Turning a 2001 Riese und Müller Birdy into a modern folding bicycle

A few weeks back a friend and I were offered a Riese und Müller Birdy that dates from 2001. The hope was that I could make something of it and use it, as the thing had been sitting in a storage room unused for more than 5 years. The bike itself had cost 2199 Deutschmarks (1125 Euro) 18 years ago. It also had a carry bag with it. Having used a Decathlon folding bike before (reasonable, but not very pleasant to ride), and not having enough cash for a Brompton, this project was worth a try.

As it looked… and below with the broken mudguard, luggage rack (removed) and old elastomer.

First an assessment: what does a foldable bike for city use need?

Mudguards (this one had an unusable cracked plastic back one, nothing on the front) and some way to mount a bag on it (this one had a bend, low luggage rack and nothing else). In addition the handlebar grips were all mushy, the pedals stiff and missing reflectors, and the saddle damaged on the edges. Further the rear elastomer that softens the ride fell apart in my hands. And a new chain is always a good idea. The tires looked OK, but the reviews of early Birdy tires were not good, so those and the inner tubes were be replaced too. There were mounts for lights, but no lights. There was also no lock. Brakes and gears all looked OK, so for the moment those stayed.

So the purchases for the repair were as follows:
1. Saddle – Decathlon Sport Komfort 500 Red – €9.99 (normally €18.99) (ordered with Decathlon online) – simple semi-sporty saddle
2. Pedals – Decathlon Folding Pedals – €12.99 (ordered from Decathlon online) – Birdy normally does not have folding pedals, but these worked well on the Decathlon folding bike I used to use, so were chosen here to save a bit of space. They are heavy but reliable
3. Tires x 2 – Schwalbe Marathon RACER 40-355 18 inch RaceGuard – €27.90 (ordered from eBay here)
4. Inner tubes x 2 – Schwalbe Nr.5 18 Zoll Presta Valve – €15.00 (ordered from eBay here)
5. Chain – KMC X8 Chain Silver Grey 8-Speed 114 Links – €9.95 (ordered from eBay here)
6. Front and Rear Reflectors – unbranded – €3.95 (ordered from eBay here)
7. Front and Rear Lights – unbranded, USB-rechargeable – €11.98 (ordered from eBay here)
8. Grips – Velo Attune, asymmetric to fit the grip shift gears – €14.90 (ordered from eBay here)
9. Rotating Bell – unbranded, goes around the handlebar so very durable but small – €6.00 (ordered from eBay here)
10. Aluminium mud guard supports x 2 – unbranded – €13.80 (ordered from eBay here)
11. Black metal mudguards – unbranded – €5.00 (one off from eBay Kleinanzeigen, similar on eBay for €19.90 here)
12. Birdy Elastomer – Standard medium hardness red – €19.90 (online from dedicated bike shop Per Pedale here)

Two items – neither of crucial importance – have long shipping times and have not arrived yet
1. Anti Theft Quick Release QR Skewers – unbranded – €9.75, shipping from Singapore (ordered from eBay here)
2. Kickstand – unbranded – €4.29, shipping from China (ordered from eBay here)

Two purchases needed a lot more consideration
1. Lock – Abus Bordo Granit X-Plus 6450/85cm – €74.99 (usually €95.99) (ordered with Decathlon online)
The issue here is where to mount a lock on a folding bike? A D-Lock is too large to mount, and chains I always find messy. So a foldable lock was the best bet. The Abus Bordo Granit was the best rated foldable lock in Stiftung Warentest’s May 2019 study, although I went for the shorter and lighter 85cm version as opposed to the 110cm version.
2. Bag – Decathlon Businessbag 500 15 Litre Black – €39.99 (ordered with Decathlon online)
Most Brompton riders mount bags on the handlebars, but there was no way to put a Brompton mount on the Birdy. A regular rear luggage rack impedes the folding mechanism. So the best compromise was a Decathlon handlebar mounted laptop bag, that uses a standard Rixen & Kaul mounting system.

Shipping for the whole lot was just under 40 Euro, and I needed a few odds and ends from my local DIY store (see below) for about 10 Euro.

So that gives a total of 330 Euro.

Then what needed to be done for the repair?

The Birdy has a special system to mount the saddle on the seat pole, but this only needs Allen keys to adjust it.

Tires and inner tubes need bike tire levers to remove and replace, and 18 inch tires are hard to fit (the smaller the tires the harder it is).

Pedals are hard to remove without a dedicated pedal wrench – without that you probably need a bike shop to do it for you.

The old chain had to be removed with a chain tool (you could saw it off I suppose!) and the new chain was precisely the right length had a quick fit link to fit it.

Lights and the elastomer could be mounted without tools. The handlebar bag can be fitted using only screws and a Phillips screwdriver.

The velcro straps provided with the Abus Bordo lock are too short to go around the Birdy frame, so I used 4 long cable ties to mount this – they cost a few Euro at your local DIY store.

The frame and all components needed cleaning – rags, and WD40 for a few places, and some acetone to remove sticker glue residue in a few spots.

In short: all of that is pretty normal…

But there is a problem. A big problem. The mudguards.

Lots of Birdy bikes do not have mudguards. For good reason! Because – especially on this early Birdy version – they are an absolute pain to fit. Doing so required hours of work, and a lot of trial and error.

Rear wheel

Here how to mount the mudguard is quite obvious – there is a mounting screw hole on the frame above the tire, and two holes above each end of the axels – as shown here:

The problem is to then get the mudguard supports mounted at the right angle – position them too low and the bike handlebars will not fold! You need an angle of about 35 degrees upwards at least!

You need a number of different 5mm bolts to secure the guards and the supports, and some fat washers to bring the mudguard closer to the wheel from the frame. I also used a Dremel to cut the supports to the correct length, and I also shortened the mudguard as well – using the Dremel to cut it. You might also need to drill further holes in the mudguard to mount it as well. But, with a few hours of work, and some trial and error, it works.

Take a deep breath. Because that was the easy one!

Front wheel

There is only one mounting point for the mudguard on this Birdy – on the front above the wheel, as shown:

The problem is that a mudguard with just one mount is always loose and wobbly. You do need to use this mount though, and need a long bolt, 5mm width, for this – the one I used was 35mm in length, and was bought from my local DIY store.

I then searched for further solutions for the second mount, and started with the one explained by Alexander Gottfried here. This uses a Rawlplug inside each hinge as a mounting point.

This was my first try, as seen from below:

Putting the aluminium mudguard supports on the outside of the mudguard, and cutting and bending them to shape, nevertheless resulted in the supports being too wide – they would snag on the frame when folding the bike (you can see the narrower frame parts in the picture above).

The solution was to cut two notches into the side of the mudguard, again using the Dremel for this, and to keep the supports straighter and narrower, as shown here:

This leaves only 6mm of so between the support and the side of the tire, but I can live with that – and the bike folds! This is how it looks:

This fix took a lot of messing around, and filing and bending metal. And without a Dremel or equivalent tool would not have been possible.

So did all this work make sense?

Time will tell. At the time of writing I have only ridden the Birdy for 20 minutes. The ride quality is excellent, and everything works well after the repairs. Folding it is a bit of a pain – I am not as good as this dude yet! All folded it measures 35 x 75 x 57 centimetres, and fits neatly in its carry bag. I will take it with me on a 10 day work trip to France, Belgium and Italy next week, mainly as a means to avoid French rail strikes in a few places, and we will see how it fares. As I gather experience with it I will update the blog post accordingly.

For the moment though, here a few photos after the repairs!

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