europe) and with high load I had some shimmy effect. This disappeared when using the hard 8.5 turn spring (which is factory installed on all R&M Birdy).

I fully agree with Glye: the solution of the Birdy with smaller wheels but full suspension and 50mm wide tires is much better than 24" max 40mm wide tires without any suspension and the ultra rigid single arm fork.

For the tires, there are almost no tires available in the Helix ETRTO507 size with a width of 40mm or less that fits for Helix, (ETRTO507 is a BMX size and almost all tires are wider at least 50mm). The lack of tires is a major problem of the Helix design, It was a very bad idea to design a bike that accepts only tires not wider than 40x507.

CEBEP

Thanks, Efneo GTRO looks very interesting. Sent them an email for more technical details regarding Birdy.

CEBEP

Are you sure about chainring equals?
efneo website says they’re equal to:1st 1:1 28T (phisical chainring size)

2nd 1:1,43 40T (phisical chainring size)

3rd 1:1,79 50T (phisical chainring size)

Roegmann

All valid points. Thank you. I am leery about spending that kind of money on someone who isn't from here or I know at least tangentially. I figured on a Thudbuster for the Helix, but I hadn't thought of dynamo solution though. Regardless, a little more patience and phone time may be needed. Thanks again.

Jipe

For the internal gear bottom bracket, the Schlumpf is the most common and it has proven to be reliable.

It still exists, it is now commercialized by Haberstock.

It has been mounted on many bikes including the Brompton but indeed I never saw one on a Birdy but I do not see any reason why it wouldn't fit on a Birdy because it can be mounted on bikes with aluminum frame.

There is a cheaper version of the Speed Drive made in Asia under license and sold for instance by Bikegang for the Brompton. He could advise you if it fits for the Birdy because he also know the Birdy very well.

CEBEP

Schlumpf speed drive is what İ was looking at first but it’s not widely available to buy. Efneo GTRO Is.

glye

This is when you use the standard 28t physical chainring. When you use a 38t physical chainring, which you can if you order it with the 130 BCD chainring adapter, you get 38 / 54 / 68t equivalent. See https://www.efneo.com/gearbox/technical-details/

You can go even bigger than the 38t physical, but I don't think there is any need. You can't use any size between 28 and 38. It must be either 28, or 38, or bigger.