Folding Bikes - can you stick in a 20 inch wheel into a birdy

was wondering if one could stick in a 20 inch wheel into a Birdy. I am only concerned about the rear wheel, IF and thats a big IF I get that thing I will use a different fork ( despite the increased folding size)


I guess the V brake studs are going to be off...wonder if a magura hydraulic rim brake could be tweaked to fit ? But that wouldnt be the biggest problem as I could go with disc ( with adapter ) orsome kind of drum brake ...

thor

Ob sie Deutsche können lessen ...the answer might be here
http://www.birdy-freunde.de/

Not without modification to the dropouts, both front and rear (such as this (http://www.foldsoc.co.uk/mudd1198.html), for example). R&M did sell a special 10 year anniversary Birdy that came with 20" wheels. Probably sold out by now.

20" Birdy (http://www.birdy.com.au/birdy_racing.htm)

This 20" is on the current Birdy web site in Australia.

Edd

Hi spambait11

This modified Birdy looks like the folding action would be comprimised with the rear rack and bottle holder, I think it is attached to the swing arm. The recommended folding action is to roll the wheel under the frame although it can be done holding the bike off the ground. What happens to the mudguards during folding and when resting on the ground?

Edd

You can squeeze ERTO 406s on a Birdy with Stelvio tyres. However, the clearance is tight and the fold more awkward.

Steve Parry has done a frame mod for Birdys to allow 20" - see Spambait's earlier link to the Folding Society. I would also go to the Yahoo Birdy Group.

I am unsure (although almost certain) Maguras will not work with the bosses sufficiently for the blocks to touch the rim. As for a hub brake, I don't know, but it seems a more likely solution. Let me know how you go. The OLN at the rear is 135mm.

The Anniversary model has not quite sold out. I very nearly got a one from Germany, but my girlfriend was not swayed by 20" wheels, 18 gears and drop bars...

http://www.flickr.com/photo_zoom.gne?id=100426345&size=o

Hi spambait11

This modified Birdy looks like the folding action would be comprimised with the rear rack and bottle holder, I think it is attached to the swing arm. The recommended folding action is to roll the wheel under the frame although it can be done holding the bike off the ground. What happens to the mudguards during folding and when resting on the ground?

Edd
If you're asking about Steve Parry's bike in particular, I don't know - he seems to like to mess with bikes, but I'm not sure what happens to them after he messes with them.

As for me, I've never used mud guards or a rear rack (was hard to obtain Birdy stuff in the U.S. in 1999). Plus, mine was an older frame. Chop (http://www.long-john.com/pagebirdy.htm) probably knows for sure.

Thinking about doing some modifications? ;)

spambait I like the way the Brompton rests on its carrier and that the mudguard is protected by it, on the 'birdybike' group there is a 'heavily' modified birdy with a brompton carrier on it. Adding weight to a bike needs careful consideration with respect to usefulness and if the fold is affected then why have a folding bike.

The birdy rear carrier I have seen gains support from the seat stem and has supports in front or behind the elsatomer, I prefer the Brompton style. This is modification I am currently thinking about, it would have to be light and with this I'm not sure about the casters/wheels or if 'skids' would do and/or use the alternative fold in the air technique. It could even be better if the mudguard was also incorporated into it. Sorry for getting of the original theme of this thread.

Edd

If you're asking about Steve Parry's bike in particular, I don't know - he seems to like to mess with bikes, but I'm not sure what happens to them after he messes with them.

As for me, I've never used mud guards or a rear rack (was hard to obtain Birdy stuff in the U.S. in 1999). Plus, mine was an older frame. Chop (http://www.long-john.com/pagebirdy.htm) probably knows for sure.

Thinking about doing some modifications? ;)

As you can see we used Moulton rims, as these allowed a greater choice of tyres without affecting the fold, we also used Disk brakes

I have just realised that the modified birdy was probably "Chop's" birdy, it was a big project.

Edd

Have a look at this Tokyo site ... run it thru Babel Fish ... to see a 20" conversion a bike shop offers. See the entry for 26th February (2-26)

http://birdyinthailand.seesaa.net/

bangkok thanks for that reference, the green birdy is a grat looking bike.
Edd

If you're asking about Steve Parry's bike in particular, I don't know - he seems to like to mess with bikes, but I'm not sure what happens to them after he messes with them.

Many people request modifications to their bikes and Steve carries out the work. I have a seen a quite few bespoke SP folders in London. A particularly impressive looking beast was a Brompton with disc brakes and Rohloff hub...

Many people request modifications to their bikes and Steve carries out the work. I have a seen a quite few bespoke SP folders in London. A particularly impressive looking beast was a Brompton with disc brakes and Rohloff hub...
I have seen many of his B. mods over the internet, and I agree that many are quite impressive. But as for his many other 'modded' bikes - were they for customers or were they for fun? In any case, he's got skills.

No you can't... :)

were they for customers or were they for fun?

Both - I have seen Birdys and Dahons modified by Steve, but were owned by enthusiasts who wanted substantial changes to their bike. Seemingly, he will take on most folders - I guess he enjoys the challenge!

I've known Steve on & off for a while now and have ridden a few of his SP Bromptons and seen many more around and about in the UK, though I was not aware that he had modified a Birdy. But here's a pic of his latest, Steve claims that it is the World's lightest Brompton, it has Merc bike Aluminium chassis, Brompton titanium forks & rear triangle, carbon fibre seat post & cranks and is single speed.

http://www.long-john.com/SP-light.JPG

That Brommie/Merc chimera looks like it is made for speed. The flat-barred models give a good aerodynamic position.

What is the weight - about 9 - 9.5kgs?

This pic is making me reconsider my forthcoming Dahon purchase...

Dayum, nice!

How is he able to obtain B. parts, particularly the ti fork and rear triangle? Did he used to work at B. or something?

If the frame is merc not brompton then can it really be called one? That's like saying a VW Beetle with a Porsche Roadster body conversion is a genuine Porker....

It's nice though - anyone know how much lighter the alu frame is? Is it strong enough?
A bit jittery compared to steel surely or Brompton would be making them themselves wouldn't they?

I think Steve Parry needs a better lock too! ;)

The rights were sold to reproduce the Brompton for Asia only, with no right to sell in the West, I believe Merc has been stopped from selling whole bikes but you can buy the bits. As for the Ti Brommie bits, I think he just buys the from Brompton, as can anyone, but you'd have to ask Steve (link on my list)