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Birdy thread

Old 06-03-20, 08:16 AM
  #1301  
glye
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Originally Posted by RandomHajile View Post
Yes, if they can take abuse I was thinking that would be ideal, I donít mind it being a bit heavy, and the small range of 18Ē wheels I saw on sourcebmx website (I cant post links yet) most of them had similar grip/tread pattern like the Big Apples.

one has caught my eye, Cult Dehart Slicks, which are semi slick down the middle, so am thinking they could handle roads better than the aggressive bmx tyres out there
That one is nearly slick on the sides too, should roll well if you can fit it. I like all the colour options you can get for bmx.
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Old 06-03-20, 12:25 PM
  #1302  
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Originally Posted by RandomHajile View Post
i could get the green PU as Iím sure it would make a big difference, but really want that Multi-S shock, esp if the blue/gold is still obtainable to match my dark blue frame.
Multi-S rear is harder that the red PU.

If you are interested, I do not use my set of Multi-S suspension. Contact me by private mail
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Old 06-04-20, 02:30 AM
  #1303  
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Originally Posted by Jipe View Post
Multi-S rear is harder that the red PU.

If you are interested, I do not use my set of Multi-S suspension. Contact me by private mail
great.

i would of replied sooner itís just this forum only letís be have 5posts over 24h period and couldnít reply to the PM until I had 10posts...

Edit.

Last edited by RandomHajile; 06-04-20 at 07:20 AM. Reason: Remove contact
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Old 06-12-20, 10:06 PM
  #1304  
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Originally Posted by Jipe View Post
The chain tensioner I am talking about is the one mounted on the bottom bracket, all recent Birdy are equipped with this tensioner that works very well. But it limits the chanring size to 55t or maybe 56t.



Standard Shimano cassettes are indeed cheap but start with a 11t cog that combined with the limited size of the chainring produce a relatively short gearing even with 20" wheels that are limited in total diameter to about 462mm (ETRTO 406 with 28mm wide tires, 28-30mm is the max with 20" wheel for the front fork).

I've mounted a 60t successfully with the pacific cycles tensioner. It just BARELY clears... but useable!
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Old 06-18-20, 08:42 PM
  #1305  
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Hi fellow birdy owners!

When folding in the front wheel, how close to the rear wheelset does it actually go?

Currently, my front wheel QR nut hits the Rear derailleur (currently using XTR midcage) --> Is this normal?
Anyone have pics of how close your front wheel folds in to the rear?


Assuming i had NO rear derailleur, I'd probably be able to fold it in another 5-10cm.

Thanks!
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Old 06-19-20, 01:46 AM
  #1306  
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Originally Posted by sprockett View Post
Currently, my front wheel QR nut hits the Rear derailleur (currently using XTR midcage) --> Is this normal?
My bike came with a Deore XT derailleur and the frontt nut would shove the derailleur out of the way when closed. Caused some wear on the casing but didn't seem to be a problem otherwise. I currently have a current gen 105 derailleur on the bike and there is no interference.
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Old 06-19-20, 03:07 AM
  #1307  
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Originally Posted by sprockett View Post
Currently, my front wheel QR nut hits the Rear derailleur (currently using XTR midcage) --> Is this normal?
Anyone have pics of how close your front wheel folds in to the rear?

Assuming i had NO rear derailleur, I'd probably be able to fold it in another 5-10cm.
Yes, this is a consequence of the design. My Touring with Deore Trekking derailer had this problem. I could improve on it by carefully positioning the front wheel in the optimal position. It also depends on the QR skewer, I used one from PitLock that is absolutely minimal on one end, nearly flat: https://www.pitlock.de/en/shop/quick...en/set-01.html

Now I don't have a derailer, and the shimano chain tensioner doesn't have this problem. I guess it folds a bit closer, I can take some pictures. Either way, you have to beware of this interference when transporting the folded bike. If you avoid touching the derailer, it will hit something else instead. Hub, spokes, or frame. Vibration can cause damage or at least ugly marks. Some foam/rubber in a strategic location can help.
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Old 06-19-20, 09:28 AM
  #1308  
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Currently the limiting factors for my fold is the front tyre (good, that's a soft buffer)...


IMG_20200619_112648767 by gunnsteinlye, on Flickr

...but also the "shoulder" of the shimano chain tensioner hitting the front hub/spokes:


IMG_20200619_112725124 by gunnsteinlye, on Flickr

If the tensioner "shoulder" was less beefy it could fold closer. The Rohloff tensioner seems narrower, but also has less chain uptake, so might give a slack chain when folding.

Assuming no tensioner, the next limiting factors are the fork hitting the rear mudguard stay, and the front pannier distance bar hitting the rear wheel spokes. Perhaps also the QR nut hitting the cassette, if you have one. With no mudguard and no front carrier, the fork would hit the upper part of the rear dropout, unless stopped by the tyre/frame touch point.


IMG_20200619_112915235 by gunnsteinlye, on Flickr


IMG_20200619_113049811 by gunnsteinlye, on Flickr

Top view of the fold:


IMG_20200619_113237200 by gunnsteinlye, on Flickr
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Old 06-21-20, 12:48 PM
  #1309  
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Originally Posted by glye View Post
That one is nearly slick on the sides too, should roll well if you can fit it. I like all the colour options you can get for bmx.
I ordered a pair of Salt(wethepeople) ďtracersĒ tyres in 18Ēx2.20Ē (apparently are only 2.11Ē wide)

to replace my 2Ē big apples, as I saw there was easily 8mm clearance on each side of the 2Ē big apple tyres so should be doable.

i got them in Teal colour, as itís summer after all, I didnít have the guts to go for the neon red ones. Ha.

am hoping I can run these tyres faster than the big apples, but with similar air suspension properties

Iíll post some pics when I get them installed later this week.

and if they run well, líll May venture into more bmx tyres ha.

now if only some genius can figure out how to install 20Ē skyway tuff wheel 2s...
with panaracers of corse
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Old 06-30-20, 07:40 PM
  #1310  
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Does anyone know if a 30mm crank fits the Birdy?

I know the following:
BSA threaded (so in theory we can fit in BSA24 Bottom bracket)
24mm cranks work with BSA24 BB.

Im thinking of getting a BSA30 BB, which will allow me to fit a 30mm crank.
While the Bearings of the BSA30 BB will fit the crank, I'm not sure if the CENTER of the BB (inside the frame) will allow a 30mm crank through.

Thanks!
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Old 07-14-20, 04:14 AM
  #1311  
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New Birdy!

Just ordered a Birdy City from Mighty Velo here in Singapore, spent 3 days reading through all 53 pages of this thread. What I only say is "wow" at the passion for this bike! Can't wait to get mine!
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Old 07-14-20, 04:42 AM
  #1312  
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What a nice way of saying that we fight too much
Congrats with the bike, wish you tailwind and great rides!
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Old 07-14-20, 11:14 AM
  #1313  
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Originally Posted by Ecentian View Post
Just ordered a Birdy City from Mighty Velo here in Singapore, spent 3 days reading through all 53 pages of this thread. What I only say is "wow" at the passion for this bike! Can't wait to get mine!
Congratulations. Don't forget to post pics and let us know how the buying experience was. Did they carry the new Birdy R20 11spd?

I know there are Birdy cycling groups in Singapore. Enjoy your bike.

Last edited by gleearch; 07-17-20 at 01:09 AM.
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Old 07-15-20, 03:41 AM
  #1314  
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Originally Posted by gleearch View Post
Congratulations. Don't forget to post pics and let us know how the buying experience was. Did they carry the new Birdy R20 11spd?

I know here are Birdy cycling groups in Singapore. Enjoy your bike.
Thanks.. shipping is scheduled for next Monday, apparently they have a huge backlog of orders not just for Singapore but throughout the region. Bromptons are all out of stock in LBS and secondary market is going crazy, with used bikes going for more than MSRP for new bikes. Some are just snapping up whatever new ones left to sell for a profit.

Yes Mighty Velo carries R20 as well and locally they are advertising 17 colors to choose from. Not sure if they really carry that much stock but guess Taiwan is not too badly affected by COVID19 so the supply chain has not been disrupted. Guess we are lucky in Singapore!
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Old 07-17-20, 01:12 AM
  #1315  
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Too bad I can't sell my used folders there. Makes no sense that people would pay over MSRP for a used bike.
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Old 07-20-20, 09:01 AM
  #1316  
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Changing from 7speed to 8/9speed

Hi, I have the old Mk1 birdy with 3speed hub with 7speed/cassette gears on the back wheel.

is it easy to just change the ďcassetteĒ 7speed gears with a 8speed or 9speed cassette?

and then prob would have to change the grip shift gear selector on my handle bar also to a 8-9speed setting one.

as Iím after a couple more slower/lower gears to save my knees from surgery in the future

any help would be appreciated
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Old 07-20-20, 09:37 AM
  #1317  
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Originally Posted by RandomHajile View Post
Hi, I have the old Mk1 birdy with 3speed hub with 7speed/cassette gears on the back wheel.

is it easy to just change the “cassette” 7speed gears with a 8speed or 9speed cassette?

and then prob would have to change the grip shift gear selector on my handle bar also to a 8-9speed setting one.

as I’m after a couple more slower/lower gears to save my knees from surgery in the future

any help would be appreciated
The simplest and cheapest way of getting lower gears is to get a smaller front chainring. But that also gives you a lower top gear. It requires no other changes except maybe shortening the chain.

To keep your current top gear but add lower gears you can switch to 8/9 speeds as you say. Going from 7 to 8/9 speeds you need to replace the cassette, the chain (probably, at least for 9 speed), the derailer, and the gear shifter. You can probably keep the front chainring you have. But there are several important caveats:

You need to know if you have a cassette freehub (good) or a freewheel hub (less good). Your hub is either an SRAM DualDrive or a Sturmey Archer. As far as I know, both are cassette only, but I'm not sure. More info:
https://sheldonbrown.com/free-k7.html

8/9 speed cassettes will normally not fit on 7-speed hubs: https://sheldonbrown.com/k7.html#bodycompat
But you may be able to find an 8/9-speed cassette body that fits your hub, look for it in the 2nd hand market or ebay.

Beware that upgrading from 7 to 8/9 speeds may increase your hub width, which requires spreading the rear dropouts apart, a dangerous operation on a small wheel alu frame. This may be a dealbreaker. Try to measure the hub/dropout width. If it's less than 135 mm, it may not be possible to go beyond 7 speeds safely.
https://sheldonbrown.com/k7.html#up7

If you have the SRAM DualDrive, this has a combination shifter that shifts both the hub and the cassette. You'll need to find an 8/9 speed one, and since they're not made anymore afaik you may have to look for it in the 2nd hand market or ebay. You don't need a special DualDrive derailer, but it must be an SRAM MTB derailer.

If you have a Sturmey Archer hub it's easier, you can choose between SRAM or Shimano style derailer/shifters, just make sure both are of the same type (or if not, verify they are compatible).

If all this turns out to be impossible or too expensive/risky, you may be able to find a 7-speed cassette with more range than the one you have. Count the number of teeth on the smallest and largest cogs, and compare with what's available, e.g. https://www.bike24.com/mtb-cassettes...%5D%5B424%5D=1
NB: If your smallest cog is more than 11 teeth, it may be because your hub doesn't allow that small cogs, in which case you shouldn't buy any cassette with an 11t cog.

Last edited by glye; 07-20-20 at 09:49 AM.
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Old 07-20-20, 01:34 PM
  #1318  
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Interesting news on the rumour mill. Looks like Campy are poised to announce a 10T or smaller compatible cassette body. Another choice for us small teeth needing Birdy users as an alternative to the SRAM XD/XDR and SunRace hubs.

https://weightweenies.starbike.com/f...p?f=3&t=162492
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Old 07-20-20, 01:42 PM
  #1319  
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Originally Posted by glye View Post
If you have the SRAM DualDrive, this has a combination shifter that shifts both the hub and the cassette. You'll need to find an 8/9 speed one, and since they're not made anymore afaik you may have to look for it in the 2nd hand market or ebay. You don't need a special DualDrive derailer, but it must be an SRAM MTB derailer.
The original Birdy Blue with Sachs (prior to SRAM buyout, when it went 8sp) had a 7 Speed based dual drive with separate twist shifters both with standard shimano 7 sp pull ratio's. Any old shimano/sram compatible 7 speed Rear Mech and shifter will do the job. I had a pair of standard Sachs Waveys that did the job nicely with an M739 XT rear mech. Still have set in the Shed afaik.

RandomHajile Im surprised the Dual Drive (if thats what it is) isn't low enough for you, with a 52T chain ring I could climb cliffs with it, I must have used that gear <10 times on 5+ years of London commutes. I wonder if the if you have a bigger than standard chain ring?
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Old 07-20-20, 02:20 PM
  #1320  
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Right, if OP has this one then they could keep the 3x shifter and replace the 7x one, if they go 8/9x. But the easiest/cheapest way to lower gears is a smaller chainring. And the easiest way to bigger range is a 7x cassette with bigger range, if it exists.

I found a SRAM/Sachs Spectro 3x7 manual at https://sheldonbrown.com/sram/dtm_ghs_my00_e.pdf
According to this, the hub is 135 mm OLD, which means newer 8/9/10 speed versions of dualdrive or Sturmey Archer 3x cassette hubs will fit the frame, in case other solutions don't work.

It also says that a 12-28t cassette is standard (and that others may cause malfunction, but I wouldn't worry much about that on a small wheel bike). And it is indeed a cassette hub, not threaded for freewheels. I've seen that 7-speed 13-34t cassettes exist, this would also give lower gears in a simple way, while sacrificing a top gear.
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Old 07-20-20, 04:30 PM
  #1321  
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Gears

Thanks for the replys

yes I have the shimano deore derailer and hub.
with 7position grip shifts. SRAM I think.


i guess I could go to the lowest hub gear, but I like to keep the hub gear on the highest of the three as on the lowest hub gear, the hub does not click as much, as in the hub clicking noise is reduced a lot!

and I like the clicking noise when not pedalling as itís a nice heads up for people to hear so I donít run them over ect...

silly reason but its better then ringing bike bell all all the time.

ahh yes I could get a smaller chain ring then
But figured getting a cassette is easier than changing chain ring/crank ect
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Old 07-21-20, 12:35 AM
  #1322  
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Originally Posted by RandomHajile View Post
But figured getting a cassette is easier than changing chain ring/crank ect
Opinions may differ... If you've replaced a cassette before you know what that involves. Replacing a chainring means
1) Measure what BCD you have, and find a chainring with the same BCD, same number of arms, and right number of teeth: https://sheldonbrown.com/cribsheet-bcd.html
Also it must be a chainring made for derailer chain, as single speed chainrings are too wide for the narrower derailer chain.
2) Undo the 4-5 chainring bolts, replace the chainring, and tighten the bolts well again. Requires a hex tool and chainring bolt tool, I use a simple one like this: Bikeman Shimano TL-FC21 Crankset Dustcap Pin Tool with Chainring Nut Tool
On a bike like the Birdy you usually don't need to take the cranks off. Obviously the wheels can also stay on the bike.
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Old 07-27-20, 03:23 AM
  #1323  
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Originally Posted by RandomHajile View Post
i guess I could go to the lowest hub gear, but I like to keep the hub gear on the highest of the three as on the lowest hub gear, the hub does not click as much, as in the hub clicking noise is reduced a lot!
i think your hub needs a service. I donít recall mine clicking in any gear. AFAIK the direct drive on those hubs (where the hub is most efficient ) is the middle gear. The ratios for that hub are 73% , 100% and 136% so you are making yourself work really really hard just to avoid the clicking.

Also if you are not using it you should consider having the wheel rebuilt around a standard hub and save yourself a load of weight And get the gears you want. A service on those hubs isnít particularly cheap, mine had to go back to the importer/wholesaler.
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Old 07-28-20, 11:44 AM
  #1324  
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Campy 13 speed 9t Gruppo confirmed. Interesting option for us Sunrace users. Guess you will need to go drop bar though....

https://road.cc/content/tech-news/ca...5#comment-form
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Old 07-28-20, 12:59 PM
  #1325  
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Originally Posted by secret_squirrel View Post
Campy 13 speed 9t Gruppo confirmed. Interesting option for us Sunrace users. Guess you will need to go drop bar though....

https://road.cc/content/tech-news/ca...5#comment-form
9-42t! Interesting. The drop bars is a deal breaker for me, but other than that it could be good. Enough range, considerably more than the Alfine 11 I have now. Presumably Campagnolo knows how to make hubs that survive hard pedalling, unlike Sunrace. It would have to be 135 mm QR to fit the Birdy though, thru axle won't work. It doesn't seem to say what kind of axle it will have. Interesting to see if they will use offset derailer pulley and horisontal movement, like SRAM does, and Shimano too now. Derailer length will be similar to the SRAM 1x11-speed mtb derailer I expect, which I've tested. It's close to the ground, but it works if you're careful.
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