thanks but mine is Driveline and they don' t sell it on their website it has only the AL 6061 20 I code. I ordered a Shimano Ultegra SMBBR60B, 68 mm wide with 24 mm. diameter, let' s see if I can manage to change it

To turn a gen 3 City into a double chainring + cassette tranmission, what Hollowtech crankset and rear hub should I get?

I already have a Litepro clamp, a 2s braze-on, down-pulling front derailleur + 8s rear derailleur, dual chainring, and shifters available.

According to Sheldon, a 50/34 and a 11-32T provides a 1,5 - 6,2m development, good enough for touring.

There is no need to change the crankset. The original BCD 130 crankset allow the mounting of a compact 50-34t chainring

For the rear hub, its a standard 135mm OLD rear hub, so any standard rear hub with a Shimano body will fit. Depending of the freewheel type of the hub you will buy, you may need some spacers to mount a 8s cassette.

Personally, I do not like a 11-32 8s cassette because the gaps between the gears is too big. A 10s Deore like mounted on the Birdy Touring is better. Matching cassettes exists in 11-32, 11-34 and 11-36t.

I read BCD130 only goes down to 38T.

Any links to a 34T in BCD130?

My mistake, I forgot that you wanted to go to 34t. Indeed, for 34t, you need a BCD 110 crankset or any of the latest 4 arms crankset.

I never dismounted the crankset of my Birdy 3, I do not know the diameter of its axle.

But the bottom bracket box is standard, so if you also change the external bearings, you can mount any crankset with an integrated axle with its matching external bearings or if you prefer a classic bottom bracket, any standard square taper (but I wouldn't do that) or Isis bottom bracket + crankset..

I could simply replace the Hollowtech with a square taper BB and use the double chainring I have handy.

Does someone know what axle length I should get to use a 50/34 dual chainring on the Birdy?

Older Birdy had a square taper BB. the Hollowtech of the gen 3 was chosen because it weight less and is more reliable, its a pity to go back to a square taper.

The drawback of the square taper type are well known: its often creaking, there are two different sizes, JIS and ISO that are not really compatible and more over most manufacturers do not accurately follow the specs with as consequence that often cranks and BB of different manufacturers, supposedly of the same type, in practice do not fit well.

Its the reason for the development of the ISIS BB.

What Hollowtech with a good price/performance ratio would you suggest for a gen 3 Birdy? I'm not willing to spend too much money considering I'll only ride it a few times a year.

If the axle diameter is the same, maybe a previous type of Shimano 105, you can for instance search on ebay or since you are in France on Troc-velo.

Since it's easy to find, I'd still like to first try a square taper and see how it goes. Is it 68mm? What axle length should I get for a dual crankset?

The BB shell is 80mm wide.

As said, I never had any problem with the BB or crankset of my Birdy 3 and never dismounted it.

And I do not know the specification nor the brand of the crankset and external bearings mounted by Riese & Müller on the Birdy 3, there is no type or brand name on mine, only Birdy written on it.

In case of a square taper, there are several axle length and its the combination of the axle length and crankset that defines the chain line.

You need to have a chain line that fits with the rear hub and cassette you will install instead of your current Nexus IGH.

To use two chainrings on a gen 3 with a 8-10s cassette, no one in this thread has replaced the Hollowtech with a square taper BB and could tell me the axle length I should get?

In the front, the chainline is ~50mm

--
Edit: Would a 122.5mm work for use with a dual chainring?

https://www.birdybicycle.com/product...-foldable-bike

As already said, going back to a square taper is a downgrade.

The square taper is only mounted on the low end Birdy Classic.

If it helps, on my Birdy Titanium, which comes with a front derailleur, its a compact road 52-36 crankset (FSA SLK-Light) equivalent to a Shimano 105 crankset that cost about 56€ with 50-34 chainrings with a shorter road chain line and it works.

If the external bearings mounted on the Birdy 3 do not fit, the BBS-RS501 Shimano external bearings for the 105 cost about 13€. The best would be to firts dismount the original crankset to measure its axle diameter.

Thx. I'll order the Shimano FC-RS510, along with a 8s cassette so I can test-try an 8s derailleur I have handy, and see if it works.

Does 175mm vs. 170/172.5mm make a serious difference?

No. not really.

Update: after greasing the bike on some parts the squealing noise from the bottom bracket persisted, and was scared of trying to change the BB myself and brought the bike to the shop. They claimed that lubricating the BB ball bearings should fix the problem. They did it and nothing happened. The only thing that changed was my wallet got € 60 lighter. Now I asked to find me a new BB to replace.

Do you think the new Birdy G4 will meet the expectations of the EU market regarding quality build and components performance? Even assistance from a manufacturer that is in Asia? There was a video reviewing the limited edition P 45 titanium that cast some dark shadows on the frame which could bring forth to the G4 bike. Pacific Cycle recently had 2 E- bikes that had major flaws and are giving me some doubts on the ability to carry over a G4 Birdy in the rest of the world apart from Asia.

The e-assist should be a Bosch Performance SX which is built in Europe available and supported worldwide by Bosch.

The frame of the P45 seems to be identical to the frame of the limited edition P40 sold 5 years ago. Its an aluminum frame, not a titanium frame.

Now will Pacific Cycles be able to sell the Birdy worldwide, I do not know, up to now they had no resellers in Europe.

Interesting. I have a Birdy Gen 3 Touring which I was thinking of upgrading to Rohloff. I contacted R&M who said it is discontinued. I was thinking of switching to a 12 speed Brompton instead. Maybe I should wait to see if Pacific Cycles start exporting to UK.

I tried 2 webshops in Germany that sell Birdys and parts - to buy a carrier.
They say they don't, because R&M no longer supplies anything for Birdy.
It's not good.

One of the straps of the rear carrier broke and ordered 1 online on Fratello webshop hopefully will work


Elastic strap for luggage rack - Riese & Müller × 1

Those Birdy specific components are not manufactured by R&M but by Pacific Cycles, R&M had to buy them from Pacific Cycles I guess that they do not want to buy them anymore?

Pacific Cycles has an online shop where you can buy the rear carrier.

I'm turning a Gen3 Birdy City into a touring bike with a double chainring, and a spare 7s cassette (1,9 - 6,5m, 342%) which I might replace with an 11-32T 8s later (1,6 - 6,5, 406%).

The original crankset with a 52T ring is a hollowtech with unused space for a, internal chainring.

After adding a 38T internal ring and a two-speed Shimano Sora FD-3000 derailleur, it rests barely above the outer ring, which means I'd have to use a ~10mm spacer to move the crankset outward.

I know a square taper bottom bracket is heavier and not as efficient, but it's also cheaper.

Does someone know how wide its axle should be to fit?

Edit: Or do I simply need to get a wider BB (source)? The BB on the bike says "Driveline EX-TYPE BC1.37" "

I had nothing but headaches when trying to adapt a front derailleur to my Birdy. To keep things simple, I mounted an XTR 9000 Di2 rear cassette and derailleur with an 11~40 range. I run 20" wheels on my bike, so the ground clearance is less of an issue. The gear range is sufficient for the hills here in Tokyo.

I have a similar solution with a wider range 9-34t cassette to avoid to use a front derailleur.